Folic acid, or folate, belongs to the family of B vitamins. Folic acid was first identified in the 1930s as helping to prevent anemia, or a low level of red blood cells. It has also been found to help prevent neural tube defects, such as spina bifida, which is why women are encouraged to consume enough of this nutrient during pregnanacy. According to the American Dietetic Association, the B vitamins, including folic acid, also contribute to the metabolic, or energy-producing, process in the body.
The USDA maintains that the average Recommended Daily Allowance, RDA, of folic acid is 400 μg/d. For women of child-bearing age, this increases to at least 600. Folic acid was named from the Latin word folium, or leaf, as noted by the American Cancer Society, because it is found in green leafy vegetables. The American Dietetic Association states, "Easing folic acid into your eating plan is easy: the delicious way is eating folate-rich foods."
Fruits, Vegetables and Legumes
The National Institutes of Health (NIH) confirm that 1/2 cup of cooked spinach has about 131 μg/d, the same amount of asparagus has about 132 μg/d, and 1/2 cup of cooked broccoli has about 39 μg/d. Beans, including black beans, lentils, pintos and kidney beans, offer a range of 50 to 100 μg/d per serving. Citrus fruits, like oranges, are an excellent source of folic acid. One medium orange provides over 50 μg/d. Avocados are also a good source of folate.
Other Food Sources
Beef and chicken liver provide a large amount of folate. A 3 1/3 ounce serving of chicken liver provides over 700 μg/d of folic acid. The same amount of beef liver provides a little over 200 μg/d. Whole grains offer folic acid in the range of 60 to 120 μg/d per serving, and breakfast cereals provide anywhere from 100 to 400 μg/d. One tablespoon of wheat germ has 38 μg/d.
Due to extensive research regarding the preventive effects folic acid has on neural tube defects, a law was passed in 1998 requiring all grains and cereal products to be enriched with folic acid. Though many whole grains and cereal foods naturally contain folate, most of the absorbed folic acid from these foods is, in fact, man-made, according to the website of the National Toxicology Program of the NIH. Flour, by law, is enriched with folic acid. The USDA reports that no adverse effects from folic acid intake have been documented.
Natural sources of folic acid include a variety of fruits, vegetables, grains and some animal products, such as liver. Most registered dietitians, and the American Dietetic Association, recommend a balanced diet that includes a variety of foods, representing each food group. This type of diet will offer the necessary amount of folic acid. But, when an individual's diet, especially for a woman of childbearing age, does not include each food group, especially fruits, vegetables and grains, supplemental folic acid is indicated.