An Overview of Science of Nutrition

and we are really honored to have dr christopher gardner today here with us he doesn't really need introduction uh most of you already know him he's a renowned uh professor of medicine in nutrition science uh he has more than 25 years of research experience and he has he has been the frontier in the uh in helping uh public and scientists figure out how to eat what to eat and uh and uh what to avoid for optimal health and he has done more than 20 nutrition intervention trials that involved uh uh involved more than 2000 participants um he is also actively involved with american heart association american diabetes association and many use of change that is a collaborative uh project involving scientists business leaders chefs that focus on unapologetically delicious and healthy foods so we are really honored to have you here dr uh gartner and uh please uh as we said uh feel free to raise your hand if you have a question and you wanna unmute be unmuted or feel free to put your questions in the q a and i will monitor them and we can get started and thank you so much dr gardner thank you susan i do want to tell anybo everybody how intimidated i was so susan invited me to do this and i said cool is it a half an hour lecture an hour lecture she said no it's two hours and then i got a notice that i was offering a course i said of course i thought you asked me to give me a lecture and so she explained that two hours is a course and you know i'm pretty well known for doing about 100 or 150 slides in a half an hour and she said two hours i said oh my god this is going to be hundreds of slides so literally i have hundreds of slides but the way i've arranged this is i kind of have a hundred slides of how i start the nutrition class that i teach to human biology undergrads and it's really all about study design so it's a very nutrition science focused talk today my class is really about carbohydrates fats proteins vitamins and minerals but in the front end i talk i talk about how we know what we know about with science and at the back end when we finish the class i kind of get into how we apply that to studies so you're going to get the beginning and the end the first half i'm probably not expecting any questions i'm kind of going to roll through pretty quickly and then maybe we'll take a bio break at 10 o'clock and then the last half i have a whole bunch of my studies and i have some interactive uh slides where i'm gonna i'm gonna get you to sort of help me think through designing a study applying what we learned in the first hour okay now it is when i share my slides i can't really see uh who's asking questions so i have to every once in a while pop up to see don't worry i will monitor the question and we'll let you know actually you focus on your slides and i will interrupt you when the questions come yeah actually i can't even see the chat anymore i can just see q a okay never mind that's the thing about yeah when you share your slides it kind of but you can decide i think to go off the full screen yeah um yeah that's the problem with sharing slides if the chat goes on the option under the options you there's a drop down under the options i think the chat and everything goes there but i will monitor it for you don't worry yep okay so everybody susan's going to help me out here team effort shameless self-promotion if at the end of this you think you want more the center for health education helped me in creating an online class i've actually had a thousand people take this class globally and it's been really highly ranked it costs a lot of money i don't know if you can apply staff funds i'm guessing are cost 2 300 bucks that's not up to me that was up to the stanford center for health education but a little shameless self-promotion if when we're done you want more so when i do that online class it's eight weeks for eight to ten hours a week and when i teach my human biology undergrads i get two two hour lectures for ten weeks in a row for you guys i get two hours so i'm just gonna talk super fast and go through everything in my class by showing tons and tons of slides maybe okay i'll start with an intro and just say nutrition is tough we have all these patterns that we would like people to consider eating i don't know who's tried keto and who's tried mediterranean who's tried vegan right and at the end of the day what we would like is to see if you ate some way could you prevent the major chronic diseases that we know afflict many americans and people all over the globe right but really to do that we see what kind of foods are part of those patterns and what kind of molecules are in all those foods and on this end wow it's really hard to wait for people to get those diseases so we try to find intermediate proxies uh aspects of physiology and metabolism that are risk factors for those diseases and then oh my gosh if you work on this campus have so many colleagues that can measure very specific things for all these areas of physiology and metabolism and i'm sad to say that in my field one of the reasons i think nutrition is so confusing is to get a study funded and published you often have to pick one of these molecules and study one of these markers that's how you get your grant funded and how you run a study and publish it and then you say oh yeah you know that nutrient came from that food so it's relevant and that homa ir oh my god that's related to endocrinology and so that's part of physiology metabolism so i think that means if you eat that food as part of that pattern that molecule we measured is part of metabolism that relates to this disease and it's actually not that simple it's really complicated plus i think there's different doses of foods different foods sources of them and there's different durations and there's different population issues oh my god are you studying sick people healthy people old people athletes so i say my whole field is a data rich environment and there seems to be a lot of nutrition confusion and you are in luck i'm gonna help you resolve all the confusion out there in now less than two hours okay i'm gonna come back to this question later there's this isn't a pop-up it's not a poll i want to see if you think you could answer which one of these i think relevant nutrition questions you could support or refute the most definitively with science because the seminar today is about nutrition science some questions are easier to answer than others and an underlying theme for all of today will be answerable versus unanswerable questions a lot of the questions that i get are super practical christopher is garlic healthy for me i actually did a 1.4 million dollar study on garlic and i was only able to show at a specific dose of a specific amount of time for a specific population for ldl cholesterol if it was good or bad and that's not the answer they wanted they wanted to know if they should have more garlic or not and that's not answerable it has to be really specific okay we'll come back to this question and we'll get into the basics of nutrition study design this is how i start my nutrition class in humbio how do we know what we know and i'm going to start out with a study framework and then i'm tediously then going to go through a whole bunch of different types of studies so you will know the secret sauce behind how we make dietary guidelines by looking at all these different types of science so i'm going to come back to this slide later and you'll understand it more but i this isn't a clever acronym it doesn't make any sense but i think all these factors affect the evidence that we're evaluating did you get data from a country or an individual what kind of nutrition and health outcome data did you get was it an observational or an interventional study was it cross-sectional or perspective did you study a risk factor or a disease outcome was it primary prevention or secondary prevention my the thing i like the best is if i have nutrition data from individuals and health outcome data from individuals in an interventional study that was about diseases not risk factors and if we were preventing it by doing primary prevention not secondary prevention there are almost no studies like that very few oh by the way as you know i'm at zoom and my kids have to wake up for school that doesn't start till 10 and have a bunch of log dogs so uh hopefully my ham family will help me with my kids waking up for school and the dogs barking when somebody comes to the door okay that's my goal i want to get you there and to get there usually to answer questions we have to use all the tools that we have observational epidemiology human trials when we have them animal studies tissues and organs cell and molecular i really feel like we we rarely have adequate evidence to give really clear nutrition answers and we draw on all of these i really want to emphasize we draw on all of these when we try to make dietary guidelines for folks and another framework that i like to use is oh you see something in the newspaper and it says x is good or bad for y and i want you to think was it a study of a single isolated nutrient or a single isolated food or is it more like the mediterranean or the ketogenic or the vegan diet because this is simpler to study because it's isolated foods are more complicated but culture oh my god culture is more complicated than food and then did they study something with an acute onset and an acute resolution like let's say a cold vitamin c and colds or iron and anemia are they studying risk factors like blood pressure or cholesterol are they really waiting to see who lived or died of cancer or heart disease or whatever and so i have found in my field that this is the best place to find the best evidence but often the least interesting a single nutrient for a single disease with a quick onset and a quick resolution you can quickly try different doses and sources and nutrients and you can do this over and over again until you get the answer but as you get farther away and to the other corner of this grid if you want to know if the mediterranean or the ketogenic diet will prevent diabetes or heart disease no one's done that and no one's actually ever going to do that can you imagine agreeing to sign up for a study so sure i'll eat mediterranean for the rest of my life oh no you changed your mind sure i'll eat carnivore for the rest of my life oh oh no you want me to be vegan for the rest of my no people aren't willing to do that and so it's really hard to have chronic disease outcome data for things as practical as should i go vegetarian or vegan or keto or mediterranean okay i think that's what people want to know what should i eat or what diet pattern and sadly that's where it's the hardest to get the evidence so as i go through my talk today i'm frequently going to go back to this grid so i do the undergrads and then there's the added layer of complexity is it an observational study which is association only or as an intervention with cause and effect i'm super proud of sprc where i work because our focus is behavioral interventions will cause and effect but they're hard to do and they're expensive and you can't do a lot of them so i'm going to flip back and forth between observational and interventional and my grid here and think about this for a sec is it possible that nutrient or food x does improve health doesn't improve health is it possible these can both be true i mean you wouldn't think so this says yes and this says no i actually think this is a problem in my field not a problem is this a tip for you they can both be true if you vary the domains of this question you can make it so it's both true and false and this is from my when i was finishing my phd i saw these two papers 91 and 1990 and one said oat bran does lower ldl and one said it doesn't that seemed really annoying for headline but you didn't have to look very far this one where it did lower ldl was done in hypercholesterolemic men who had room for improvement this one where it didn't was done in college-age students who didn't have high cholesterol they had normal levels so oat bran wasn't able to lower their cholesterol lower than normal can't you have both those things at the same time yes but the headlines made it look crazy it does and it doesn't it wouldn't have taken long to look at the study designs and see how they're they're both true if you can put it in context so in my field the term i use the most often is it depends give me the context of what it is and then maybe i can tell you if it's good or bad okay all right so ready we're going to fly through a bunch of designs i'm probably going to go a little fast here i'm going to guess a bunch of you know this already and [Music] hang on one sec can i mute jackson can you wake up the boys thanks okay here we go so it often starts with ecological studies because these are inexpensive you can do these in the library you basically go say oh from one country to the next what kind of imports and exports do they have and then instead of trying to figure out um what each person eats i'm just sort of averaging something for that country as well as averaging rates of disease i'm going to look at national morbidity and mortality data i can compare country a to b to c to d and here's a classic from 93. death rates from coronary heart disease this is back in the days when we only studied men sorry about that and here were rates of disease in the different countries and here it was a cholesterol saturated fat index per thousand calories per day look at that beautiful line there is a correlation here if you are in a country that eats more cholesterol and saturated fats you have higher rates of heart disease ooh not causal just association and plus look at some outliers here's finland and here's france they actually have just about the same amount of cholesterol unsaturated fat and they have like a fivefold difference in heart disease rates so it looks cool but then there's some flaws with that so this is one of these observational studies it's cross-sectional they're just seeing what's going on in the country that day they were focused on nutrients in this particular case and so we've got some associations so there's a there's a problem with this kind of study and an advantage right so for these ecological studies there's many alternate hypotheses oh there are other things going on in the country that were associated with eating high cholesterol and saturated fat but that wasn't the cause so many alternate hypotheses you can't prove it but it's pretty quick and inexpensive you just get a graduate student or an undergrad to go to the library and you mentor them and they look up the data and you get published so plus in the u.s sometimes everybody eats fairly similarly and it's hard to see a broad range of intakes if you go globally you can pick some countries with really high versus really low intake since you can actually get sort of a wider spread of things to look at so there's value here but not a lot so we need to go to the next level up for observational studies i'm going to spoke on case control and cohort studies okay so in our case control cross-sectional study i got an example of tofu i'm a big tofu eater and they were looking at tofu risk and breast cancer okay so check this out they got about a thousand women without breast cancer and they asked them how much tofu they ate these are from la san francisco and hawaii and then they got 600 cases and they asked them how much tofu they ate and so here are the rates of here's how much tofu they eat between the cases and controls and they use this low intake of tofu as sort of the reference ratio can you see how the ratio is changing at the low level right there's more cases than controls and at the high level if you eat tofu a lot there's more controls than cases and if you do an odds ratio and you make this the reference group you can publish your paper and say ah the implication here is that if you were a really high tofu eater like once a week instead of once a month you had a 33 percent lower rate of getting breast cancer but it's not getting cancer they already had breast cancer so this is cross-sectional it's actually possible that it wasn't eating more tofu that led to less less breast cancer it could be that once you got breast cancer you changed your diet and you wouldn't know because i don't have a temporal association everything's cross-sectional here so there's a big limit about the cross-sectional nature of this and which came first the tofu or the breast cancer but it's interesting it's sort of a i ate tofu and i was looking at breast cancer but observational association only i got another one for you that i'm going to bring up later for a clinical trial neural tube defects and vitamin use in particular folic acid but i'm not really going to get too deep into that right now they asked about 1600 1700 women [Music] about whether they had taken vitamins when they were pregnant so they had to ask them in the past and so they found about 600 women who had had a kid with a neural tube defect which is horrible and they found controls and they found another group here that had a birth defect that wasn't a neural tube defect now basically what they found was very few women were taking these vitamins okay across the board these are not different at all they were really hoping to see that some group was getting 60 or 80 percent of them were taking them or at least the controls who had normal births more of them were taking it to show that taking vitamins was good for you it's really not there why do you think they have this group i'm gonna bring up this term of recall bias just think about this if you're a woman who had a child with a birth defect and somebody said you know is there anything that you did that might have caused this oh my god you're racking your brain you actually might remember differently than you asked a woman who had a normal birth and so it's possible that some of these women were blaming themselves thinking that and they actually had taken vitamins and they forgot oh i never took vitamins but they they did they're actually remembering differently sort of blaming themselves or racking their brains for what happened so a problem with this kind of study when you're asking people to remember in the past what they did when something bad has happened is that they're remembering differently than the controls now this particular study cross-con case uh cross-section of wood and did conclude doesn't seem to matter if you take the vitamins or not that's not what's going on and we even have this recall bias control a group that had a poor health outcome but wasn't likely related to taking vitamins or not okay where does that belong so i'm gonna call neural tube defects acute onset because it happens right after the pregnancy and they were looking at folic acid as an interesting possible nutrient okay remember this one because we're going to come back to it so a major limitation of case control studies as with all observational studies is alternate hypotheses are available and then that temporal relationship which came first the breast cancer or the tofu and the recall bias i just wrote brought up the major advantage to case control is it is quick and inexpensive because it's cross-sectional you can do it all in one year or particularly pro if it's a rare disease i'm going to show you how rare neural tube defects are i'm going to show you a clinical trial later where they looked at it but we'll compare the numbers of who they got to study it's a really rare disease so sometimes the advantage of case control is that so keep in mind limitations of the temporal relationship and the recall bias and the major advantage being rare diseases so let's go on to the type of study that i think gets more headlines than any other type of nutrition and i'm green with envy and so i'm going to make fun of them it's a bunch of my friends at the school of public health at harvard that do the nurses health study in the health professionals study oh my god they have a paper in the new england journal of medicine every week because they pl this is the game they play they asked between three studies nurse's health one nurse's health 2 and the health professional study which is all men i think they have a combined three or four hundred thousand people that they asked what they'd eaten and every two years those hundreds of thousands of people get a letter in the mail say are you dead are you alive okay if you're alive did you have any outcomes that brought you to the hospital uh okay nothing you're good you're healthy okay we're gonna write you again in two years and so over 30 or 40 years now many of those three 400 thousand people got sick or died and so they can just sit there and spin their things once a week i know it they sit around the table and say what do you guys want to study this week okay let's study coffee okay cool what do you think it should be related to i know he collected a lot of data depression cool so should we study all of them no let's do the men that were 25 to 40. and then somebody says wait didn't we do that last year oh you're right we did it last year no no no that was five years ago oh well if it's five years ago we can do it again because more people got sick or die and so they often if you look at their cycle every five or ten years they redo their analyses because they have more events anyway this drives me nuts they're really great people and they actually do really good science but they this is the most common thing you'll see in the newspaper in a headline these hundreds of thousands people told people what they were eating and decades later we can see who got sick and who didn't and we know what they were eating beforehand here's a classic this happens to be the iowa women's health study where they were looking at relative risk of heart disease after nine years of follow-up and it had to do with who's eating more whole grains who ate the most and the least whole grains so compared to the ones who ate the least which will be our reference group here if you ate more and more and more and more servings of whole grains during the week it turned out fewer and fewer of you had cardiovascular disease after this follow-up so literally if you trace this back this looks like a 30 protection if you ate more now do you have to eat this much no actually there was a 30 production this whole time so basically you just got to get a median of eight servings a week 13 and 22.5 don't help anymore so you basically just got to get over this hump is the implication but think about this so what's the alternate hypothesis what do you think is associated with eating more whole grains that might not mean it's mechanistically the whole grain it's something else and i'm pretty sure you can all guess that these folks if you look sleep more exercise more take more vitamins eat better in general and so you can't actually say it was the whole grains now the folks who do these analyses know this and they actually have sleep data and they have exercise data and they have data on their other diet and they statistically adjust for it as best as they can but we do have to recognize that the data they have on the sleep and the exercise and the rest of the diet isn't perfect so they can't perfectly adjust but when they do this they do say independent of other things this was helpful and then they have to look for a plausible mechanism ah well whole grains have a lot of fiber and i did a rat study and i looked at their rat's cardiovascular system and i was able to sacrifice the animal and and open up the arteries and i can see the plaques or not and so you start building a case for whether this could be real but this study is just association not cause and effect right so we go to our grid here it's whole grains it's a chronic disease but it's an association here's another one i'll show you some specific numbers in this one so there's a mediterranean diet score to see how mediterranean you are and you basically this is kind of a weird way to score it they pick they find a range of all these things in a diet in a in a population and if you're above or below the median you get a point and if you're the other way you don't get a point so in this particular scoring you got a point if you ate more than half the group of vegetables legumes fruits and nuts cereals fish and you got a point taken away or you only got a point if you ate less than half the group for meats poultry and dairy alcohol is the funniest one so you get a point against you if you don't drink and you get a point if you drink a little bit and you get a point against you if you drink too much this is how they make the mediterranean diet score it's that simple and then they had 22 000 greek adults they followed them for almost four years 275 of them died so only one percent died they don't actually have a lot of data but they had enough they published a paper and they said ah of the 275 what did they die of heart disease cancer and their total deaths and in their final result they said look it's there's about a 33 reduction from heart disease 24 from cancer and 25 total deaths for every two point shift in the nine point scale so they're suggesting that if you were a four on the scale if you moved up to a six you'd get this protection what if you moved up four points well the implication it would is it would be double that what if you went from a one to a nine oh my god you'd be disease free and you'd live forever okay but this is all based on 275 deaths for four years of follow-up and 22 thousand greeks it's not perfect did the people who ate more mediterranean sleep more yes exercise more yes eat a better diet overall yes interestingly of all those components i showed you they did try to look one component at a time to see if that offered protection and none of them individually predicted health protection or health promotion it was the sum total it was being mediterranean you can't just cheat and just drink olive oil at night it doesn't work you can't have a big mac and a whopper and chicken mcnuggets and then drink olive oil at night and say you're mediterranean you're supposed to do all nine of the things okay back to this one later too where does that one go well i think of the mediterranean diet as a food pattern or sort of a cultural thing and they saw who lived or died chronic disease but it it's still association we still know for sure what did it right so in a cohort study the major limitations or again alternate hypotheses because it's only observational it's association oh my gosh those are expensive long studies if you're going to track 22 000 people for four years keep the retention up continue to contact them and get follow-up data from very expensive the big advantage this has over the observational cross-sectional studies is the temporal sequence is there because you know what they were eating in the beginning and then they got sick later another thing that i think is practical and advantage of this is if you're doing these cohort studies it's you're not asking anybody to change your diet you're just observing what they're eating and so it's always an achievable range you always get to compare the people who are the lowest versus the highest and you know that real people eat that because it was just real people eating so another advantage i like in these cohort studies is that you know it's not ridiculous it's achievable because it was what real people were eating okay and then this is not the kind of research that i do but a lot of this research happens on our campus and i cite their studies all the time i just don't do them so i'm just going to quickly go over this animal and cell studies super helpful for giving us mechanistic uh and biological plausibility data here's one that i thought was really clever okay this had to do with soy and breast cancer i don't know how many of you have heard that soy contains a set of molecules that the family name of them is phytoestrogens and molecularly they look quite a bit like mammalian estrogen and if you are aware um there's good data show that women who are postmenopausal who are taking hormone replacement therapy and estrogen for the sake of reducing menopausal symptoms they've tied that to increased risks of breast cancer and then they looked at asian populations and they said wow asians have less breast cancer than americans i wonder what that is oh that's interesting they eat a lot of soy i wonder if the soy is protecting them from breast cancer but that seems weird because hormone replacement therapy and estrogen mammalian estrogen is a risk for breast cancer is there some way to plant estrogen is protective and the mammalian estrogen is harmful for breast cancer how would you do that in women oh my god that would be a really long study okay so they did it in mice so they took mouse pups and they injected them with a carcinogen and sure enough they got mammary tumors and then they did this they took the mouse pups injected the carcinogen gave them a bunch of soy phytoestrogen and yeah they got tumors anyway and it didn't change and then they said okay let's try this let's give them the soy phytoestrogen before we inject the tumors and in fact there were fewer tumors when they did it that way and then they did the last one they said wait let's give them the soy phytoestrogen before we inject the tumors and after we inject the carcinogen sorry not the tumors inserting the carcinogen and they got the fewest tumors of all and i was fascinated to hear the guy explain this when he presented these data so this actually looks like what we see when we look at asian women who migrate to the u.s and give up their diet and they adopt a more american diet and they have less soy and so that would be they had it as a kid and they continued in adulthood versus giving it up so here's having it in an asian country giving it up and even though you have fewer tumors for being exposed there you have more tumors relative to asian women who ate it all the time and then if you look at american women you see that they have more tumors and so they had this this very elegant discussion like this and they said okay here's the american women who didn't grow up with it they hear about it they try to have it later and it's not enough and it doesn't have any effect what's going on here and the whole hypothesis was that in the development of mammary glands as you're an adolescent if you're exposed to soy phytoestrogen there is some benefit conferred and you don't get it unless you're exposed early so if you do it later only later it doesn't work but then if you actually stay in an asian country and you get exposed and you get this protection early on and have it later you get an extra protection i hope that story made sense i loved this story when i heard it the first time and i thought yeah right there's no way you can do this in women you cannot insert you cannot inject women with carcinogens and you cannot play with them like this and if you can imagine with mice this can be done in years in women this would take decades to do this kind of thing to see who did and didn't get breast cancer right so a summary of what i just said is right here and i was really impressed to say that they see that they had created this mouse model that seemed to parallel what happened with breast cancer rates in japan and the u.s and japanese women who migrated to the us versus staying there including japanese women who migrated to the us and kept up their intake of soy it it was consistent with different rates of disease in those populations and so mechanistically they were studying that in a mouse model which i appreciated now i'm going to go to a bizarre trial that they did in humans about vitamin e i actually participated in one of these in my doctoral work at berkeley they were trying to see if the ldl particles that carry cholesterol get oxidized or not and if vitamin e would help this so they randomized eight groups of eight people and uh let's see yeah eight per group no no okay so maybe six groups six groups of eight people and this group got no vitamin e and this group got 60 units 200 units 400 800 and 1200 and after doing this for eight weeks they took blood samples and then they put the blood samples in a cuvette and they added iron and what they wanted to do was track over time to see basically if the particles would rust to see if there was oxidative degradation when exposing the blood and the low density like protein particles to iron and if there was oxidative degradation the fatty acids would break down and you'd have this color colorimetric response in a spectrophotometer and you could see how long it took for the things to break down and color to change and the goal was they wouldn't break down they'd have so much vitamin e in them that they would be resistant to eating this oxidative stress this iron in the cuvette and so they were looking for a change in the lag phase of being exposed to this so all the white was baseline and all the red was after getting the vitamin e so no difference at low doses at higher doses the lag phase increased so it was longer before the particles were oxidizing and the color was changing in the spectrophotometer and so they said ah this is what's happening if we give them vitamin e we can tell from this cuvette after we insert iron in it which is totally non-physiological that the protection from this suggests that vitamin e is an antioxidant and it will protect you from heart disease and this this isn't heart disease this is eight weeks i'm getting vitamin e and then non-physiologically using this method to see if it oxidizes it makes sense it's plausible it's not very physiological but it's plausible and so this is where we took a nutrient like vitamin e and we just studied a risk factor and it looks like we improved the risk factor doesn't mean we help disease we only know about the risk factor at this rate so when we do animal and cell studies um we have a major limitation extrapolating a human health that often doesn't extrapolate but it really helped us explaining some biological plausibility and understanding mechanisms better okay so i tried to go everything that leads up to the gold standard doing a randomized controlled trial so this is i whipped you through these sorry if that was too fast let's see how oh pretty much on time okay okay what we really want to get to is the clinical trial so we can see cause and effect so we before nih will give me the big box to do the clinical trial i often have to cite all these preliminary things particularly all these observational studies so they don't answer the question but they're really helpful in making the case especially if you have some mechanistic plausibility to go with it that we should eat this to prevent that in a clinical trial now i want to intervene on people i want to do behavioral interventions and i want to attract people to see who gets sick or not and so here is the secret sauce to my success i'm giving it away for free right now the double-blind placebo-controlled randomized clinical trial if we feed x versus something else to a group of them at a certain dose for a duration of this there will be more or less of it that's it that is the secret to my success as a professor at stanford university in the department of medicine the stanford prevention research center all you have to do is fill in the blanks but you have to be really good at filling in the blanks and i can tell you lots of times i'm not really good because i get so many grant rejections i get way more great rejections than grant acceptances so sometimes i can't even fill this formula out enough to convince reviewers that i have a good idea so let's go back to vitamin e which i just showed you there was a risk factor that worked well here's an intervention they actually chose this dose partially based on that last study that i showed you they got almost 10 000 women and men who are sick already why do they get people who are sick already because they're more likely to die first okay and so sorry that's kind of morbid but that's the way it works so we get people who are at high risk thinking that we need some people to die and some people to live to have statistics to run to see if we made a difference we're going to follow them for four and a half years and see if anybody has a myocardial infarction stroke or cardiovascular death or just the mi or just the stroke or just the death or the total death can you see the amazing effect that vitamin e had in this study it had absolutely no effect at all none i think they were hoping it would work but it didn't i think this is like health outcomes preventing with vitamin e study okay well their acronym didn't work they hoped it would work but totally didn't work so it was this one oh this this was cause and effect this is vitamin e and a chronic disease and if you went back 15 20 years at this point and asked how many cardiovascular medicine folks were taking vitamin e supplements almost all of them were if you ask today none of them are not only did this trial have null findings but a lot of nih funding trials got funded at the time because of all the other plausible mechanism data and because of all the observational epidemiology which i'm going to spare you and it didn't work here was an alpha tocopherol beta-carotene study the alpha tocopherol that's vitamin e it didn't work i'm not going to show you that one for now they picked smoking finnish men at the time they started this study the highest rate of heart disease was in finland and it was even higher in smokers okay and they had five to eight years of follow-up and they were trying to see if beta-carotene would help it was a supplement study so you got placebo or active agent beta-carotene and they thought it would help with lung cancer and when they did this study they actually got statistically higher lung cancer and higher heart disease on the folks getting beta-carotene this is super famous as a horrific result in nutrition they were trying to save people and actually killed people doing this part of the reason is this beta-carotene in a supplement form was much higher than you'd get from food how did they pick the dose actually i'm we're going to do that in some of the follow-up i'm going to challenge you to pick doses what would be the appropriate dose what's too little what's too much so in this paper they actually hurt people with this and they proved they heard it hurt them it's a randomized controlled trial right and so this is intervention with beta carotene vitamin e didn't work at all but it didn't hurt anybody and the beta-carotene actually hurt people okay interestingly someone went back and said god that's so bizarre because you know when we look at all our observational epi the people who have the most beta-carotene in their blood have less heart disease and less lung cancer god how can i assimilate those two things wait a sec i want to go back to this study and i'm going to look just at the placebo group because if you only look at the placebo group it's almost like it's an observational cohort so i said okay let's look at blood levels in the placebo group who had the highest blood level of beta-carotene and who had the lowest and when they did it the folks with the highest beta-carotene in their blood at baseline had the lowest rates of cancer and heart disease okay help me assimilate this if you have high levels in your blood at baseline you have low you have low rates of disease later but if you give people the beta carotene it hurts them and kills them how how can that possibly work what does that even make sense well picture for this placebo group how did they get high beta-carotene levels in their blood i'm going to oversimplify and tell you they ate a lot of carrots a lot of beta-carotene and carrots okay but eating a lot of carrots means you also got lots of other things with it maybe it wasn't actually mechanistically the beta carotene or maybe it was a lower dose of beta-carotene in conjunction with the other things that came in the beta-carotene in the in the carrots and what they did here say you know we think there's a possibility that it's just the beta carotene and it's too hard oh my gosh a lot of trouble to get thirty thousand smoking finnish men to change their diet let's just give them a pill or a placebo like a drug and let's make sure it's a pretty high dose just so we don't miss anything they actually ended up hurting people in this trial and it actually has happened in a couple of other trials so we know that high doses of supplements can have adverse events and that one you know the retake on this was more of an observational study when they only looked at the placebo alone here's another trial let's go back to folic acid remember that one about the neural tube defects that i mentioned remember i showed you there are almost 600 mothers with kids with a neural tube defect or another birth defect or control there's 570 people roughly women kids in each group okay so if you really wanted to know you shouldn't do a case cross-sectional study you should do a trial so i got 18 000 women who are planning to come pregnant randomized to getting vitamins including folic acid or not sorry i don't have time to go deep into detail on that but it's probably the folic acid for mechanistic reasons and they got a sort of a fake thing got a trace element supplement and vitamin c that was the comparison and then they looked to see how many neural tube defects there were of the 18 000 women only 4 000 got pregnant because these were planning to get pregnant this is who got pregnant and among those who got the placebo or comparison group there were six cases of neural tb effects and none in this one they totally prevented it here this is really compelling randomized controlled trial wow this is pretty good right so we've got an isolated nutrient and we only had to wait a few years to get this we proved it folic acid supplementation prevents neural tube defects okay but think about how rare this is so there are only two thousand people in each group so not uh 1994 women didn't notice the difference only six notice the difference of taking this thing through their pregnancy or another way to look at it is they randomized eighteen thousand women so really there were nine thousand randomized to each group and it was only worth looking at the women who got pregnant wow that is a really small number you have to treat 9 000 women to get six benefits ah look at this here's an advantage of doing this neural tube defects are really rare here's an advantage it's almost 600 neural tube effects there's a lot more data to work with here but the trial design is not as rigorous this is observational the other one was experimental trial it's cause and effect and in fact we now fortify the u.s food supply with folic acid and since doing that neural tube defect have gone down in the u.s i had to put the whole thing together and at the end of the day the challenge here right is that we all eat a lot of food and to do studies like this we tend to focus either on one food like tofu or one nutrient like uh phytoestrogen in the soy and then i'd love to focus on all of your health but we typically focus on something very specific like cholesterol or blood pressure most of my studies have to do with risk factors i don't really wait for people to get heart disease or cancer i usually wait for their blood pressure or cholesterol or weight to go down that can be done pretty quickly good biological plausibility that lowering the risk factor would lower the disease but then we only focus on one disease at a time otherwise it's a fishing expedition and we know that the whole composite of health is very complex and at the end of the day what we get are some of these reductionist isolationist approaches i'm not going to show you today but there's a cool thing called a stanol ester that's in some plants it's kind of like mammalian cholesterol but it's plant uh cholesterol and if you take it you'll lower your blood cholesterol and then we know that there's some statins that do a great job of lowering blood cholesterol and saving people from heart disease and then they make the leap and say yeah you should take this new medical margarine that we make and sell that has this in it because it lowers blood cholesterol and we know lowering cholesterol saves people from heart disease and that that's actually a big leap you don't know you didn't actually test this to see if it prevented heart disease you you put it into your model so i studied isoflavones these phytoestrogens in soy for about a decade and i quit eventually it was it was too complicated i looked to see if they would lower blood cholesterol and they did a little i did that because hopefully that would help prevent heart disease but the whole breast cancer thing came up that i wasn't studying i might be hurting them we knew it was hurt could be hurting them because women taking hormone replacement therapy that had estrogen for menopausal symptoms had more breast cancer i don't often get to look at this whole thing so even when you see that something in food provides a benefit that may lead to prevention of disease there might be another angle here i know a lot of ob gyns have been frustrated oh my god what do i tell these women about soy which is supposed to be good for the heart because it lowers cholesterol when it might hurt them you actually have pretty good evidence that it does not ob gyns you can tell women to have soy part of it is that mouse model i showed you before it probably helps it probably doesn't do anything unless you for breast cancer unless you're exposed at an early age and a lot of women in the us weren't exposed at an early age anyway it should be protective but we don't know and it's this whole constellation of things going on and that's why we need to appreciate the different kinds of trials that are yielding the information that we get okay so uh clinical trials randomized clinical trials super important we can establish cause and effect and the human relevance is obvious because we do them in humans and the endpoints are clinically relevant but i do this for a living i do randomized trials i tend to do risk factors not disease outcomes and i know that the generalizability of my trials is often really limited because i pick one specific population one specific dose one duration and if people are eating one thing it also means they're not eating something else so was the effect the thing that i gave them to eat or was that the thing that they stopped eating and there might have been a lot of different things they stopped eating i tend to study risk factors when i have some classic examples like the vitamin e where the risk factor there's a benefit but you don't change the health outcome that's happened multiple times in nutrition and we're usually focused on one health outcome not overall health just because nih won't let us do fishing expeditions then we really need to reproduce our results and they're often not reproducible at the end of the day yes i'm a firm believer in randomized controlled trials but in my world of nutrition you get one specific answer to one specific question and then really quickly there's so many meta analyses out there i just want to mention from a scientific basis i'm i'm no fan of meta-analysis people meta-analyze and pull the data from observational studies interventional studies both i see a lot of these the potential value is it's better than a review it's actually a statistical approach you can get a quantitative finding you can say here's a p-value it's not just my opinion as an expert it's better than that it's more objective except it's actually way more subjective than people would like to believe because you need inclusion exclusion for which trials you will accept for the meta analysis if you're really broad and you accept them all what happens is you get sort of garbage in garbage out you end up including a bunch of crappy trials as soon as you start excluding something ah i'm an expert in this field i know that this trial shouldn't be included and i know that this study shouldn't be included now you're bringing subjectivity back into the whole thing you're saying ah wait i'll include everything no that includes crappy trials okay i'll only include these uh well then it's not as objective anymore then we're counting on you as an expert to have made the right inclusion exclusion criteria and i can tell you people disagree all the time on what those inclusion exclusion criteria would be so at the end of the day i when i write grants when i write papers i'm always pulling from all these different types of studies how do we know what we know it's really rare that we have adequate evidence um to definitively say eat this and that will happen but to do it we pool all these kind of things that i tried to summarize and that's why i would love to have individual nutrition data individual health outcome data i'd love to have an intervention that waited for a disease outcome and started early enough that i prevented anybody from ever getting sick but i hardly ever get to do this and in my field it's almost never done so hopefully this slide makes a little more sense now after everything that i just went through this is what i look at when i'm trying to answer my questions and so let me go back to this slide and give you another minute i'm not quite going to make it interactive yet but i want you to look at this again and see if you feel any more clearly about which of these could be most definitive can you tell what do you think okay i'm just gonna let's see oh i can answer comes in one uh d okay nah doesn't let us fish does it mean we're doomed we need private funding um we have a and c and then c again okay so i'll tell you what the answer is you ready the answer is um we have to look i haven't looked at this for a long time the top one so this is a nutrient and an acute onset of something so i can vary the dose and the source and everybody gets a cold so i can do multiple trials until i nail this i and i can tell you this is really sad we've done a bunch of trials everybody and vitamin c doesn't prevent colds or shorten their severity and people take them anyway go ahead and get back to me on another day how many of you have prevented all your colds by taking vitamin c it doesn't work and we actually can do those studies it's an answerable question and people still take it like it's a religion or something okay i'll tell you why this one is hard for two reasons one breast cancer is a really hard thing to study definitively you have to randomize trials and wait decades to see who doesn't or doesn't get breast cancer and a vegan diet some people have a crappy vegan diet some people have a good vegan diet so this is actually hard to define the diet and a long term to weight calcium is good oh my gosh it's a nutrient i can vary the dose hip fractures mmm harder to study than colds you've got to wait till women and mostly women sorry are in their 70s 80s and 90s to get hip fractures this is hard to study and then i do this for a living i study low fat versus slow carb these are really hard to define what is a low fat diet i can think of a whole bunch of different options and what is low carb is it zone is it atkins is it keto is it south beach so this has a huge problem in definition this is the question you can answer most definitively because it's an isolated nutrient and an acute onset all of these are more challenging with the scientific tools we have in terms of defining the vegan diet or the low fat or low carb diet waiting for the breast cancer or the hip fracture okay does that make sense so this is my world i'm trying to come up with answerable questions and sometimes the most answerable questions are not as interesting as the ones that are unanswerable like christopher i don't care i want to know if i should take calcium for my hip fractures that's a much more practical question that's so much harder to study and have a definitive answer for i have a whole lecture on this in my nutrition class it's fascinating yeah it helps if you take it but it doesn't work as a public health measure because most women don't take their calcium regularly so it actually works if you do it but most people don't so it's not a good public health approach because we don't have good adherence to it okay there's a question uh here it says since nih doesn't let us fish does it mean that we're doomed or and have to get private funding or are there other ways yeah so i would be a perfect example of that um i would say in my 20 years half of my funding is nih and half is private because i'm trying to study the microbiome right now and justin sonnenberg and i submitted four ro1s and they all got rejected and we've now done six studies with private funding and we have another nih granting and i'm hoping this time when they've seen how much we've done with it that they'll fund our r1 which is going to be reviewed on february 17th so i'm on the edge of my seat it is frustrating frustrating getting funding for nutrition studies is really frustrating and i'm super happy to be at stanford with the support i get because they've enabled me to get a lot of funding and do a lot of studies some of which i'm going to share right now okay so hold these thoughts because we actually another question if you if i may um sure absorption of the nutrients by the intestine may play a role how nutrients are utilized is there any study that correlates and correlates this hypothesis uh yes you definitely have to absorb it to be able to use it um and so there's a i wouldn't have time to go into that in any detail is there any study that correlates this hypothesis there's there's things that can increase absorption and decrease absorption and you'd have to go nutrient by nutrient population by population and outcome by outcome okay i know back to slides i'm going to give you guys a bio break in just a sec my next section is really short so let me do this next section and then we'll see if we want to buy a break and or i'll answer some questions while some people take a bio break okay okay so think about this how many of you drink coffee i bet a lot of you is it good for you is it bad for you isn't that a simple question why don't the scientists study this why don't they decide if coffee is good or bad for me i've heard both things okay it's just a food right can we do an intervention study with coffee and see if i'll live or die or if something good or bad will happen okay coffee is a fantastic example when they used to do this with observational epidemiology they found that people who drank the most coffee had the most lung cancer oh that was the initial observation that maybe coffee is bad for you turned out when they did this decades ago most people who drank coffee smoked a lot and if you separated out the people who drank coffee and didn't smoke some people who drank coffee and did smoke it turned out the lung cancer was totally due to smoking not the coffee coffee was actually good for you okay so this is why maybe we needed a trial or this is why in the observational studies they can try to adjust for confounders and they did this is a classic example in the world of nutrition and confounders okay so i want you guys to help me design a study the nih just gave me four million dollars you and me and we get to do it we're gonna see if coffee is good or bad for you except oh now they gave us the money we have to tell them exactly so what dose do you think we should use and you know have to have group a and group b so we can't have everybody drinking different amounts of coffee we have to stand up can everybody agree what dose i bet you can't okay now do we have to make everybody drink black coffee is that fair well what about the people who like mocha frappuccinos does that even count as coffee should we count mocha frappe frappuccinos and black coffee is it like any coffee how about oh what about the latte and the milk and the sugar you feel oh crap there's sugar and there's dairy and there's oh wow coffee isn't as simple as just drinking or not right and should we include everyone or should we focus young adults no men with cancer are we going to measure cholesterol i can measure cholesterol in a couple weeks but what if that doesn't change your heart disease maybe we should wait for heart disease or cancer okay but that will take decades okay we're not doing that with just four million dollars what have we studied joy isn't there something to joy here what if we studied coffee and joy do you think the nih would fund that i bet they would not but isn't it important and should we fund it for we should we have them drink a versus b for a month or a year or a decade you know for some of these we need a hundred thousand people for a decade and for joy you know i think we could do that with a hundred people in a month so if you if you're wondering why we haven't been able to tell you if coffee is good or bad for you you'd have to think how many people would be willing to say yes i'll sign up for a randomized trial and i promise i'll drink four cups of coffee every day for 10 years or i don't mind i'll have no coffee a day for 10 years who would sign up for that right i could say people you know i drink coffee i'd be happy to drink a little more how about drinking none oh no don't take away my coffee for a decade i can't do that are there people who don't drink any yeah i don't mind i won't drink any coffee yeah but what if we randomize you the group that drinks four cups a day oh my god i'll never sleep right okay how about alcohol oh don't we know if we should drink or not do you know the new dietary guidelines said people's men should drink less they did they used to say women could have one drink a day and guys could have two and the new dietary guidelines said no no nobody should have more than one okay how do they base that is that based on a new randomized trial no there's no no new randomized trial they looked at the availability of data in a bunch of places now could we get a trial funded so we would really know could we just say okay drink or not drink and see if you live or die it's possible okay but is it and we actually have observational data that suggests alcohol is protective if you look at the observational data it says it's protective but the dietary guidelines just said to drink less because they don't think so anymore if you look at the totality of evidence i want to tell you that just recently the nih funded a massive hundred million dollar trial of alcohol but does anybody remember in 2018 this became a huge debacle that the money actually had come from the alcohol industry to fund the trial the whole trial was halted some of my friends were actually sites for recruiting the people and they had start started recruiting people who willingly agreed to be randomly assigned to drink regularly or to be abstainers regularly i think that would be a to recruit for to be perfectly honest but they did they'd started it and the trial got halted because of the politics of who provided the money and the conflict of interest so we're that is unanswerable no one's ever gonna do this study but we still have dietary guidelines how did we get them they put together the totality of evidence of all the types of things i showed you is it perfect nope really should do a randomized controlled trial could we double blind it yeah right you're going to double blind people i don't know if i'm drinking alcohol or not something's going down my throat it's kind of bubbly and fizzy and i'm drunk now but it might have been the placebo drink no you can't blind i get these ridiculous comments sometimes how come you didn't double blind it it's food you can't double blind food or coffee or alcohol would that strengthen the design yes it would strengthen the design is it possible no it's impossible okay so in all these studies even when you get to trials there's a range of stuff around rigor and generalizability and the kind of trials i do you can imprison people you can incarcerate them or as kevin hall likes to say domicile them and you can feed them all the food so you have total control over what they're eating and you know they're not eating anything else in my kind of trial i recruit people and give them advice and i try to get them to change what they're eating and so kevin hall has done these amazing studies with huge rigor with sample sizes of 20 for 14 days and a couple years ago we published a big weight loss study of low carb and low fat that i'm going to come back to 600 people for 12 months did i really get people to eat low carb and low fat wow their their adherence was actually all over the map but i think we had the advantage generalizability i mean kevin does his studies he has the advantage of rigor and so some of the people said oh you should have done this and some people criticized kevin and said oh you should have done that in my world we need both i need small highly rigorous studies and i like to have bigger generalizable studies but i also like to think that we can raise the bar kevin does a really good job of making his stop his trials as generalizable as possible in his high rigger situation and i try to make my generalizable trials as rigorous as possible taking advantage of all the fabulous stanford folks that we have to help me collaborate on things and trying to raise the bar all together okay susan let's pause for a couple questions i actually am going to run through some studies that we have done and i kind of have some exercises to make you think wow what were they thinking when they designed it that way so the the last 50 minutes is supposed to be interactive but i'm gonna pause for just a minute so why don't you take a bio break or ask a question we have already two questions here if you if anybody wants to take a break by all means um but we have two questions we can answer right now in under the q a okay and i got them i can read them susan so in a nutshell can you please give us a summary what diet as well as how much often it can help prevent and reduce risk of cardiovascular diseases no i can't tell you that in a nutshell that's an unanswerable question that is perfectly practical and there's no way to do it there's just there is no way you can look at the dietary guidelines and if you you know that's actually going to be my last slide is sort of an aspirational diet and i'm going to say it's a whole food plant-based diet which means it's mostly whole foods and it's mostly plants does that mean you can have some meat and eggs and dairy yes absolutely would you do better without any meat eggs and dairy if it was a whole food plant-based diet you wouldn't do much better by going from mostly plants and whole foods to all plants and whole foods it would be trivial it's really the problem we have in the u.s is too much added sugar and too much refined grain so the whole food thing gets addresses that and then the plant-based diet doesn't mean vegan or vegetarian it just means you got lots of veggies and beans and fruits and so that's how you should reduce your cardiovascular risk okay so i answered it live what percentage of diagnosis type 1 and type 2 is related to nutrition versus genetics versus lifestyle versus other fabulous question i know plenty of people who eat well and do all the right things and have great families and i have a good neighbor down the street their kid got diagnosed with type 1 diabetes just the other day and so that is a lot of genetics uh and i'm not sure how much you know environmental exposure it is type 2 is very largely nutrition lifestyle that we could we could wipe out we could totally get rid of type 2 if we could manage weight eat a whole food plant-based diet get lots of fiber check out our microbiome so type two definitely okay i'm going to move to the third one might be a first world problem what about for parents who are wondering does prenatal consumption of food make my kids smarter are these trials realistic nope easily funded nope because smart is not a risk factor for disease now you know smartness and intelligence quotient there's there's i i don't want to get in trouble here i'm sure there's i'm sure there's genetics involved there is there nutrition no in nutrition it tends to be the case that once you have adequate nutrition and in the first world you whoever wrote this as a first world problem in the in the us we do we really do have adequate we have access to good variety and a largely adequate diet there's certainly some problems with it but if you get there's a difference between getting enough nutrients and more than enough in nutrition more than enough doesn't usually count if you find somebody with deficiency and you address it you see a huge benefit but it's really hard to hedge your bets and say i'm getting a great diet and so i'm going to get more more doesn't often help is more sort of like more of that beta-carotene hurt in that trial instead of help okay i'm only going to take one more and then i want you to participate interactively with me okay all right among others revisiting keto style diets for brittle diabetics oop fred hex group successfully getting diabetics off medication lowering everyone sees well also surprisingly to me changing their lipid profiles where does the evidence start oh but my last example is keto we just finished keto diet and we're writing it up so i want you to walk through that with me okay all right bio break over here we go again hope you got a chance to use the restroom or i hope you enjoyed some of those frantically answered questions okay let's try applying this are you ready again we're going to go back to this and i had to deal with this just uh in the fall of 2019 in the annals of internal medicine a report came out a clinical guideline don't get me started it might take me the whole hour to do this if you get me started on this where they concluded that we should continue to eat current amounts of unprocessed red meat although that's a weak recommendation and we should similarly continue to eat current amounts of processed meats unprocessed and processed go ahead um the main conclusion here was there's hardly any evidence for this we're really missing clinical trials and since we don't have them go ahead and just eat whatever you're eating my colleagues and i went nuts when we saw this this drove us absolutely bonkers okay so try try to come up with a clinical trial for red meat try to use my formula if these people eat that added also something instead of something else for this amount of time there will be more or less of it okay okay the nih just said oh yes red meat is controversial let's give stanford and the gardner lab a bazillion dollars this time and first they're going to have to give us a protocol so we'll have to pick a type of red meat we'll have to pick a dose for the people who aren't eating red meat they have to eat something else and we'll have to see what kind of outcome we're waiting for in a particular population okay sorry i'm going to choose for you because we just don't have time and the format doesn't allow i think we should pick steak and hamburgers and you should either have two versus six ounces daily we're not going to have none we're just going to have a lot less versus six ounces daily or the people who get two have to replace those four ounces of calories with beans and we're going to wait for heart disease and we're going to use heart attack survivors to make this study a little shorter because heart attack survivors are more likely to have a second heart attack than the general population is likely to have one okay do you know how long and how much money that study would take to be sure that they were really eating two versus six ounces do you think anybody would cheat any less or more do you think they'd eat all their beans this is this would be massive this is like holy crap this is like a 100 million dollar study seriously right here and i get it and it's published in jama and i'm feeling really good and the the marketing folks said yes stanford has done it they've answered the red meat question yes or no and the first question i get back is well but what about pork i actually was thinking about bacon and i'm more interested in zero versus four ounces and if they don't eat that i was kind of interested how that would compare to poultry and i had more of a cancer focus so i would focus on cancer survivors so what does your study tell us about that and i said nothing i didn't do pork i didn't do poultry i used a different dose and it was heart disease focused can i have another bazillion dollars and wait another 10 years to do this study and then i'll know about red meat and health except then as you can tell though somebody will have a different permutation of all those domains and i won't be able to answer it so these people were crying out for more trials these trials aren't going to happen no one's going to fund that no one's going to agree to be randomized to eat red meat forever or to not eat it we have to use the totality of the other evidence and all these groups all these health organizations have pretty much said americans eat too much red meat eat less and they say oh but you don't have definitive answers well we're never gonna have the randomized control trial if anybody wants this is a new slide that's actually not in the deck this doesn't have so maybe you'll have to update it pretty funny this doesn't even have an actual issue number yet i kind of wrote an editorial on it and it got published over the weekend and it was sort of to address people who are going to say oh there's another observational epidemiological trial in red meat which is worthless isn't it it's not worthless we're not going to have a trial and what they actually did in this observational epi study is did a great job of addressing instead of what and they used a new twist on their observational epidemiological data to take it farther along the pathway of causal inference they didn't get all the way to cause in fact but it was really clever what they did statistically and methodologically and since we're not going to have a red meat trial they helped they added to the database and the next time i'm involved in one of those groups it's making dietary guidelines i'm going to pull up this study that dealt with type 2 diabetes it didn't deal with cancer and it didn't do with heart disease i assure you this group is going to publish on cancer next and then on heart disease next they just keep cranking out papers like this and then the twitter world will have a heyday in fact i posted this on my twitter account but carnivores are mad at me they're just accusing me of being biased and oh my god what a horrible world twitter sometimes okay anyway that's available okay how about low carb low fat this is something i've done two big nih studies with okay here i'm thinking about the nuts wait nuts are pretty healthy they're high fat what is this thing about low fat is good but wait nuts are okay so help me work on this one low fat versus low carb my interest is weight loss and i think i should do it among adults who have overweight obesity the question is which one is better okay so i've actually given you a bunch of this i've filled out most of these already and i hope you agree that's a pretty practical question which is better for weight loss among adults with overweight low fat or low carb so i've got the if we take these people i got what to eat low fat i've got what to compare it to low carb i'm going to do it for 12 months that's actually what i got funded to study i was trying to see if i could lower weight or body mass index okay tell you what's missing here is at a dose of oh what do you guys think the dose should be it's a pretty standard question low fat versus low carb but what's the what does that even mean dose oh i want you to wrestle i want you to struggle how low is low are we talking about grams 20 50 100 grams of fat or carb are we talking percent of calories i can assure you if i submitted a grant and didn't tell you how many grams or percent of calories it would come back to me and say nope not funded you didn't define it what do you mean by low carb and low fat [Music] and if we had a more interactive opportunity here it would be fun to do a polling but susan i thought that would take too long and i can tell you what the answer would be you all wouldn't agree there wouldn't be a consensus over how low is low fat and low carb so i'm going to tell you how we got this funded and we'll see if you want to criticize me or not but it's too late because i already got funded and i already published the paper so it worked okay we call it this is just going to roll right off your tongues the titrate limbo quality method the titrate was in the first few weeks up to eight weeks of the study how low can you go and we gave everybody 20 grams a day as a goal of carbs or fat now i hope you know that people get 300 grams of carbs a day typically so this is massive and they get about 100 grams of fat a day and this is a massive reduction and i actually think when you get that low to eat the foods that you need to eat to get that low i don't think you get all the nutrients you need so we told all the participants that we were trying to psychologically anchor them and we weren't sure they should be that low but we wanted to make them feel like we're in a study we're supposed to lose weight we're really supposed to change our diet we're going to take this really seriously and i said once you get there after eight weeks and to be honest most of them did we had 600 people in the study 300 on each diet you could titrate up if this isn't working socially if you're hungry then it won't be something you're able to sustain so add a few grams of carb or fat back and see how you do if you're still doing okay and losing weight and you're still hungry add a few more back if you find you've added so much back that weight's coming back on and you really could have done better than that titrate back down so find this place where it's the lowest you can be um but it's sustainable and you're not hungry and you think when the study's over if it really worked for you you could keep that up that was our definition of limbo psychologically anchoring you and then titrate and then the other thing we said is and you can't do this with packages of processed crap don't go buy the brownies because they say low carb or low fat we want you to eat a whole food diet and so if you're on low fat we want you to get skim milk and organic whole grain pasta and fresh berries at the market but you really shouldn't have avocados and a lot of fatty meats for the low carbs we said you should get organic whatever you want farmer's market avocados and eggs and you should get some fatty meats in not a requirement but if you can get grass-fed you know good quality meats do that but you really shouldn't have any skim milk and you shouldn't have pasta and you shouldn't have fruits but everybody should have a salad every day these actually don't have a lot of calories but they have a lot of fiber and they have a lot of nutrients in them so even the low carbers we're told to have a lot of non-starchy vegetables every day basically everybody got told to have a salad every day and these folks ate here and these folks ate there so we called it limbo titrate quality doesn't it just roll off your tongue the gardener method of defining healthy low fat and healthy low carb and this is what they ate so here's the graphic from the paper they reported eating more than 2 000 calories at baseline and i'll just quickly show you that the protein didn't change much but look at their you know 35 versus 45 for carbon fat so in the beginning when they were the most enthusiastic we had huge differences in carbs and fat and then by six months they had slipped a little about 12 months they slipped a little more but these are in my world these are huge differences this is 30 fat versus 45 and this is more than 45 fat versus 30 carb these are huge differences they really as a group ate very differently and this is with advice we didn't feed them we didn't provide the food we had fabulous dietitians okay do you agree with dos did i pick the right dose did i pick the right description do you think any of my colleagues said you did it wrong a ketogenic diet is low carb and that's 20 grams of carbs a day and your folks were higher than 20 grams of carbs so you didn't do low carb and our response is you know we actually told them to get 20 grams and if they couldn't sustain it we let them get higher and they said this is the lowest they could go and maintain because you know people who go off a diet just go back to what they were at before so this is supposed to be sustainable so i can tell you that the grant was funded and the paper was funded and so apparently somebody bought into our explanation that this is how we were going to define low carb and low fat we even looked at glycemic load which is a combination of the glycemic index and how many of the carbs you're eating and we really did get a much lower glycemic load and the healthy low carb than the healthy low fat so it's supposed to be a big thing the insulin carbohydrate hypothesis um the raging thing about low carb is better for weight loss and satiety and things like that we're pretty proud of how we defined it and the adherence we got in a generalizable study where it wasn't a feeding study for four weeks it was for 12 months and the result of our study was this huge range of response in both groups we had in both groups healthy low carb and healthy low fat these are kilos we had people losing 20 25 kilos and we had people gaining 5 and 10 kilos on each diet and those aren't outliers you can see how this is a total continuum and i could get into this more about how adherent these people were more adherent to low fat and more adherent to low carb we have a postdoc who's done a great job looking at the quality of the diets if you got higher quality low fat or low carb you lost more weight so it was a combination of being as low as you can in low fat low carb and it's high in quality and if you didn't get very low and you didn't choose quality that puts you in this category here so i don't know did i pick the right how did i do for dose you guys think i picked the right dose or the right i didn't actually define it i let the study population define it i let them go as low as they could go we gave them a lot of support and we try to make it as generalizable as possible and as rigorous as possible and at the at the end of the day the average was identical we had to conclude that you know healthy low carb healthy low fat are the same the challenge is getting to a healthy low fat and a healthy low carb diet and i think there's some other factors involved my next study may be on satiety i think there were important differences in satiety here but there was actually the whole point of the study if you look at the conclusion here we actually thought there was a genotype predisposition and a metabolic predisposition it wasn't really just to compare low fat and low carb and neither of these worked we thought maybe we were predisposed to do one better on one or the other and it wasn't i i had a good plausible reason for both of those and neither of them weren't so at the end of the day we said you know what both of these are options for you we encourage you to eat a healthy low fat or a healthy low carb diet but they in personalized nutrition both of those could be options for you dr gardner you mentioned quality there is a question actually here uh participants all all the whole foods can be expensive does everything yes to be organic to no definitely not so organic isn't even more nutritious the biggest deal i teach a whole class on organic stuff to be honest the person who benefits the best is the farm workers organic has a much very very limited set of pesticides they can use so the farm workers get less exposure in terms of inhaling it and touching it there's even arguments about the environment it's a trickier subject than you think so organic costs more if you yeah that is not you don't need to buy organic there you go sorry i'm mumbling a little bit there but no that's not essential quality is more about getting seasonal vegetables think about how inexpensive broccoli and cauliflower and cabbage is dried beans so many different dried beans or grains whole grains i make a really great wheat berry salad instead of having bread with wheat bread how about making a wheat berry salad or a three bean salad some of those can be very inexpensive with some small amounts of herbs right vinegar oil yes you can get olive oil you don't have to you could eat a less expensive oil if it was a whole food plant-based diet it doesn't have to be expensive can it be yes in the greater palo alto area can be super expensive but it doesn't have to and you get most of the benefit just from getting the lentils and the beans and the apples and bananas for fruits which aren't expensive you don't have to get mangoes and having dried beans dried grains whole grains whole intact grains how about that for an answer keep going there is one or two more questions i don't know if you want to take it or wait for the end i'll take one more uh okay the the this one is a follow-up to the previous question they asked about hedge group um is for a true keto diet high fat but only moderate protein and at low carbs so protein restrictive too um okay so i don't know until the end because i i have a keto thing that i'm going to show you so hold up hold on save it for the end yeah okay i'm going to give you another thing here okay sugar americans eat too much sugar so i happened to be on the american heart association's nutrition committee when they came out with really strong recommendation in 2010 to eat less sugar and americans wrote and said does that mean we should eat artificial sugar and the american heart association ah we didn't think about that we wanted to tell people to eat less sugar we didn't say you should eat more artificial sugar so i actually got assigned to a writing group and we had to look at the data and give a position statement on artificial sugar ready okay let me just tell you that the us eats more sugar than anybody in the world it's pretty scary and interestingly we eat a whole lot of high fructose corn syrup whereas most other countries don't but if you put them together high fructose corn syrup is basically just sugar and so we eat a lot there is a lot of room to cut back so let's design a study come on team okay and here is the very generalizable simple question should we eat them our artificial sweeteners which are also known as non-nutritive sweeteners if you want me to explain i will but just let's call them artificial sweeteners for now are they a healthy substitute for sugar sweetener what word should we use sugar so let's use sweeteners and so let's let's try to frame this question as a testable hypothesis okay so what are we going to call sugar well all these things are sugar oh crap you can't just say sugar we actually had to say sugars throughout the whole paper because there are so many sugars and then how many artificial sweeteners are there well you guys are all familiar with these which are about 200 to 600 times sweeter than sugar so do you guys know that most of the white stuff in these is filler there's only a couple milligrams of sucralose and saccharin and aspartame in these and if you only added enough to be as sweet as sugar you wouldn't even be able to see it so to trick you they have to put a bunch of filler in here so it looks like you're adding a teaspoon of something but it's it's so much more sweet than sugar it's a tiny tiny little amount and you probably haven't heard of a sulfur k or neotame but if you look you'll see this in a lot of foods and beverages and now we have stevia which is the all-natural it's not all natural the way they extract it and put it in a powder and people are using it it was if you chew the leaves it's natural how many of you been chewing stevia leaves lately i bet not many of you okay so how can we wow okay so there's different populations and you'd be eating something with artificial sugar which one do we have to compare all oh crap there's a lot of them which dose that's a lot of different doses and certainly we're going to replace sugar but it's sugars oh my god there's a lot of different sugars wow it's more complicated than i thought and how long would we study it for what should we study it for blood glucose should we study it for weight okay i'm going to skip that for now and just tell you what our writing group did we found that all of those new those artificial sweeteners i showed you are approved by the fda as being safe okay that's not very encouraging it won't kill you wait i thought i was having it so it helped me okay so let's just get out of the way in theory they're safe let's not debate this for now it looked like they could be beneficial and they could contribute to weight loss or weight control if you use them to replace current products with added sugars like a diet soda instead of regular soda coffee with sucralose instead of a thing of sugar when it got to foods it was a lot harder so if you ended up cookies with artificial sweeteners they're still cookies they're still refined grain and they still have lots of crap in them you take the sugar and you put stevia in them they're not health food all of a sudden and the other thing that had to happen when we saw these studies is it would only work with weight loss and glucose control etc if you didn't compensate for this because what we found in a lot of studies that had been done they were only done for one meal and if you looked at studies that were done for the rest of the meals in the day we found that people compensated like they had a diet soda for lunch instead of a soda and when it came to time for dessert at dinner they patted themselves in the back and said oh yeah wait a sec i had the diet soda for lunch that means i can have chocolate cake for dinner and if you looked at the whole day a bunch of people were either completely or over compensating and they're getting more calories and more sugar for the whole day plus we're perpetuating a preference for sweet taste plus the things that have artificial sweeteners are crap it's never in red bell peppers did you see a red bell pepper with stevia in it did you see garbanzo beans with a sulfame k no it's always in cookies and crap so a huge challenge was compensation that people compensated later for having their non-nutritive sweetener then and that the things that we were getting people eat instead of things with sugar were still crap they're still cookies and things so here it is i'm the lead author of a scientific statement from the american heart association published in circulation and diabetes care and i want to show you how compelling our conclusion is here at this time there are insufficient data to say what to say we spent two years on this our conclusion is that it's unanswerable we don't have an answer oh are you disappointed in me i really worked hard at this i had this whole team of super smart people and we looked at all the literature and of course people wanted us to say yes or no you should have artificial sugar instead of sugar and we couldn't it's an it depends question it depends what you're having it instead of it depends how much you're having it depends on a lot of things and we didn't have a simple public health statement we do have one for sugar eat less americans should eat less sugar they eat too much should you question that is oh sorry um no the question is staying high about um high about natural sugars in like raw uh honey and agave nectar maple syrup they're all the same they're all just they don't have nutrients in them they get absorbed really fast in your bloodstream and they cause a glucose spike and that causes an insulin spike unless it's on something so i actually make a couple of soups where i drizzle maple syrup into the soup but the soup is full of plants and flavor and lots of other things so in that context oh the wheat berry salad that i make one of the key ingredients is pomegranate molasses and if you leave out the pomegranate molasses which is just fabulous which is just sugar i eat less of the wheat berry salad and i can eat bowl after bowl of it if i've drizzled some pomegranate molasses on it so i don't think any of the natural things are any better they are just sugar don't unless we add fiber to it yeah right so here's the yes i've seen that there is sugar with fiber in it now no just eat food with fiber please [Music] okay ready for another example here we go how about plant-based meat versus red meat oh wow beyond meat an impossible burgers oh my gosh okay is alternative plant-based meat better than red meat can that be a testable hypothesis okay i'm gonna i'm gonna tell you because we did this we published it over the summer we pick generally healthy adults do you agree should i pick people with heart disease i don't know that's who we picked you should be beyond meat because they gave us money so i'm conflicted here i didn't make any money but they gave me the money to do the study because the nih wouldn't so the twitter world has accused me of being biased but actually i think we did a very unbiased job but you can get me on that later what do you think i should pick for a dose i only get to do one study you're gonna have red meat or beyond meat should i pick a hamburger a week uh three hamburgers a week uh a hamburger a day uh only hamburgers you can only eat hamburgers the whole time that would be too much is there an obvious answer for dose what's the obvious there isn't we picked two two servings a day ended up being 25 year calories came from beyond meat or red meat which we bought for you and delivered to your house for how long well oh yeah instead of the red meat so we have the beyond versus the red meat and we did it for eight weeks because we were trying to see if some blood factors would change and i can usually change blood factors from people who change their diet from a to b in four weeks sometimes two weeks so eight weeks is really fine and we actually picked something called trimethylamine oxide which is sort of a hot emerging new thing to make this sexy in the cardiovascular world it was discovered by a guy named um stan hazen at the cleveland clinic stanford tried to recruit him i don't know what happened to that i think he's still at the cleveland clinic okay and we called it i hope you appreciate our acronym we're very proud of our akron do you like that swap meet i think it's pretty cute okay i got a lot of kudos for our acronym and we published it uh last august-ish and anthony cremarco fabulous postdoc is the lead author of this but we have lots of other postdocs in here and team staff members maybe some of them are listening if you guys are listening i'm acknowledging you see if anybody's listening you were acknowledged okay good okay so we got the meat phase and the plant phase and it's a crossover study so everybody was their own control which makes it possible to have a smaller group we use beyond meat and we didn't just use meat we actually went to a company called good eggs in san francisco who focus on sustainable locally grown agri you know regenerative agriculture organ we spent a lot of money on the red meat to be fair we spent a lot of money on beyond meat and a lot of money on this meat and our study was to get uh people to cross over 36 healthy adults eight weeks per phase two servings per day and we drew blood uh they picked up food we collect poop justin sonnenberg is analyzing their stool right now did diet assessments study questionnaires and here's the tmao results which were really unexpected so we randomized them to which one you got first i'm actually going to start on this side the people who got the red meat first their tmao levels which is supposed to be an inflammatory marker and a pro coagulation went up but not in everybody can you see in some people it didn't go up but if you take the mean it went up over the eight weeks and then we switched him to beyond meat and went right back down and stayed down okay so this is kind of what we thought red meat would be bad for tmao okay we were not expecting this so people got beyond meat first and their tmao didn't go up if anything went down a little bit and then we gave him the red meat and and what what what happened it didn't go up oh crap in a crossover study you want both orders to be the same it's actually a little bit of a problem but they aren't the same that means there's a carryover effect and so actually justin sonderberg is analyzing this right now we think so the generation of this tmao happens in the microbiome in your gut and so we did some looking into some other papers and it looks like when you go on a plant-based diet you change your microbiome and the bugs that are in there that make the tmao go away when you're on a plant-based diet so we actually pre maybe don't know for sure protected these people from their tmao growing up by putting them basically on a vegetarian diet first wow so our main result actually was that we lowered tmao even though it was only one part of the group it was still statistically significant overall they lowered their weight a little bit they're a kilo lower on the plant phase of eight weeks than the animal phase that was weird that's not really statistically it's not clinically relevant that they lost a couple pounds but it's statistically significant because everybody was a little lighter even though they're getting the same amount of calories and then their ldl cholesterol went down which made sense because when they were on the plant meat they were getting less saturated fat more fiber they lost a little bit of weight totally makes sense that their ldl went down so we were able to conclude that the plant meat was better than the red meat at that dose with that kind does that mean it works for impossible i don't know we did it with beyond does that mean it works with a new tyson veggie burger i don't know we did it with beyond does that mean it works with one dose per day not two i don't know we did two doses does that mean it works in people with heart disease i don't i don't know we did it with people who are generally healthy who signed up first i only answered a tiny little question right i didn't answer them all but there were no data before and now there are more data there is a question um do you recommend individuals getting microbiome assessment oh not yet um a lot of people can get it done they don't know what to tell you we actually assess the participants microbiome and we give them a profile and we tell you what bacterial species went up or down but we actually don't know yet what it means that's why justin and i are having fun doing a bunch of studies i actually work with another group in the uk a group called zoe and they have these series of studies predict one and two and three and predict that predicts the first predict study just released in nature medicine it's microbiome results and they propose 15 specific bacteria that are healthy and 15 specific bacteria that are the least healthy you know i mean it didn't necessarily rank them but the more studies we do the more understanding i would say not don't get it done now wait a little bit we're learning more and more there are a couple of more questions so do you want to answer them now or we wait at the end do you guys want to hear about keto why don't i take two now and then i'll try to run you through keto sure uh about the beyond burgers uh it's the the question is they have coconut oil in them isn't that bad yep coconut oil saturated fat so is the saturated fat that's from animal in real burgers yup they're both bad okay but what did you have it with and what did you have it instead of was it lower and the question is since the dose replacement was two per day uh does it mean uh that those subjects were consuming two doses like servings of red meat and per day prior to study enrollment as well ah interesting you couldn't be vegetarian to join the study you had to have at least one serving a day to qualify to be eligible and we looked most people were only having one a day i think if i go back i think that's why they went up here these guys were getting about one serving a day and we gave them two so that's probably part of the explanation why they went up is because you're actually giving them more meat than they're having before okay let me do keto quickly because i actually have an aspirational diet thing to finish on that i want to tell you guys about um so that i can finish on that positive note i'm going to do this one kind of quickly according to my notes i have 10 minutes right we're going to 11. susan okay all right so just really quickly we just finished this study and here's my personal question um the ketogenic diet is very restrictive and here's what i know from from looking at the american diet we eat way too much added sugar and way too much refined grain we don't eat enough vegetables if you look at the ketogenic diet it says gotta get rid of added sugar and refined grain and you should eat non-starchy vegetables if anybody of you or if any of you are up on this you're supposed to eat non-starchy vegetables and get some carbs from them so both the mediterranean and the ketogenic diet actually what does this say here yeah um are identical in including avoiding avoiding these carbohydrate sources mediterranean and here's what i'm frustrated about is the keto diet says no beans are legumes no fruits and no greens even if they're whole intact greens the mediterranean diet would say yes eat lots of legumes and fruits and whole intact grains so my personal question here is if you did this if you just got rid of the added sugars and refined grains would you really get an additional benefit from avoiding these which the whole public health community thinks is healthy okay i question that i think our focus should be here not here so the two diets are the same in this and they're different in that okay for the sake of time i'm going to have to skip this the hypothesis is one will be better than the other we focused on the well-formulated ketogenic diet so again we try to make a really healthy ketogenic diet to be fair and then we try to have a really healthy mediterranean diet whereas the absence of added sugar and refined grain isn't technically part of the definition you saw the definition before in one of the other studies i showed you so he said it's all the same things as the other studies including olive oil plus you should get rid of added sugars and refined grains so we're going to focus on glycosylated hemoglobin but we are measuring tons of other things so i'm going really fast so i can finish on my aspirational note it was once again a crossover diet so 20 on each arm this is actually 10 on each arm with type 2 diabetes and 10 with pre-diabetes for 20 total 40 all together collected same kind of things blood poop diet assessment study questionnaires and a twist to this was to make it as rigorous as we could we actually for four weeks delivered food for the first four of 12 weeks and then they switched to the other diet and we delivered food so they would be instantly adherent and then they had to be dietitian supported and learned on their own so it was generalizable and we have a follow-up time point i want to see after the studies all over what they choose to eat 12 weeks later after the studies or that's actually one of my big questions is it sustainable okay so this fabulous company that delivered boxes of food and here's a participant who took a picture of all their food for the week and that's the mediterranean in the fridge for the week okay sorry going fast i have to skip this this is all my cool diet data i'm just going to tell you they did a pretty good job but the bottom line is when you're getting delivered you're more adherent than when you're on your own as everybody would expect right and so we came up with a score i actually don't have the final results now i just want to show you something really practical we came up with a score of how well you were doing on keto and a score for how well you were doing on med and my brilliant postdoc matthew landry said okay i know they actually aren't assigned to a diet at baseline but how would they have scored on the keto diet at baseline and they would have scored really poorly 10 is best zero is worse and then when we delivered food wow they did really good but they weren't perfect even though we delivered it who who what did that person do did they throw all the food away that we gave them damn it oh we should probably study rats because rats only eat what you give them okay but these are humans so this is the variability that we got and then this is what they were when they're providing their own food their adherence went down even though we showed them exactly what to do we delivered it it was harder to do on their own and then at the end they didn't really stick with any of these they're pretty low for keto when it's all over does that make sense and we'll go over to med they actually scored higher at baseline just because normal people's diets are more mediterranean-like than keto diet this is super restrictive so even if you're not trying to be mediterranean you scored higher on mediterranean baseline here's where we're intervening and so they did better right but not everybody did the same and they got worse and then they weren't quite so much on it so for internal validity of the study this is pretty cool because according to our score when we were feeding them the two diets delivering the food they were both pretty similar in adherence seven and a half out of ten and then when they were providing it for themselves they were pretty adherent only like six out of ten but still way better than baseline okay i'm just gonna skip cool i'm just gonna show you that i we don't have the glycosylated hemoglobin i just got to show you the weight change date okay so here's a teaser in the very beginning keto lost a lot of weight really fast when we were delivering the food and the mediterranean diet lost some weight look what happens when they provide food on their own their weight comes flying back on because restrictive diets are difficult to maintain so when they switched over to the other diet these guys lost a little more weight when they got to keto and these guys when they switch to med their weight totally stabilized and this is going to be a really fun time point because out here after they've done both regardless of which one they did second they ended up with the same amount of weight i actually think their glycolytic hemoglobin is going to be really similar right here and how did they do after 12 weeks of follow-up bless their hearts they maintained that weight loss but if you do both diets no matter which one you end up on you end up with the same weight okay that's my teaser okay i have to skip all this okay now i'm going to try to inspire oh uh this is this is sort of inspirational i'll try to do this quickly this is a bad question is the ketogenic diet healthy compared to what okay is it healthier than the usual diet well the usual diet in the us sucks so that's not a good comparison how about versus really low fat vegan diets well that's that's one possibility but i actually was more interested in sort of an optional low low carb diet a mediterranean low carb that was high in olive oil but also high in legumes and beans and whole grains for what oh yeah right you have to say for what so we picked glycosylated hemoglobin and you have to say for who oh yeah we said this this this group would be more relevant and then we could have done a two week metabolic ward study like kevin hall does but i i don't i like more generalizable than that so we did maybe a four week feeding study we did a four weeks feeding study and eight weeks of self-provided food so i hope you appreciate my interest in balancing rigor and generalizability and even having that sustainable thing out here so we're trying to answer a couple questions at once for keto and med stay tuned i can't tell you what happened i'm actually still blinded to the glycosylated hemoglobin results but we are i think i'm gonna know this thursday or next thursday okay okay skip this okay let's leave you aspirationally i think most people in my field actually agree on most of this stuff i think when it gets to grains we have gluten intolerant people and poultry we have kentucky fried chicken versus you know pasteurized eggs and chicken and okay whole intact grains is what i focus on dairy and red meat are the most controversial i know in the newspapers it looks like we disagree a lot but i really think even the ketogenic people and the low-fat vegan people agree on all these things these days i try to focus on what everybody agrees on more than what they disagree on and i really think there's considerable agreement even though in the newspapers and on twitter it looks like they disagree that is both vegan and keto that is vegetarian and might be keto except for the orange in the back this isn't keto because it has it's on a bed of of sprouted beans but wow that is a really super healthy dish so a lot of this has to be instead of what right a veggie omelet versus steel-cut oats versus pop-tarts i don't know i could argue back and forth between the veggie omelette and the steel cut oats but they're both better than pop-tarts those are both whole food plant-based the pop-tarts are not and lately i've been encouraging students to think about things other than nutrients to change their diet i teach a class called food in society and i find that when students get involved in social justice issues and other things like that the environment they actually make pretty good changes to their diet and it's got a taste good so i now collaborate with a culinary institute of america on unapologetically delicious food so here it is my aspirational diet yes it should be healthy and nutritious i have a phd in nutrition science it should taste good if it doesn't do that people won't switch and i really think we could put environmental sustainability and social justice into it for an aspirational diet that is my goal pushing all of those domains and so it turns out that this talk after susan assigned it to me i realized that a bunch of my slides had to do with an invited lecture i gave for american heart association's epi and lifestyle group and so you will now understand my concluding slide from that talk that i gave i think we have agreement i think we have to embrace variability not everybody responds the same way i think we have to understand that balance and trade-off between rigor and generalizability and no for talking about nutrients or foods or patterns and keep in mind instead of what i hope everybody will eat responsibly because a lot of food choices have huge effects on other things and what i really want y'all to leave this talk with is that you should eat joyfully and deliciously stop taking that away from nutrition we really need to get back to that so that people will enjoy what they're eating and if you want more and you have 2 300 okay shameless self promotion use your staff funds i have an online nutrition course that's way longer than this two hour thing susan thank you for inviting me i hope you guys like this uh i'm happy to stay for more questions but you guys put in your two hours and i think you get your credit yes wonderful thank you so much dr garner it was really wonderful information and some of it very eye-opening thank you so much and for the participant we will send out an evaluation so to get credit you will need to complete the evaluation and if you want credit you need to put your name a full name in the evaluation uh you need to complete the evaluation within 30 days and uh again for those of you who can stay beyond the r we can we have few questions uh first dr gardner can you stay or do you have to go just for a couple of minutes i could if i could learning questions i'd like to try to get to them okay first people are asking for your wheat berry salad recipe if you could share that later on okay you can email it to me and i will share it with the partners i will and then also a quick question is coconut avocado tofu like full uh uh are they bad overall because they are you know they have cholesterol so that's one question so no plants have cholesterol so that part was wrong no plants coconut has saturated fat okay avocado has unsaturated fat avocado is a huge win any time coconut shakier just have a little bit of coconut oil okay and uh there are other questions um it seems that a lot of these available dietary studies are in white maize and how generalizable that can be across genders and races yep it's embarrassing yeah we're getting better at cultural diversity and gender diversity actually i have to say most the people who sign up for my studies are women because women care more about their health so when you look i actually have to try really hard to get men in diet studies so keep looking um we really do need to work on diversity though um so we are trying to get more culturally diverse folks signing up for our studies too okay one more question are there certain diets that may be more beneficial for people with hyper hypothyroidism oh that's oh that's a bad question for me i can't answer that one i really don't know much about thyroid already skip that another question taking multivitamins may not add any benefit because it may create imbalance so when a person's diet is reasonably good as it may complete with minerals already in please comment yeah so there have been randomized trials on multivitamins multi minerals they they don't really hurt and they don't really help they tend to get taken by people who already had an adequate diet with adequate resources and variety i would say if you are a medical intern or resident and you're working huge shifts and you can't eat right if you are a person who doesn't have access to a good variety of diet if you have a picky kid who's young there are places for a multivitamin to multi mineral so if there is a chance that you're just not eating a good balanced diet there's little to lose and something to gain the general population i don't think it's worth it if you are gonna get it get something like a centrum silver that has a hundred percent of the recommended daily allowance if you look at some of the supplements they have a thousand percent of the recommended daily allowance why would you want a thousand percent just get a hundred percent so choose one that has a hundred percent of the nutrients not more and maybe one more susan yeah one last question came in actually high blood pressure is becoming increasingly common any advice for lowering high blood pressure through nutrition low red meat and salt increase veggie what is yeah so look at the dash diet there's a website there's been some fabulous dash study diets and they do two things they lower sodium and they increase plants and the plants have a lot of potassium and so the potassium and sodium balance is pretty important so there's one of the few areas where for hypertension we have randomized controlled trials because again blood pressure is a risk factor that you can change in a few weeks they've done them look up the dash websites dietary approaches to stop hypertension d-a-s-h susan thank you and thank you we really appreciate and thank you so much for staying few minutes beyond the hour and have a wonderful day thank you thanks everyone thanks everybody wish i could bye

Channel: Stanford Center for Clinical Research

Views: 91,621

Rating: 4.6173635 out of 5

Keywords: SCCR, Stanford Center for Clinical Research, Medical Lectures, Christopher Gardner

Id: VfQtq4YTPso

Length: 120min 57sec (7257 seconds)

Published: Fri Feb 05 2021