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The Link Between Gut Health and Cardiovascular Disease

On-Demand Webinar

We are at a frontier of recognizing the relationship between gut and heart health. As science continues to evolve, so does our understanding of the mechanisms underlying this relationship. In this webinar, Dr Joel Kahn discusses how TMAO can indicate cardiovascular risk from the gut perspective.


Learning objectives:

–    Know the role of trimethylene N-oxide (TMAO) as an indicator of cardiovascular (CVD) risk
–    Identify ways to uncover and manage CVD risk with advanced testing, including TMAO


Joel Kahn, MD, FACC
Kahn Center of Cardiac Longevity
Clinical Professor of Medicine, Wayne State University School of Medicine, Detroit, MI


Time of talk: 50 minutes

Jun 14, 2019

Well, thank you, everybody, for joining. Hopefully you can hear me loud and clear from Detroit, Michigan. Great day, a cloudy day, but as always, I’m at my standing desk bouncing around and just if you’re listening and watching, try and get up and move around a little bit, too, good for your heart, good for your brain and probably good for your microbiome. So when I did medicine and cardiology and interventional cardiology training, I don’t believe we ever had any discussion of any relationship between gut health. And I’ll just say gut health starts in the mouth and ends at the other end of that tube. And cardiovascular disease, there was really no connection other than the obvious that diet has an impact on developing cardiovascular disease. But the specifics of metabolism and we’ve come a long way. We have so much more to go and we’re really going to focus on two specific bodies of science that actually are practical, that are measurable and are meaningful. There’s many others, like even just as simple as picking a probiotic that may be beneficial. I’m not going to talk about it’s very complex, it’s very uncertain. It’s very in the process of being developed further. So we are at a frontier of recognizing that everything that enters the body is coming in through our air, through our skin and through our gastrointestinal tract, again, starting in the mouth all the way down. And if the heart’s going to remain healthy, one of the biggest influences is going to be what goes into the GI tract, what we choose to put in the water quality that we ingest, the beverages we choose organic, non-organic, and we’re not going to go off on all those tangents. But this is a whole new field and really by just developing, but it’s very exciting for avenues of understanding and for avenues of treatment. But we can’t claim that we really have any vision nobody had before because all disease begins in the gut. That is a quote credited to Hippocrates. If it wasn’t Hippocrates, it was probably Dr. Oz. But it is said to be Hippocrates, and we’re catching up with that vision now with science. That’s evolving and improving and offers clinical impact. So this is more than just an academic talk. So we’re going to go off on a tangent. I find a fascinating topic, but it takes us to bacteria, it takes us to bacteria specifically inside the colon, which we know there’s trillions and trillions. Some people estimate there’s ten times more bacteria on our body in our body than there are humans. So some people estimate that if you actually look at the DNA content, there’s way more than ten times that’s bacterial, fungal, parasitic, viral than there is human DNA. And some people call us, we’re just condominiums, housing all these bacteria. But one of the components of some bacteria are gram negative bacteria is a molecule called, err a toxin called endotoxin. It is the tail of many bacteria. It’s also called LPS lipopolysaccharide. And it’s a component of gram negative bacteria in their cell wall that exists in our colon at varying concentrations can enter our bloodstream at varying concentrations. It can be measured in the blood. It’s not a routine clinical test, but it is available in a clinical lab and can increase. And the question is, can this bacterial product impact based on what we choose to put in our gut? Does it impact health? Does it impact our general health, and does it cause disease that many of you will train in the medical system and are familiar with septic shock and such that the fact that bacterial products and or toxin lipopolysaccharide are a component of the septic shock syndrome is probably not new. However, over the last 20 years this framework has been developed and proposed and is being increasingly accepted that we can develop develop, metabolic disease and metabolic abnormalities of which cardiovascular disease is a metabolic abnormality of insulin and sugar and lipids and inflammatory products. But we go to the lower left of the slide. You might be surprised that it says high fat feeding because the experiments in animals and humans have created an excess of the release of Lipopolysaccharide or endotoxin, particularly with test meals that are high in fat, that that causes changes in the gut flora, the more gram negative bacteria that are loaded with endotoxin that either the fat itself or other components of the diet can increase permeability between gut cells. Enter sites that should have a tight junction, not allowing excess colonic contents into the sub, enter a safe space and ultimately into the blood. But there can be increased permeability between cells. It could be high fat diet, could be food allergies, could be gluten could be pesticides have been proposed such as Roundup. But we’re going to get an increased amount of LPS absorption and increased concentration in our blood and in the inflammatory reaction to these bacterial toxins develops and we result in metabolic disorders. So if you were to go to pop med and put in metabolic endotoxemia that you would see dozens, if not hundreds of basic science studies, animal model studies and increasingly human studies proposing that it may be one of the or some people say the most important mechanism of chronic disease beginning in the gut with food choices. Food quality, food toxicity, releasing bacterial products, gut health, gut heart connections and, you know, do you want some endotoxemia with that burger? They look around the circle of what endotoxins can result that increase interleukins, increase anaphylatoxins, platelet activating factors, you’re more likely to clot free radicals, various prostaglandins are substances, some of which are pro coagulant, some of which are anticoagulants, tumor necrosis, factor histamine and allergic reactions all related to choices. And that’s what answers our gut. That’s what triggers lipopolysaccharide relief in terms of my field cardiovascular disease. In this review article that time about 6 years old it proposed that indeed this process of dietary choices if you go to the top of the picture LPS lipopolysaccharides impacting the population of the bacteria in our gut, allowing through the entrance site intestinal wall, particularly in the colon lipopolysaccharide to enter the subspace and get into the bloodstream, leading to a chronic cycle of inflammation which can impact nonalcoholic fatty liver. It can impact atherosclerosis. This can impact obesity. Might be able it says on the right to be modified with prebiotics, probiotics, synbiotics. Um, antibiotic treatment if there’s a actual bacterial infection like C difficile but may be connected to these very frequent and disabling chronic inflammatory conditions uh, diabetes type two, nonalcoholic fatty liver disease, obesity and certainly cardiovascular disease. So being aware, this is just a platform I always take of educating patients on the importance of dietary choices, dietary quality, Whole foods versus process. A lot of data has been in the headlines the last two weeks about the risks of hyper processed food excess calorie, obesity, type two diabetes. We’re more and more identifying. We’ve got very off path with diet, the Western diet, the standard American diet, but at a basic level is gut heart connection via metabolic endotoxemia is fascinating whether the solution is improvements in diet of course whether the solution is evidence based choices on certain aids like probiotics. Prebiotics Maybe you got to be very selective and see if the science actually demonstrates that. I am aware of some peer reviewed studies indicating there are some prebiotics probiotics that will reduce the release of metabolic endotoxins with a fatty meal as a test meal. So we have much more to go by that. Being aware of the science is important. I know that some people will question this data and ask if it’s consistent with the overall view, but this is a pig study looking at different foods that contain different amounts of fat, all compared to a saline control. And the graph on the right is the blood level of endotoxins that appears after the test meal over the course of 5 hours. But it’s very consistent literature that high fat meals do promote the release of metabolic endotoxin as opposed to whole Foods meals that are naturally lower in fat. They’re obviously more commonly plant based meals are less associated. But the king of release of metabolic and other toxins is actually coconut oil. And although there’s certainly the impression that coconut oil might be anti-inflammatory in the lay public and some clinical results and such, when you look at it, it makes one concern that high saturated fat content of the diet of which coconut oil has twice as much as red meat may be unwise in terms of treating, preventing and reversing some of these chronic conditions. So that leads us to get back to the food plate recommended by the USDA, recommended by the Harvard School of Public Health, recommended recently by the Canadian Nutrition Board, and such all of which favor, you know, majority in the diet being whole foods, plants and grains and legumes and lower fat animal products of higher quality of chosen. And certainly none of them endorse using high saturated fat diet, of which this is one supportive measure for that. But I want to turn beyond maybe the last 15 to 20 years of science on lipopolysaccharide and endotoxins and metabolic endotoxemia to a new sector of science that is linking experts in the microbiome expert on the metabolome as they say and cardiovascular disease. And that is the focus only now for about 8 years that most of this molecule, this metabolite, TMAO, Trimethylamine N-oxide If you look at the diagram there you can see 3 methyl groups. So it’s trimethyl. N being right in the middle, amine because it does have that nitro group and oxides because of the attachment at the top and something that in cardiovascular medicine until 8 years ago was not described in any way as being a possible connection between our microbiome and our cardiovascular health. So in case you have to leave or in case you just like the short version in the last 8 years, predominately of the Cleveland Clinic, predominantly with the researchers. Dr. Stanley Hazen, M.D. The idea that red meat and you’ll see in a moment there’s some reason to believe other food products, particularly egg yolk, contain specific amino acids. In fact, the red meat is more commonly l-carnitine concentrated, and egg yolk is more commonly attributed to choline concentration. Reaching our gut because we eat it being metabolized by our gut bacteria. If they have the ability to metabolize l-carnitine and choline with great rapidity into a product through the intestinal wall called trimethylamine and then in the liver, a final step from an enzyme called FMO occurs and TMAO appears in the blood. And the last part of the one minute simple explanation is female appears to be involved in the development of plaque in arteries throughout the body are a mechanism that goes beyond cholesterol, beyond blood pressure, beyond blood sugar in part goes along with inflammation. So we’re into this simple concept that’s totally novel come from. So it comes from a series of studies over the last 8 years and now can be said to be worldwide. And I would say this is again a summary. We’re going to dive into the data momentarily, but abnormalities in gut function may result in a disturbance of our microbial bacteria and their ability to take food items We ingest and metabolize them, but our consumption of animal foods and some supplements will talk about that, vitamins can lead to enhanced TMAO production. If you look in the orange pink box, the science has indicated there is a process called reverse cholesterol transport. We often talk about that being the function of HDL cholesterol. It can be impaired by high levels of TMAO in the blood, which wouldn’t be a good thing necessarily. The ability to transport cholesterol into arteries has been shown to be enhanced by TMAO, at least in our basic science models, which isn’t a good thing, leading to cholesterol accumulation. And there’s something called arteries bone cell formation. So both of those fates of arteries and increased risk for both plaque and actual cardiovascular events. So do we need to be concerned about TMAO? Do we need to measure TMAO? Do we need to understand how the physiology of female? And I think we will dive into that, and I think you will benefit from understanding that we’re yet again if you’ve seen this before. So it is a gut derived metabolite form from dietary nutrients. There’s one exception that we can talk about at the end. Step one, ingest certain dietary nutrients. If you look in the picture, the ones that have garnered the most attention on the left is the red meat. You can see the eggs, you can see they do show some shellfish, which typically aren’t a major contributor. They show some dairy. Dairy is relatively uninvolved in this pathway. But by ingesting choline, which is what it says by the arrow and l-carnitine, which exists in multiple foods, but it’s much more common in meat based foods from the word chili con carne for meat L-carnitine that in the gut flora, there will be a conversion. There’s a enzyme called a lyase. L Y A S E that converts choline and carnitine into TMA. TMA is an interesting molecule, is a very strong and offensive fish odor smell. There is a unusual genetic disorder where you cannot convert TMA through the liver. The TMAOs at TMA levels build up high and people have a body odor that strongly of fish. But most of us have a functioning enzyme in the liver that both leaving mono oxygenates and the TMA gets oxygenated to become TMAO. Trimethylamine N-oxide and via basic science studies seems to promote the development of atherosclerosis as associated with an adverse prognosis. We’re slides away from talking about is there anything known about treating an elevated TMAO? But one thought that came up was what if we can find natural or pharmacologic blockers of that enzyme in the liver , FMO, so that your TMA doesn’t become TMAO, but that doesn’t look like it will ever be a fruitful pathway, because if you blocked that and you had elevated levels of TMA in the blood, you would develop a fish odor syndrome and most people would not sign up for that program. So we’re going to have to go earlier in the chain of development of Trimethylamine N-oxide if there’s going to be a therapy developed that works routinely. So this is a mouse model published right at the beginning of research on Trimethylamine N-oxide in the animal model of 2011. And this was mice that were fed excess choline, again commonly identified as a component of egg yolk that they developed increased concentration of bone cells in their arteries as a marker of atherosclerosis control group and the choline group there on the left showing the excess amount of foam cells with choline administration. And then there is really tiny black bars there. They gave other mice antibiotics and then fed them choline. Antibiotics will temporarily wipe out their microbiome of their colon. And there are bacterial products in the colon that lead to the formation and processing the choline. So it proves the point that the development of these foam cells was the path was dependent on a functioning gut metabolizing choline into as it was measured, TMAO. So the gut microbiome is a part of it. This is a true gut part program. Now, the antibiotic arm was just part of the experimental control We’re not advocating, nor is there any data on humans giving antibiotics to lower TMAO. There’s too many adverse consequences there. So it’s choline induced from cell production to a bacterial dependent mechanism. But what is that mechanism? Other studies done. This is a 2013 that it wasn’t exclusively choline. As I said, red meat is very rich in amino acid l-carnitine certainly in amino acid we need maybe like many things we don’t need in excess and mice that are fed l-carnitine even though there has been some use in the integrated world, the natural world of L-carnitine as a supplement in humans, when you feed mice excess l-carnitine in their chow they develop more plaque. If you look there on the left side of the picture, aortic lesions compared to standard chow the number of lesions caused carnitine enhanced chow was significantly higher, almost two fold higher. And again, is this gut bacteria dependent or not so than other mice or given antibiotics? And then were challenged with carnitine and they did not develop excess plaque. So it’s again a gut bacteria dependent mechanism. So then you got to look for what is it that these gut bacteria are taking carnitine and converting it into? And there were 3 molecules, 3 metabolites that were in the the crosshairs at the Cleveland Clinic and basic science and ultimately human models. But ultimately one was betaine, which you may have heard of part of the methylation cycle, BH4, but ultimately Trimethylamine N-oxide was identified as the most likely candidate. So they early on went to human studies just to test this basic hypothesis. Is it possible that in humans there’s a relationship between the blood level of female and atherosclerosis or are we going down a pathway that doesn’t seem to have much human relevance? So this is a cath lab study at the Cleveland Clinic, a thousand people on the cap table where their blood was drawn and they developed an assay to make it convenient to measure TMAO blood levels in humans. And they determined that they had coronary artery disease that a rather crude but classic way of assessing if I was single vessel double or triple vessel coronary artery disease. And there was this relationship specifically very strong that the higher the TMAO level, the more advanced was the burden of atherosclerosis in humans. So again, this was done very early in the beginning of TMAO research in the last decade, but it certainly gave us some interest in pursuing it because there might be, based on this data in association, there might be a actual causal connection. Um, when they looked at the risk of having events, this again was 2011. Are we evaluating a metabolite that might be important to human physiology in human disease, in human health? They looked out in these people on the cath lab. People in this time extended to 1876 people that the risk in the future of MI developing myocardial infarction, heart attack developing symptomatic peripheral arterial disease of the legs are developing symptomatic and clinically important coronary artery disease. The relationship was all increased statistically in grays 1.5, 1.7, 1.3, 2.1 and such and then they adjusted for known risk factors diabetes, smoking, blood pressure, cholesterol, age, gender. Yes, there still remained significant risk for having elevated TMAO for clinical syndrome. So this is right in the beginning, 2011 and gave good credence. The idea that future research needs to be done to understand why does TMAO elevate? Is it causal? Is it just correlation and what can be done about it down the road? There is a term in my cardiology literature, MACE, major adverse cardiac events, major adverse cardiac events are heart attack, bypass, stent, death, emergency room admissions and such. And now a group of 4000 people that had a cardiac catheterization had their blood TMAO levels down at the Cleveland Clinic. This is all done right at the beginning because this is published in 2013. The New England Journal of Medicine were followed after their catheterization for 3 years. The the important numbers there are the what’s called adjusted hazard ratio on the left quartile one is the 25% lowest level of TMAO in the blood of these people undergoing a diagnostic heart calculation. On the right are the people with the highest 25% quartile of TMAO blood levels. And you can see that the unadjusted risk was 2 1/2 times higher in the group with the highest TMAO levels compared to the lowest. And then as they adjusted it again for smoking, diabetes, blood pressure, other known risk factors, they weren’t as prominent a relative risk, but still between 1.4 and 1.9 times higher risk. Statistically significant again, for a whole spectrum of clinical cardiovascular disease. Certainly a reason to pursue further research on whether Trimethylamine N-oxide was going to become the language of cardiologists and other people dealing with cardiovascular disease. Um, what was particularly interesting on the slide I just put out from the same study is the comment at the lower left that even in low risk patients, people that underwent catheterization but they standard risk factors, non smokers, very low cholesterol a younger age that those with elevated TMAO at the highest quartile particularly still had significant increased risk so that this was a predictor, a metabolite either causally or correlated with major adverse cardiac events, even when other known and recognized biomarkers of risk were low. So it seemed to have independent value for predicting heart attack, stroke, hospital admission and such. Um, there are more than one marker one can check in terms of cardiovascular risk prediction. This looked at actually measuring in that group of people both their blood level of carnitine and their blood level of TMAO and in some people both were high, in some people both were low. But the high risk group which is at the bottom, if you have a high carnitine level at the time of your heart catheterization and a high TMAO level at the time of your heart catheterization, probably have a high carnitine level because you ate meat relatively recently, red meat. Maybe you’re taking carnitine supplements, although it’s not all that common. But over the course of 3 years, the likelihood of being event free in terms of cardiovascular risk, uh, events developing is the least in the worst. In fact, 20% of those people had events and that risk adjusted was twice as high as people that had low carnitine. And certainly it looks like it’s mainly low TMAO. So if you probably look at this and say, I’d like my TMAO level to be low, if I have known cardiovascular disease or I’m seeing a cardiologist, although again, is it a marker or is it actually causing atherosclerosis? So we mentioned choline, which is a consumption in egg yolk. We mentioned carnitine, which is concentrated in red meat, particularly. This is a study where volunteers, healthy volunteers, were given either a breakfast of no eggs all the way up to six egg yolks. Looking at what happened to their blood level TMAO, their urine level of TMAO, and the consumption of eggs and it’s believed it’s the egg yolk was associated with an increased plasma and urine TMAO level. 14% of the choline and eggs became TMAO. A lot of variation. A lot of it’s dependent on the microbiome, uh, the microbiome and stool analysis wasn’t done in these. So the exact flora that was present and those that converted the most wasn’t known, but it was dose dependent and those that ate they ate zero and one egg breakfast composition had very little increase in TMAO, but those are eating four or six eggs did have a high level of TMAO that developed after meals like that. So that’s created some controversy because to this day we can argue back and forth for hours on the totality of the data, whether eggs and egg yolk are a healthy component of their diet or unhealthy component in diet and such. It’s commonly said that the most recent USDA guidelines remove cholesterol as a target of concern. But I will assure you if you read them, they came out in 2016. It still says that the goal of the diet is to have dietary cholesterol as low as possible. They just don’t put a number on it, but the wording. So it’s dangerous to decide what to do with our own diet and with our patient recommendation. Where do these precursors that seem in these studies to lead to blood TMAO levels come from and you can see that carnitine particularly is going to be in red meat, though there is some in other meats. There is some in dairy eggs as we mentioned is where choline and then over in the right for the first time energy drinks and supplements. Um, and of course things like Red Bull do have often carnitine in them as an energy boost. Can they lead to increased TMAO levels and any concern? Now it has an important note on this slide at the very bottom, it’s said if you follow the TMAO literature, the discussion on the internet such that fish contain pre-formed TMAO fish are healthy in our diet, therefore the whole TMAO story may not be authentic. What’s here and very important is most fish do not have preformed TMAO. Most fish, in fact are rich in choline or carnitine and don’t lead to the development of TMAO through the gut bacterial mechanism. There are certain buried deep water fish that do have preformed TMAO in their flesh. It helps them with buoyancy at very high pressure, deep levels. But the overall consensus, at least as of this time, is if the gut production of TMAO that’s associated with increased risk of cardiovascular disease and there is incomplete information about the role of eating fish that are naturally low in TMAO versus the role of eating certain types of fish that are higher naturally in TMAO and cardiovascular health, it’s unresolved and there is a need for more studies. There are a variety of drinks on the market. Again, if you look at the Monster drinks in the Starbucks energy drink, you can see that l-carnitine at a reasonably high dose is a component of both these drinks. Um, and many of them have, you know, more than 600 milligrams of carnitine in their can, which can be equivalent to many, many pieces of red meat. So is that an issue out there? And there has been data about both dietary choline and carnitine in eggs and red meat, resulting in increased TMAO blood levels dependent on gut bacterial pathways. There are observational studies using gene studies and others that are relating to TMAO with all forms of cardiovascular disease. There are diets that are naturally low in the precursor nutrients that lead to TMAO production. The Mediterranean diet, which advises decrease red meat and generally decreased eggs, is associated with less TMAO In human studies. There are studies in people who describe their diet as vegan or vegetarian, having lower levels of TMAO. So the story is fairly consistent across a variety of scientific venues. So as again Hippocrates said long ago, our food should be our medicine. What do we know about food choices and whether we develop TMAO and how that may relate to our risk of developing atherosclerosis? So this is a interesting study back in 2013 where they did fasting TMAO, baseline levels in people that were omnivores. That’s what it says, fasting plasma omnivores, fasting plasma, vegan vegetarians and the baseline level of TMAO was low in all groups that it was lower in those that the vegetarians, you know, rarely eating eggs and meat. The vegans probably not at all. They had lower levels. And on the right is one of the more interesting studies they actually got in a research model. People, healthy members of the public, they fed them a steak, they measured their TMAO level, their TMAO level went up, their microbiome was used to carnitine rich foods, was used to metabolizing carnitine rich foods and created TMAO. But they also convinced 5 vegetarians and vegans that normally did not eat red meat, to eat the same steak that the omnivores ate in this test study. And even though they ate the steak, they did not develop TMAO because it is a gut bacterial dependent metabolite and our microbiome shifts based on our diet. After only 2 weeks of the change from vegan vegetarian omnivore, it will shift. And similarly the opposite way from omnivore to vegan vegetarian it’ll shift, so the inability to produce TMAO despite a carnitine challenge now, they kept on eating red meat, they would shift their microbiome and they would develop a greater capacity to form TMAO. All kinds of questions. What about vegans that drink monster energy drinks? And, you know, I stop and study. This is one of the more hopeful pathways that for many reasons the Mediterranean diet or the related dash diet are used for hypertension. There have been studied TMAO levels on people on these diets. On the left, you can see people that describe their Mediterranean diet is an omnivore version of the Mediterranean diet. A vegetarian version or vegan diet have low TMAO levels. They were lowest in those in the lab. The least amount of animal products, specifically egg yolk and red meat. And if you look on the right, those that describe their diet as Mediterranean and were highly adherent to it, so they didn’t bear much from the reduced red meat and the larger amount of fruit and vegetables and whole grains and perhaps olive oil and red wine, Those are the most adherent had the lowest levels of TMAO. Those that didn’t adhere well had the highest levels. So recommending a mediterranean style diet, which are more than one version. And lately there’s a Nordic version of the Mediterranean diet a little bit more from the northern components of the Mediterranean Ocean are very popular Mediterranean Sea, rather. But that is one approach. There is a body of science that’s still experimental, that there is a molecule called Di-methyl Butanol, or DMB and DMB can inhibit the enzyme in the intestinal wall of the lyase that converts choline and carnitine into TMA. That’s stuff that occurs before the liver converts TMA to TMAO. And because it inhibits the development of TMA, it doesn’t lead to that fish oil syndrome. It basically blocks out the intestinal wall, this gut bacterial derived method of developing these metabolites. So in animal experiments and a few human experiments, you can still feed choline in carnitine rich foods and not develop elevated levels of TMAO. Whether that’s going to become a supplement or a pharmaceutical agent, uh, there are some idea that balsamic vinegars and olive oils have some content. Naturally, a Di-methyl Butanol all remains to be seen in terms of whether it’ll have clinical utility. It’s not currently anything that’s part of the clinical recommendations. It’s dietary recommendations. There’s recently about a year and a half ago, been a meta analysis, of course, in the scientific world, not every study always is consistent with every other study. So overall there’ve been a lot of studies and there were 17 of high quality that could be combined. Looking at the blood level of TMAO and the risk for cardiovascular disease and cardiovascular death, and TMAO is associated with increased risk of all causes of mortality and major adverse cardiovascular events. So if you look over there, the higher is the TMAO level, the higher is the risk based on what quartile it’s in. For every increase in TMAO by 10 micro molar, there’s a 7.6% increase in relative risk for these bad outcomes. And the association between TMAO and all cause mortality was robust in subgroups, study populations. And you know, as is done in these studies, this is includes factoring in the other co-morbidities: smokers, high blood pressure, high cholesterol, gender, age. And these are independent associations beyond the known and established cardiovascular risk factors. So I can’t tell you how many times I’ve asked people smoking, diabetes, high blood pressure, high cholesterol, family history of premature coronary artery disease. It would appear that the 6th one on the list may be you know your blood TMAO level based on that study. So there is a commercially available blood test for determining TMAO in individuals who might benefit somebody with a family history of cardiovascular disease, somebody with an elevated cholesterol where an additional risk for atherosclerosis may be important to determine people with pre hypertension, hypertension for the same reason prediabetes, diabetes, smoking, obesity, you probably have more than enough ammunition to recommend these people lifestyle related measures. But the availability of a new and unique metabolite TMAO with this large amount of data recently published is another way of assessing risk. Yeah, hopefully motivating, motivating people to make lifestyle change. Follow a mediterranean diet and such. The lab test has been available since, uh, I want to say 2017, if my memory is correct. Um, there is a normal range or medium range in the high range. It’s been based on apparently healthy people that were in the cath lab and based on whether they had atherosclerosis or not um, it’s a simple, you know, serum blood test, uh, that is available for measurement in my own clinic. I think I’ve drawn 3 or 4000 TMAO blood levels in people. I’ve seen them change their lifestyles, seen repeat testing, change their supplements, repeat testing and such. So in conclusion, our gut microbes populating our digestive tract certainly play a role in our human health and metabolism. And one of the metabolites TMAO produced by gut bacteria is now associated with cardiovascular disease risk. In fact, most accurately, is a cause by inhibiting reverse cholesterol transport and enhancing forward cholesterol development of bone cell development of any choline product carnitine product are the substrate for TMAO production, whether they’re in food or whether they’re in energy drinks, whether they’re in supplements. Um, in our choices of food obviously affect their health, but they specifically affect this development of TMAO. And finally, other than the avoidance of eggs and meat, specific therapies are being pursued, I mentioned you Di-methyl Butanol (DMB), Mediterranean diet and others. I think we’ll be looking for more science. It’s an exciting area of science to follow on Pub Med. I resolved and I’ll just put in TMAO and see what’s new. It is now a worldwide pursuit of both further understanding of this, and I encourage you to stay up to date on that. So I’m going to say thank you, thank you to Quest, and we will try and take and answer any questions that the listeners have come up with. Thank you so much, Dr. Kahn. Yes. It is time for the questions. Also, they’ve been flooding in the door, so we’ll get to some of the chat questions right away. But first, operator, if you can review the instructions for anyone who would like to ask a live question. Thank you. We will now begin the question and answer session. If you’d like to ask a question, please press star followed by the number 1 and record your name at the prompt. Your name is required to introduce your question. To cancel your question press star followed by the number 2. Thank you. Dr. Kahn, we’ll start with we’ve had so many questions that are specific about diet and such, but I’m going to ask one that Bethany proposed. It says it sounds like foods rich in TMAO precursors plus gut dysfunction would create cardiac disease. If the gut is healthy, then this may not be an issue? Is that correct? Well, it is an unknown. It’s a great question in an unknown area of science because there isn’t studies yet that do careful and detailed analysis of the microbiome and blood levels of TMAO and dietary histories and have enough numbers and put it all together so you know exactly which bacteria are producing TMAO in the gut In our sites, there has been an attempt to study probiotics and TMAO, and there isn’t yet a probiotic known that lowers TMAO consistently, even though some of the most potent and well known probiotics have been studied. So that sounds reasonable, but it isn’t clearly known if a apparently healthy person with an apparent healthy gut continues to eat foods or supplements or drinks rich in carnitine and choline, will they form TMAO or will they develop atherosclerosis is unknown. Um, yeah. The only group that we know that isn’t very good at creating TMAO at this point are people who habitually don’t eat, uh, you know, meat and egg yolk. And that would be, you know, the plant based population. Thank you. Has there been any studies? I’ve got several questions about this, about commercial beef versus grass fed beef or Wagyu beef? Yeah, great question. That comes up. In fact, even this week in the news, um, you know, there’s a study out, if you haven’t seen it quite an impressive study by Dr. Ronald Krauss at UCSF on red meat, white meat, plant based protein and cholesterol serum levels. But they specifically said these were, uh, the 96% of the US population, that’s this statistic in the paper this week in the American Journal of Clinical Nutrition, 96% of the American public eats factory farmed meat. 4% of the American public eats grass fed beef. So in the study they just published, they used factory farmed beef because that represents the vast majority of Americans. None of these studies with TMAO have subset it out people eating grass fed beef. Now, if it’s carnitine, carnitine is going to be in beef, it’s not going to vary. We’re not talking about, you know, necessarily omega three composition and such. Thank you. Several people are asking about administering intravenously the l-carnitine if it bypasses the gut, does that still lead to increased levels of TMAO? I’m sorry, the administration of l-carnitine how? Intravenously. Oh, um, I would I would presume that that would not lead to TMAO elevation. Yes, it bypasses the gut. Um, I’m not sure how often other than like in TPN administration and check hospital patients carnitine is given I.V. but um, I think that would not likely be of much concern. Thank you. Operator. Let’s check and see if there’s any live questions. Yes. Our first question over the phone is from Ashley, Your line is now open. Okay. I was wondering, you have mentioned that you have used this TMAO test with your patients. Do you know if insurance companies cover the cost of it? And what was the cost on average for the patient? Yeah, I know for anybody that couldn’t hear well, cause at least from my end, I heard it but it was scratchy. The question is the availability of this blood test and the cost and frankly, the second part, I don’t know. I can only share that I’m in a real life practice where my patients, you know, use their insurance for lab work. And I’ve not encountered any difficulty ordering TMAO levels. And it’s thousands and thousands of people of all different kinds of insurance. Perhaps some of the other moderators of the webinar could answer more specifically. The test was developed at the Cleveland Clinic. It was licensed to Cleveland HeartLab, which is now a subsidiary of Quest Labs. Uh, it’s become much more available all over the United States at Quest, but I believe it’s exclusively through Quest, uh, which is still thousands of drop sites, right? Okay, perfect. Thank you. Yeah, there are no operator. Any other live questions? We don’t have any question at this time. Once again, to ask a question, please press star followed by the number 1. Thank you. Well, we have plenty, so we’ve we’ve got lots and lots. Here’s another question. Ron asks, How does the microbe change from childhood to adulthood following a treatment with antibiotics? Does the microbe return to normal or does it remain altered? That’s a fascinating question, and I’m not sure I actually know that. We do know that antibiotics will profoundly alter the microbiome temporarily, just as in these basic science studies, where a course of antibiotics clearly alter the microbiome because there was now the inability to produce TMAO that was present before the course of antibiotics. There are some interesting clinical studies on the rates of anxiety, depression and other actual markers of overall health in the weeks to months following a course of antibiotics in humans that have been used as, you know, an observation about the impact on our health of antibiotics, it’s led to the recommendation that, you know, treat when needed. But the overtreatment of upper respiratory infections with antibiotics that are probably viral should be curtailed. But specifically, you know, I have recently and I’m quoting others there are by about two years I think the the pediatric microbiome is very similar to the adult microbiome in terms of its complexity and components. And it’s very dependent on environment and dietary choices being, you know, whether they be quality foods, whole foods, some mixtures with whole food plants or whether properly processed food, fast food, high in saturated fat, sugar and salt. So and it changes. There’s a classic, classic amazing study from Pittsburgh University in Pittsburgh by Dr. Steven O’Keefe. If you take inner city people in Pittsburgh with a rather unattractive processed food diet and you for two weeks feed them a diet that represents the native diet of rural South Africa with roots and tubers and natural foods within two weeks, their microbiome completely transforms a much healthier microbiome. And they flipped the study. They took people living in rural South Africa and fed them like they were living in inner city Pittsburgh with Wendy’s and Hardee’s and McDonald’s and milkshakes. And their microbiome went to hell in two weeks. So it’s it’s a pretty quick transition, but it’s very hopeful that we can also, you know, improve upon it with a good long term whole food non processed emphasis on our diet. Thank you. Is a consumption of eggs and the red meat and the effect of of it on TMAO based on a daily consumption or something less frequently? Yeah. The frequency you know what if you’re a you know a there’s a there’s a famous book I call Vegan before 6:00 by Mark Bittman, New York Times food writer. I mean what if you eat meat one meal a day and plant based two meals a day? What if you eat fish on Friday and eat or eat red meat on Friday? That wouldn’t be very Catholic. But at any rate, all those questions are unknown. I mean, they’re taking healthy volunteers that describe their diet as omnivorous, which is usually one or two animal based meals a day, comparing them to, you know, either Mediterranean eaters or a vegetarian slash vegan self-described diets. But the nuance like, you know, if if you ate meat infrequently would you produce TMAO is not been studied. In my practice when somebody has a very high TMAO level not related to supplements and I encourage them to for 3 or 4 weeks alter their diet you know I don’t expect them to hear perfectly, adhere perfectly. But the TMAO level comes down very rapidly with dietary change. Egg white omelet rather than egg yolks it’ll come down quickly. If they’re on supplements and I’m not you know, I’m a very supplement friendly cardiologist. But if you know nobody has to take a choline or carnitine supplement and you stop it, you very rapidly will see the TMAO level drop dramatically. In fact, the highest level so far ever measured in humans in terms of TMAO have been from supplements, not even from food. Oh, and that that does lead to a couple of people asked which supplements specifically are harmful or beneficial? Well, again, we you know, we can’t say harmful or beneficial. We can just say which ones seem to elevate TMAO level and which ones don’t. And it’s you know, there’s really just l-carnitine is one family and it could be in a multivitamin multi supplement, it could be just l-carnitine alone. Choline, there’s a range of supplements with choline and phosphatidylcholine and such. So, um, you know, you need to read the label. The, the only shred of evidence for that being of concern right now other than a high TMAO blood level is there are studies both in animals and humans of giving acute loads of supplements rich in carnitine or choline. And one of the actions of TMAO appears to be increasing the propensity for platelet aggregation for platelet clumping, which could theoretically lead to clot formation and an acute load of l-carnitine, l-choline raising TMAO from supplements has resulted in measurements of increased platelet aggregation. So theoretically there are people that that would not be a good idea. Those that have atherosclerotic disease, strokes, TIAs, stents, and also it isn’t crystal clear that it’s dangerous to use carnitine and choline supplements in people. I have the habit and I have no data to publish, but I have the habit that if I do keep people on those supplements, I’ll measure their TMAO level. And if it’s sky high, I need to question with them. If that’s a choice, we’re going to continue or alter.

Page Published: October 17, 2023