Folic Acid

Many people with depression may be suffering from low folate status. A recent study by the US Department of Agriculture and Tufts University found that subjects who met criteria for a lifetime diagnosis of major depression had folate concentrations lower than those of subjects who had never been depressed. In studies of depressed patients, 31 to 35 percent have been shown to be deficient in folic acid. In elderly patients, this percentage may be even higher.

Folic acid exerts a mild antidepressant effect, presumably via its function as a methyl donor in the manufacture of brain neurotransmitters and DNA. Folic acid supplementation has been shown to increase methylation reactions in the brain, leading to an increase in serotonin.

Folic acid and other methyl donors also reduce body concentrations of homocystine, which is implicated in a variety of conditions, including atherosclerosis, cancer, and osteoporosis. In osteoporosis, elevated homocystine levels lead to a defective bone matrix by interfering with the formation of proper collagen (the main protein in bone).

Homocystine may also promote atherosclerosis by directly damaging the artery as well as reducing the integrity of the vessel wall. Consequently, elevated homocystine levels are an independent risk factor for developing heart attack, stroke, or peripheral vascular disease. It is estimated that folic acid supplementation of 400 mcg daily would reduce the number of heart attacks Canadians suffer each year by 10 percent.

Folic acid supplementation beginning either before or very early on in pregnancy and continued throughout has also been shown to prevent the birth defect spina bifida. Daily consumption of 400 mcg folic acid by women of childbearing age may reduce incidence of this neural tube defect.

Long-term folic acid supplementation has also been shown to reduce the risk of colon cancer by 75 percent and may produce equally impressive results for other cancers. Folic acid supplementation has resulted in improved or normalized Pap smears in patients with cervical dysplasia, probably because many abnormal Pap smears reflect folate deficiency rather than true dysplasia. This is especially true in women who are pregnant or taking oral contraceptives because estrogens antagonize folic acid.

Not only do estrogens interfere with folic acid absorption but alcohol, various chemotherapy drugs (especially methotrexate), sulphasalazine (a drug used in the treatment of ulcerative colitis), barbiturates, and anticonvulsant drugs also reduce its function. Oral pancreatic extracts containing trypsin and chymotrypsin may also reduce folic acid absorption, so they should be administered away from folate supplementation.

Folic acid supplementation should always include 400 to 1,000 mcg vitamin B12 daily as folic acid supplementation can mask an underlying vitamin B12 deficiency. The danger is that while folic acid will reverse the macrocytic anemia it will not prevent or reverse the neurological symptoms of a vitamin B12 deficiency.

Given the critical role of folic acid in brain chemistry as well as in the prevention of cancer and heart disease, supplementation with a daily dosage of 400 to 800 mcg per day makes a lot of sense.