Plant Food Toxins in an Evolutionary Context — George Diggs, Ph.D. (AHS14)

okay everybody please take a seat I'm very pleased to introduce George Diggs PhD he is an evolutionary biologist and botanist who has taught for more than 30 years at Austin College in Sherman Texas he last year published a book called the hunter-gatherer within health and the natural human diet and he will be signing the book at 4 o'clock I believe here he goes oh thanks so I'm going to talk about some of the plant food toxins that many of us have heard about and put try to put them in an evolutionary context so obviously the first couple slides here in one minute just the background creatures defend themselves in very different ways so animals obviously can flee but plants are helpless this is a very vicious predator here eating these innocent plants and plants though however are not so innocent they defend themselves in a variety of ways I'll just mention two or three before I get to the chemical and it's just very briefly physical defense we all know about it's it's not very complex animal guard defense is quite interesting there are a lot of plants that actually hire ants using various types of rewards different kinds of food shelter and these ants in fact defend the plants vigorously from their predators actually attack things that would try to eat the plants and there are some fascinating visual defenses as well the passion flower for example has evolved egg mimics these are these little dots you can see on the surface of the leaves and they we think mimic the eggs of certain kinds of butterflies which choose these plants visually and this prevents then the butterflies from laying the eggs because there's already eggs there and there wouldn't be enough food for the new eggs to hatch and turn to larvae and eat them but chemical defense is what I want to focus on and there's a wide variety of toxic plants that affect many kinds of creatures and plants are really biochemical factories they're not simple things my students sometimes say act like plants are so much simpler than we are well plants have many more genes in many cases than we do rice for example has at least 32,000 genes humans have somewhere around 23,000 wheat has even more and in the last few decades there's been a tremendous increase in our understanding particularly about chemical defense and how plants are able to protect themselves against herbivores and pathogens it's not just things that would large things that would eat them but it's also various kinds of bacteria and fungi that have pathogenic attacks now I've spent my career doing a lot of research in Texas some of the plants there and in a couple of my books in the past these are some of the conditions that animals face when eating certain plants most of these I don't think any of us want the blind staggers I particularly don't want the slobbers big head limp neck crazy cow syndrome now this doesn't usually happen in wild animals this usually happens in domestic livestock when they get trapped in a pasture and they're so desperate they eat things that they would not normally eat now there are various ways you can divide up chemical defenses in plants you can do it by the chemical structure you can do it functionally I think this is a pretty effective way to do it functionally so I'll mention today three categories at some length and I'll just talk about this one first briefly but toxins are things that actually damage the eater in some way hormone disruptors I think that's pretty obvious the gest ability reducers this makes the food that's eaten in the Jess table it makes it basically not worth eating so let me just give the 30-second version on semi Oh chemicals to show you the sophistication of some of the plant defenses and then I'll actually get to the the toxins and other things so the sameö chemicals are something we've note we've now known about for a number of years but I find them particularly interesting these are chemical signals to a tract the enemies of your enemies it's like calling in the cavalry so let's take for example a caterpillar that's being damaged or sorry a plant that's being damaged by a caterpillar so this plant maybe is being damaged by a caterpillar and that plant then is sending out signals volatile molecules that disperse the environment and attract parasitic wasp which come in and then attack those caterpillars so this is an indirect sort of defense pretty sophisticated way to do it and so this for example is another situation wasp can laid eggs and this this caterpillar is literally eaten from the inside out there they may still be moving but they're the living dead at this point so semi owe chemicals are pretty sophisticated ways of plant defense I don't know of any examples of where that has an effect on us there are many defenses though that do affect us in a variety of ways so toxins as I say are defenses that damage the eater and I think of these as things that either disrupt the metabolism or the structure and I'll give examples of both of these and there are many different kinds of toxins some of these infect the nervous system some stop respiration some inhibit digestive enzymes some damage the gut lining so there's a host of different ways and there are think all of these can have effects on us so just to give you one example of of a pretty poisonous plant one of the most poisonous plants in the Northern Hemisphere and one that's very common where I'm at and it also comes over here to the west coast water hemlock or cow Bane we now understand how that's so poisonous it disrupts the central nervous system technically it's a gaba receptor antagonist and it results in seizures and coma and death in minutes this is not something you want to eat and here's a little quote I wrote years ago it's very poisonous a single bite is reported to be sufficient to kill a human children have even been poisoned by whistles made from the stem so this is a very poisonous plant dr. Noel said earlier this morning everything that's natural is not necessarily good necessarily good I couldn't I couldn't emphasize that more and this isn't really so strange though when you think about there are certain pills that a small amount can can do very potent things to people but this plant is widespread and it's quite toxic fortunately most people are never exposed to it now the way I'd like to develop my ideas I want to give examples of chemical defense in nature and then follow that with a similar example of chemical defenses in our food so show this makes sense in the evolutionary context plants have evolved this kind of thing to do it to various creatures and we are sometimes the unfortunate beneficiaries of their defenses very few of these it probably probably none of them evolved actually to defend against our species and in many cases not even against mammals but that doesn't mean that they don't have harmful effects on us and that's because at the cellular level we are remarkably similar to insects and all other animals and many of these same compounds have similar effects against things even as far from us as fungi in fact some of the things that harm us probably evolved to defend against not even animals so let's think first about digestive enzyme inhibitors so these are things that inhibit the enzymes that we make to digest our food and one example of this is a protease inhibitor these inhibit our ability to digest proteins now if you're a herbivore and you're eating plants if you're an insect and you can't digest proteins that means you can't get essential amino acids and that's going to compromise your nutrition now when you put this in the context of natural selection these things don't usually kill the herbivore directly so it's not like the herbivore eat the plant and then the creature died what it and then some people say well why does that matter well it matters because or befores that choose other plants survive and reproduce better and so plants have evolved ways to make themselves less likely targets and so herbivores will then eat other plants and they're the ones that survive and reproduce and then their offspring tend to select those other plants as well so let's look at one particular protease inhibitor the one in soybeans and we know that has an effect on the digestion of many insects this has been studied in many many insects things like beetles tobacco hornworm corn earworm many many and we see similar digestive enzyme inhibitors in in many seeds and by the way the the soybean protease inhibitors also affect lab animals and how about humans and at what dosage dosage is a very big thing we can often stand small dosages of many things but if we up the dosage so if somebody's eating huge amounts of soy that is not properly processed then it wouldn't be surprising that the protease inhibitors might be having some effect wheat protease inhibitors are I think maybe more of an issue for many people because they've now been shown to be a be strong triggers for an innate immune response in cells both from celiac and non celiac patients so this is not something that's this is totally different gluten this is not related to celiac because it apparently if can affect cells from a wide variety of patients and it looks like it's fueling inflammation there's a paper published about a year and a half ago wheat amylase trips and inhibitors drive intestinal inflammation via activation of toll-like receptor 4 so we're now at the mechanistic level understanding how this is happening could this be involved in what we call non-celiac gluten sensitivity might it be not actually gluten in the case like this but some other component of wheat because wheat has multiple defensive compounds it's something that hopefully in the future we'll know more about but I find it pretty interesting I want to emphasize this is different from gluten gluten is a storage protein and obviously it can cause very serious problems really not going to talk about it today today I think this audience is sophisticated and probably very very um familiar with this kind of situation but I will mention one thing we do know that storage proteins in other seeds and in other plant organs are also known to function in defense so just because a protein is its main function is storage does not mean it can't also function in defense because many things about organisms have more than one function natural selection has driven too often one compound having multiple functions so I'm gonna focus on the other plant defenses I'm not really gonna say anything else about gluten now what I was just telling about would affect the metabolism it affects the digestibility of the digestion enzymes this is something different this is where the digestive system is actually physically damaged so this was a paper published a number of years ago the title is insect feeding mobilizes a new plant defense protease that disrupts the para trophic matrix of caterpillars what a mouthful that just means it's screwed up the digestive system of the caterpillar so this is a popular press translation of that the title bitten plants deploy gut rotting enzyme so it actually damages the gut of the animal and they do not grow properly so in this article that said it leaves the gut lining in tatters well that's pretty dramatic when you think about it you wouldn't want to be that poor insect right I don't think anything we're gonna get served for lunch today we'll leave our gut lining in tatters certainly hope not so it's almost like molecular scissors if something is a gut rotting enzyme so this is what we see in a case in insects but how about other things that damage the gut for example plant lectins now lectins are a type of defense protein that bind to sugars and in our gut cells have sugar molecules attached on the surface and so some of these lectins can actually bind to the lining of our intestinal epithelium our gut lining and we've all heard of lectins but what did they evolve to do probably not to defend against us so it turns out that lectins are very ancient molecules there in animals they're in plants there but they probably did not evolve to defend against mammals and it turns out that plant lectins are probably protection against pathogens things like fungi and insects so let me give you a specific example in the animal world and then we'll turn to a human example so wheat germ agglutinin we've all probably heard of this WGA it turns out it inhibits the growth of fungi and it also binds to bacterial cells this probably is a pathogen defense and here's a paper from years ago the inhibition of fungal growth by wheat germ agglutinin so may have it well evolved as a pathogen defense maybe also as an insect defense because wheat germ agglutinin is so potent against insects that biochemical biotech companies have now genetically engineered crop plants to express wheat germ agglutinin so you can now get corn with wheat germ agglutinin you can now get Tomatoes with wheat germ agglutinin goodness I hope we're not going to get any of those but we know this is very potent stuff against insects enough so they're trying to genetically engineer their crops we know also that wheat germ agglutinin damages the gut of rats and enters the systemic circulation and we know that it affects human gut epithelial cells leaky gut so this is we've known this but people could and we know it causes inflammation this is a paper from about a little over a year ago and this focused on we one of the focuses were wheat germ with gluten and so we know that it can do these things but people will say it's temperature sensitive and indeed it is if you cook things that if you at the right temperature for long enough you can break down much of the wheat germ agglutinin but let's think about in our society do we actually eat things that have the wheat germ of gluten completely knocked out or even mostly knocked down I don't think so we know from research there's you can I've got a reference here you can look in that in some cereals is wheat germ agglutinins still there so depending on the processing how about other processed foods how much wheat germ ablute mean is there how about poorly cooked or uncooked wheat products pasta that's not cooked properly kids eating cookie dough and how about wheat germ which is often eaten wrong so it turns out we eaters are probably getting significant amounts of wheat germ agglutinin and we know that this has biological activity in fact you can recover it from fecal so you can recover active biologically active wheat germ agglutinin from fecal samples so ironically though this wheat germ agglutinin damage is probably a quirk of our similarity at the cellular level you know it did not evolve as a defense against humans that's pretty clear how about science cyanogenic glycosides it's a big word this just these are just compounds that release cyanide so I think all of us have heard about cyanide it blocks respiration it's a quick way to to die if you're exposed to large amounts of cyanide entomologists use it to kill insects because it'll kill the insects quite quickly and they're cyanogenic glycosides are in a number of plants things like cherries and peaches in the in the pits and there's good evidence that this is a defense against herbivores it's in a lot of plants we know it in over 2,500 plant species and this stuff is released upon tissue so it's an inactive form and when tissue is damaged by something eating it then that causes the cyanide to be released and it's in a number of things bitter almonds is one that has a lot of cyanide almost very small amounts cherries most cherries the the fruits tiny amounts cherry foliage is significant as I'll mention it's known another number of other things sorghum is a grass and there's a lot in the leaves in some cases the only case where we're probably getting very much in human food is from cassava or yuca that's the one I'm most concerned about and I'll mention it to you but let's look at livestock first sorghum it's the grass some people may call it one of the related grasses sweet sue or Sudan grass but ranchers and farmers have to be quite careful not to let their cattle graze on these grasses at certain times because it can be very serious likewise cherries wilted cherry leaves I grew up on a farm in Virginia and we were quite careful if a branch of a cherry tree fell in a pasture you had to get those wilted cherry leaves out because that could be problematic for your cattle so we know this can have effects on mammals and the onset of symptoms can be quite rapid and you can have things like weakness and in coordination seizures and rarely even death so the cyanogenic glycosides are not trivial now how about is there any real worry for most of us probably not because we're not going to be eating huge amounts of this particularly in an unprocessed in an inappropriate form and also many of the cultivated varieties are fairly low in cyanogenic glycosides this plant if anybody's ever been into a third world country in the tropics you've eaten up probably a good bit of cassava or yuca I certainly have and it's often what's called sweet cassava it has fewer of the toxins but people who are in areas with problems with herbivores things eating their crops they often grow the bitter because which has a lot of cyanide and then it has to be processed properly or there are problems so cassava is not trivial it's the third most important source of calories in the tropics after corn and rice and it's the primary source of calories for almost 500 million people so there are a lot of people eating cassava well how about toxicity well long term consumption of cassava particularly if it's improperly processed or if the person is malnourished and this is the case particularly in some parts of tropical Africa this can result in very serious thyroid and neurological problems very serious and over all this another subject cyanogenic glycosides plants probably not a problem from people but it has been quite problematic for some people causing a lifelong disability so let's switch gears and look at another one that i find particularly fascinating and that's photosensitizers now why am i tempting you with a margarita here in the middle of the day before lunch well photosensitizers are toxins that make animals sensitive to light and these are important in plant defense okay so it makes them sensitive to light one example of this is celery I'll tell you a little bit more about it another example is wild parsnip these are both in the carrot family I'm gonna mention two families the carrot and the citrus family that are well known for photosensitizers so the carrot family the citrus family there are a number of others and these photosynthesizers sensitizers are technically called Ferrando coumarins these are phenolic that just means poly phenolic multiple ring compounds that become light activated so when light hits them it changes them chemically and they become activated and they can then cross link with DNA and they can also modify proteins so they actually die DNA and proteins in the presence of light this is an example of one this is an throw toxin you can see the multiple rings and that rings are important because they're involved in the light activation so here's a title of a paper from another number of years ago the toxicity of a furanocoumarins to armyworms so these protect the plants by actually damaging the animals so an animal comes and eats the plant and then light hits that animal and the animal is severely injured this can be quite a good plant defense now can also affect mammals so this is a problem for livestock in some areas sheep cattle through either contact with the plant or through eating it if they eat it then these compounds will move through the blood and where they are where the skin is not well covered with hair any exposed area then the animal gets a reaction so this is a poor sheep that has had a foetus photosensitive reaction its photo dermatitis and it's ears and face are not good there can be blistering lesions swelling of the head the head will actually get large because it swells particularly unpigmented or exposed areas utters for example or another place that don't have a lot of hair so animals can really suffer from this now there are some insects like this nice black swallow tail which is native where I'm at these black swallowtails and this is its caterpillar these guys actually preferentially seek out plants that make these so they eat these poisonous things okay so they're very unusual they choose the plants and this is where the animals have evolved in response to the plants so this hope this is not just a one-way thing there's all this coevolution going on as one evolves the other it's like an arms race and so these black swallowtails have actually evolved a way to break down these toxins so they've evolved special cytochrome p450 detox enzymes now we all have p450 detox enzymes in our livers we've heard of phase 1 and phase 2 liver detox these p450s are involved in the first step phase 1 of our liver detox and so these butterflies can just eat the plants and this is like they've got their own specially guarded food supply and so once they've broken through that defense that's really advantageous for them and so they seek out these compounds they seek out the plants with these compounds now let's put this in the human context some of you have probably heard on the news that grapefruit can be a problem with certain medications we now know of about 80 prescription drug grapefruit interactions one of the best examples of this is statins so some people can have pretty serious reactions and we now understand how this works so it turns out that grapefruit has some of these furanocoumarins now they're not the ones here are not going to be causing photosensitisation but they're still toxic them have to be broken down and so we have p450s in our liver that come that are trying to break down these grapefruit toxins but those same p450s are the ones that have to metabolize the drugs and so if the p450s are busy with fira no coumarins they can't detoxify the drugs and so you get higher than normal levels of the drugs in the bloodstream so we now understand that they're here these molecules that have evolved to protect plants against predators and they're affecting us when we are taking certain drugs celery is also kind of fun it's a known occupational risk for celery handlers and celery pickers people who are exposed to lots of celery they get what's called celery dermatitis if they go out in the Sun after being exposed to lots of celery then they get these reactions and this is particularly if the if the celery has been infected with a fungus because the plants response is to make more of these toxins so the plant is not necessarily making lots and lots of any particular toxin at a given time it's making some but it'll make more if it's being damaged by some type of pathogen now the reason I showed a margarita is because lime juice is a well known cause of photo dermatitis so if you squeeze limes and then go out in the Sun you're at pretty serious risk and this can actually be a horrifying manifestation your hands will swell up they'll be they'll be blistered it's just and people who don't understand what's happening they go to the physician often dermatologists know about this but often other positions don't recognize it they don't know what's happened but the people's hand I've seen this it's horrifying here for example it's made the news last year national news limes blaze blame for girls second-degree burns she had I don't know if it's large enough for you to see but she's got pretty serious burns from Lyme exposure so again these plants did not evolve this to do to us but they evolved it to do to they're things that would hurt them now these liver detox enzymes detox many different plant toxins and one of these that I think is kind of a fun example that can put this in a little perspective is that caffeine and chocolate are much more toxic to dogs than to humans some of you've heard about this you can't give your dogs chocolate and that's because they have slightly different p450s dogs have slightly different p450 enzymes detox enzymes and they can't break down very well what are called xanthines in both caffeine and theobromine the compound and chocolate are xanthine and so dogs are sensitive to this they're so sensitive in fact that here's the paper from a number of years ago the evaluation of cocoa and coffee derived methylxanthines as toxicants for the control of pests coyotes so we're actually testing this stuff to use as poisons on coyotes so the pretty toxic to canines a fatal dose is in the range of a hundred to 250 milligrams per kilogram of bodyweight literally death by chocolate wouldn't be such a bad way to go I guess now what let's put this into perspective what does this mean how much chocolate could you give a dog by the way here are some of the symptoms vomiting staggering agitation seizures in some cases even death it affects the central nervous system an 18-pound dog can be poisoned by consuming two ounces of baking chocolate so two ounces is not that much now milk could take a lot of milk chocolate to kill a dog because there's not much of the theobromine in it but nonetheless this is pretty toxic to animals now why did I mention this well clearly different species have somewhat different p450s right thank you but people can have different p450s so I might have a p450 with a different activity level than mark would okay and if I take a certain amount of drug or if I take a certain amount of coffee marks is a little different it may have a radically different effect on him than it does me so some of these individual differences are probably pretty significant it's not surprising we have different tolerances for different types of materials okay let's look at hormone disrupters this is a different group of plant defense chemicals and obviously these are things that mimic the hormones of herbivores and we know them from many plants this is just an example so there's a particular sub of plant hormones that affect metamorphosis in insects and these are called phyto egg die zones here is a poor pupa an insect pupae with three heads so this creature unfortunate creature ate some of a particular plant is called a bugle weed that has these fight oeq Dyson's and as a result its whole developmental pattern was thrown out of kilter now if we think about this this is a gross physical manifestation but it wouldn't have to be this gross physical manifestation to have profound influences would it but this is just I use this because it was such a dramatic example how about hormone mimics in our own food well let's look at the phyto estrogens the compounds that mimic female hormones in soy as a as an example in our food so soy beans make these compounds called isoflavones and these are plant defense phytoestrogens and they're excellent fungicides so this is a soybean leaf with some rust it's a it's a type of fungus and so they probably evolved to protect the plant against fungi and possibly insects and we know that plants under attack make more so this is what you'd expect of a defense chemical in it the plants being attacked makes sense for the plant to upregulate its production and we can see that this is the this is one of the phytoestrogens from soy and this is human estrogen and you can see there are similarities in the molecule and it's not surprising that there may be some our body may confuse this at the receptor level now so these are phytoestrogens we can go to a health food store and we can find books like this this is by an MD the soy is recommended for menopausal women here's a supplement that talks about it okay so this is one of these things that it really makes me think we compartiments can compartmentalize our minds so remarkably we can say okay postmenopausal women take soy and then we give we give children this as their sole nutrition in some cases soy formula which to me I just think about I think Wow and when are we most sensitive to hormonal influences when we're very young now if some people would say well Asians eat a lot of soy well it's not really that simple they usually don't eat soy foods in large quantities unless forced to do so by famine or poverty it's mainly as condiments and flavoring not meat replacements and they then they also eat it in traditional fermented forms which can reduce some of the toxins so and we know that these kinds of plant phytoestrogens can have profound effects on mammals we've known since the 40s that they can cause serious reproductive problems in sheep this is very well known and we know if it can cause problems from many other animals so what's it doing in humans how sensitive are humans to this well it's not clear but there are certainly a number of studies that raise red flags for example a study from 2008 soy cause of reduction in sperm quality in men a study from a number of years before that it changes the causes changes in the sex hormone ratios in people and study that came out in 2010 raises real concerns about children how much research has been done on this how much do we need but it certainly is something that we should be concerned about I think we do know that some research shows that urine levels of these isoflavones are 500 times higher in infants fed soy formula so we know that a lot of it is being metabolized and going through the body and can potentially be having effects so I would say why do it certainly there can be children who are lactose intolerant but there have to be it would seem to be other alternatives that could be figured out now one other category I'll mention just very quickly and I won't spend much time on this is kind of a fun one is digestibility reducers these are things that and these are not proteins these are things like what we call tannins that actually make proteins indigestible so if we had to get nutrition from leather shoes or belts we couldn't do it because those proteins in there have been bound up with tannins and that's what the tanning process does in Mexico those proteins can never be used and they come from certain plants these are large multi ring chemicals and they we know they have strong negative effects on insects how about other animals it's kind of interesting this they're well known tannins are well known to cause problems in animals so this is the from the Angus beef bulletin not one of my usual references but this talks about a corn poisoning in cattle if cattle are trapped in an area and they have to eat acorns you can poison a cow with too many acorns they can stand to break down some they cannot stand to break down huge amounts Native Americans in some places would use acorns at certain times of the year but they carefully leached tannins out of the acorns the Native Americans who use these as a significant part of their diet so these digestibility reducers how about in humans now well we know that tannins can cause kidney and liver damage in very large amounts they can cause poisoning in humans and animals but the good news is problems are unlikely for most modern humans from the food and drink we get some in wine we get some in chocolate we have the ability to detoxify some and if we are eating a mixed diet we're not getting huge amounts and so they're probably not a problem for most of us unless there's some compromised metabolic pathway but it's all about dosage Native Americans were careful to leach out the tannins now I want to kind of wrap up my last example is with a with a fern and I spent a good bit of time in the last several years doing research on ferns and this is Bracken fern this is a very common fern in Texas and also I'm on it or a close relative is worldwide it's one of the most widespread plants on the planet and I'm using this example to show you the complexity of chemical defense the multi-layer approach some of these plants have evolved so this thing has an enzyme that causes a fatal vitamin V deficient B deficiency in livestock if they eat too much it has a toxin that's known to be mutagenic and carcinogenic it has a cyanide producing toxin and it has a hormone mimic that disrupts insect metamorphosis you would think this is not what you're going to choose to snack on right but unfortunately people do eat BRAC and turn fiddleheads and in Japan and Brazil where this is done there's a close association between bracken consumption and cancers of the upper elementary tract and we know that this toxin can cause DNA damage so but this is a long-term effect how many other things do we eat where we don't see the long term effect it could be years before this had some effect so summary the problems caused by the consumption of some plants particularly in large amounts is not at all surprising in the evolutionary context plants do fight or bite back sometimes and beware what you eat I don't plants give us a lot of good things but they're not necessarily our friends thank you very much okay we are technically at the end of our slot here but I'd love to give an opportunity for some questions so if you have to go please go ahead but let's go ahead and take some questions I think there's one here thank you thank you so are you saying that I shouldn't eat carrots and celery or are you saying that I shouldn't eat large amounts of carrot I guess I'm saying I wouldn't base my diet on any one plant so that way we get in trouble I eat good number of carrots and I eat celery and I enjoy but I wouldn't eat you know celery three meals a day so yeah because our bodies can detoxify a lot of stuff and it actually may helps us help us through hormesis to detoxify some things yeah so and then I have another question and that is about fungi I have this craving I eat so many raw mushrooms I don't know if that's a good thing or a bad thing do do fungi have the same defenses plants do absolutely in fact I've been involved in trying to help in fungal poisoning cases I wouldn't advise eating any wild fungus unless I know exactly what I was eating and even some cultivated fungi have some pretty potent toxins so I would look into it and choose some fungi are great some are not so great it's some it's too complex to talk about here I can talk to you a little bit more later afterwards are you aware of any toxins in garlic or anything from the garlic family uh they certainly have toxins I know that if you feed certain livestock there were some examples as I recall from famine during World War two where they were trying to keep some livestock alive on larger you know feeding them large amounts you can with large amounts poison creatures so there are defense chemicals there and some of those defense chemicals may be good for us in moderate quantities but like anything else if you eat huge amounts so I would say yes but I've never heard of any problem in humans with the amounts we eat and did you have any thoughts on tubers and other below ground vegetables and peeling them before eating them how does that help or does it you know it's a it's a great question we know that in some tubers are more defense chemicals around the outside so that turns out to be the case with cassava yuca so out towards the edges higher levels of chemicals if you think about potatoes or something there there's a higher higher level of some of the alkaloids out at the skin now again I would say it's probably a dosage effect how much you're being exposed to knowing that most plants seem to have something that can affect us in terms of preparation in terms of eating him is it just safer to cook most things to a certain level is there a certain method of cooking I I don't know of any research that's looked into that I think that you know I've been talking about some of the toxicity there are obviously a lot of benefits that plant compounds give for us and so when we cook them we change what we're getting so we may reduce some toxins but we may remove some things that might be helpful to us so I think you'd probably have to look almost on a plant by plant basis and you'd also have to look at what component of your diet so if you think about hunter-gatherers they were not eating over long periods of time huge amounts of any one thing they had a mixed diet and their body you know we have all kinds of different p450s and we can break down all kinds of toxins in that in other ways and so I would say a mix from the standpoint of what we see in animals a mixed diet would make sense I don't know of any that are available in the you know standard testing system there might be but I don't know of any I'm not sure if my question is a question but I'll ask it anyway I saw that you had a koala bear eating a eucalyptus yeah one of your first pictures and I will either have a very tragic life where it's the only thing they can eat but also they find it very unpleasant and it makes them grumpy but it's the only thing they can eat I was wondering if there's any parallels with with us and I I've actually been up close with koalas I've I've not heard it makes them grumpy they've evolved to be able to detoxify those eucalyptus leaves very effectively and when you are close to one they literally reek of the eucalyptus toxins like so I can't address it the Bt toxin in in GMO plants I know it's not naturally a plant toxin but now it is and is it true that it that it has no effect on mammals I cannot answer that I don't know I've not looked into bTW I've used it in my organic garden but I've not looked into it how it affects us hi quick comment I did the book the whole soy story so very Oh wonderful I'm delighted to have you here thank you I just wanted to comment quickly that besides the isoflavones in in soy beans there's the chemists ins in other alfalfa sprouts and clover and lignans and flax oil so it's not overdose on these things and we're seeing a lot of people having absolutely no defense another defense with oxalates so people switch from say McDonald's burgers to spinach salads to get healthy and they develop kidney stones another agony that's a great thing I'm really glad you mentioned that I have a student a number of years ago who for some reason ate spinach every day and she was you know a 19 or 20 year old college student she had had repeated efforts of kidney stones and I said you know you really want to think about how much spinach you're eating you know I I'm not a physician but if I was you I would think about the quantities of finished she probably couldn't detoxify oxalates properly probably not but I wanted you to comment about something it seems to be more and more epidemic with people problems with salicylates having to do with the peeling of vegetables maybe eating fruits and vegetables that aren't ripe some of the other things we're seeing in the stores and I just wondered if you'd research so listen I have not looked into that but I need to now that you've mentioned it but it's interesting thank you thank you

Channel: AncestryFoundation

Views: 126,147

Rating: 4.8911567 out of 5

Keywords: AHS14, plant toxins, evolutionary arms race, yt:quality=high

Id: fnjX3cZ4q84

Length: 47min 28sec (2848 seconds)

Published: Fri Aug 22 2014

Reddit Comments

[u/Ricosss]

Not super keto related but part of our quest to know what was our evolutionary diet. Depending on your P450s I can imagine you may feel much better cutting out some of these plants.

[u/dem0n0cracy]

Great talk. Despite what he eats, I think this is further evidence that questions whether we can be facultative carnivores. I love that someone talked about soy and oxalates at the end there.

https://www.amazon.com/Hunter-Gatherer-Within-Health-Natural-Human/dp/1889878405

Here's his book. This review makes it sound like it's up our alley.

I have 2 degrees in Biology, and I have spent the last 20+ years studying natural health, diet and nutrition and applying what I have learned to heal myself.

Two years ago, my husband and I went on the Paleo diet after I read Robb Wolf's book on the subject. We haven't looked back. Changing to a more natural diet eliminated cravings, helped a lose a little extra weight and gave us an energy boost. While Wolf's book explains some of the biology behind his recommendations, this book goes into far broader and deeper detail. I really enjoyed reading it.

Very much written like a textbook for a college-level course, this book has all the information in it you could ask for. It isn't popular science. It's real science. Yet it is very accessible to anyone who is willing to read.

I believe that the traditional Western diet is a root cause of health problems for humans, and that moving to a more natural choice of foods would eliminate many health issues, even serious ones.

This book is not for the casual reader, but instead for anyone who wants to full story on how diet affects health. It's well written, enjoyable to read and full of useful information. If you are ready to make a change in your health, and you are interested in what diet would work best for you (and by diet, I mean long-term eating plan, not short-term weight loss regime), this book will help you understand the choices and make an informed one.

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[u/Lhun]

this was absolutely fascinating.

I truly wonder about what we eat. It seems that plants with a closer relationship with water tend to be safer for our biome. I would love a list.

[u/TomJCharles]

Animals have defenses too :P. Lots of animals are extremely dangerous to hunt without modern technology, some even with. Organic, non-GMO bacon has tusks that can kill you.

You wouldn't be too happy if you bit into most frog or toad species. Just ask any dog. Frogs are very digestible, but eating them is probably not worth it and/or very dangerous unless you know what you're doing, depending on species.

Not sure what the 'some plants aren't good to eat' argument is supposed to demonstrate, to be honest. Of course some are not good to ingest.

I'm sure every animal has plants in its environment it is not adapted to eat.

And just because some are toxic doesn't mean they don't have compounds that are good for us. Most medicines are molecules that were originally found in plants.

Anyway, I'm with you guys that we shouldn't be eating grain or soy. Or most seed oils.