People who get enough folate in their diets seem to have a lower risk of stroke than those who eat fewer folate-rich foods.

The results are based on nutritional surveys of almost 10,000 adults conducted between 1971 and 1975 as part of a nationwide government health survey. The study authors also used medical records and death certificates to assess who amongst those surveyed later suffered stroke or cardiovascular disease.

The researchers showed that over an average of 19 years, people who reporting consuming the most dietary folate were 21% less likely to suffer stroke than people who ate the least amount of dietary folate.

Folate, also known as folic acid, is a B vitamin. Previous research has shown that extra amounts of folic acid help reduce levels of an amino acid called homocysteine, which certain studies have suggested can decrease a person's risk of having a stroke. It has been suggested that an excess of this amino acid, which the body makes when it absorbs and uses protein, can somehow weaken the walls of the arteries that lead to the brain.

Folic acid is naturally found in fruits and vegetables. Recently, the US government mandated that manufacturers fortify grain products with folic acid, adding 140 micrograms to every 100 grams of flour, rice, pasta and cornmeal.

Stroke May 2002;33