Researchers have zeroed in on TMAO, trimethylamine-N-oxide, as a new culprit in heart disease. “We’ve long recognized that two individuals could have the same LDL—or bad—cholesterol, yet one goes on to develop heart disease and one doesn’t,” says the Cleveland Clinic’s Stanley Hazen.
That started the hunt. “First we said, ‘Let’s look at all the compounds in the blood that differ between people who have heart disease and people who don’t,’” recalls Hazen. “And we discovered that TMAO was one of the top things that tracked with risk.” But where did the TMAO come from?
When bacteria in our intestines “eat” carnitine or choline, they make TMA (trimethylamine), which gets converted to TMAO in the liver. Carnitine is found largely in red meat. Egg yolks and liver have the highest levels of choline, but it’s also in meat, poultry, fish, grains, vegetables, and other foods.
“You can’t get away from choline,” says Hazen. “It’s in everything, and you don’t want to completely eliminate it from your diet. If you got absolutely none, you’d get a deficiency, just like you’d get scurvy if you didn’t get any vitamin C. So you can’t eat your way out of that problem.”
Until we know more, you can hedge your bets by cutting back on red meat and ditching supplements of carnitine, choline, or choline’s most common form, phosphatidylcholine (lecithin).
“Unless you’ve been instructed by your physician to take carnitine, which can happen with mitochondrial disorders or with long-term dialysis, you probably don’t need it,” says Hazen. “Your body can make all the carnitine it needs even if you’re a vegan or never eat any meat.”
You don’t need choline supplements either. “Deficiencies are exceedingly rare,” says Hazen. “We just don’t see it in the United States. You have to be very malnourished.”
“There’s a potential for long-term risk from both carnitine and choline,” he adds. “And I know of no clear, hard benefit for an otherwise healthy person. Supplement companies may argue that they’re helpful because they’re nutrients. But cholesterol is a nutrient too, and we don’t take cholesterol tablets.”
And don’t bother asking your doctor to test your TMAO. “Unfortunately, the test isn’t currently available for clinical use,” says Hazen. “It should be before the end of the year .”
Other relevant links:
- How consuming triglycerides leads to plaque build-up. See: Why are Triglycerides Linked to Heart and Disease?
- Studies continue to link red meat with a shorter life. See: Eat Less Red Meat, Live Longer
- Do you want to know the best diet for avoiding heart disease? See: How to Diet – Best Menu Planning Guide for a Heart-Healthy Diet