As a fetus grows, it steals folates from the mother's blood, which in turn creates a shortage in the mother. In addition, preliminary evidence suggests folic acid may protect against colorectal and lung cancers. Because of its control over homocysteine, an amino acid produced by the body, folates are thought to afford some protection against heart disease. High levels of homocysteine in the blood may be a risk factor for heart attacks. Many foods contain a little folic acid, but the best sources are legumes, yeast, dark green leafy vegetables, some fruits, whole grains and fortified cereals.
Folic acid has a higher absorption rate than natural occurring folate.
Lengthy cooking can destroy folates. A study conducted by Subar et al. 2 showed that the major contributors of folate in the United States diet are orange juice, white bread, rolls, crackers and dried beans. This study was conducted in 1989, long before the fortification law for adding folic acid to refined grain products was enacted. A study conducted by General Mills from 1990-92 showed that 34.8 percent of the total folic acid intake of the general population came from grain products.