Most pregnant women will know the importance of taking folic acid pills. For decades a daily dose of 400 microgram (mcg) has been recommended even if a woman is simply trying to conceive – and if she then becomes pregnant, to take the folic acid for the first twelve weeks. The reason for this is that folic acid, a man made version of the B vitamin folate, protects babies in the womb against spinal and brain deformities.
A major study by University of Toronto scientists found that pills taken by millions of people – from multivitamins and vitamin D, to calcium and vitamin C – won’t reduce the risk of heart disease or help you live longer. The exception was folic acid. This seems to be the silver bullet for heart attacks and strokes.
The findings were based on a review of the results of all previous major studies. The benefits of folic acid emerged in a large study from China included in the review.
It involved more than 10 000 men and women with high blood pressure – and therefore at high risk of a stroke – and found those taking a daily 800 mcg folic acid tablet, as well as the prescribed blood pressure pills, were up to 75% less likely to have a stroke than those on blood pressure pills alone. Less than 2% of patients on folic acid supplementation and blood pressure pills for at least four years suffered a stroke.
Folic acid is a form of folate, a type of B vitamin found in green vegetables including spinach, broccoli, asparagus and Brussels sprouts as well as beans, citrus fruits and whole grains. Many breakfast cereals and some types of bread are also fortified with folate.
The body needs a regular supply of folate (about 200 mcg per day for an adult) to produce healthy red blood cells – and most people get what they need from their diet.
A daily intake of 200 mcg of folate is equivalent to six or seven asparagus spears a day, or a dozen Brussels sprouts. As we cannot store the vitamin, we need it in our diet every day.
Studies highlighting the potential benefits of folic acid for cardiovascular disease first emerged more than 20 years ago. These studies suggested that folic acid works by lowering the levels of homocysteine in the blood. Folic acid releases an enzyme that stops the formation of homocysteine. Some studies suggest eating excessive amounts of protein – such as red meat – can increase homocysteine levels, and that this damages the walls of arteries, leading to increased risk of heart disease and stroke.
A 2014 US study found taking daily folic acid supplementation could cut the risk of a heart attack by around 25%. A professor of cardiology at Barts Health NHS Trust, David Walt, says the case for folic acid is conclusive. He says a study nearly 20 years ago showed that harmful homocysteine levels can be lowered by taking folic acid. Increasing the folic acid intake could cut the number of strokes by an additional 10%.