Hi Reddit! Gary Frost, Julian Marchesi and James Kinross here. 

This AMA is part of #ImperialLates - this month exploring the science of food. Check out the full programme here.

We are researchers and clinicians who work at Imperial College London and we’re all interested in gut function. Did you know, our gut is a central signal organ for the rest of the body? Far from just digesting, it plays a huge role in health and disease, as well as influencing the way we eat, think and feel. 

Our gut, or gastrointestinal tract, begins at our mouth and ends at our rectum. It processes food from the time it is eaten until it is either absorbed by the body or passed as our stools (faeces). Bacteria live throughout this system in what is known as the gut microbiome.

In many ways, your gut microbiome is as vast and mysterious as the Milky Way. About 100 trillion bacteria, both good and bad, live inside your digestive system. Our bodies have co-evolved to live with these bacteria and they interact with our cells and organs in intricate ways that we still don’t fully understand. From altering the way that we respond to drugs, to influencing cravings and appetite, this culture of microorganisms perform a myriad of processes, which we’re trying to unpick. 

The gut is also a driver of health and disease, from malnutrition to colorectal cancer, Crohn’s disease to obesity, there is a lot that can go wrong! Our work tries to understand these diseases so we can promote better gut health and wellbeing for all. 

During this AMA we’re happy to answer all your questions on the gut microbiome and its role in health and disease, appetite regulation, colorectal surgery and much more. Please read bios below for more information on our areas of expertise. We'll be here 4-6 PM UK time today but will endeavour to answer follow up questions over the next couple of days.

Gary works on nutrition, food and dietetics

As head of the Section for Nutrition Research and lead of the Imperial Nutrition and Food Network Gary works on a wide range of fascinating projects. His interests span from carbohydrates’ impact on appetite regulation, metabolism and body composition, to the short chain fatty acids produced by our gut microbiome, as well as food structure, obesity management, and nutrition in the elderly. 

Julian works on the gut microbiome 

As Professor of Digestive Health at Imperial, Julian’s research tries to understand the roles that bacteria in our gut microbiome play in maintaining health and promoting disease. His work looks at the metabolites produced by the gut microbiome, and how they drive health, control infections and provide protection against invading pathogens aka colonization resistance, as well as their roles in diseases like cancer, inflammatory bowel disease, and obesity

James works on colorectal surgery and the gut microbiome

As a consultant colorectal surgeon at St. Mary’s Hospital London, James’ clinical interests are in minimally invasive and laparoscopic surgery for the treatment of colorectal cancer. He also has an interest in how we can modulate the gut microbiome to improve the outcomes of operations, and the role the gut microbiome plays in colon cancer, Crohn’s disease and obesity through inflammation. 

Proof - https://twitter.com/imperialcollege/status/1334157976983244801

Further information:

Centre for Translational Nutrition and Food Research

Comments: 1288 • Responses: 36  • Date: 

yellowcrestedwarbler500 karma

What are some common diet mistakes that damage our gut microbiome? Is there anything specific that we really should (or really shouldn't) eat to maintain a healthy gut?

ImperialCollege611 karma

Gary here - This is a great question. You have to remember this is a new field so we are at the beginning of our understanding. However, there is interesting research that points out that western diet causes a microbiota that is related to many non-communicable diseases (diabetes, obesity and heart disease). High-fat diets seem to be associated with microbiota patterns that affect your immunity. Low fibre diets also have an effect on the microbiota that have been related to cancer. Alcohol has effects on the microbiome which has been linked to fatty liver disease.

denjanin255 karma

How much do probiotics like Greek yogurt and kombucha actually help your gut? And how do they do it?

Edit: changed my question like five times lol

ImperialCollege298 karma

James here - Thanks for your excellent question!

Yes, they do help your gut and I regularly recommend Kefir or probiotics to my patients with some specific gastrointestinal symptoms. Specifically, probiotics are live bacteria that have a defined health benefit. They function by colonising the gut and either produce metabolites or small molecules that influence the health of the gut e.g. by regulating the immune system. The question is not entirely easy to answer however for three reasons:

1) Everyone’s gut microbiome is different, and we cannot yet target specifically which probiotics each consumer should have to meet a specific health benefit.

2) Probiotics all have differing types of bugs within them at a strain level, or they have varying combinations of bugs, or even fibres (prebiotic) that these bugs need to live on. This may change further depending on how probiotics are stored and manufactured (e.g. Kefir can be made with different types of milk) and digested.

3) The research trials that assess these food stuffs are variable in their quality. The evidence is therefore not there for widespread clinical use, and they are typically not prescribed yet by doctors. However, this may change.

Sea-Biscotti2088177 karma

How is our gut connected to our brain? Can it influence our mood and feelings?

ImperialCollege248 karma

Julian, Gary and James here! Great question, and we will do our best to unpick the “gut-brain” axis but the bottom line is that this area is still being worked out.

Essentially, it is connected in three ways:

  1. Physically / anatomically - The gut contains a huge collection of nerves called the enteric nervous system. This is the gut’s neurological network and it is wired into the lining of the gut, but the gut is also directly linked to the brain by the vagus nerve. So there is a bi-directional connection between the brain and gut via the nervous system and the gut microbiome can signal to the brain through this. Within the brain, the hypothalamic pituitary adrenal (HPA) axis responds to environmental factors, and the microbiome is very likely to be playing a role here.
  2. Indirect signalling - The other way the gut communicates with the brain is by the chemicals made by gut bacteria from the food you eat, for instance neurotransmitters such as serotonin and GABA. There is very strong evidence from animal work that what happens in the gut can affect our behaviour and moods.
  3. Hormones - The gut releases a large number of hormones that help control a number of systems in our body. For example our work has shown that high fibre intakes increase the release of two hormones called GLP-1 that helps control your blood sugar and appetite and PYY which control appetite. GLP-1 hormone signals through the vagus nerve whereas PYY signal directly to the brain

sinkingsand116 karma

What do we know about the impact of antibiotics on the gut microbiome and subsequent disease development?

ImperialCollege277 karma

James here - Such a topical question. Antibiotics were discovered at St. Mary’s Hospital in Paddington where I am sitting right now! Their impact on the health of the human race (and arguably on all living animals) has been one of the greatest gifts of modern medicine. In the 19th Century, you were most likely to die from an infection caused by a pathogen. Penicillin was first used to treat sepsis from a rose thorn! But with great power comes great responsibility and we have not been very responsible… and so it has also had a very serious set of unintended consequences that have had a negative impact on our health.

Sinkingsand, we know a lot about how antibiotics impact the gut microbiome. Even short doses of antibiotics can have quite a significant impact on ecology, and that this can be long lasting. In its most dramatic form, antibiotics cause such a dramatic change in gut ecology it can lead to the overgrowth of bad actors like Clostridium difficile (typically in frail individuals) and this can be disastrous. Epidemiological data suggests that women even having intermittent doses of antibiotics in their twenties are at greater risk of adenoma (colonic polyp) formation later in life.

Unpicking the role of antibiotics in human health is hard because antibiotics are now everywhere. For example, they have been used in farming and they are in our water. They are also naturally occurring and in the earth. So, we are still working out what role they have in causing chronic diseases like inflammatory bowel disease.

The real problem we now have is that most of our antibiotics don’t work!!!! This is the really scary part. Antibiotic resistance is now one of the most serious challenges we have in modern medicine.

So, bottom line: if you are sick with a bacterial pathogen - TAKE THE ANTIBIOTIC. But, use them sensibly and don’t use them when you don’t need them.

ClemyW110 karma

I'm curious if there is any established link between gut health and endometriosis, especially endometriosis of the bowel/colon. Do you know of any research being done in this area?

ImperialCollege154 karma

James here - Need to be careful with the word “link” here. The microbiome is associated with lots of diseases, but causation and mechanism is not always straight forward. The microbiome of the female genital tract is obviously of significant interest and importance to health and there has been a lot of great work on this field. Check out Niki Klatt’s work here: http://www.klatt-lab.com/nikki

Having said this, women with advanced endometriosis do have a different faecal microbiome to those with mild disease. Moreover, the gut microbiome affects estrogen metabolism and is quite likely to be important. Although some of these findings may just be that those women are taking different medications, foods, or are having treatment that is driving it. It doesn’t necessarily imply causation. A nice review is here: https://www.sciencedirect.com/science/article/pii/S0002937816003367?via%3Dihub

satelyte103 karma

[serious] - What are your thoughts on Fecal Transplant for those who are suffering from UC/IBS/Crohn's?

I've talked with several people that have used this to make significant, positive changes in their journey with these diseases.

ImperialCollege123 karma

Edited - copy error!

Gary here - thank you for your question.

Fecal Microbiota Transplantation (FMT) is a serious therapy being used to try and treat IBS and IBD (both UC and CD). There are currently several proper clinical trials being undertaken to see if FMT can help with IBS and IBD, so yes we need to wait and see what the outcomes of the trials are.

Nerdmaster12199 karma

What is the healthiest global diet? I’ve heard lots of people say is the Mediterranean diet, is this true and if so why?

I also wondered if there is any scientific evidence behind links made between the gut microbiome and mental health?

ImperialCollege254 karma

Two great questions!

1: Gary here - I think you are right that, as far as scientific evidence goes, a diet that follows common healthy eating guidelines recommended by the WHO are reflected in the Mediterranean diet. If we all followed these guidelines as a global population we would be much healthier

2: Julian here - There are many animal experiments which show that there is a clear link between the gut microbiome and mental health, for example how we respond to stress and anxiety. We can also transfer these features by transplanting the gut bacteria from one animal to another, which shows that the feature comes from something that the gut bacteria are making. In one experiment the gut bacteria from rats, which are bold and explore their environment more, was transferred into a rat which is shy and timid and turned it into a bold rat which explored its environment more. However, humans are much more complex and we are still trying to make a cause and effect link in humans, but the evidence is getting there!

yulitt82 karma

What are the best scientifically proven ways to improve your gut health? There's a lot of misinformation floating around on the Internet, so would be great to hear your answers!

ImperialCollege156 karma

James here - thanks for your question.

We have a term for this type of misinformation in the nutrition-microbiome community… its called “bull****”.

This is an infuriatingly hard question to answer, because this is in fact two questions:

  1. What is a healthy gut? (and which bit do you mean).
  2. What is a healthy microbiome?

After just over a decade of microbiome research the most important discovery has been that the gut microbiome varies massively between people, and that its function (and structure which is more stable) changes over time and that is discrete to specific regions of the gut.

If we assume the gut runs from mouth to anus, and a healthy gut means the absence of disease then we know from epidemiology that there are things you can do to maintain the status quo. These things are simple and commonly reported. E.g. de-westernising your gut by increasing the amount of fibre you eat each day, reducing excess fats and refined sugars, reducing alcohol consumption, exercising, avoiding smoking and avoiding the use of unnecessary drugs. Simply taking a probiotic does not make you healthy, nor does eating green shakes or foods simply because they say that they are “targeting” the microbiome. However, this may change depending on specific health goals you may have, your age, your intestinal anatomy (you may have had surgery), the medications you take etc…

The future is the development of “personalised nutritional strategies” that will mean we can give individualized recommendations that target the microbiome in a measured way. There are lots of companies promising this but few delivering it at present.


How much damage are we doing to our gut with artificial sweeteners? Are some artificial sweeteners better than others?

ImperialCollege132 karma

Gary here - The first thing to say is that artificial sweeteners are very safe. What we know is the gut microbiota does change with high intake of some of the artificial sweeteners e.g. the microbiota can metabolise Aspartame, but we do not know what this means.

exwasstalking71 karma

Does Seltzer water have an adverse impact on the gut biome?

ImperialCollege113 karma

Gary here - At the present time we do not know if any form of fizzy water effects the gut microbiota

_zarkon_62 karma

On the lighter side, South Park did an episode about microbiomes (Season 23 Episode 8) where they did fecal transplants and ended up trying to steal Tom Brady's poo. Did you see it and if so what did you think?

ImperialCollege154 karma

James here - I did and it was hilarious!!!! I also think that Mr. Hankey the Christmas poo could be the face of microbiome research.

mulgr_naal54 karma

How does a plant based diet affect the microbiome?

ImperialCollege128 karma

Gary here - The simple answer is, if you swap from an animal-based diet to a plant-based diet it has a massive effect on the microbiota. In general, a plant-based diet is much richer in dietary fibre which is an important food for the microbiota and increases the number of bacteria that are associated with health. It is interesting that a plant-based diet is linked to lower risks of colon cancer which is thought to be due to the microbiota and the molecules they produce from the metabolism of dietary fibre which is rich in plant-based diet.

Isgrumberinos54 karma

I've read an article a while ago that said Alzheimer's Disease was related to specific populations of bacteria in the gut. Is it legit? How significant is this correlation?

ImperialCollege169 karma

Julian here - Thanks for the question, and a very hot one at the moment - yes there are links between AD and the gut bacteria - mainly those in the oral cavity. There are links between poor oral hygiene and AD as well. In particular a bacterium called Porphyromonas gingivalis has been linked to AD, and it was proposed that this bacterium can get into the brain and can make proinflammatory proteins that can trigger AD.

very_nice_how_much52 karma

What’s more of a factor in gut biome diversity; region, ethnicity/genetics, or diet?

ImperialCollege105 karma

Gary and Julian here - Another fantastic question, the short answer is they can all play a role in the development of your microbiota.

Added to this list is the starting point that is the microbiota you get from your Mum when you are born, how you were born e.g. caesarean v vaginal birth, when i.e. preterm or full-term and the types of food you get as a baby, breast v formula milks.

On a day-to-day basis, diet possibly plays the most important role. If you change your diet your microbiota will change within hours. This is not surprising as the diet you eat fuels the microbiota in your small and large intestine.

laurekavka38 karma

Is psoriasis gut related?

ImperialCollege32 karma

James here - thanks for your question!

This is the old “cause and effect” chestnut. People with psoriasis most definitely have changes in biodiversity, but these changes are non-specific and may well simply reflect that these patients are on treatment. ‘Metagenomic’ studies of the gut are starting to identify more specific differences.

In my view, the challenge in studying the gut microbiome when chronic skin conditions have manifested themselves is that the causative organisms are likely to have long gone. It is intuitive that the microbiome plays a role in this as it has a significant role in shaping the immune system and psoriasis is an autoimmune disease. This is why we also see a link between the microbiome and other autoimmune diseases such as rheumatoid arthritis.

In my opinion the key here is what happens in early life and we need better longitudinal studies to help answer the causation question. However, the gift of the microbiome in this setting may be in the treatment of psoriasis. We have some evidence that patients being treated with faecal transplantation for Clostridium Difficile infection have improved psoriasis after treatment! (a link to the paper is here: https://www.ncbi.nlm.nih.gov/pubmed/30943129)

Mcginnis36 karma

As somebody who suffers from IBS, is there a way to transplant somebody's healthy gut biome into me? I wanna eat like a normal human!

creepy_doll11 karma

Fecal transplants are a real thing but I have no idea if it can help with ibs

DigitalGeek2133 karma

What food additives have the biggest impact on the gut?

ImperialCollege70 karma

Gary here - It depends what you mean by food additives. If you mean colourings and preservatives then there is very little scientific evidence from trials to suggest they have detrimental effects on your gut. Though lots of people believe that they do, this has never been proven in trials. However, if you mean the addition of dietary fibre to products to food these do have a positive effect on bowel health.

ninjagrover32 karma

What seemingly unrelated thing is influenced by your gut?

ImperialCollege45 karma

Julian here - Quite a few things:

- the brain and how it functions

- the hormones you make

- the drugs that you are given to treat your diseases and how you respond to them

- the methane and CO2 made in the human gut and ruminant’s guts (sheep, cows etc) add to the carbon footprint and global heating

aye_min28 karma

How dangerous are antibiotics to our gut microbiome?

Cat_inabox24 karma

Would love to hear more about how carbohydrates impact appetite. Does that mean carbs aren't 'bad'?

ImperialCollege59 karma

Gary here - Fantastic question, I do not think it is a case of good and bad. What we know from population studies is that diets high in fibre, and where carbohydrate foods are consumed with cell structure intact, are associated with lower body weight. Our research has consistently shown that high fibre and carbohydrate diets are associated with the release of gut hormones that reduce appetite. On the other hand, carbohydrate that is not associated with dietary fibre does not have these effects. Carbohydrates are not bad and are very important to the microbiota.

Nerdmaster12124 karma

What’s the coolest discovery you’ve made in your different areas of research?

ImperialCollege63 karma

Thank you for your great question!

Gary here - We have developed a way to increase some of the molecules that the gut bugs make in the colon to show positive effects on health. Paper here https://gut.bmj.com/content/64/11/1744.abstract

Julian here - discovered that the bacteria growing on gut cancer tumours are different to those living right next to them in the same gut, which shows that the local tumour habitat is different (paper here https://pubmed.ncbi.nlm.nih.gov/21647227/).

James here - I am proud of the fact we have found that the gut microbiome is a critical mediator of how a western diet causes cancer. More information here: https://www.nature.com/articles/ncomms7342 But basically, the best thing is that we found out more mad things about how the microbiome influences human health every day. Right now I am obsessed about its role in early gut development.

vaelroth22 karma

Super cool research y'all are doing, thank you for stopping by.

This one might be best for James, but I'll take any responses: What do we know about the interactions between Crohn's medications and the gut microbiome? I know that's open ended, but do we have evidence of medications like Humira affecting the ratio of species in the gut?

More generally, is anyone looking at whether the gut microbiome has any relationship with the skin microbiome?

Do any of you expect that we will recognize the microbiome (gut and/or skin or others if we've identified them) as a human organ in the future?

ImperialCollege37 karma

James here - Thanks for your brilliant question!

We are starting to learn quite a lot and the field is moving so fast, so I will do my best. Firstly, diet and the microbiome is important. We have literally just published a study in a paediatric cohort suggesting that the microbiome plays an important role in how effective enteral diets are in controlling the symptoms and severity of Crohn’s. We can even use metabolites (e.g. TMA) produced by target bugs to predict who will respond and who won’t. (Paper here: https://www.nature.com/articles/s41598-020-75306-z).

Obviously lots of drugs use in inflammatory bowel disease (e.g. ASAs) are designed to be activated in the gut by the microbiome. Metabolites produced by bacteria such as butyrate seem to influence how medicines like Azathioprine work, and this further supports advice to go onto a plant based diet in inflammatory bowel disease. So, we have known about their importance for some time. However, the complexity of gut-bug-drug interactions is just being re-discovered. We know that patients with Crohn’s disease who respond to drugs like Humira have changes in diversity and abundances of specific bugs. Specifically, Faecalibacterium prausnitzii is higher in responders compared with non-responders at baseline. When we have looked at “biological” drugs in other diseases, we also find that the microbiome influences how they work because it orchestrates the immune response. So, the bugs that are driving these changes are not always those existing at the site of disease, and their role may be indirect.

The real gift of the microbiome science is NOT in the improved treatment of diseases like Crohn’s, but in their prevention. We need our patients off these expensive drugs with side effects forever!! So, I think in the future we will understand how the microbiome influences causation, and that we can engineer the developing gut by avoiding triggers and using precision nutritional therapies, 3rd generation probiotics or xenobiotics (chemicals to produced by bugs) to treat the gut

Formal_Rhubarb386818 karma

How does the gut microbiome impact surgery outcomes?! I know nothing about the gut microbiome so can’t see how they’re connected.

ImperialCollege55 karma

James here - This is a topic very close to my heart.

Short answer: ALOT. Outside of anaesthetics, antisepsis and antibiotics have had the most important impact on improving surgical outcomes over the last few hundred years. However, our understanding of how the microbiome influences healing and recovery from surgery is just beginning and it is challenging surgical dogma.

It is just so important because the microbiome influences the inflammatory response to injury and an operation is a controlled trauma. Moreover, it influences how our body heals. Interestingly, germ free animals (they are born sterile without any bacteria in the gut) don’t form scars! The microbiome plays a big role in how joins in the gut are made after surgery. My good friend and mentor John Alverdy in Chicago is the grand master on this topic, and you should check out his very influential work on this topic: https://www.uchicagomedicine.org/forefront/news/in-late-post-surgical-colon-leaks-finger-points-to-microbes

It influences how successful nutritional strategies are in those that are recovering and how well their gut begins to function after an operation. Our group is very interested in trying to understand how a post-operative gut which has had big changes in the gut microbiome (either because it has been removed, or because antibiotics or bowel preparation have been used) metabolises drugs. The microbiome is critically important in this respect and it will influence how your anaesthetic works and how effective your pain killers are. In fact, morphine (a strong pain killer) changes the microbiome… Most importantly, they may influence how chemotherapy works and this is commonly given after surgery to treat cancer. So, the surgical microbiome may also influence how well you respond to chemotherapy after surgical treatment.

If we are going to safely manage surgical patients in the post-antibiotic world, we really really need to understand the microbiome.

yellowcrestedwarbler18 karma

Is zinc really important for our gut microbiome? and are any other metals as important?

ImperialCollege36 karma

Hi, Julian here. Good question, and the answer is yes it is, just as we need zinc, iron and magnesium etc., so do bacteria and they will try and compete with us for these essential metals in our diet. I don’t know of any data which shows the gut bacteria can cause us to have any deficiencies in these metals, but some pathogens will take iron from our hemoglobin.

Social_media_ate_me15 karma

Thanks for doing this. There are claims that when there is fungal overgrowth in our digestive tract that it can create a systemic candida infection. Is there any truth to this?

ImperialCollege34 karma

Julian here - Fungi do live in us and on us, but they rarely overgrow and are at very low numbers, unless in immunocompromised e.g. HIV or immunosuppressed people. So healthy people do not really suffer from fungal overgrowth by such species as Candida albicans. In a study we did many years ago we found very low levels of fungi in the stool samples of otherwise healthy volunteers.

And James here - Having said this, there is significant interest in the role of the “mycobiome” in diseases like inflammatory bowel disease and IBS. My good friends Wouter de Jong and Jurgen Seppen looked at how the fungome influences gut sensitivity in IBS, and found good evidence in rat and human models that fungi are important. You can read about that work here: https://pubmed.ncbi.nlm.nih.gov/28624575/

bddutchg13 karma

In the past, I was treated for the H Pylori bacteria, but continue to have excess acid and chronic IBS. I would like to improve my gut health, but have never been able to identify a clear strategy. Help?

ImperialCollege19 karma

Thank you for your question - unfortunately we are unable to offer medical advice here. We would recommend that you contact your doctor/physician to seek help on this topic.

50StatePiss10 karma

Hello, what do you think of procedures like gastric sleeving? Obviously there are enormous and immediate benefits to those who have it, but are they doing more long term harm by eliminating most, if not all, of their gut biome?

ImperialCollege27 karma

James here - Thanks for the question. Our group has done a lot of work looking at the impact of gastric bypass surgery on the gut microbiome. We published our first paper back in 2011 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677150/?report=reader). Bottom line is that it has a really dramatic effect. We see a lot of gamaproteobacteria and protobacteria, and in our experiments, we found faecal water from bypass patients to be very genotoxic! (this is not a good thing). The changes in the microbiome are long-standing and it is unclear at the moment if this leads to health problems in the colon later in life. However, there is some data from Swedish registries suggesting that gastric bypass may increase the risk of colon cancer. A gastric sleeve does have an impact on the gut microbiome too, but it is more subtle as we are not completely diverting the flow of the gut. It also seems that how the microbiome responds to surgery predicts how successful the weight loss will be. The long term goal here is to engineer the gut microbiome so that we don’t need any weight loss surgery at all!!

zipzap2110 karma

How bad is processed sugar for you?

ImperialCollege31 karma

Gary here - thank you for your question. Sugar is a source of empty calories, by that it means it only provides the body with a concentrated source of energy. A diet with a high sugar content has been associated with weight gain. This is why there is a sugar tax. Also sugar has a detrimental effect on dental health. So over all not good!

strayaares9 karma

Are gut biome/diet testing useful or is the research and interpretation not there yet?

ImperialCollege17 karma

Julian here - At the moment the tests, which tell you what microbes are in your stool samples and the numbers, are purely academic and of interest to scientists. So if you’re interested in what is in your gut, then go ahead and do it, but we can’t say anything about what is healthy and what is not.

jochilds1128 karma

How do you think that covid has influenced people’s nutrition? Is there any research on how global or British diets have been affected?

ImperialCollege21 karma

James here: Really good question. So, the answer to this is two-fold:

1) The poorest in our communities have not been able to access high-quality food. At the beginning of this crisis, the WHO made it clear that food shortages were going to be a major problem, and this has indeed been the case. Food security is also a challenge. https://www.worldbank.org/en/topic/agriculture/brief/food-security-and-covid-19

2) The second challenge is that we are eating more of the wrong foods, either because we are relying on takeaways or foods that are more frequently available. This, when combined with the fact that we have been less mobile has meant that obesity is becoming an increasing problem. This is doubly bad news as Obesity is a risk for covid. We have termed the phrase “Covesity” in response to this. More information can be found here: https://www.pansurg.org/covesity/

sinkingsand7 karma

What role does nutrition have in managing frailty?

ImperialCollege20 karma

Gary here - This is a fantastic and challenging question. There is strong evidence that the diet we chose to eat throughout our life affects aging and frailty, however, this can not be disassociated from other lifestyle factors such as exercise, smoking, sunlight and vitamin D and alcohol. All evidence suggests that eating a healthy diet reduces the risk of frailty. Also if you are frail then what you eat is really important, you need a diet that meets all your nutritional needs and you need to try and do as much resistance exercise as possible.

Timesmyth5 karma

How far off are we from being able to take a pill that completely replenishes the gut microbiome?

Why are premature babies and babies born via cesarean section not yet immediately given probiotics to make-up for the lack of exposure which full-term and vaginally-birthed babies receive?

ImperialCollege8 karma

A long way off for now, but Fecal Microbiota Transplantation is close.

Why are premature babies and babies born via cesarean section not yet immediately given probiotics to make-up for the lack of exposure which full-term and vaginally-birthed babies receive?

Great question, and it is more of what is the local practice in the pediatric ward. So countries' standards of care does include regimes of probiotics, usually bifidobacterial species, as soon as they can to help the baby's gut. However, some places also give antibiotics routinely to prevent lung and gut infections, and these can wipe out any probiotics, So it is a balance between the different treatments in the ward.

whatevenisthis1234 karma

A very simple question but: What are your opinions on the ketogenic diet?

ImperialCollege13 karma

Gary here - I assume that you mean for weight loss? If it is it is one diet of many that can decrease weight in the short term. There is no real magic, it is a method of reducing energy intake. However, most people find it difficult to follow over a long period of time so the long-term success is not good. If you are trying to lose weight you need a method you can follow for the long term .

Professor_squirrelz4 karma

Is there any proof that the carnivore diet is beneficial to some people?

ImperialCollege31 karma

Gary here - thanks for your question. Human physiology is such that it can survive some very extreme diets of short periods of time. However, given our longevity, 80 years plus, all the evidence suggests that a high meat based diet is unhealthy. However, in other species a carnivore diet is essential for survival e.g. cats

rjcarr3 karma

So many people think 2000 calories of butter is the the same as 2000 calories of sugar cubes, often citing “thermodynamics”. Can you explain how this isn’t true, how we aren’t burn calorimeters, and there’s more to it then just caloric energy? Or maybe I’m the one that’s wrong?

ImperialCollege5 karma

Gary here - I am afraid that they are the same and thermodynamics rules. However, what does make a difference is the signals that nutrients produce that many affect physiological processes like appetite regulation. For example, 2000kcal of high fibre carbohydrate will increase appetite suppression so you may not eat as much later in the day.