Feed Your Microbes - Nurture Your Mind | John Cryan | TEDxHa'pennyBridge

[Applause] growing up in the West of Ireland my grandmother lived with us but it's only recently that I started to reflect him how come she lives so long and so well with all of her cognitive faculties in place was it genetics well longevity ran in her family but more recently I started to think that there could be something else and I'd have a gut feeling that it was and one of the things my granny used to say is long before it became a TV catchphrase she said you are what you eat so eat well and indeed the quest for finding this Fountain of Youth is something that has fascinated mankind for millennia none less than the famous Russian immunologist elie metchnikoff now Mexico worked in the Pasteur Institute in Paris at the turn of the last century and he won a Nobel Prize for all of his famous work in immunology but as often happens to famous scientists later on in their careers that can start coming up with some crazy ideas and metchnikoff wasn't short of these and one of his crazy ideas was why did people in parts of what is now Bulgaria why do they live longer and he put it down to the fact that they ate a lot of fermented foods containing lactic acid bacteria so you are what you eat but mash the cuffs work also hinted at something else what if you're not just what you eat but you're what your microbes eat and what's important to it to reinforce is that over the last two decades we've began to really understand that there is a very important relationship between our microbes and our overall physiology but first thing I want to really reinforce is that we are living in a microbial world these trillions of bacteria that are that are within us and honors are really shaping a lot of what we do for example in terms of genes we are 99% microbial it's quite humbling if you think of all of the money we've spent on the Human Genome Project well it's less than 1% of our genes now if I given this talk eighteen months ago I would have told you that we have 10 times more microbial cells than we do human cells but this is a really fast moving field with changes in technology and mathematical models happening all the time and so more recently this ten-to-one has been downsized to one point three to one so we're still more microbial but just about so later when you go to the bathroom and you shed some of these microbes just think you are becoming more human recently we've been revisiting metchnikoff ideas and we've shown that for example in aged animals that there is a decline in how this microbiome is working and that we can carlay changes in the microbiome with cognitive decline and anxiety moreover works from my colleagues in Cork have shown a clear relationship in an elderly population between the composition and the diversity of the microbiome with health outcomes with elderly people with more diverse microbes has much better indices of frailty and cognitive health so you are what you eat and you are what your microbes eat and that would have been interesting enough but they the Cork researchers went one step further and they showed that what was in they investigated what was driving this diversity and they put it down - actually it was the diversity of the diet with people who have a bland diet full of processed food that was very repetitive having a large shrinking in their microbiome whereas those that are much more diverse diet full of fruits and vegetables having a much better diversity in the microbiome so your are what your microbes eat and this will affect your overall health and one of the big questions we have in this field is how do microbes in your gut influence your health in so many ways and what the main thing I want to get across today is that microbes are little factories producing all sorts of weird and wonderful chemicals that our bodies would not make without them and these chemicals depending on what foodstuffs you take in can be really benefiting all aspects of health so we can modify our diets or we can actually modify the microbes to actually shape this and perhaps there is no better example of this interaction between microbes and diets than early in life in breast milk human breast milk is is unique among mammals in its complexity it contains a lot of very specific sugars that is not present in cow's milk for example and we know that these sugars are very good for supporting gut health and immune function but for me perhaps the most startling thing is that these sugars cannot be digested by the baby they are as an exquisite example of coevolution they are digested by the microbes instead and so we we know that the chemicals that these microbes make then will support a lot of different aspects of health including brain development and this is probably underlying some of the beneficial effects as seen with breastfeeding another component of breast milk are the fatty acids and among fatty acids you may have heard of Omega threes well we've recently shown that omega-3 fatty acids can also affect the composition of your microbes and if we deplete omega trees and the diets and animals we can really change the trajectory of brain development and behavior so your brain health depends on what your microbes are eating another component of the diet that is receiving a lot of attention are the polyphenols now when I first heard about polyphenol it sounded like some sort of 70s disco Queen but polyphenols are really important dietary substances most talked about as they're found in dark chocolate and in red wine let's talked about is how they're also found in onions and grape juice and green tea but polyphenols have been shown to have really good anti-aging properties and affect learning and memory as well and more recently it's been shown that a lot of polyphenols actually don't get don't get absorbed but get down to your lower gut and get acted upon by your microbes moreover polyphenols will affect the composition of these microbes so once again you are what your microbes are eating so Omega threes polyphenols could we devise a diet that would be rich in these that might have some beneficial effects on our health well we don't have to go too far just to the Mediterranean the Mediterranean diet has long been known to have beneficial effects in cardiovascular health and to lower the incidence of stroke diabetes obesity and heart disease so and it is a really rich source of both polyphenols and Omega threes and what about the Mediterranean diet and brain health well just this year a study was published from Australia to show that adding a modified Mediterranean diet to normal psychotherapy or anti depressed medication was was enough to have profound effects on mood and these types of studies are ushering in a whole new discipline of nutritional psychiatry where we can target mental health through dietary means in a way going back to Hippocrates where he said let food be our medicine and perhaps the missing part of this puzzle is or what is the role of the microbes in mediating these positive effects and that's still to be resolved but I really think that they play a crucial part and why can I be so confident well it goes back to some of our studies in basic neuroscience studies that we have in animals now you don't need to be a neuroscientist to see here that when we take microbes out of a system these are germ-free mice they've never had any microbes and these brains grow up without any any gut microbes but you can see clearly that there are marked differences in this nerve cell from the germ-free versus the control animal and we've we've shown that almost all aspects of brain health are dependent on having microbes in our gut for example in the last year we've shown that myelin myelin is the key insulation in which nerve cells communicate and that myelination is totally regulated by microbes in the gut and so if we can develop diets that will target the microbiome to support brain health at crucial developmental windows we may benefit a lot of people and where this is going to be really important for example is in areas of severe malnutrition and under nutrition such as in sub-saharan Africa where you have lots of individuals with stunted growth and cognitive decline delay and neurodevelopmental problems and so a lot of efforts are going in to try and develop strategies for this now up until now everything I've told you has been about how diet affects our microbes but could our microbes also affect our diets and food choices and that's something that I find quite into and again just this year a study came from Lisbon where they used a lab fruit fly to actually ask this now fruit flies madhu Prive them a protein in their diet and you give them a choice of yeast or sugar with yeast for a fruit fly is kind of like their steak so if they're if their protein deprived they'll go right after the yeast however if you put microbes into the situation you can see that the animal no longer chooses the protein either actually gravitate towards the sugar as well and if this could be shown in other species it would have huge implications for our drive we have to take certain foods and perhaps later the next time that you crave that dark chocolate bar full of polyphenols perhaps it's your microbes that's telling you to go for it one of the best ways that we have for studying microbe diets interactions is looking at the microbes of some of our ancestors and scientists have gone out into the fields and started to study what is going on in communities that maintain ancestral like diets and for example in the Hadza hunter-gatherer community and in Tanzania they've shown that this day have diets very rich in fiber fiber is key in this regard and in when they looked at their microbiome they were able to see a very very diverse microbiome moreover we can chart the influence of the introduction of Agriculture by looking at the microbiome and the diets of people in rural Malawi and Venezuela and you can clearly see that it starts to be in decline in in this microbiome and then in our Western world what you see is with the introduction of processed foods and sweeteners and emulsifiers all of which are having negative impact the microbiome that we are more or less extinguishing microbes that our ancestors had the intriguing part of this story is that if you look at diseases like multiple sclerosis inflammatory bowel disease diabetes obesity these are not present in these ancestral communities and a lot of interest is now being put into understanding the relationship that these missing microbes have in driving these diseases and we know little about what's going on in relation to brain health and the contribution of this depletion of microbes has two brain cells but we do know is that in the society that we're living in which is increases in stress and overuse of antibiotics hyper cleanliness a huge upsurge in births by cesarean sections all of which will impact the composition of the microbiome that we are potentially having a public health problem in our midst and this will also potentially affect our brain and how we deal with stress but how do we deal with this and can we develop strategies perhaps to target the microbiome for mental health benefits and that brings us to the whole concept of a term we coined in Cork psycho bioethics and these are targeted interventions that will focus on our microbiome to actually promote brain health and to date most of the studies with psycho biotics have been only at the preclinical stage in animals but slowly we're doing more and more and around the world more and more work is going into get evidence-based for this whole new area and just paint though your genome you can the genes that you got from your parents and your grandparents you can't do an awful lot with it but your microbiome you can modify potentially through diet prebiotics probiotics and even fecal plans eventually so there is a slow psycho biotic revolution taking place and changing how we met might consider treating mental illness into the future so in conclusion I guess my advice is always trust the words of an Irish granny eat well and perhaps some of that wisdom comes from the trillions of bacteria within your gut and I hope that's given you some food for toss today thank you very much [Applause]

Channel: TEDx Talks

Views: 442,061

Keywords: TEDxTalks, English, Ireland, Health, Biodiversity, Biology, Genetics, Medicine, Microbiology, Neuroscience, Science

Id: vKxomLM7SVc

Length: 16min 11sec (971 seconds)

Published: Tue Jul 11 2017