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Choline and carnitine-rich foods—meat, eggs, and dairy—can be converted by gut flora into trimethylamine, which can then be turned into TMAO in our liver—a toxic compound which may increase our risk of heart failure, kidney failure, and atherosclerosis (heart attacks and strokes). The good news is, though, that this “opens up exciting new nutritional and interventional prospects” for prevention.
Okay, so how are we going to do it? 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…strains.”
Hmm. How about probiotic supplements? Maybe if we add good bacteria, it will crowd out the ones that take the meat, egg, and dairy compounds, and turn them into TMA, which our liver turns into TMAO. But, it doesn’t work. Adding good bacteria doesn’t seem to get rid of the bad.
What if we added a new bacteria that could somehow siphon off the TMA made by the bad bacteria? Well, there’s a bacteria inside the guts of cows and sheep that turns trimethylamine into methane. So, maybe we could use the bacteria to get rid of some of it from our gut, like a cow fecal transplant. The problem is, if it didn’t take, you’d have to keep giving it to people. So, maybe the fact that Consumer Reports found “fecal contamination” in every sample of beef they tested may 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.
So, 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. These same foods raise our cholesterol, but dietary change isn’t very profitable. So, the drug industry came up with statin drugs that cripple the liver enzyme that makes cholesterol. So, hey, “pharmacologic inhibition of” the enzymes in our liver that make TMAO could “potentially serve as a therapy for [cardiovascular disease] risk reduction.” But, there’s a genetic condition in which this enzyme is naturally impaired, called trimethylaminuria, in which there is a buildup of trimethylamine in the bloodstream. The problem with that is that trimethylamine is so stinky, it makes you smell “like dead fish.” So, “given the known adverse effects…from sufferers of [this] fish odor syndrome, the untoward odorous side effects…make it a less attractive [drug] target.” So, do we have to choose between smelling like dead fish, or suffering from heart and kidney disease?
If only there was some other way we could somehow 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 really bad BO, 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 [just] 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 bacteria that eats up trimethylamine, but the simplest, safest recommendation may just be to eat healthier. You can completely eliminate carnitine from the diet, since our body makes all we need. But choline is an essential nutrient. So, we need some, and 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? Cruciferous vegetable consumption is associated with a significantly longer life: less cardiovascular disease mortality. 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, and their TMAO levels actually went down. It turns out that Brussels sprouts appear to downregulate that TMAO liver enzyme naturally—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 choline and carnitine, and not even a bump in TMAO, since 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, hey, forget the cow—how about getting a fecal transplant from a vegan? From a TMAO standpoint, maybe we don’t have to eat like a vegan, as long as we poop like one.
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