Currently having an existential crisis over my stash of L-Carnitine, a supplement I have used off and on for about 10 years. I am now being loudly informed it can cause heart disease. Oh, such fabulous news!
The reason I started taking it, was because I learned it was an amino acid mostly concentrated in red meat and dairy... and as a vegetarian I assumed (there's that word, ASSUME) that any nutrient I would be missing out on (by eliminating meat from my diet), must somehow be necessary. That is so WESTERN of me; it certainly never occurred to me that one basic reason vegetarians have lower rates of heart disease might be due to the actual CARNITINE ITSELF, duh! (who knew?)
Apparently, it is. From HuffPo comes the following report, emailed to me simultaneously by three different people:
Two years ago, [cardiology researcher Dr. Stanley] Hazen and his research team discovered that microorganisms in the intestines can convert substances found in choline, a common dietary fat, to a by-product known as TMAO, trimethylamine-N-oxide.Italics mine.
This new study looked at l-carnitine, which has a similar chemical structure to choline.
Carnitine is a nutrient found at high levels in red meat, but fish, poultry, milk and other dairy products are also good food sources of it. Carnitine is also a popular over-the-counter diet supplement, often billed as helping to boost energy and bulk up muscle. It's found in some energy drinks and muscle milks.
The researchers looked at fasting levels of blood carnitine in nearly 2,600 men and women. The findings showed that carnitine levels could quite strongly predict participant's risk of existing coronary artery disease, as well as the risk of having a major cardiac event, such as heart attack, stroke, or death over a three-year period, but only in adults who had high blood levels of TMAO.
Hazen's group also compared mice fed their normal chow, which is basically a vegetarian diet, with mice whose food was supplemented with carnitine.
"We saw that carnitine supplements doubled the rates of atherosclerosis in the mice," Hazen said. It did this by dramatically increasing levels of TMAO, which is produced by gut bacteria that metabolize l-carnitine.
As for how carnitine in red meat may be linked with heart disease, Hazen explained that chronic ingestion of carnitine fundamentally shifts the metabolism of cholesterol. "It's changing it in a way that will make you more prone to heart disease," he said. Eating carnitine causes more cholesterol to be deposited onto artery walls, and less to be eliminated from the body.
My existential crisis also comes from the fact that I have counseled approximately 40,000 (give or take) people to use it, also. (sigh) It was my job, remember? (sigh again) I even talked to a vegetarian cardiologist from India who told me he believed heart-conduction disorders in vegans might be related to a general lack of carnitine in vegan/vegetarian diets. He believed this because heart-conduction issues are more common in India (he said) than in the West, although coronary artery disease is more common in the West than in India. (Maybe they are both right? Is there NO WAY to win?)
And now, of course, you know what's happening... I am worrying about all of my other supplements. Good God. Its the domino effect! (I refuse to relinquish my beloved Ashwagandha, but I am now skeptical of other amino acids, such as L-Arginine... even though I really like its effects!)
In any event, I figured I would try to undue some of the damage by sharing this disturbing health information. I guess the vegetarian impact on my karma is intact (which is comforting), but the health effects? Probably a wash, at this point. Since carnitine is expensive (and I guess that will quickly change!), I have often gone without it for long periods. I have usually picked it up again because I noticed an energy boost from it... perhaps this mimics the energy boost from red meat? I assumed (there's that word again) that this meant it was a good thing, since ENERGY = GOOD. Again, Western stupidity writ large, yes? I mean, meth gives you energy too, and we all recognize that its not the good kind.
Yes, I trashed my L-Carnitine, and so should you.