How to Reduce Your TMAO Levels

Should we be concerned about high-choline plant foods such as broccoli producing the same toxic TMAO that results from eating high-choline animal foods such as eggs?

Choline- and carnitine-rich foods—meat, eggs, and dairy—can be converted by our gut flora into trimethylamine, which in our livers is then turned into TMAO, a toxic compound that may increase our risk of heart failure, kidney failure, and atherosclerosis, or heart attacks and strokes. The good news, though, is that this “opens up exciting new nutritional and interventional prospects” for prevention, as I discuss this in my video How to Reduce Your TMAO Levels.

Okay, so how do we do it? Well, if our gut bacteria can take meat, dairy, and eggs and turn them into TMAO, all we have to do is…destroy our gut flora! We could give people antibiotics to eliminate the production of TMAO. However, that could also kill our good bacteria and “facilitate the emergence of antibiotic-resistant bacterial strains.”

What about probiotic supplements? Maybe if we add good bacteria, they will crowd out the ones that take the meat, egg, and dairy compounds and turn them into the TMA that our liver turns into TMAO. But, that doesn’t work. Adding good bacteria doesn’t seem to get rid of the bad. What if we added new bacteria that could somehow siphon off the TMA made by the bad bacteria? Well, there’s a bacterium inside the guts of cows and sheep that turns trimethylamine into methane. Could we use that bacterium to get rid of some of the trimethylamine from our gut, like a cow fecal transplant? There’s a problem with that. If it didn’t take, you’d have to keep giving it to people: “Continuous administrations may be necessary if subjects do not become colonized.” So, might the fact that Consumer Reports found fecal contamination in every sample of beef it tested be a good thing? No. Methane-producing bacteria may be able to eat up our TMAO, but, unfortunately, these bacteria may be associated with a variety of diseases, from gum disease down to colorectal cancer, as you can see at 2:15 in my video.

If antibiotics and probiotics aren’t going to work to prevent gut bacteria from taking meat, dairy, and eggs and turning them into the trimethylamine, which our liver makes TMAO out of, I guess we have no choice but to cut down on…our liver function!

That was the billion-dollar answer to cholesterol. The same foods—meat, dairy, and eggs—raise our cholesterol, but dietary change isn’t very profitable. So, the drug industry developed statin drugs that cripple the liver’s enzyme that makes cholesterol. Could “pharmacologic inhibition” of the enzymes in our liver that make TMAO “potentially serve as a therapy for CVD [cardiovascular disease] risk reduction”? Trimethylaminuria is a genetic condition in which this enzyme is naturally impaired, in which there is a build-up of trimethylamine in the bloodstream. The problem is that trimethylamine is so stinky it makes you smell like “dead fish.” So, “given the known adverse effects…from sufferers of fish odor syndrome, the untoward odorous side effects of inhibiting this enzyme make it a less attractive [drug] target.”

Do we have to choose between smelling like dead fish or suffering from heart and kidney disease? If only there were some other way we could stop this process from happening. Well, what do those with trimethylaminuria often do to cut down trimethylamine levels? They stop eating animal products.

About a third of those who complain of bad body odor despite good personal hygiene test positive for the condition, but reducing or eliminating meat, egg, and dairy intake can be a real lifesaver. But, given what we now know about how toxic the end product TMAO can be for normal people, cutting down on animal products may not just save the social lives of people with a rare genetic disorder, but help save everyone else’s actual lives.

The “simplest point of intervention” is to simply limit the consumption of foods rich in choline and L-carnitine, which “can be an effective strategy to limit circulating TMAO.” But, wait! We could always try to genetically engineer a bacterium that eats up trimethylamine, but “the simplest and safest recommendation” may just be to eat more healthfully. You can completely eliminate carnitine from the diet, since our body makes all we need, but choline is an essential nutrient so we do need some. Thankfully, we can get all we need in fruits, vegetables, beans, and nuts. “However excess choline, such as that found in eggs, may be worth avoiding.”

Need we worry about high-choline plant foods, like broccoli? Consumption of cruciferous vegetables is associated with a significantly longer life and less cardiovascular disease mortality, as you can see at 5:34 in my video. To see what was going on, researchers took the vegetable highest in choline, brussels sprouts, and had people eat two cups a day for three weeks. What happened? Their TMAO levels actually went down. It turns out that brussels sprouts appear to naturally downregulate that TMAO liver enzyme—not enough to make you stinky, but just enough to drop TMAO.

And, people who eat completely plant-based may not make any TMAO at all—even if you try. You can give a vegan a steak, which contains both choline and carnitine, and there will not even be a bump in TMAO because vegetarians and vegans have different gut microbial communities. If we don’t eat steak, then we don’t foster the growth of steak-eating bacteria in our gut. So forget the cow—how about getting a fecal transplant from a vegan? From a TMAO standpoint, we may not have to eat like a vegan as long as we poop like one.


Can you sense my frustration as I read paper after paper proposing those ridiculous (but profitable!) answers when the safe, simple, side-effect-free solution was staring them in the face the whole time? It makes me think of so many parallels, not the least of which are:

For more on TMAO, the “smoking gun” of diet-microbiome-disease interactions, see:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Is Candida Syndrome Real?

Does the presence of Candida in stool correlate with “Candida-hypersensitivity” symptoms, such as headaches and tiredness? And what happens when people are placed on a high-sugar diet?

Despite its extensive use in the brewing and baking industries, only about 5 percent of healthy people—1 in 20—have anti-yeast antibodies in their bloodstream, whereas that percentage is more like 60 or 70 percent in people with Crohn’s disease. Most people with Crohn’s have antibodies that react to regular baker’s, brewer’s, or nutritional yeast, which are all just different forms of a yeast known as Saccharomyces cerevisiae.

But baker’s/brewer’s/nutritional yeast has never been directly implicated in Crohn’s. Maybe the antibodies are a direct reaction to it, or maybe they are a reaction to another yeast altogether and just mistakenly cross-react with regular yeast. Indeed, it was discovered that antibodies against Candida, a totally different kind of yeast (the yeast that causes thrush and vaginal yeast infections), can cross-react with Saccharomyces. Is it possible that baker’s/brewer’s/nutritional yeast was just an innocent bystander all along? I investigate this in my video Is Candida Syndrome Real?.

For nearly 30 years, we’ve known that antibodies to Saccharomyces are linked to Crohn’s disease, but instead of bread, beer, and nutritional yeast leading to Crohn’s disease, perhaps Candida is causing the Crohn’s disease and the antibodies. Or maybe Candida is the innocent bystander, and exposure to food and beverage yeast is the real culprit. You don’t know until you put it to the test: Remove yeast from the diet of Crohn’s patients, and see if they get better. If they do, then yeast was indeed the culprit. If they don’t? Then maybe Candida is the real cause.

Before I get to the study, let me first bust some Candida myths. Candida is a normal constituent of our gut flora. Get some Candida in your bloodstream, though, and it can cause a life-threatening infection. But it is normal to have some Candida in your mouth or colon—what’s important is location! location! location! It’s similar to how having stool bacteria in our colon is normal, but stool bacteria in our blood or a wound would be bad. Because of the ability of Candida to cause problems in the wrong location or in people who are immunocompromised, a Candida-syndrome theory arose, linking the presence of Candida to all sorts of health problems. This led to “mycophobia”—or fungalphobia—“spreading due to the false interpretation” that the finding of Candida in your mouth or stool is evidence of some kind of infection, rather than just being totally normal. (If you think the authors of that paper were being a little overdramatic with their phobia talk, just google “Candida” and you’ll see.)

Not only is it normal to have Candida in your gut, you apparently can’t get rid of it even if you wanted to. Give people powerful antifungal drugs, and you can drop levels down, but they pop right back up again as soon as you stop the antifungals. What about the concept that sugar feeds yeast, so you should go on a low sugar diet? It doesn’t make much sense because sugars should get absorbed high up in the small intestine and never even make it down into the colon unless you’re lactose intolerant. Indeed, there appears to be no correlation between Candida counts and sugar consumption. You can put people on a high-sugar diet by adding an additional 14 spoonfuls of sugar to their diets and still not see an effect. Of course, there are lots of science-based reasons to cut sugar from your diet, but Candida does not appear to be one of them.

There does not appear to be good “evidence for the existence of the so-called “Candida-syndrome” at all. But those are fighting words! “Few illnesses have sparked as much hostility between the medical community and a segment of the lay public as the chronic candidiasis syndrome.” The medical community has dismissed purported sufferers as emotionally disturbed and they’ve also been dubbed just plain crazy. Of course, you can’t just come out and call people crazy. “Psychiatric diagnoses need to be presented gently…” Some patients, for example, prefer to believe their mental illness is caused by the Candida, in which case doctors may just pat them on the head so they’ll take their pills. “However, patients self-diagnosed as having the yeast connection will only infrequently relinquish their illness”—some even to the extent they attempt to use their yeast as a drunk driving defense: I wasn’t drinking, your Honor. My yeast was just self-brewing beer in my gut!

The whole concept of Candida syndrome is officially derided by the American Academy of Allergy and Immunology as “speculative and unproven,” without any proof that it exists. The presumption that “the ubiquitous C. albicans [Candida] has some toxic effect on the human immune system…[is] without a trace of clinical evidence or scientific proof.” If you want proof, argued a response to the study, what about the millions of unnecessary tonsillectomy surgeries and all the radical mastectomies? At least putting people on low-sugar diets doesn’t disfigure them. Though some anti-Candida therapies can be “potentially dangerous,” antifungal drugs might breed resistance and can have side effects. Nystatin isn’t so bad, but ketoconazole can damage your liver. And, indeed, there are reports of people being treated for what may be a fake diagnosis and ending up in quite dire straits because of it. So, it’s important to know if the syndrome actually exists. Researchers decided to put it to the test in a super simple study: Give subjects stool-tubes to take samples, and ask them questions about their symptoms—headaches, stomachaches, tiredness, and all the other typical Candida syndrome symptoms. The result? The researchers found no relationship to whether or not the subjects had Candida growing in their guts. No hints of Candida syndrome could be found.


This was a bit of a tangent from the topic of my video Does Nutritional Yeast Trigger Crohn’s Disease?. I return to that topic in my video Is Nutritional Yeast Healthy for Everyone? and then offer hope for sufferers of another inflammatory condition in Dietary Cure for Hidradenitis Suppurativa.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Arsenic in Rice Milk, Rice Krispies, and Brown Rice Syrup

I recommend people switch away from using rice milk

For kids and teens, the amount of arsenic flowing through their bodies was found to be about 15 percent higher for each quarter cup of rice consumed per day, and a similar link was found in adults. A study of pregnant women found that consuming about a half cup of cooked rice per day could raise urine arsenic levels as much as drinking a liter of arsenic-contaminated water at the current upper federal safety limit. These findings “suggest that many people in the United States may be exposed to potentially harmful levels of arsenic through rice consumption.” which I explore in my video Arsenic in Rice Milk, Rice Krispies, and Brown Rice Syrup.

Do you know where Americans get most of their rice arsenic? From Rice Krispies, though brown rice crisps cereal may have twice as much, as I discuss in my video Arsenic in Rice Milk, Rice Krispies, and Brown Rice Syrup.

“Organic brown rice syrup (OBRS) is used as a sweetener in organic food products as an alternative to high-fructose corn syrup.” Big mistake, as organic brown rice syrup products “may introduce significant concentrations” of toxic arsenic into people’s diets. For example, two energy chews sweetened with brown rice syrup might hit the provisional upper daily arsenic intake based on the water standards.

“Toddler formulas with added organic brown rice syrup have 20 times higher levels of inorganic [toxic] arsenic than regular formulas,” and in older children, thanks to brown rice syrup, a few cereal bars a day “could pose a very high cancer risk.”

What about rice milk? A consensus statement of both the European and North American societies for pediatric nutrition recommends the “avoidance of rice drinks for infants and young children,” and, generally, toxic “inorganic arsenic intake in infancy and childhood should be as low as possible.”

To this end, the United Kingdom has banned the consumption of rice milk for young children, a notion with which Consumer Reports concurred, recommending no servings a week of rice milk for children and no more than half a cup a day for adults, as you can see at 1:56 in my video.

The arsenic in various brands of rice milk ranges wildly—in fact, there’s a 15-fold difference between the highest and lowest contamination, suggesting manufacturers could make low arsenic rice milk if they wanted. As you can see at 2:16 in my video, Consumer Reports found rice drinks from Pacific and Rice Dream brands were right about average, though, for Rice Dream, it appears the vanilla or chocolate flavors may be lower. It doesn’t seem we have anything to worry about with rice vinegar, but rice pasta and rice cakes end up similar to pure rice in terms of arsenic levels, which makes sense because that’s pretty much what they are—pure rice. However, pasta is boiled, so we’d expect the levels to be cut 40 to 60 percent, like when you boil and drain rice.

If you just couldn’t live without rice milk for some reason, you could make your own using lower arsenic rice, like brown basmati from India, Pakistan, or California, but then your homemade rice milk might have even less nutrition, as most of the commercial brands are at least fortified. Better options might be soy, oat, hemp, or almond milk, though you don’t want kids to be drinking too much almond milk. There have been a few case reports of little kids drinking four cups a day and running into kidney stone problems due to its relatively high oxalate content, which averages about five times more than soy milk. More on oxalates in my video series starting with Oxalates in Spinach and Kidney Stones: Should We Be Concerned?

I have about 40 videos that touch on soy milk, discussing such topics as how it may normalize development in girls and reduce breast cancer risk, as well reduce prostate cancer risk in men. Some of the latest science on soy milk includes an association with better knee x-rays, suggesting protection from osteoarthritis, and an interventional study suggesting improved gut health by boosting the growth of good bacteria. However, drinking 3 quarts a day, which is 10 to 12 daily cups, for a year may inflame your liver, but two cups a day can have an extraordinary effect on your cholesterol, causing a whopping 25 percent drop in bad cholesterol after just 21 days.

An ounce and a half of almonds, about a handful, each day, can drop LDL cholesterol 13 percent in six weeks and reduce abdominal fat, though a cup of almond milk only contains about ten almonds, which is less than a third of what was used in the study. So, it’s not clear if almond milk helps much, but there was a study on oat milk compared to rice milk. As you can see at 4:37 in my video, five weeks of oat milk lowered bad cholesterol, whereas rice milk didn’t, and even increased triglycerides and may bump blood pressure a bit. However, the oat milk only dropped LDL about 5 percent and that was with three cups a day. As plant-based alternatives go, it appears soy milk wins the day.

So, why drink rice milk at all when there are such better options? There really isn’t much nutrition in rice milk. In fact, there are case reports of severe malnutrition in toddlers whose diets were centered around rice milk due to multiple food allergies. Infants and toddlers have increased protein requirements compared to adults, so if the bulk of a child’s diet is rice milk, coconut milk, potato milk, or almond milk, they may not get enough, as you can see at 5:23 in my video. In fact, cases of kwashiorkor—that bloated-belly protein- and calorie-deficient state of malnutrition—due to rice milk have been reported in Ethiopia…and Atlanta, Georgia, because literally 99 percent of the child’s diet was rice milk. So, these malnutrition cases were not because they drank rice milk, but rather because they drank rice milk nearly exclusively. I just use these examples to illustrate the relative lack of nutrition in rice milk. If you’re going to choose a milk alternative, you might as well go for one that has less arsenic—and more nutrition.

I have released several videos on soy milk, but only one on almond milk video so far: Prostate Cancer and Organic Milk vs. Almond Milk. I plan on producing many more on choosing between various milk options, so stay tuned.


If you’ve missed any of the useful material on dietary arsenic I’ve also shared, please see:

The final four videos in this series take all of this information and try to distill it into practical recommendations:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: