Summary

Elevated levels of the amino acid homocysteine are a risk factor for heart disease, and folic acid can lower them. However, a long-term trial of folic acid, and other B vitamin, supplementation in a large group of women did not show any benefit in terms of reduced risk of heart disease.

Introduction

We already know that there is a direct link between homocysteine levels and heart disease risk. Folic acid, a B vitamin abundant in citrus fruits and leafy green vegetables (folic comes from the Latin word for 'leaf) can reduce homocysteine levels - this much is known from many studies. It might seem a logical next step that folic acid supplements can reduce heart disease risk. And if there were so, it would be a simple measure that could greatly reduce the risk of heart disease and stroke. But, till now, the studies that have been done on folic acid supplementation and heart disease have given rather mixed results. Moreover, the studies have not included many women. Past menopause, women face the same heart disease risk as men do, so they need to know whether folic acid can help them.

What was done

The Women's Antioxidant and Folic Acid Cardiovascular Study was set up to determine whether a combination of folic acid, vitamin B6 and vitamin B12 could prevent heart problems women who either had a history of heart disease or a high risk of developing it. A group of 5,442 women aged 42 years or older enrolled in the study and received a daily combination pill containing 2.5 milligrams of folic acid, 50 milligrams of vitamin B6 and one milligram of vitamin B12, or a placebo. The study lasted for around seven years, during which time incidences of heart attack, stroke, coronary revascularization - a procedure to open blocked arteries - or death from cardiovascular disease were recorded.

What was found

During the study, 14.6 percent of the women experienced some kind of cardiovascular event, as described above, on one or more occasions. No difference was observed between the vitamin group and the placebo group. Not that the supplement was not doing its job - levels of homocysteine were 18.5 percent lower in the vitamin group.

What this study means

The researchers note that similar outcomes have been seen among men with a history or risk of heart problems, so maybe these new findings are no great surprise. However, this study group of women had already developed heart disease, or were at risk of it. It is still possible that folic acid and other B vitamins may have a role in primary prevention - that is, among women who are healthy with no risk factors. Folic acid is an important component of the diet - but it may be best to boost your intake of foods containing it, rather than rely on supplements.