Folic acid occurs in a wide variety of foods. Best sources include dark green leafy vegetables, brewer's yeast, liver, and eggs. Other good sources are beets, broccoli, brussels sprouts, orange juice, cabbage, cauliflower, cantaloupe, kidney and lima beans, wheat germ, and whole grain cereals and breads. The body's “friendly” intestinal bacteria also produce folic acid.

Interactions

Drug/Nutrient Interactions • Aluminum and magnesium containing antacids • Bile acid sequestrants • H-2 receptor antagonists • Potassium-sparing diuretics Drug/Nutrient Depletions • Alcoholic beverages • Anticonvulsants • Salicylates • Corticosteroid medications • Nonsteroidal anti-inflammatory medications (NSAIDs) • Oral contraceptives • metformin • methotrexate • Trimethoprim-containing antibiotics • sulfasalazine

In women, folic acid is crucial for closure of the fetus' neural tube during pregnancy. This makes adequate folic acid levels essential for preventing neural tube birth defects such as spina bifida.(2, 3, 4) In general, pregnancy increases a woman's requirements for folic acid.(5, 6) Women with higher intakes of folic acid may have a reduced risk of ovarian cancer.(7) Also, of importance to women, folic acid may treat cervical dysplasia and decrease the necessity of hysterectomies.(8)

Studies also suggest that many people with major depression or schizophrenia may benefit from folic acid supplementation.(9) Benefit may also be extended to alcoholics, who are commonly deficient in folic acid.(9) One form of anemia that arises from folic acid deficiency can also be reversed with supplementation.(10)

Studies have shown cognitive skills such as knowing, thinking, learning, and judging can be impaired in older adults with low levels of certain B vitamins. Supplementation with folate, vitamin B12, and vitamin B6 has been effective in enhancing cognitive performance in older adults.(11) In fact, studies in older adults noted that subjects with low levels of vitamin B12 or folate had more of a risk of developing Alzheimer's disease.(12, 13)

Folic acid can also lower homocysteine levels, even when the levels are increased by lipid lowering medications.(14, 15, 16, 17, 18) Because homocysteine is an amino acid that is a significant risk factor for atheroslerosis, folic acid may prevent the development and progression of the disease.(19) The same effect has been noted when folic acid is given in conjunction with vitamin B6.(20) Hemodialysis patients were treated with B-vitamins and folic acid which significantly lowered homocysteine levels.(21) Dietary supplementation with the B-vitamins prevented hyperhomocysteinemia but did not prevent the development of vascular dysfunction or atherosclerotic lesions.(22) Other studies involving hundreds of patients who had undergone successful coronary angioplasty have evaluated these individuals following six months of therapy on vitamin B6, vitamin B12, and folic acid, comparing the results to patients on placebo. After one year, the patients on the vitamin therapy had lower rates of related cardiovascular events including heart attacks and repeated angioplasty.(23, 24) Homocysteine can also interfere with normal bone structure, folic acid's homocysteine-lowering function may also be of benefit in the prevention of osteoporosis.(25, 26, 27)

Finally, folic acid in mouthwash form may offer treatment for inflammation of the gums, or gingivitis.(28)

Large doses of this dietary supplement may mask vitamin B₁₂ deficiency.(30)