Feeding Your Microbiome: Dietary Strategies for Wellness and Disease Prevention (Transcript)

And you don’t need to have any strong background in organic chemistry to understand these. But I basically wanted to show that glucose, AKA sugar, what is in a can of Coke, has this simple ring structure. And this goes directly into the bloodstream.

Fiber, however, as you can see, these little rings of sugar are actually cross linked and connected via these little bridges. And these bridges are quite unique to the way that plants store these carbohydrates. And some of these are not actually broken down by the carbohydrate enzymes that I mentioned earlier that our genomes have. And we require bacteria to break these bonds and to slowly release the energy that then will feed us as well as our microbiomes.

So again, this is the difference between drinking a can of Coke versus eating oatmeal is that this fiber in this instance of beta glucan fiber will be present and as it travels through our small intestine will inhibit the absorption of other forms of sugar in the small intestine. And then when it gets to the colon, will be processed by the microbiome to promote microbiome health and to promote beneficial metabolites in our bloodstream.

Types of Fiber in Nature

And then I just wanted to run through, you know, depending on how these rings are connected, there are six sides of the ring and it can connect in any sort of linear formation or branched formation, depending on which side of the ring that it attaches on. And so you could imagine that in nature, there are many, many types of fibers depending on the linear and branched chain structures, potentially thousands of different types. And when we eat a food, what we’re eating is actually all of the different fiber types contained within that food. The cellulose in the cell wall, beta fructans, galacto oligosaccharides.

I just wanted to give an example of what these different fibers look like and what types of foods have them. So for instance, the beta glucans, as I mentioned, were high in oats, also found in mushrooms and whole grain rice. These galacto oligosaccharides are enriched in lentils, beans, chickpeas, and xyloligosaccharides are in more roughage such as bamboo shoots, corn cob and sugarcane. Then we have the pectins, and this is what is on the surrounding of an apple. Resistant starch, which I’ll talk about a great deal later, is found predominantly in foods such as unripe bananas, oats, beans and potatoes. Then we have galactomannan and arabinoxylans.

The Importance of Fiber Diversity

So these are all different types of fibers. And I think the important thing, if you can take away one thing from today other than our microbiome loves fiber, is that the value and the real key to eating a whole foods is that it contains a diverse array of fiber types. We don’t have any supplements that are available right now that have a diverse array of fibers to promote the microbiome and particularly are in a vehicle that delivers them to the colon.

Whole foods are really the perfect supplement because they have a diversity of fiber types. Really, we have evolved so that when we eat a food, that that fiber is delivered to our colon in its ideal form.

So really, the best way to promote microbiome diversity is to eat whole foods because they harbor a diverse array of fibers within them. And each member of our microbiome actually has a specific set of fiber types it is able to use. And it’s like a community. Each feeds on a separate type of fiber, and with a diverse array of fibers, the community really optimally thrives.

It’s also worth mentioning that some fibers are more readily fermented than others, and it really refers to the speed with which they’re fermented. Some of you might feel when you eat a high fiber diet that you have side effects such as bloating or potential gas. And this may be that you’re eating too many types of fibers that quickly ferment and you want more slowly fermenting fibers. And we can discuss that later.

Understanding Resistant Starch

And I wanted to take a step back and just talk about resistant starch. There’s a lot of data emerging that resistant starch is a potent microbiome stimulator. And I just wanted to tell you a little bit more about resistant starch.

So there are many types of resistant starch. I’ll be discussing four of them today. And essentially, resistant starch is the type of carbohydrates that are tightly packed in a plant, usually in a plant seed or some sort of storage vessel like the root within a plant.

And resistant starch type one is actually physically inaccessible due to the cell walls and protein matrix. So this would be like if you were to eat like a seed or a nut or raw corn off the cob. It’s basically an unprocessed grain.

And then what happens as we then grind flours to make them more processed or even cook it, what happens is that these carbohydrates then break out and the degree to which we cook foods really determines how resistant the starch then becomes. And if you cook, for instance, rice and you cook it for a long time, and then you actually let it cool down and put it in the fridge, what will happen is all of that carbohydrate that has then been liberated will actually recrystallize into a form called retrograded starch. And this is type three starch.

This example of this is cooked and cooled potatoes, rice or pasta, which I’ll talk about in a little bit. And then the fourth type of resistant starch is essentially a type of processed food. It’s a processed fiber. It’s a chemically modified starch that generates new molecular structures of starch, thereby increasing its resistance to amylase. And amylase is something that our pancreas secretes.

So essentially, in theory, if one were to take, for instance, a pasta and cook it, and if your pancreas secretes a lot of amylase, a lot of that will be absorbed in the small intestine and not all of it will reach the colon. Only the resistant starch portion will reach the colon.

The Structure and Function of Starch

And then I just really wanted to reiterate the structure of this. So this is actually what all of these carbohydrates look like when they’re packed in. You saw a single glucose molecule earlier was just that free floating kind of six structure. And if you were to connect it all together, it would create this ring. And you see in A, there’s this reducing end. So actually, the bacteria and independent of our amylases, our bodies can really only use the sugar that’s at the distal end of this huge chain.

What happens when we eat this is that our bodies then take over our entire small intestine and actually our colon to digest it. So I really want to also stress that not all carbs are created equal, that eating these starchy vegetables does not mean that you’re eating a lot of sugar as sometimes you may hear online and particularly some influencers would suggest.

But actually, this causes a slow release of sugar across your entire small intestine, and then most of it reaches your colon and is actually feeding your bugs.

One thing that’s interesting about starch, it’s the most abundant biomolecule on earth after cellulose. It’s the major carbohydrate reserve in plant tumors and seed endosperms. So this is something that’s very common and something that we’ve highly evolved to consume. It’s really what our GI tracts over the last 10,000 years have evolved and our microbiome has evolved to consume.

And these linkages, as you see in B, when they measure them, they can actually be up to 10,000 carbohydrates long. So this is essentially due to the reducing end limitation. It’s about one ten thousandth of the bioavailability of sugar.

Comparing Simple Sugars to Complex Carbohydrates

And so I really wanted to stress this. When you consume a can of Coke, has 39 grams of sugar in it, you’re just consuming 39 grams of this easily accessible glucose that will go directly into your bloodstream.

When you have, for instance, an einkorn whole wheat spaghetti, it may seem like quite a bit of carbohydrates. Two ounces of this pasta might seem equivalent to a can of Coke. But by the way it’s absorbed and stored, actually, this is very tightly packaged. And a lot of this, even with cooking the pasta, doesn’t come unwound. And this is delayed in its absorption across the entire small intestine.

The Power of Whole Foods vs. Simple Carbohydrates

DR. SEAN SPENCER: Actually, forty grams of this starch, five grams of it is fiber that your body is unable to absorb actually. So this is five of that gram is actually being eaten by your microbiome. So if you are having a can of Coke, all of it gets absorbed into your bloodstream and none of it is available to the microbiome in your colon.

Whereas if you were to eat an equivalent carbohydrate load of a whole wheat spaghetti, actually five grams of that is going to go into your colon to feed your microbiome. Most of this, because of its linkage, is going to be delayed in its absorption across the length of your small intestine and even into your colon.

And this is the importance of eating whole foods and foods that have fiber in them. So I want to convey that carbohydrates are not your enemy. They’re actually your friend and they’re your microbiome’s friend. And most of the carbohydrates that exist at the grocery store or at restaurants are in the form of simple carbohydrates.

But if we focus on eating plant-based carbohydrates that are in their native plant matrix, actually, come with a lot of fiber and that they’re delayed in their glycemic load, and they’re really going to not cause that spike in blood glucose.

Thus, we should aim for complex carbohydrates that slow digestion and feed your microbiome. Sugar, on the other hand, does not feed your microbiome and will go directly into your bloodstream, leading to a glucose spike as well as an insulin spike.

The Truth About Leftover Pasta and Rice

And in reference to the type three resistant starch, you may have seen this article that was widely circulated from The New York Times last year, around this time, saying that “pasta and rice may be healthier as leftovers. Here’s why.” And this may be true because of what I’ve told you.

And I wanted to dig into the data from the original publication that this New York Times article is based off of, in particular because you’ll notice that they display a large amount of white rice. And this is extremely misleading based on the data.

So if you look and what this was, this was a review of measurements of resistant starch in foods in published works over the last forty years. And so if you see here, pasta that’s cooked and then pasta is cooked that then chilled actually reduces its resistant starch. So you’re not getting any benefit here.

However, if you were to move to a whole wheat pasta and, you cook it here, it has 1.2. Actually, when you chill it, it increases to 3.4. So you really want to strive again for these whole wheat products and the non-processed carbohydrates.

You can see this white rice here. When it’s cooked, 1.4 of resistant starch, and then when it’s cooked and chilled, 0.9. So we’re not really seeing the benefit with white rice or with pasta. It’s really the whole wheat.

Potatoes, on the other hand, in any form seem to be able to contain a large amount of resistant starch and it’s increased with cooking and chilling. So here you get 3.1 per gram and sorry, grams or one hundred grams of food, and then it goes to 4.3 when cooked and chilled. So again, I want to stress eating whole grains and whole foods is important.

The more purified the food, the less resistant starch it has in it and the less benefit you’ll get from cooking and chilling it. Other foods that have a large amount of resistant starch, you see bananas, unripe bananas in particular have a good amount. Semolina, just cooked, actually has a large amount. And the legumes, which are powerhouses for your microbiome, have a really good amount within them, particularly lima beans, black beans, and chickpeas.

The Fiber Gap: A Critical Health Issue

So I’ve mentioned a lot about the theory around fiber, and I wanted to go over some of the data and the epidemiology of fiber consumption. So the USDA and the Institute of Medicine recommends 26 to 38 grams of fiber intake daily. However, the standard American diet and the average fiber consumption in the US is 10 to 15 grams.

So that’s well below, and there’s about a 10 to 15 gram called the “fiber gap” to make up the difference between these. And only five percent of men and nine percent of women are getting the recommended daily amount of fiber. This is shockingly low, given the recommendation of 26 to 38.

And from evidence that we have over evolutionary time, about four hundred years ago to one thousand years ago when we were hunting and gathering and really before wide scale agriculture, there’s evidence that we were consuming up to 100 to 150 grams of fiber per day.

So 26 to 38 grams may be on the low end of what evolutionarily we were consuming. And certainly, 10 to 15 grams is exceptionally low, probably lower than evolutionarily we were made to consume.

Fiber’s Impact on Mortality

So what happens when you look at fiber consumption and how it relates to all cause mortality? So essentially, this meta-analysis that was a review of 185 prospective studies and 58 clinical trials found that a 15 to 30 percent decrease in all cause mortality with sufficient fiber intake.

So if you look at those that were actually consuming adequate amounts of fiber, they were 15 to 30 percent decrease in all cause mortality. And there was a similar trend for cardiovascular related mortality, coronary heart disease, stroke, type two diabetes and colorectal cancer.

And you can see that with more fiber intake, it looks like it’s almost a linear trend. So, as we go beyond the recommendation, if you were to get into the 40 or 50 grams, there may be a linear and even greater benefit at higher levels of fiber intake.

Simple Solutions to Close the Fiber Gap

And what would it take to close that fiber gap? And I just wanted to give a visual demonstration of what 10 grams of fiber is. So this is 100 grams of oats, so just a cup of oats that one could easily have in the morning. And the other thing to mention about oats is that actually this amount of oats has 13 grams of protein.

The advantage of plants and whole foods is that they actually come with a lot of protein in them as well. So in these oats, are getting quite a significant amount of carbohydrates. But as we discussed, they’re complex carbohydrates with delayed absorption, comes with a significant amount of protein, and just this addition of a cup of oats a day would close the fiber gap.

And then if you’re feeling particularly interested in taking your game to the next level, what I recommend to patients when I see them in clinic is actually to take their oats, to add a tablespoon of flax seeds, an ounce of chia seeds, a cup of walnuts and a cup of blueberries, resulting in essentially your entire daily value of fiber. So you can get 26 grams of fiber in this.

And the advantage of mixing in additional sources of fiber and diverse types of healthy fats is that it will further blunt the glycemic index of these oats, and so it won’t be absorbed as quickly.

Ultra-Processed Foods: The Anti-Fiber

And how about ultra-processed foods, which have become all too common? So I like to call ultra-processed foods “the anti-fiber.” And there’s a lot of data to suggest that just like the benefit of fiber for the microbiome, ultra-processed foods actually damage the microbiome and are harmful to the microbiome.

So ultra-processed foods comprise 57.9 percent of energy intake in the US. And we can just pause and reflect on that. That means almost 60 percent of the total calories consumed in the US are in the form of ultra-processed foods. These aren’t processed foods. These are ultra-processed foods.

These are typically foods you look with more than 10 ingredients that often take the form of something not even recognizable as food. And this is almost 60 percent of the calories in the US.

So ultra-processed foods appear to reduce microbiome health independent of the lack of fiber. And this is through the use of food colorants, emulsifiers, artificial sweeteners, nanoparticles like titanium dioxide. These can actually be directly toxic to beneficial members of the microbiome.

And we have this data largely from preclinical studies in mice and direct exposure of microbes to these substances, but also fairly compelling epidemiologic data as well.

So you’ll see the line goes the exact opposite way of fiber. A higher consumption of ultra-processed foods, more than four servings per day, was independently associated with a 62 percent increase hazard for all cause mortality. So for each additional serving of ultra-processed foods, all cause mortality increased by 18 percent.

And again, you see this appears to almost be linear. So more processed food is worse for your health. And this is the exact opposite of fiber. So I think what these two epidemiologic studies suggest is that if we were to take even a small portion of the ultra-processed food calories that we’re consuming and simply replace them with whole foods containing fiber, I think we would see a massive benefit in our patients’ health and in your health.

The Obesity Connection

So what happens when we don’t get enough fiber? So you see here, this is a map of self-reported weight and height among U.S. adults. Essentially, this is just a map of where we currently stand in terms of obesity in the US. You see these dark reds mean that over 40 percent of the population in these areas is overweight and has obesity.

And even in some of the yellow areas, you’ll see a quarter of the population in these areas are overweight and have obesity. And it is highly likely that the decreased dietary fiber and increase in processed foods is a major contributor to this obesity epidemic. In fact, I would hypothesize that it is the major contributor to this obesity epidemic.

The Microbiome’s Role in Weight Management

And what about the microbiome? As I told you, fiber is so important for the microbiome and processed foods potentially and likely damage it. So is a lot of this effect being mediated through the microbiome? And there’s a mounting evidence base to suggest that this is possibly the case.

And one of the first threads of evidence for this was actually in a preclinical study looking at what’s called a fecal microbiota transplantation. So essentially, you take the poop from one animal and then you put it into another animal to ask if they’re eating the same thing, can the microbes then change the organismal phenotype?

So essentially, if you’re taking two mice that are eating the same thing but have different microbes, does their weight gain differ? And this is exactly what was done in this groundbreaking study from now almost twenty years ago.

So what they did is they had mice with a genetic lesion. And this is a genetic mutation that happens in humans that lose the leptin gene. And essentially, leptin regulates appetite and fat storage. And without it, mice eat, overeat and don’t regulate fat storage and become significantly overweight.

But the real groundbreaking part of this experiment was when they then took the microbiome from these animals that were genetically different and they transferred them to mice that were genetically identical. They transferred either the lean microbiome or the obese microbiome to genetically normal mice that had no microbes. They were germ free.

And essentially, the question was, if these mice eat the same thing and have the same genome, what happens to their weight gain if they were to get the obese FMT? Do they then become obese? And if they get the lean FMT, do they then stay lean? And this was the case.

So if your donor is genetically normal and lean, you will then have a normal increase in body fat over the course of the experiment. However, if you have the microbiome from an obese mouse that has this genetic lesion, independent of the genetic lesion, the microbiome can actually cause you to gain twice as much weight as compared to the control mouse.

And so this was shown to be due to the microbiota of obese mice having increased capacity for energy harvest and transfer for the host. So they’re actually taking a lot of the energy and then telling the host to absorb it. Whereas, as I’ll show later, a healthy microbiome processes the energy and then actually uses it for synthesis of bacteria, and then a lot of it is lost through the stool.

Evidence in Humans

And so as a physician scientist, I think that preclinical studies are great, but it’s always nice to see something in humans. And this was a case report that came out. Fecal microbiota transplants occur in humans, and they’re used as therapies for an infection called C. Diff diarrhea.

So it’s been known for a long time that if someone suffers from this condition, if you administer a healthy microbiota, the infection will dissipate and go away. And in 2015, there was a case report where before we had standardized stool banks, someone received an FMT from a relative. And that relative actually had an excessive weight and had an elevated BMI.

Soon after receiving the stool for treatment of this infection, the recipient of this stool then had a BMI that matched the donor, showing that this likely doesn’t just happen in mice. This is potentially happening in humans as well. And after that, now the donation criteria for stool includes that one must have a BMI under a certain value.

And so this was all very exciting when we saw these mouse studies that potentially the thought was that if you were to take a lean microbiome, that you could then use it as a treatment for those with metabolic syndrome. And in some early clinical data, there was a hint that this may be the case.

And so here you see from this study in 2012, they were looking at insulin sensitivity. If you give a lean microbiome, can you then prevent metabolic syndrome and essentially cause the recipient to have more insulin sensitivity? The opposite of diabetes. Diabetes is insulin resistance. This would be reducing that. So promoting insulin sensitivity.

Fecal Microbiota Transplant Studies and Fiber Supplementation

And what you see is that in one of the groups here that got the lean donor, they actually increased their insulin sensitivities significantly, suggesting that this is undoing some of their insulin resistance. And to be honest, it was significant, but it was not a biologically significant effect. You wouldn’t want this as a monotherapy for treating your insulin resistance.

And what would happen if you combined this fecal microbiota transplant with fiber? And that was one of the next trials that was performed.

So essentially, what they did is they took a FMT and then they administered it in the setting of fiber supplementation in patients with severe obesity and metabolic syndrome. What they used is they used a low fermentable fiber at the time they thought was low fermentable cellulose and then a high fermentable fiber, soluble corn fiber, and resistant wheat starch type four. So this is the chemically modified processed starch and then acacia gum.

And what they found was actually fairly unimpressive, and they could increase again the insulin sensitivity. But it was only in the FMT group that got the lower fermentation fiber. So they had higher levels of GLP-one, lower insulin levels and increased insulin sensitivity. So still, a lot of people are trying this, but it does seem that just giving an FMT in fiber alone is really not going to be the game changer here. So still a lot in development.

And then this is another FMT trial where they, after bariatric surgery, gave an FMT. And the microbe transfer after bariatric surgery didn’t change the weight loss. So no change in weight loss here.

Promising Results with Type Two Resistant Starch

And then I wanted to show some more encouraging trials. So there was a recent trial that was published just this spring looking at type two resistant starch. So this is a different type of starch that had been tried before. And again, this is the type of starch that’s found in green bananas, in corn and some potatoes.

And what they did is they delivered forty grams of this. So they didn’t do anything else other than tell the patients to consume forty grams of this fiber every day. And then they did a washout and actually it was a great clinical trial design because they did a crossover where each patient was their own control. So they energy matched. And so each patient had a control phase and then a resistance starch phase.

And what they found was quite exciting that in the resistant starch phase, that each patient tended to lose weight. And in the control phase, each patient tended to have a slight increase in weight. And a lot of this was fat loss and particularly abdominal fat loss, the type of fat that we think is particularly that particularly drives insulin resistance.

And where did this where do these calories go? And what they found is that this actually was causing a fecal fat loss, that this resistant starch by feeding our microbes in our intestine was actually causing some of the fat in the diet to actually come out in the stool. This is about two hundred kilocalories per day, which equates to about twenty pounds per year.

And this adds up with what we know with the current trends in obesity, that it would make sense that if we have adequate amounts of fiber, that potentially two hundred calories per day would come out in our stool, and that would equate to about twenty pounds per year of total fat loss or, I guess, fat prevention.

The Microbiome Enhancer Diet Study

A very similar study came out in 2023 where they actually created a diet called the microbiome enhancer diet. So they tried to create essentially the perfect diet for the microbiome and feed it to people to see what happened.

And they say in the article, “The microbiome enhancer diet was high in fiber and resistant starch, which are known substrates for microbial fermentation. They also provided larger food particles, old nuts versus nut butter, for example, because food grinding of foods make nutrients more bioavailable to the human host and less bioavailable to the gut microbes. One final element of our diet was minimizing processed foods.”

So I think there you have a good map of how to optimally feed your microbiome: high in fiber, whole foods, large food particles and minimizing processed foods.

And what did they find? Again, they found that when they look at the stool, there was more calories in stool. And essentially what this is, it means that you’re feeding your bugs rather than feeding yourself. So you’re creating this thriving community within you that is actually sharing all of your food with you, and you’re feeding not only yourself, but your microbiome.

And this shows that when you feed your microbiome, more of your calories come out in your stool as you foster this healthy community inside of you. And because of that, the metabolizable energy here is then decreased anywhere from five to ten percent.

The Evolutionary Advantage of Feeding Our Microbiome

And as I said, the key to doing this, why you would make this sacrifice, evolutionarily, losing calories in our stool was not to our advantage. So there must be some advantage to this. And there actually is an advantage because you’re telling your microbiome and helping your microbiome make these beneficial metabolites that then enter circulation. They reduce inflammation. They promote stem cell function. They promote healthy organ systems throughout your body.

So the sacrifice that we make in reducing our energy intake to us actually in turn promotes our microbes that then make these small metabolites that don’t give us energy, but they instruct our physiologic systems how to behave, reduce inflammation and really allow us to be healthy. And this is what happens when we feed our microbiome.

You see these short chain fatty acids increase, and particularly butyrate, which is known to be a potent molecule that helps feed our epithelial cells of our gut and reduce inflammation, is increased. And again, they find something very consistent. It’s about two hundred calories per day in stool, about twenty pounds of total fat loss per year.

And the participants actually and encouragingly didn’t lose a significant amount of weight. They’re losing, some of them did, but in large part, a small amount of weight loss over the course of the study. And the other thing is when they look at satiety hormones, the microbiome diet actually increases satiety.

So if you’re eating a microbiome friendly diet, you’re going to feel more full. You’re going to feel more satisfied. This is not just a diet that we have to sacrifice our well-being to feed our bugs. This is a diet that’s going to be delicious and feeds our microbiome and makes us feel more satisfied after we eat. Also worth mentioning, there was a trend towards more GLP-one in these trials as well.

Comparing Western Diet to Microbiome Enhancer Diet

I wanted to give you an example of what the Western diet looked like and what you might want to add to your diet to follow this microbiome enhancer diet.

As you can see, the Western diet is grape juice, Rice Krispies, a little bit of sugar on top, white bread with margarine, and reduced fat milk. It sounds like a pretty typical standard American breakfast, but a microbiome enhancer diet. We had raw blueberries, steel cut oats, water, still a little bit of sugar. You can add a little bit of sugar as long as it’s in the appropriate context. Whole nuts and then lemonade. We still drink lemonade, but again, they added this type two resistant starch to it, a potent microbiome friendly starch.

Then for lunch, the Western diet, lettuce, salad dressing, white bread, pickles. We have some corn puffs, turkey breast, and then some cheese. Sounds like a pretty typical lunch. And for the microbiome enhancer diet, we have squash, cheese, raw spinach, tomatoes, oil, salad dressing. So it sounds like a salad. But the white bread is switched out for rye bread. And then we have a little bit of lentil soup that has the cornstarch mixed in, barley and carrots. So again, you see the whole foods working their way into the diet and then more of the lentils and the cornstarch.

And then finally, for dinner, we have a lean beef. We have some Italian sauce, some spaghetti, cauliflower. We have a lemonade drink, chocolate pudding, dinner rolls. Sounds again pretty typical. And the microbiome enhancer diet still has a little bit of beef in it. Same Italian sauce, cheese, spaghetti, dinner rolls, butter. But again, you’re adding in raw strawberries and then peas. These little bit of things that you can add into your diet will really help your microbiome.

And again, these dinners don’t seem that different. You’re just doing small substitutions here, adding in a little bit of raw strawberries and throwing in some peas on top of your pasta. So even these little changes, as you see, can have big effects.

Key Takeaways

So what are the take home points? That there’s an emerging evidence that excess weight and metabolic dysfunction is likely caused by two key environmental factors, your diet and your microbiome. And going forward, we’ll likely need to target both as a prevention and treatment strategy. But it’s still unclear how to exactly target the microbiome, and the best we have for now is to eat a diet, as I’ve just described.

And microbes that promote or protect from weight gain and metabolic dysfunction are still not clear. And it’s also very likely, almost certain, that we can’t rely on microbes alone, that the diet is going to be key and particularly fiber. You have the right microbes. They won’t live inside of you for any period of time unless you’re feeding them with fiber.

So even if we were to give people the ideal microbiome for it to persist within them, they would have to feed it and they would have to feed them those microbes fiber throughout their entire life. So it’s likely that you need the right bugs and the right diet. But it appears that in most people, the right diet really can be key.

Emerging evidence suggests that some fibers are particularly effective to positively alter energy balance. Resistant starches emerging as a really potent one. And the key advice that I give to patients, there are a lot of fad diets out there and a lot of apparent conflict within the literature. But I think almost every diet can agree that eating whole foods with large particle size, particularly nuts, fruits, and beans, are beneficial. And avoiding processed foods and added sugars is really one of the keys to a healthy diet.

Future Directions in Microbiome Research

And what is on the horizon? So as scientist, I’d like to give you a preview of what we’re working on and what we hope to have some point in the future. I think it would be great if we knew how to rationally manipulate the microbiome with specific fibers, likely plus bugs.

We’re at a point in microbiome research when we can culture all known bacteria in the human microbiome. So a popular myth that sometimes is perpetuated is that a lot of these bugs we can’t culture. As a matter of fact, we can culture nearly all bacteria in the microbiome now, and that means that we can administer them as therapeutics.

So we’re learning which bugs consume which fibers, and it’s likely that in ten years, diet plus microbes may be the first line therapy for treating overweight individuals and really will be a key for preventing weight gain in all patients. These substances may be over the counter and able to be purchased and consumed even without interface with medical practitioners.

Understanding Probiotics and the Biotic Spectrum

And so this all brings me to kind of what is a probiotic, because you may think, if we’re talking about these specific bugs and giving them that it would be a probiotic therapy. So I wanted to talk a little bit about the language around probiotics and what an optimal probiotic may be in the future.

So probiotic, in its current form, are live microorganisms, which when administered in adequate amounts confers a health benefit on the host. So these are essentially any live organism that we take that confers some health benefit.

To break out into the larger sphere of biotics, I mentioned prebiotics briefly earlier and probiotics. Prebiotics are substrates utilized by host microorganisms conferring a health benefit. These are fibers. Probiotics, as I mentioned, are live bugs. Postbiotics are actually killed bugs that still confer a benefit largely through direct action on the immune system. And a symbiotic is a mixture of live microorganisms and substrates selectively utilized by these organisms.

And I think this is really what we’ll move towards in the future, is having a mixture of live organisms that we know will engraft persist and that you can feed with certain types of fiber or different types of food in your diet.

Current Limitations of Available Probiotics

And so what do we have now? Most strains of probiotics were developed for their capacity to resist gastric pH and produce lactic acid. These are the bifidobacteria and lactobacillus. But currently available probiotics are not selected for fiber use. A lot of these symbiotics that are currently marketed are not the types of selected fibers that you would want and don’t really engage in the full diversity of fibers. And the evidence that those bacteria that are packaged with it use those fibers is quite limited.

So I just wanted to stress that traditional probiotics are a small portion of the human microbiome. So if you take a human microbiome and you look at what component of it is Bifidobacterium or lactobacillus, it’s on average about 0.01 percent. That means that 99.99 percent of the remaining human microbiome really remains untested and unadministered outside of FMT trials.

So what I want to stress is that the future here largely remains uncharted and has extreme potential and much different from the current probiotics that we have available. So that’s a key point that I wanted to convey. I also wanted to convey that the current probiotics that we have are largely clinically untested, clinically unvalidated, and the medical evidence to support their use is largely lacking.

Probiotic Regulation and Clinical Testing

And why is this? It largely has to do with how they’re regulated. They can be sold as supplements, and there’s no incentive for them to be clinically tested because testing things clinically is very expensive. And that is why when you go to a physician and for any typical diagnosis, we’re not writing prescriptions for probiotics largely because they’re untested and not made through the same regulatory pathway that drugs are. And I’m not trying to argue that bacteria should be drugs or we should write prescriptions for them.

I just wanted to stress that the incentives for clinically validating them are misaligned with the ability of companies to make profits from these probiotics without testing them rigorously or validating them. The incentives are really misaligned at present, and hopefully we can figure out ways to more closely align those, because I think going forward we will have more effective probiotics.

The thing I wanted to test that to say, though, is because they are untested, we don’t really understand their benefit fully. We also don’t understand their risk fully. And this is why when you test a drug, you are both trying to understand if it’s effective, but also if it’s safe.

And I think because of the lack of rigorous clinical evidence, some probiotics are emerging as potentially carrying significant clinical risk that I think as providers, we need to become more adapted counseling patients around.

The 2019 Antibiotic-Probiotic Study

So I wanted to discuss these. Essentially, one of the canaries in the coal mine was a study in 2019. And as we know, even as some society guidelines in medical practice are when you take an antibiotic, that you should take a probiotic afterwards to support your microbiome. But this evidence or lack of evidence is largely due to anecdotal reports and not based in sound microbiome science.

And when a group actually sought to test, if you take antibiotics and then follow-up by probiotics, what happens to your microbiome? Is it actually improving your microbiome? And they compared this either to a placebo or to an autologous FMT. So this means that if you were to just take your poop, bank it, take your antibiotic, and then just take your poop back, would that be the best strategy?

And so what they did here, they took the participants at baseline, they gave them antibiotics, and here they either gave the microbiota transplant collected from before to the same person, They gave them probiotics for 28 days or they did nothing, as is most common.

And then they followed over the course of time how the microbiome repopulates. And as expected, here we’re looking at observed species. So this is the diversity of the community. And during the time they took antibiotics, you plummet in microbiome diversity because antibiotics are killing your microbes and they’re vanishing. And the key here is to look at how quickly it recovers in the days after.

If you were to take an autologous FMT, so have your microbes from essentially the brown line here, give them back, At day five, you’re back to normal. If you were to do nothing, you dip and then the recovery back to normal takes about three months. If you were to take probiotics, you see you stay quite low for the five days after, persistently low to three months. And then if you look out here, after a couple of months after that, persistently low, suggesting that probiotics reduce microbiome recovery after antibiotics, potentially permanently.

And I think one of the issues and why this hasn’t been more apparent earlier, we haven’t had the technology to measure this. No one has wanted to measure it. And the microbiome is not considered a clinical endpoint at this point in time. We don’t have physicians that monitor microbiomes. We don’t have physicians that treat microbiomes. And I think in the near future, we will have physicians that do both. And I hope to become one.

Probiotics and Cancer Immunotherapy

The other line of evidence that probiotics may carry risk is in the setting of cancer immunotherapy. And this was a study that was done quite recently in 2019. What they did is they just surveyed patients that were getting cancer immunotherapy for melanoma. So this is a newer therapy, and it’s basically a therapy that blocks the brakes on the patient’s immune system so that enables them to fight their own cancer and their immune system to defend themselves.

And what they found was that when they surveyed patients, patients were taking probiotics, it was linked to a 70% lower chance of response to immunotherapy. This was very common. 42% of all patients reported taking over the counter probiotics. Probiotics were linked to lower microbiome diversity, previously shown to associate with poor responses. Conversely, patients eating high fiber diets were five times as likely to respond to immunotherapy treatment.

So here you have what appear to be a conflict against fiber and probiotics. Probiotics are inhibiting cancer immunotherapy and fiber is enhancing it. But how do they compare when mixed? And this is potentially the most striking figure from their paper that was ultimately published in 2021.

When you look at survival probability so again, this is a very significant graph. These are patients that are living because they’re eating fiber. Dramatically different survival outcomes when they’re eating fiber and not taking probiotics. And then in this, it’s no fiber, no probiotics, probiotics. Or included in here are people that are eating adequate fiber and taking probiotics. So probiotics seem to be a dominant negative over fiber.

So here really showing that fiber alone is beneficial and that taking probiotics can inhibit it.

Dr. Spencer’s Recommendations

So what are my take home messages and what do I recommend? In terms of prebiotics, yes, best in the form of whole foods, maybe to purified fibers. Psyllium husk has good benefits. It’s a non fermentable fiber that tends to promote GI health and bowel movements. And then in terms of your purified fiber for fermentation, resistant starch seems to have the best evidence to support its use. So maybe. Again, I think Whole Foods are winning.

Probiotic, so the live bugs. I’m going to say no slash maybe. It’s really an evidence free zone, so it’s really hard to say. But I think particularly the purified probiotics and the high dose are a likely no. I think a yes to probiotic containing foods.

The key here is that when you measure probiotic levels in yogurts or in fermented vegetables, they’re in the 100,000 to one million range. Whereas if you look, there’s the temptation to go to a grocery store and buy the highest dose probiotic. Indeed, they’re advertised based on their potency and their high dose. So you’re taking billions and billions, potentially even trillions of live probiotics. And that is much, much higher, potentially even a thousand to a 100,000 fold higher than are in fermented foods. So I think the amount of lactobacilli and bifidobacteria in yogurt and fermented foods is probably the amount that that we’ve evolved to to ingest much lower amounts.

How about postbiotics? I think that, again, fermented foods are shining here. They contain a ton of postbiotics, both inanimate microorganisms as well as metabolites. And I think if you’re looking for a postbiotic, fermented foods are probably your best bet. So really, whole foods and fermented foods are really going to have everything you need. So I would recommend if you’re concerned about your gut health and improving it, whole foods and fermented foods would be the best first approach.

In terms of Symbiotic, I don’t think there are any current formation formulation formulations that are adequate. I think they’re in rapid development, and I think they will be here soon, potentially in the next year to five years. And I think these are going to be where the microbiome diet space will really shine. Think identifying the bugs that can engraft and sharing your diet with an identified fiber or food type to really promote health. And that’s where we’ll be.

And I think that these are going to be more rigorously clinically tested. Now we have the understanding of how they may promote health, be used in the setting of diabetes or to promote metabolic health. And these are trials that will be done in a rigorous fashion.

The Future of Probiotics

So what is the optimal probiotic? Probiotics of the future will be closely matched to our diet and optimized for fiber degradation. Probiotics will not replace a healthy diet, but rather will enhance the health benefits of eating fiber and whole foods. So really, it’s not that it’s one or the other. It’s that by selecting the right probiotics and modulating the microbiome, we can take a healthy diet and make it even healthier and take those grams of fiber that you’re eating and make it even more impactful to promoting your health. And I think that’s where we’ll be in the near future.

Summary and Guidance

So in summary, what are my guidance for promoting a healthy microbiota? As I’ve said repeatedly, gut microbes love fiber. It encourages a better mucus layer, something I didn’t mention today, but is one of the prime mechanisms through which it acts. And current probiotics are less helpful. You should stick to the food and the fiber. Increase fiber in fermented foods gradually. If you have any GI side effects, hopefully they reverse over time by just increasing these things gradually.

And I like to stick with simple directions. I tell my patients who want to help their microbiome eat more fiber, eat whole foods, or just simply eat whole foods. Those are just three words. And I try and aim for recommendation of eating 30 different types of plants in a given week.

There’s some epidemiologic evidence that if you look at microbiomes across the US, that those with the healthiest microbiomes are eating 30 different types of plants per week. And it may seem daunting, the thought of 30 plants, but if you go to the grocery store and start looking around, spices count, sauces can count, you’ll find that it’s pretty easy to get to 30 and some patients who want a challenge even get to like 60 or 100 after that. And it becomes fun because you can go to the store and now you have an objective and you can introduce new types of plants and foods into your diet.

Large particle size is important. You know, raw nuts, whole fruits and beans and avoiding processed foods and added sugars. And with that, I’ll end saving a lot of time for questions. Happy to discuss and answer questions. Thanks for listening.

Q&A Session

NATALIE MARSHALL: Thank you so much, Sean, for that great talk. That was really, really informative, and we have a lot of very good questions. One question, there’s several questions about glycemic index and carbs. So one question is, can taking the fiber supplement before a sweet dessert have the same effect on lowering glycemic index?

DR. SEAN SPENCER: Yeah, and I think one of the keys is that the optimal time for a sweet dessert may be after a meal. If you’re looking, if you’re hungry around three or four pm and you’re grabbing a sweet snack, I think that’s very different than if you were to have a sweet snack after dinner. I think there’s a lot of evidence that the food matrix with which we’re ingesting things matters a ton.

So, yeah, I think I’m not a strict puritanical about this. I think we should eat sugar. It’s one of the pleasures in life, but I think timing of sugar and amounts of sugar is very important. I think that’s a very good point that eating after a meal should lower the glycemic index of it.

NATALIE MARSHALL: Know, kind of going on that glycemic index question, there’s a question about a patient who’s been eating no processed or refined sugar, used to eat organic cooked oats with flax and blueberries and strawberries, and then was told no, can’t have oats or potatoes or bananas. So she’s really confused, and I think there’s a lot of bad information on the Internet about how carbs are the enemy. And I think you talked about resistant starch and maybe that would be a way to enter that and the answer to that question.

DR. SEAN SPENCER: Yeah, and I think there are The thing that I didn’t mention is that there are foods that could be a potential mismatch with your microbiome. We don’t have any diagnostic tests for this, but you tend to know if that’s the case. If you eat a food, you don’t feel well after you eat it, then I don’t recommend continuing to eat that food.

I think the thing that I want to stress is that there’s an entire universe of plants and foods. We live in a time when we can go into a grocery store and there’s almost limitless potential of what we can get. And I think that I encourage patients, if they have any restrictions, to explore within the space of your restrictions. But I think that a lot of the books out there and diets saying that oats or certain types of vegetables are harmful, I think that the claims around that are a little blown out of proportion.

But the thing that I want to stress is that the evidence in this space is not robust in either way. I think that is one of the calls to action that I feel strongly about is that as a medical profession, we need to collect this data over the next five to ten years. That’ll be really important.

NATALIE MARSHALL: So there’s a question about reheating chilled whole wheat starches or potatoes like you discussed. If you reheat them, does the resistant starch have a lower glycemic index? Does it stay as a resistant starch? And is it healthier to eat it if you reheat it? Or do you have to eat it cold?

DR. SEAN SPENCER: Yes, you can reheat it. Yeah. Yeah, it should stay because that linear structure because it’s like if you were to reheat pasta, you wouldn’t have to re boil it per se. You would just be warming it in a microwave so that those structures should still stay intact.

NATALIE MARSHALL: There’s a question about what do you think about meat versus soy in the diet and processed meats? I mean, not processed meats, but like the incredible burger, you know, meat substitutes.

DR. SEAN SPENCER: Yes, there’s a ton of ongoing research at Stanford looking at this of comparing different types of meat. And particularly, there’s a study that has come out.

Meat Alternatives and TMAO

There’s this metabolite that’s made from meat called TMAO, and it is thought to be one of the chemical mediators by which meat is harmful and promotes heart disease. When you intake meat, the choline within meat gets transformed by our microbiome to promote this harmful metabolite. And in the study, what they did is they fed people either meat or the impossible meat. And what they found was actually quite incredible. And it was a crossover study, as I suggested, as I alluded to before in that other study design.

And what they found is that if you eat the impossible meat for a period of time and then switch back to normal meat, that actually your ability to make this harmful metabolite is greatly reduced. So there’s still a lot that we don’t know. But I think the key things that I stress in my clinic is that reduction is always good, so I don’t counsel strict avoidance of red meat, but reduce whenever possible. And again, I think mixing and taking breaks in between meat, I think there’s great evidence that this is protective from the negative consequences of red meat production.

So I think it’s not that you should remove meat from your plate. It’s that you should reduce the size, add fiber and then potentially mix that meat with these newer alternative forms of meat. But I think in balance that these meat alternatives are processed foods. But I think as compared to the known ill effects of red meat, they’re probably on balance better or equivalent.

Circadian Rhythm and the Gut Microbiome

DR. SEAN SPENCER: Okay, the next question is how does circadian rhythm influence the gut microbiome?

Very good question. We know that it affects it profoundly, but we don’t quite know what that means in terms of concrete recommendations. We have a ton of evidence from mice, but also in humans that when you’re changing time zones that your microbiome shifts and that the microbiome is very susceptible to changes in circadian rhythm. But I would say the thing that I try and stress is that the physiology of our gut is adapted for meals. So when possible, I think structuring your day around eating meals, particularly whenever you want to choose one larger meal, it helps to place that at some point during the day with two smaller meals and then maybe some snacks in between.

But I do think that one of the factors of our Western existence that I think potentially works against a microbiome is the constant snacking. I think that being a little bit more conscious of planned meal times and the planned snacks in between does have some evidence that it would support gut health.

Inulin as a Prebiotic

There’s a question about inulin. Is it a good prebiotic? Inulin tends to be the most widely sold prebiotic, and there is not great evidence to support its health benefits.

I think there are other fibers that are potentially a little bit more friendly to the gut. One thing about inulin in particular is that it is thought to be the most common offender in terms of bloating and the ill effects of fiber. So I think particularly taking purified inulin, a lot of probiotics are sold with high doses of purified inulin, that it can actually be a source of GI symptoms to be aware of. And I think the thing to also say explicitly is because of this fiber microbiome connect, the way that one person senses and responds to fiber is going be different than another. So if you’re taking an inulin supplement and it makes you feel better, then I think that’s something you should think about continuing.

If you are having GI symptoms and you take an inulin supplement and makes you feel worse, then I think that that would suggest that you should stop it. Or if you’re having active GI symptoms in the context of an inulin supplement, it might be something that you consider stopping. I found that a lot of patients that I see in GI clinic are having symptoms and taking high dose probiotics or purified fiber supplements, and it’s simply by discontinuing them we can eliminate their symptoms.

Antacids and GERD Treatment

The next question is how do antacids interact with the microbiome and do you have suggestions for treating GERD that can be more microbiome friendly? Yes, very good question.

We do have some evidence that antacids can promote increased microbial density in the small intestine, which actually we have some trials that we’re going to perform soon, looking specifically at antacids and how they affect the regional microbiome. So the small intestine as well as throughout the rest of the GI tract. And the answer is that we don’t know in particular, we know that it changes, but we don’t know if that’s a good thing or a bad thing in terms of anti reflux measures apart from antacids. I like alginate based therapies, so this could be they aren’t widely available in the US. You can order sometimes Gaviscon double action or one of the local products around here is called Reflux Gourmet.

It’s made by a chef in Sonoma. And what this does is it just forms a raft with a seaweed base, and then it prevents it physically prevents the acid from coming up. And some patients either adding this to an antacid or replacing an antacid do get some degree of relief. But if this is something that I would encourage you to have a discussion with your GI provider about, if you have a desire to try and get off an antacid medication, they should have some tips and tricks around this.

Fiber for Toddlers and Resistant Starch

So I’m going to combine these two questions. One is how much fiber should a toddler have per day? And then the second one is how do I add resistant starch to my diet?

So toddler, I would say that what we should strive for in toddlers is for them to be eating as many whole foods as possible. I’m not a pediatrician, so I don’t know exact guidelines. I do have a two year old and a four year old at home, and I can say that they are on very high fiber diets and enjoy them and enjoy eating a diverse array of plants and high fiber foods.

So it can be done. And I think that we should be encouraging our kids to eat as many plants as they can. And in terms of resistance starch getting into the diet, I think beans are your best bet. Just try and eat lentils, beans, and that’s going to get a ton of resistant starch into your diet. If you want it in the form of a supplement, particularly if you take a smoothie in the morning, you can buy green banana starch on Amazon.

You just Google green banana starch. You should be able to find it, and then you can just add a scoop to your smoothie in the morning. So there’s a question about how does one obtain the high oh, the RS2 sorry, RS2 starch, and does it change the flavor of foods or just the texture? Yes, so that’s the green banana powder. Yeah, it makes the smoothies a little gritty.

And this is the other thing to recognize is that a lot of the protein powders and supplements will come with emulsifiers to make things not gritty. But what that does is it actually prevents your microbiome from accessing those fibers in a productive way and can actually harm the microbiome. So this is a bit of a tricky thing. Why, again, I think foods are probably your best bet. Try and eat your bananas when they’re a little more green, if you can, or just make a smoothie with a green banana rather than an ultra ripe banana.

But yes, a word of caution. Adding in a scoop of green banana powder to a smoothie does make it a little thick.

Managing High Fiber Symptoms

So there’s I’m going also put these two questions together. What if the high fiber foods cause stomach pain and bloating? How do you ease these symptoms? You did talk about maybe slowly increasing the fiber and then is there a downside to consuming more than the recommended amount of fiber? Can you get too much fiber in your diet? I think those are somewhat connected.

I think if you’re eating one hundred grams of fiber and you’re feeling great, that’s wonderful. If you’re eating thirty grams of fiber and you are having symptoms and it’s too much, then I think it should always be balanced against how you feel.

The goal of all this is to make you feel better. And if you’re having excess bloating or gas, I would encourage you to see a GI provider or talk to your primary care provider as it could be a sign of something else. But I think that is what I’m passionate about moving forward is if you’re eating healthy foods and your gut is not cooperating with you, is there something in the microbiome that we could alter to make these foods a little bit more synergized better with your gut health and your physiology? And I think that’s an area and a next frontier which will hopefully get to in the near future.

Colon Surgery and Digestion

So there’s a question about how does the removal of the ascending colon affect the benefit of a good diet or the process of digestion? And a second question about how do you know if you’re digesting your food properly?

Yes. So if you remove a portion of your colon, there’s still there should still be enough to undergo proper fermentation. So losing a small portion of your colon should be fine. And what was the other question?

How do you how does a person know if they’re digesting their food properly? I suppose, if they’re having symptoms, maybe they’re not digesting properly. I think that’s maybe what they’re asking. Yeah, I think there’s a couple of things that I see in GI clinic. There’s a lot of reports of people that have quick intestinal transit will eat something and then it will essentially come out undigested in their poop, a lot of undigested plant matter.

And that does it can happen normally. But if you’re seeing your food come out in your poop undigested within a couple of hours of eating, that may be a reason to see a GI doctor and get an evaluation. But I think this question of digesting food and optimizing the digestion of food, I think is something that we’re moving towards being able to measure. I think we’ll get there soon. But I think the key is that you should find foods that cooperate with your gut and your physiology.

So experimenting with different types of food to find foods that really cooperate with your personal digestive system is the best approach.

Almond Butter vs. Sliced Almonds

So this next question is you kind of answered it because you said eating larger particles of food. It says asking the difference between almond butter versus sliced almonds and then placing both of these on a spectrum in your Western diet breakfast example. Yeah, I would say almond butter is great. Sliced almonds are better, but that doesn’t mean that almond butter is not great.

I think it’s on the grand scale of things, almond butter is amazing and sliced almonds are even more amazing. So I don’t want to get too in the weeds here. But if you’re striving for absolute perfection, some mix of the two would be fine. You know, nuts are just a great snack. They’re super easy to transport.

When I’m traveling, I always advise patients, you know, constipation can be a big issue with travel because airports are not always a source of fiber containing foods. So just stopping and getting a bag of trail mix that you can take on a plane super stable, doesn’t need to be refrigerated, is really good for warding off any gut health issues that can happen while traveling.

Gluten Sensitivity and Fiber

Can you speak about gluten sensitivity and a patient that’s gluten sensitive and who has arthritis symptoms, could they still apply your tips on fiber prebiotics? I mean, I guess if they’re following a gluten free diet, they could still apply this to whole foods that are just not gluten. Definitely.

There are so many great cookbooks out now. So essentially, there are even apps that you can put in all of your food restrictions and it will pop up a bunch of whole foods and recipes that you can make. It’s a great use case for chat GPT. Artificial intelligence is a really good cooking companion to have. You know, there are so many foods, whole foods that don’t contain gluten.

And there are grains on the spectrum of, you know, there are those that have celiac disease, which is a specific allergic reaction to gluten. And there are those that are gluten sensitive. So gluten containing foods cause GI symptoms, but they don’t have celiac disease and experimenting with different types of grains can sometimes be helpful. I find that some of the more ancient grains are gluten very low in gluten levels. They’re not gluten free, but they can sometimes be much better tolerated.

So it would be like teff, kamut, the einkorn that I showed earlier. These can sometimes be tolerated in those that have a gluten insensitivity, but not celiac disease.

Intermittent Fasting and the Microbiome

There’s a question about intermittent fasting in the microbiome. One is just does intermittent fasting affect the microbiome? And another was that the sixteen:eight fasting, does it improve the microbiome compared to other forms of fasting?

I think the data are still out on this. And I would say that it just gets back to eating enough fiber. I think if in those meal in that eating window, if you’re eating enough fiber, I think that is fine for the microbiome. But yeah, we need more data in this area, I think.

Ayurvedic Food Combining

There was a question about in Ayurvedic medicine. Patients are told to eat fruit by itself and that only cooked vegetables should be eaten at night. Do you feel that these food combining or that it affects the microbiome or is that not actually something that you have to separate?

I have to say that in the traditional Chinese medical practices and the Ayurvedic practices, there’s a deep wisdom collected over thousands of years that we are just growing to recognize. And I think that a lot of these things remain untested. But I think something that the Western medical field, I think, needs to do over the next short period of time is to take this wisdom and test it.

Traditional Medicine and Microbiome Research

DR. SEAN SPENCER: I think that a lot of it is really impacting the microbiome. There’s a colleague at Stanford who did a screen of traditional Chinese medicines and its potential effect on the microbiome finding profound effects, suggesting that traditional Chinese medicines may be targeting the microbiome, and that is one of their effects.

So I don’t ever like to discount any knowledge that comes with these practices that have gained wisdom over thousands of years. It’s really hard to discount any of that. It just needs to be better studied, I think.

Q&A Session

DR. SEAN SPENCER: So we’ll take two more questions and then we’ll have to stop because of time. Is wine a good source of fiber? This is coming from Northern California, and maybe commenting on are there some prebiotic effects that are not fiber but like the substrates of fermentation in wine that may be healthy? So that’s one question. Yes is the answer, very much so.

This is one of my topic areas of study of looking at fermented foods. And this distinction between a postbiotic and a prebiotic is somewhat artificial because these ecological networks have a ton of cross feeding in them. So one organism may take sugar and make lactate, for instance. We have this malolactic fermentation process of when you kind of finish a wine, you’re changing the concentration of lactic acid. There are bugs within the microbiome that love lactic acid.

So the answer is yes. When you eat sauerkraut or drink wine, some of those metabolites will then feed your other bugs. So the answer is yes.

Closing Remarks

NATALIE MARSHALL: Okay, well thank you so much. We hope that you learn things that will help your health and your health span. Thank you and good night.

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