Harvard Heart Letter

Heave-ho for homocysteine?

High doses of B vitamins lower homocysteine but don't fix heart disease.

After a troubled and contentious birth, the homocysteine hypothesis grew up to be embraced by some doctors, researchers, and a public hoping for an easy and inexpensive fix for heart disease. According to this theory, homocysteine — a by-product of protein digestion — wreaks havoc in blood vessels and contributes to the artery-clogging process known as atherosclerosis. If that's true, then lowering homocysteine levels in the blood with a trio of B vitamins should fight atherosclerosis.

There's just one small problem. So far, this strategy isn't paying off where it counts — preventing heart attacks, strokes, and other forms of cardiovascular disease. Three large trials, two of them presented at the annual meeting of the American College of Cardiology and published in the April 13, 2006, New England Journal of Medicine, show no benefit from high-dose B vitamins.

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