Some studies also have shown that taking high levels of folic acid in addition to beta carotene, vitamin C and fiber, may reduce the risk of some cancers. One study of 50,000 women claims to have shown that taking adequate amounts of folate reduced the risk of breast cancer. In addition, deficiency of folate (folic acid) has also been linked to heart disease and male infertility.

The minimum US RDA for folic acid is 400 micrograms per day for men as well as women. Bear in mind, supplements usually contain more than this amount. Besides liver, dark leafy greens, and brewer's yeast, folic acid can be found in some seafood, milk and orange juice. You can find smaller amounts of folic acid in whole grains and some root vegetables.

When taking folic acid supplements (or any supplements for that matter), it is important not to overdo it. Adverse side effects from folic acid supplements are rare but can occur if the dose exceeds 15,000 mcg. It is interesting to note that because B vitamins work together, taking any one of them alone can cause a deficiency in the others.

If you think you need to take a folic acid supplement, talk to a healthcare professional to see if it is right for you. Some medicines like antibiotics and warfarin can react adversely to supplementing with folic acid, and ibuprofen and aspirin can cause a deficiency. Methotrexate, which is used to treat some cancers as well as rheumatoid arthritis, increases the body's need for folic acid. Adding this vitamin to your supplement list can greatly reduce its side-effects while still keeping the effectiveness, so if you must take this drug, be sure see your health care professional about adding folic acid to your diet.