Your Gut is the Gateway to Good Health: Understanding Your Microbiome

Transcription:

[00:00] Moderator: It is now my great pleasure to introduce our speaker today, Dr. Christopher Damman.

Dr. Damman is a board-certified gastroenterologist at the Digestive Health Center at the University of Washington Medical Center and an Associate Professor of Gastroenterology and Medicine at the University of Washington. He previously led the Food and Microbiome Initiative at Bill & Melinda Gates Foundation. 

Dr. Damman is also editor-in-chief of Gut Bites MD, a website that features the latest research on the relationship between the gut microbiome, metabolism, immunity, the mind, and it's all presented in easy-to-understand language. The site also features Smart Bites, a science-based nutrition app designed to help simplify healthy food choices.

Please all join me in welcoming Dr. Damman.

[00:52] Dr. Damman: Thanks, Penina.

Gosh, what an honor to be part of this mission. And thank you so much to the organizers for the invitation to speak today.

Reporting from Seattle, super happy to talk about a topic that's really near and dear to my heart. It's a topic I'm quite passionate about.

It's the intersection of food, microbiome, and health, and it begs the question, why is a gastroenterologist talking about nutrition? Truth be told, in medical school, we actually received very, very little training formally on nutrition. I can quite literally count the number of lectures on my fingers and toes, maybe even just fingers, and it really wasn't until my time at the Gates Foundation that my mind was opened to the possibility of the power of nutrition in medicine, both in treating disease, but even more powerfully in preventing disease.

In traveling the world, meeting with children and mothers and fathers in Africa and Asia, treating malnutrition, it became very clear to me that many of the approaches that we were taking in treating disease there could be used in treating disease right back home. And we were taking a very microbiome-focused approach and nutrition-focused approach.

[02:18] So, that launched a second stage in my career, and that was really how nutrition can impact chronic disease, not just non-nutrition diseases that we struggle with here at home.

That is the topic of the presentation today. The gut is the gateway to health and nutrition in your microbiome.

And so just some disclosures. I consult for different food companies. These are companies that are developing next-generation products like Oobli and Supergut and BCD Biosciences with some of the key things that have been removed from foods restored.

 I'll begin with this curious question. Is a calorie a calorie? And is nutrition as simple as an accounting practice? Calories in, calories out.

[03:16] As I used to tell my daughters when they used to ask me, Dad, what do you do for a job? I would explain to them, well, I help people with their gut. And the gut is what helps them digest food. And I'd put things in simple terms like the food goes in, the food comes out. And yes, that is true.

We are, in some ways, very complicated tubes with a mouth and the other end. But there's a lot that happens to that nutrition as it passes through our gut, and it's not just the nutrients, not just the calories and the vitamins and minerals.

There's other elements to that food that's incredibly important, the bioactives, and it's those bioactives that we've missed. Those bioactives that are relevant to the trillions of organisms, the little microbes that live in our gut, the microbiome, and their brethren, the mitochondria that live within each and every one of our cells.

Mitochondria are actually anciently evolved from bacteria, amazingly. They're the powerhouses of our cell. They're what help translate the nutrition into useful energy that our cells can use.

[04:37] Well, these bioactives are incredibly important as instructions for how to do that. This is really a missing part of our nutrition story, so then lastly, I'll talk about some of the approaches that we're taking in order to embrace these new lessons in nutrition, functional foods, and how smart tech can help us measure whether food is quality or healthy or not.

[05:05] Well, let's start first with the problem, and this is a big problem, and it's a mounting problem. Some ways, it's an epidemic.

The epidemic of obesity, diabetes, and chronic disease at large. These are some of the outdated statistics from 2017. Statistics are even more remarkable now.

But you can see three quarters of people in the United States as of 2017 are either overweight or obese, and 45% either have prediabetes or diabetes. It's quite staggering. It's higher than that now.

This has led to a drop in life expectancy. We can see here in the United States, there are these inflection points in the red line relative to the average of other countries, which is in the dark gray line.

Inflection point that seems to happen around 1982. Another inflection point, maybe around 2008, and then a very clear inflection point when COVID hit.

What's remarkable is there's a similar inflection point, but not as deep. And there's a relatively quick rebound in other countries. So there's something very different about the baseline health in the United States.

[06:31] Now, what's contributing to that life expectancy and increase in death? This is a chart from the Journal of the American Medical Association, again, a little bit outdated, 2020, and it basically breaks down the causes of death across all the different diseases. What's remarkable looking at this is most of these diseases you can trace pretty immediately back to nutrition. For example, heart disease, cancer, even stroke, Alzheimer's disease, certainly diabetes.

By some estimates, upwards of 50% of disease is attributable to nutrition, maybe more, and if we look at what maybe caused this inflection point, which occurred sometime, you know, between 1970 and 1980, an increase pretty dramatic in chronic disease. This predates the death inflection point in the 80s.

[07:31] But what is it that caused this? And this inflection point hasn't been being seen across the world. There are parts of the world, pockets within the world, where people live very healthily until senior years. You know, parts of the world where disproportionately people live to 100 plus years.

These are the so-called blue zones, popularized by National Geographic; certain parts of the world where people do disproportionately live longer. So, places like Nicoya Peninsula in Costa Rica, in the Mediterranean, are Sardinia, Italy, and Ikaria, Greece, Okinawa, Japan, and Loma Linda, California, of all places. It's a pocket of Seventh-day Adventists and population that eats largely vegetarian.

[08:34] Dan Buettner is the National Geographic correspondent that popularized the blue zones, and he identified nine key factors that are contributing as common denominators in lifestyle across these different populations.

Now, nine factors is a lot to keep track of, and I like to keep things simple. So, I've condensed these into four different factors. social factors, movement or exercise, mindfulness, and diet.

[09:04] I call these the four pillars or the four Ms. It's a rebranding of pillars of health that probably seen in different contexts, and you'll see that these four Ms stands on a firm base of community. Those are our relationships with people, community at large that give many of us meaning.

[09:31] Now, the four Ms are movements, mind, molecules, and microbes.

Movement would be exercise, and the flip side would be being sedentary, couch potato, watching screens too much, for example.

Mind would be being mindful, maybe meditating or various practices that develop the mind sleep. Flip side would be insomnia and stress.

Molecules that would be eating healthy foods. Flip side would be ingesting toxins, additives.

And then lastly, microbes. Our microbiome would be the positive side of microbes. And then certainly pathogens would be the negative.

[10:23] And I'd like to focus on the diet. By some estimates, nutrition, the molecules, contributes as much as 40% to health and probably have a disproportionate impact.

There are tons of studies now looking at the Mediterranean diet, and this is one of the best study diets and its contribution to health across all dimensions and preventing various diseases and promoting neurocognitive health, preventing cancer even. 

Now there's mounting studies around these so-called ultra-processed foods. These are the foods that come in flashy packages in the grocery store. And these foods have been increasingly connected in epidemiological studies to poor health, whether that be metabolic health, cancer, longevity, the list is growing there.

These are just some of the studies linking ultra-processed foods to, at the top here, diabetes, showing a 10% increase in ultra-processed foods leads to a 15% higher risk of type 2 diabetes. And also in obesity, as households have relative availability of ultra-processed foods of increasing percentage across different countries, the prevalence of obesity increases as well. And then lastly, all-cause mortality. As ultra-processed food consumption and servings per day increases, all-cause mortality has been shown to increase.

[12:11] Now, this is epidemiological studies, meaning it's correlation, it's not causation.

But there are now some key studies that have actually looked at interventional trials where processed foods versus non-processed foods have been given to the very same individual in a crossover trial. So, they started with a diet of processed foods and then switched over to ultra-processed foods.

This is a landmark study that was done by Kevin Hall and colleagues at the National Institutes of Health (NIH), and they had about 20 subjects that were living at the facility for two weeks straight. So really well-controlled study. And they were given all their foods and had everything that you could imagine measured over the course of those two weeks.

[13:10] These two different diets, the ultra-processed and the minimally processed, were controlled as best they could for things like the number of calories, the types of nutrients that were present there.

They looked at the A, energy intake, so how many calories were consumed on these two different diets when people were left to eat as much as they really wanted. It's called ad libitum.

Then also what their body weight did even over the course of just two weeks. The results are quite stunning. The energy intake and the ultra-processed food consumption was significantly higher. You can see here on the top graph on the right. And not only that, but body weight increased just over two weeks. Now, a lot of this body weight was probably water weight due to the sodium, but the energy intake difference stands. And over time, it is possible that weight would also reflect not just water weights, but fat mass as well.

[14:18] So this begs the question, what are ultra-processed foods? ultra-processed foods is a label that can be traced to a paper out of Brazil that first coined the term the NOVA classification, and it broke foods down into four different groups.

The first group is what we would consider as whole foods or minimally processed foods. And you can see a picture in the orange on the left here. Things like fish and meat and fruits and vegetables, nuts and seeds, milk. Then we get into group two. These are processed foods, but not ultra-processed foods. So things like olive oil or honey or salt or butter. Group three would be even more processed foods, things like bread, canned foods, cheese, wine. And then lastly are these ultra-processed foods, group four. Foods that have added sugars, added components.

They're almost like frankenfoods where you take a fat, carbohydrates, and a protein, and you kind of put it all together as powders and create these foods.

But what are ultra-processed foods really? And let's dive a little bit deeper. And so one way of thinking about ultra-processed foods is they're really just concentrations of the things that we already get a lot of and probably too much of and shouldn't be eating as much of.

Michael Moss has a wonderful book titled Salt, Sugar, Fat, and this encapsulates this idea. We're just eating too much of sugar, salt, fat, and additives.

[16:25] That's one possibility. Another idea around ultra-processed foods is it's not just that we're getting too much of these things, but in processing the foods, turning them into the powders, creating these frankenfoods, we are creating hyperpalatable foods.

So, we're creating very specific combinations of these components of the sugar, the salt and the fat. And these very specific combinations actually are triggering our reward system in the brain. And there's a number of studies now that show these ultra-processed foods actually do have some addictive-like properties.

[17:07] And then there's this idea, well, maybe it's more about we take these whole foods, which are composed of cells, just like every plant is or every living being is, and we grind it up. In grinding it up, you're basically getting rid of that structure. You're disrupting the matrix, and you can see up on the top here, kind of the blue picture, this is a grain that's been ground up into flour. And you can see these tiny little particles.

Those particles never make their way down into the lower GI tract. They don't make their way to the colon where the microbes are. Microbes end up missing out.

[17:52] But in an unprocessed food, the cell structure is intact, and there's less digestion that happens in the upper gut, and more of that food actually makes it down to the colon. Less gets absorbed into the body, and so the relative number of calories that are available to you are less.

All right, well, that all seems very plausible.

[18:19] Now here's a fourth idea I'd like to introduce. We've had the added, we've had the hyperpalatability, we've had the disrupted matrix, but there's this concept that when we process foods, we're taking things out as well. We're not just concentrating for salt, sugar, and fat, but we're removing these things which traditionally haven't been considered nutrients.

But as it turns out, are really important, as alluded to in the very beginning, as instructions for how to process the nutrients. These are things like fibers and phytonutrients in the bioactives, bioactive fats. Proteins actually have bioactive components as well.

[18:56] So I've labeled these, the four Fs of food. One of them is a little bit of a cheat because it's phytonutrients. It's a phonetic F. So maybe it's better to call them the phonetic Fs of food.

[19:08] And that's fibers, phytonutrients, bioactive fats, and ferments.

So, fibers, we've heard so much about fibers. and that we need to increase our fiber. What we hear less about is there's an incredible diversity of fibers. And so just increasing one fiber is likely not sufficient, but increasing the diversity of fibers is really important.

You see pictures of the allium family, onions and shallots, where fructans type of fiber are particularly high. And then another grouping underneath where resistant starch is high. It's things like green bananas and oats.

Phytonutrients, that's a broader term for polyphenols. These are the components in food that give them their color. You'll see pretty bright colored foods on the left here, turmeric and grapes. And these are just small molecules. They are used by the plant to deal with adversity and stress, whether that comes from drought or from the sun. But within us, really important for informing how to process the nutrients that are coming in, informing our microbiome and our mitochondria, the powerhouses of the cell.

[20:32] Bioactive fats would be things like omega-3s and then ferments. So it's not just the bacteria that are present in ferments, but the things that those bacteria are making that are incredibly important. And so, you know, yogurt and kefir and sauerkraut and kimchi.

What's super interesting is if you look across the blue zones, and you can see I've kind of grouped them into Japan and Nicoya Peninsula, Loma Linda, and then the Mediterranean countries, there are common denominators across each of these four Fs, the fibers, polyphenols, fats, and ferments, that are found in all these diets.

For fiber, you'd see beans and potatoes and whole grains. Phenols, you'd see teas and coffee, cacao, turmeric, herbs, spices, fruits and vegetables. For the fats, you see olives and avocados, nuts, seeds, fish, free-range meats. And for ferments, you see vinegars and drinks, fermented vegetables, beans and dairy. So, the common denominator is there.

The cuisines are different, but these key elements of the food are similar. And the key elements can actually be grouped together in terms of their four Fs.

[21:57] All right. Some have called this the dark matter of nutrition and begs the question, well, how did we miss these things? I trace my time back to the foundation and working in low and middle income countries where things like scurvy and kwashiorkor and pellagra, were still present. These are vitamin D deficiency, protein deficiency, and B3 deficiency.

Back at the turn of the century, we were very good at finding individual nutrients that correlated with individual diseases. You take that nutrient away, you get the disease, you add the nutrient back, and you cure the disease. It was that simple. That is the beauty of the reductionist approach to medicine, to nutrition.

[22:47] Similarly, in infectious disease, there's so-called Koch's postulates, where it's a single bacteria that causes a single disease. You take that bacteria, you give it to somebody who causes disease, you can isolate it from that person that has the disease, and then you can give it to another person. That is the reductionist approach to medicine. That is what modern medicine has been very good at.

What it's been less good at is identifying systems and interacting parts. And the microbiome and these instructions, the fibers and polyphenols work differently.

It's not a one-to-one ratio. You can't say this particular fiber is linked to this disease, but there's a bunch of fibers and there's a bunch of different bacteria that are translating those fibers into key molecules that are important for disease. So this is one of the reasons, maybe not the only one, we've missed these key signals, But now we're keen to understand them.

[23:50] Coming back to this inflection point, it's not just the things that we've added, as I've said, simple carbohydrates, additives, fats, sodium, but it's these things that are missing truly. And it's the relationship between these or the ratios between these that might be particularly important to health.

This is what I call the microbiome mitochondria axis. And it basically breaks down in a snapshot how all this works.

So let me walk you through this. So, on the left here is food. Food has its nutrients, but it also has these bioactive factors, the 4Fs. Those 4Fs are very important to the microbiome, both to support a healthy microbiome, that community of trillions of organisms that lives within our gut.

[24:45] The microbiome is also transforming those factors into other bioactive molecules that are more readily absorbed into the body. And those impact then the powerhouses in our cells, the mitochondria, the brethren of the little microbes within our guts, the evolutionary related structures that power our cells.

When this breaks down when you have unhealthy food that's missing these factors it depletes the microbiome you lead to dysfunctional mitochondria and that dysfunctional mitochondria leads to disease now this is a very simple way of looking at disease but I think it's a powerful lens certainly not the only approach but it's a very important element to how food is linked to disease and you can see underneath here I've listed just about every disease.

For each of these diseases within the literature, there's very deep research that's making these connections between food, microbiome, mitochondria, and metabolic disease, immune disease, frailty, neurological disease, and cardiovascular disease and cancer.

[25:53] So, I've talked about how these bioactives, these four Fs of food are transformed by the microbiome into bioactive signals that then get absorbed into our body.

Let's trace some of these as examples. So, fiber. Fiber is transformed by a microbiome into many different things, but one of those things is butyrate.

Butyrate is called a short-chain fatty acid. It's basically like a fat, but super tiny. And this is a busy slide, but it's just to say this transformation happens. There's more than just butyrate, there's acetate, there's propionate, and other things too. All of these are contributing to the health of our different cells in our body, which you can see across the bottom.

[26:46] Now, what's interesting, butyrate also helps stimulate GLP-1. That's a completely different story but this is how GLP-1 which is the analog for the actual ingredient in Wegovy and Ozempic which are these breakthrough weight loss drugs there's an analogous system that happens within our gut but that asides butyrate itself directly is impacting all these different organs and cells okay that's all fine and good but what does this mean for health 

So, this is one study an interesting study in a pediatric population that basically took 54 patients that were obese broke them into two different groups one group that got butyrate and then another group that got placebo, so just a sugar pill. And over the course of six months, there is a pretty dramatic difference in the weight loss between these two groups.

[27:51] Now, both groups were also counseled around traditional weight loss methods. And the only difference between the groups was really just whether one got the butyrate supplement or not.

So yeah, really intriguing, interesting signal here around butyrate and pediatric obesity. Just one clinical intervention trial that showed some positive results with one of these bioactives produced by the microbiome from fiber.

[28:24] But, what about the other Fs? In this case, a phonetic F, phenols. These are the compounds that give plants their color, largely. So there's one polyphenol called ellagic acid.

Again, this is a busy slide, but I'll break it down for you.

[28:43] Ellagic acid is a polyphenol present in berries and pomegranates and walnuts and some other nuts too. And when it makes its way down into the colon, it's converted into Urolithin A. Again, Urolithin A is one of these molecules that has dramatic effects across the body. It's impacting the health of mitochondria and how rapidly they're turned over within the cells and how healthy the mitochondria are.

[29:10] All right, so let's look at a study that investigates this bioactive Urolithin A. Now, this is an adult population, and it was 16 men, 50 women, 60 participants total that were given the placebo, and then the other half were given Urolithin A. This was done for four months. And then they were asked to essentially walk six miles and it measured how far they went in six miles.

The primary outcome study was not sensitive for it. There was not a significant difference, but was interesting. And it looks like this slide is missing this part. So, my apologies, but what they did find is the strength of muscl. One of the muscles in the hands and one of the muscles in the legs, a tibialis anterior, were quite remarkably stronger in the group that received the Urolithin A versus the placebo. So, a negative study, but still intriguing results around muscle strength, if not ability to walk six miles.

[30:28] All right, and then so now the last example, looking at the third phonetic F, and that's fats.

Fat, linoleic acid is one type of fat, and it is converted to something called conjugated linoleic acid, CLA, by the microbiome, and this again has pleiotropic effects on the body.

This compound has been studied much longer, and these are forest plots for weight, body, and fat. A forest plot is basically just a way of looking at many studies at once. So, each of these horizontal lines represents a study. And whether that line crosses that center line, that determines whether it's significant.

[31:14] So you put all these studies together, and then you get the diamond at the bottom. If that diamond crosses that center line, then it's not significant, but if it does not cross the center line, then there is basically a positive signal there. Therefore, body fat and insulin resistance, there's both positive signals.

[31:41] Here we are now back at the microbiome mitochondria axis, and you have healthy foods, you create a diverse microbiome, you have functional mitochondria, and metabolic health. So, the flip side of disease, if we have the full complement of these Fs.

And back to this model of changes in disease in our population, the question is, what do we do at this point now in the green arrow?

And if we look to the advice of one of the fathers of modern medicine, Hippocrates, he said, let food be thy medicine, might add to that, and its 4Fs, which would be fibers, phenols, fats, bioactives, and ferments.

[32:36] We talked about essentially how we missed this already, and, you know, you have the deficiency model, the reductionist model on the left here, what modern medicine is good at. On the right, these systems, complexity, diversity, redundancy, and this is where nutrition science is moving and studying.

[32:59] So the question is, can we add these things back? Yes, we should eat all foods. But can we take some of these things that have been removed in processing and turn them into useful products?

This is a model for how that might be done. On the left, you have whole foods, the healthy lifestyle slog. On the right, you have this sort of magic bullet dream. Single pill is going to fix everything. Some might say that's GLP-1s, although there's side effects associated with those, and it's not a perfect solution for sure.

In the middle here, there's this idea of functional nutrition, where you're adding some of these things back to processed foods. You're making processed foods incrementally better, things like the fibers and the phytonutrients, the healthy fats.

[33:55] Kind of a pragmatic approach recognizing that eating whole foods for everyone is not possible in our busy lifestyles and truth be told it can be quite expensive to eat fresh whole foods as well. This is the heart of my research; I'm working on a way of measuring the quality or the balance of foods, not just the concentrated bad things, but the missing good things, and coming up with an algorithm for doing that. So, you can take the really complicated nutrition facts panels and effortlessly transform that into a zero to 100 score.

There's subscores to this as well for protein and carbohydrates, but there's an overall score that the algorithm will produce. And this helps you look at the relative health of, for example, different raisin brands or different snack bars to choose the one that is going to be a higher quality or better balanced food.

[35:01] There's other algorithms that have done this. You can see NutriScore, even NOVA classification, which was the original definition of Whole Foods, and HealthStar and Food Compass. This is just how Nutrient Consume Score, which is a score I've been working on, measures compared to those in terms of p-values and significance.

NCS on the left and the other systems on the right, NCS having a pretty big jump in significance and how it associates with the healthiest foods and the least healthy foods correlating with percent obesity in the NHANES cohort.

This is theory of change, where in the future, I see continued emphasis on whole foods, but introducing these functional foods, which are incrementally better, how certain mobile technologies can help us determine which of those foods might be healthier. So, it's not just purely based on marketing.

[36:05] There will always be early adopters. There will be these early better-for-you foods, and much like power locks in cars of the 1970s and 80s, they will become the standard, is the hope, as there's public adoption and greater use of these foods; prices will come down. This ideally can lead to a transformation in health.

So, this is the overall model here where we've had these inflection points of imbalanced foods leading to an increase in disease. And our future, ideally, will be recognizing, gosh. We need to add these things back, recreate balance in our food, not just focus on avoiding carbs and fats and now increasing protein, but actually it's the full package. How do we measure the balance of that full package?

[37:06] So hope for the future. And back to where we started, nutrition is as simple as I used to tell my daughters. The food goes in and the poop comes out.

Question & Answer

[37:50] Moderator: Thank you, Dr. Damman.

That was an excellent presentation. We do have a few questions already submitted and if anyone else has questions that they'd like to submit, please use the question box on the lower left side of the screen. We will answer as many as we can. But let's start with a few of the questions.

You had mentioned the four Fs of the microbiome. Are there any fibers that are best one year post-transplant for someone with a very sensitive stomach?

[38:25] Dr. Damman: Yeah, that's a great question. I mentioned all fibers are not created equal. Some fibers create bulk and help you have a better bowel movement. That's a lot of fibers on the market.

Some fibers are better for the microbiome and some fibers create more bloating in some people and others less. That last point really has to do with how readily that fiber is being consumed by bacteria in the upper gut, in the small intestine.

The more fiber is consumed in the upper intestine, the more side effects you can have, like diarrhea and gas and bloating. The more that that fiber is consumed in the lower gut and the colon, the less that tends to be the case. There's variability from person to person in which fibers will do that.

There are some broad brushstrokes and there is a diet called the low FODMAP diet, which originated out of Australia. And foods that are high in FODMAPs tend to be the foods that ferment in the upper gut and are more troublesome. So, looking into low FODMAP diets can be helpful for folks that tend to have more symptoms from fibers.

And the FODMAPs, those are things like onions and garlic. And these sneakily make their way into a lot of processed foods as onion powder and garlic powder, but certainly other fibers that are present within the FODMAP classification beyond just those.

[40:10] Moderator: Great. Thank you.

We have a question about, which is something that comes up often in this community. Someone has been diagnosed with cachexia, and they have been referred to a gastroenterologist and a nutrition to follow up.

Is there anything that they should know going into those appointments or questions that they should ask? How can you help guide them?

[40:36] Dr. Damman: Yeah. Well, cachexia is a tricky problem where your body is so metabolically active, maybe because it's treating an infection or maybe because it's being tricked into feeding cancer cells. So that all the nutrition that you're taking is going towards that infection or towards the cancer cell and less towards the healthy cells in your body.

So, treating the underlying cause is going to be the most powerful way of addressing cachexia. But there is nutritional support that nutritionists could help partner with you on that treatment. and one of the things that they will focus on is it's really important to increase the amount of protein that you're taking to address cachexia. But there's certainly other things, too.

And I think as we learn more about these bioactives, the fibers and the polyphenols, we already have seen signals that these are really important for turning on new cell growth, whether it be in muscle or in bone. So, I think that's a really important story to keep our eye on as we learn more about nutrition and cachexia.

[41:57] Moderator: Great. Thank you.

 Some questions about really more about access. There was a question about studies that show that vegetables, fresh vegetables are cheaper than other sorts of foods or questions about where frozen vegetables fall.

Can you speak to affordable ways to access whole foods?

[42:27] Dr. Damman: I absolutely love that question. It's very timely as the cost of foods goes up, and you're absolutely right in wondering about frozen fruits and vegetables. As it turns out, they're actually great and they're cheaper. If you're in a pinch, frozen fruits and vegetables are a wonderful way to go.

The reason that they remain healthy is these foods are flash frozen at their source. So sometimes they actually have higher amounts of these phytochemicals in them than the foods that you'd get at the grocery store. Frozen foods are a wonderful way to go.

Canned foods actually are a great way to go, too, as long as you're mindful of the amount of sodium that is in them. Taking a look at the label, making sure the sodium isn't low, using one of these methods for measuring the food quality of different canned vegetables can be very, very useful. So canned beans would be a great example.

Then among the fresh fruits and vegetables, there are some that are much cheaper than others. Cabbage is always going to be relatively cheap. Carrots tend to be cheaper and they're both highly nutritious. So just being mindful of costs when you're going through the produce aisle and choosing those that are going to be a little bit cheaper is a great way to go.

[43:51] Moderator: Thank you.

We have a number of questions about different types of supplements. We have a question about the best probiotics to take five years post-transplant.

We have a question about whether or not supplements are themselves considered ultra-processed.

[44:14] Dr. Damman: Wonderful question there.

The solution is always better going to be in the context of a whole food. These are nature’s packaged nutrients in the right balance. If you're talking about a probiotic, the alternative would be to eat a fermented food or a wide variety of fermented foods, kimchi and yogurts and kefir and sauerkraut and things like that.

In terms of taking a probiotic post-transplant, I would talk with your primary physician about that and the state of the research around those probiotics. Some probiotics have been shown to be useful for certain conditions. For example, if you're traveling to a part of the world where traveler's diarrhea is prevalent, taking certain probiotics can actually help prevent from getting one of those diarrheal illnesses.

But just generally taking a probiotic for overall well-being, the evidence there is quite limited, so if you are taking a probiotic, generally it's best done in the context of a health practitioner's advice and around a very specific condition or disease that is being treated.

[45:42] Moderator: Thank you.

Is there a test for the quality of a person's microbiome and their mitochondrial function?

[45:48] Dr. Damman: Yes. Tons of companies that are offering the consumer different tests for your microbiome health, your mitochondrial health, your metabolic age is kind of the new buzzword. The recommendations that can be made based on those tests are still quite murky. And the value of those tests is still somewhat questionable. Again, best done in the context of a medical practitioner that is well-versed in these tests and can help you interpret the results. Otherwise, there can be a lot of noise there.

There might be associations like, this particular microbe is associated with this bad disease, and then there's unnecessary worry about getting that disease or do I have that disease? They're not without some risks in taking these tests. If you do decide one, be mindful of some of these considerations and always best to be done in the context of medical advice.

[47:16] Moderator: We have a few more questions about fermented foods because folks are hearing conflicting views about consuming fermented foods specifically when immunosuppressed.

Since this is usually an immunosuppressed community, what are the safest fermented foods to ease into as a transplant patient? Someone mentioning specifically that they miss kombucha. And what is the current thinking on risks of fermented foods in an immunosuppressed population?

[47:48] Dr. Damman: Yeah, that's a great question. It’s best to discuss this question directly with your health provider, but that said, you can have a fermented food that doesn't have live bacteria in it. It's little known that that fermented food still has benefit because it's not just the bacteria that are present, the healthy bacteria that are present in that food, but it's also all those bioactives that have been transformed by the bacteria.

A good example would be just plain old vinegar. I don't recommend everyone go out and start taking swigs of vinegar, but adding vinegar to the foods that you're preparing might not be a bad idea. And what vinegar has been shown to do is blunt the spike in blood sugar that you get when you have foods that are loaded with sugar.

It slows how quickly that sugar gets absorbed into your bloodstream, much like fiber. Fiber and actually polyphenols do a similar thing. That's just one example of how a so-called metabolite or bioactive that's being made by the microbiome in a fermented food is still useful.

If your practitioner tells you best not to have a fermented food, discuss with them, well, are there still some foods that don't have active bacteria like, you know, kimchi or sauerkraut that has already been sterilized in a bottle, not in the refrigerated section? Is it okay to have those types of foods? That's the conversation that you could have with them.

[49:31] Moderator: Great. Thank you.

There is a quick question about how to spell FODMAP. That is F as in Frank, O, D as in dog, M as in Mary, A, P as in Paul. So, for whoever asked that question.

Back to vinegar and just thinking about acids. We have some folks in the chat who are asking about GERD treatment and low acidity in the gut and how that affects nutrient absorption and the microbiome.

[50:12] Dr. Damman: In terms of acidity in the gut and GERD symptoms, generally, if you decrease the acidity, and that's what things like omeprazole or so-called PPIs do, or famotidine is a different class of medication, they decrease acid in the stomach. When your stomach contents is less acidic, it's less irritating to your esophagus, so you experience less heartburn.

Now, some people say, well, when I have vinegar, which is an acidic food that controls heartburn, I'm not sure how much good research and evidence there is around that. I would be mindful of not consuming too much vinegar unless it's in the context of a whole food or meal because vinegar can erode the enamel in the teeth. It can be caustic in the esophagus as well if consumed too much.

[51:25] Moderator: We have a lot of GI symptoms that people are experiencing.

Some folks are writing about post-transplant daily vomiting and hunger-induced vomiting and how to help figure out a root cause. Then some folks are describing switching between constipation and diarrhea.

Can you talk a little bit about different GI symptoms in the transplant community and what they should do in terms of symptom relief, but also root cause, being to the right provider.

[52:06] Dr. Damman: I would say if you're experiencing any GI symptom post-transplant, it's incredibly important that you chat with your provider about that because graft-versus-host disease is highly prevalent and something that's treatable and not best treated with diet.

So that would be my highest recommendation.

Now, in an average non-bone marrow transplant population, if somebody is experiencing diarrhea alternating with constipation, there are certain red flags that I would look out for that would warrant further investigation through testing and maybe even a colonoscopy.

That would be things like weight loss or blood in the stool, mucus in the stool, abdominal pain, multiple bowel movements throughout the day, five plus. These would be things that would make me think, okay, well, we need to take a deeper look here.

In the absence of red flag symptoms, what I might recommend would be increasing fiber. Fiber can help regulate stools and you experience less of the extremes. So, less constipation, less diarrhea, and you kind of meet that sweet spot a little bit better.

Psyllium husk is a great go-to, but there's certainly other fibers that can help with that. But again, it's super important, A, talk with your provider, B, watch out for those red flag symptoms.

[53:48] Moderator: Great, thank you. What do you think about microwaving food?

Dr. Damman: Any type of heating of food whether it's microwaving, whether it's on the stove or in the oven, is transforming that food. That's why we're heating it and those transformations can be both beneficial and come at a cost.

They're beneficial in the sense that they make things delicious and more palatable. They also help almost pre-digest the food, so they're easier for our GI systems to digest.

There're very real examples of how those transformations can be less helpful. For example, if you're grilling meat on the grill outside, that tends to create more carcinogenic compounds, or if you're toasting toast to the point of being black, that can be carcinogenic.

Now, microwaving, is there any good evidence that that is transforming our food in a less advantageous way?

When you heat any food, you do decrease the polyphenol content a little bit, so with microwaving, that's going to happen just like it would in the oven or on the stove.

Is there anything unique to microwaving? I'm not sure I've seen good evidence on that, but, you know, always keep an open mind.

[55:31] Moderator: Great. Thank you.

We are also getting questions about your work, so this is your chance to plug, and we would appreciate it.

Questions about your website and what's on your website, about your app, and specific question about whether or not it's available on Android.

Can you speak a little bit about the content there?

[55:52] Dr. Damman: Absolutely.

The Gut Bites website that I keep, the Smart Bites calculator, has been a labor of love. It's what I call my passion project. I do my clinical work so that I can support it. I feel passionate about it because I want to bring alternate ways of finding health through nutrition to everyone.

Gut Bites was inspired after writing an article for The Conversation through the University of Washington. I thought, well, why not just start publishing these directly?

Now, both through my website and Substack, I put out articles on nutrition and gut health and microbiome and general healthy lifestyle. Maybe do that every couple of weeks. And there's an archive of a number of articles that you can digest, so to speak.

Then in addition to that, the research I've been doing on this way of capturing the balance of food through a score and its subscores, I didn't want that to just be another publication.

The publication is under peer review, will be a publication, and out soon, available in a preprint already on bioRxiv. But I want it to be accessible. I wanted it to be useful to people, and so that's why I started developing this Smart Bites calculator app, which is sadly just available on Apple right now, not on Android yet. That's really just due to my limited resources. and supporting this all myself.

I do hope to get it to Android at some point, but working on coming up with sustainable business models to make this available to everyone. In the meantime, it's available on Apple, and it's always going through iterations and getting better.

I just released a version now where you can just take a picture of your food, and it automatically will input all the different components of that meal into a virtual meal. You can review it, make sure it's correct, delete things if it's added them erroneously, change the quantities if you feel like it's not quite right.

You can even ask an assistant called Berry. He's a little strawberry, spelled B-E-R-R-Y. And he'll give you advice on how you can improve that meal. It's advice that's based on the subscores that NCS provides, so still work in progress.

Always really love feedback from folks. What's not working, what's working, what I could improve. But, yeah, it's been a labor of love, and I sincerely hope it's useful to people. That's really my guiding light in putting it together.

[59:07] Moderator: Thank you so much for this work.

Beyond your resources, are there good sources for additional information on the main topics you covered? The 4Fs or mitochondrial impact?

[59:24] Dr. Damman: Yes. 4Fs is something that I coined, but there's other frameworks.

There's plenty of other practitioners that are focused on complementary health, holistic health, both trained conventionally with MD or not, and there is a lot of good advice out there.

There's a lot of misinformation too, and it's truly hard to know which is good information, which is not. I wish I had a better bit of advice on telling people how to tell the difference between the two.

Generally, going to reputable websites, finding information that is associated with universities, can help you be on the right track.

[01:00:22] Moderator: Thank you.

What about dried foods, particularly dried fruit?

[01:00:29] Dr. Damman: Fresh and as it turns out, frozen are better ways to go than dried. When you dry a fruit, you lose more of the bioactive components in it, but not completely. Dried fruit also very often has tons of sugar added to it. So being mindful of that.

Those are the ones that taste more delicious, like the really sweet mango that you can find at Costco, which I absolutely love. I'll use as a little appeaser to my sweet tooth after a meal. Everything in moderation is really my motto.

My girls like to remind me it's okay to cheat every now and then so, if you like dried fruit that is a little bit sweeter, it's going to be better than having a candy.

If you're really interested in knowing how much better or is this fruit better than that fruit, this dried fruit better than that fruit, that's actually where this Smart Bites calculator comes in. It helps you figure those relative food qualities out really just in a snap.

[01:01:49] Moderator: Great.

Speaking of better choices, is organic food healthier?

[01:01:54] Dr. Damman: Yeah, wonderful question.

Just because it has organic slapped on the label doesn't mean it's healthier. But foods that are raised in kind of a pastoral setting, you know, with manure for fertilizer and things like that, that you'd find at a farmer's market or that, you know, ideally even grow in your own garden. Studies have shown that that actually does often have more nutrients in it, and just like the saying, you are what you eat.

So, too, is our food. The plants are what they grow in. If you eat animals, the animals are what they eat. S, there's growing evidence that how you grow food does pretty importantly impact the nutrient quality that's present there.

[01:02:51] Moderator: What about the impact of ingested microplastics?

[01:02:56] Dr. Damman: I don't know what to make of microplastics yet, to be honest. They're incredibly hard to avoid. They're everywhere. So, theoretically, you can imagine that a microplastic might trigger immune responses and things like that.

Generally, they're oil-based because plastic comes from oil and oil is pretty inert in the body, so there's certainly a lot of talk around them.

It's a bit of media frenzy, but honestly, the evidence is still pretty weak. In my mind, the jury is out.

[01:03:38] Moderator: A late incoming, but really important question.

Following this person's stem cell transplant, it was explained to them that their gut had been stripped of its protective lining and therefore very sensitive and perhaps not receptive to probiotics and supplements.

Now that they are a little bit out from that transplant, what are the best ways to help promote rebuilding their gut microbiome?

[01:04:03] Dr. Damman: Yeah. Whenever I get that question, how do I rebuild my microbiome? I always turn to a wonderful study that was done by a colleague of mine, actually two colleagues, Justin and Erica and their colleagues at Stanford. It was a study that was brilliantly done.

It looked at giving fermented foods ad libitum in the context of somebody's regular diet versus increasing high fiber foods. What it found is that it was actually the fermented foods that increase the diversity of the microbes in the gut, but counterintuitively, it wasn't the microbes that were present in that fermented food that were being increased in the gut.

It was microbes that were coming from someplace else, probably in the gut itself, but just in very small quantities, but given an environment in which they could grow again. This goes back to this idea of what is the value of a fermented food? Is it the microbes in it or is it the things that they're making? Can you get a lot of bang for your buck by even having a sterilized fermented food?

The short advice would be to eat fermented foods if it's safe and discuss with your provider, whether that's okay or not. Discuss whether if it is not live microbes, if that might be better.

[01:05:50] Moderator: Great. Thank you.

Then one more question, also really important.

First of all, this person starts with excellent presentation, I agree. And you've given plenty of ideas to practice daily.

This person's ongoing concern, which I know is a concern of a lot of folks on the call, is persistent low T cells due to CAR T. Is there anything that you know of that could help or benefit T cells particularly or white blood cells in general?

[01:06:29] Dr. Damman: Yeah, it's a really good question. Admittedly, I'm not well-versed in that specific literature, if there is one, so couch my advice in that context.

But that said, my hunch would be the general rules of healthy eating probably apply. If you think in terms of every cell in the body needing healthy powerhouses or mitochondria, including T cells, then the idea of the food microbiome mitochondria axis is relevant. So, eating a diversity of largely plant-based foods that have these four Fs in them might not be a bad way to go.

Now, is there tons of evidence around that? Probably not.

But is it something that one should be doing anyway, as long as there aren't contraindications that your provider are suggesting to you?

My advice would be to eat a healthy, diverse, plant-based diet just like anyone should.

[01:07:48] Moderator: Thank you. That wraps up the questions on behalf of BMT InfoNet and our partners.

I would like to thank Dr. Damman for this excellent, excellent presentation, and thank you to the audience for your excellent questions.

Thank you so much.

[01:08:14] Dr. Damman: Thank you.