B vitamins and homocysteine

There is some evidence that B vitamins, including folic acid, B₆, and B₁₂, may help lower blood levels of a substance called homocysteine. Why is this important? A good deal of research has implicated high homocysteine levels in heart disease and stroke. One analysis of several studies found folic acid cut down homocysteine levels by about a fourth, according to a 2002 article in the Journal of the American Medical Association. When folic acid was combined with vitamin B12, homocysteine levels sank another 7%. In this study, B6 had no additional effect. The Nurses’ Health Study, however, found that folic acid and B6 offered more protection as a duo than when used alone. The risk of heart attack or death from heart disease was nearly halved among women who consumed the most folic acid and B6 from diet and supplements compared with those who consumed the least. Smaller but still significant effects occurred with folic acid or vitamin B6 alone.

Several large trials should provide more definitive information that will apply to a broader range of people. Meanwhile, aim to get the DRIs for these nutrients: 400 mcg of folic acid, 1.3 mg of B₆, and 2.4 mcg of B12. You can get these vitamins by taking a multivitamin each day and eating foods such as lentils and other legumes, nuts, and vegetables as well as fortified breads and cereals.

B vitamins

Just how mighty could a few vitamins be? One analysis of multiple studies found that folic acid lowered homocysteine levels by about 25%, according to a 2002 review article in the Journal of the American Medical Association. When folic acid was combined with vitamin B12, homocysteine levels sank another 7%. In this study, the addition of B6 had no effect.

The Nurses’ Health Study, however, found that folic acid and B₆ offered more protection as a duo than when used alone. The risk of heart attack or death from heart disease was nearly halved among women who consumed the most folic acid and B₆ from diet and supplements compared with those who consumed the least. Smaller but still significant effects occurred with folic acid or vitamin B₆ alone.

In yet another study that supports the role of B vitamins, a small, randomized controlled trial of elderly people who were first given folic acid and riboflavin (vitamin B₂) for several weeks found that low-dose vitamin B₆ supplementation for three months effectively lowered homocysteine levels. The next step for researchers is to show whether suppressing high homocysteine levels can really ward off heart disease. So far, one small, randomized controlled trial of people who’d had angioplasty has shown that it can help. Significantly fewer deaths, nonfatal heart attacks, or repeat angioplasties occurred among patients given folic acid, vitamin B₁₂, and vitamin B₆ compared with those who got a placebo. Several large trials should provide more definitive information for a broader range of people.

Significantly fewer deaths, nonfatal heart attacks, or repeat angioplasties occurred among patients given folic acid, vitamin B₁₂, and vitamin B₆ compared with those who got a placebo. Several large trials should provide more definitive information for a broader range of people.

From the Special Health Report from Harvard Medical School
The Benefits and Risks of Vitamins and Minerals: What You Need to Know