Nutrition and Weight Control Special Report
Research Update on Folate
Recently, the American Heart Association (AHA) removed folic acid from its list of dietary supplements that might help prevent heart attack or stroke. The research behind the AHA’s decision raises questions about the other purported benefits of folic acid. Is folic acid still worth considering?
Folate is a type of B vitamin that is found naturally in foods such as leafy green vegetables, citrus fruits, dried beans, and peas. In supplement form it is called folic acid.
Folate plays a crucial role in the formation of DNA, RNA, and red blood cells. Since 1998 the U.S. grain supply -- and subsequently, products like bread and cereal -- has been fortified with folic acid to help prevent birth defects. Folate and other B vitamins also break down the amino acid homocysteine. If you don’t get enough folate, your homocysteine levels rise. The problem: Folate deficiency and high concentrations of homocysteine are associated with heart attack, stroke, cognitive impairment, Alzheimer’s disease, and some cancers.
Experts hypothesized that taking folate supplements -- and lowering homocysteine levels -- would help keep these diseases at bay. Research has not borne this out unequivocally.
Studies based on the self-reported dietary habits of large populations suggested that people who consumed folate-rich diets were less likely to have a heart attack or stroke. However, more reliable placebo-controlled clinical trials of folic acid supplements found that even though homocysteine levels dropped among participants who took a daily supplement, these participants were no less likely to have a heart attack or stroke than participants who were assigned to a placebo.
Many studies that show protective benefits against Alzheimer’s disease and cancer are also based on less reliable self-reported dietary information. Not only is it impossible to confirm that participants’ information is accurate, but the way observational trials are designed makes it impossible to prove a direct cause-and-effect relationship. Until large-scale, placebo-controlled trials confirm the protective benefits of folic acid supplements, their benefits remain questionable.
Bottom-line advice: Getting enough folate is still important, even if it won’t protect you from heart disease or cancer, and this is relatively easy to do, partially as a result of fortification. The FDA’s Recommended Daily Allowance of folate is 400 micrograms (mcg). However, some people with kidney or liver disease or anemia may need more, as do people taking certain medications. In these instances, a boost from folic acid supplements may be necessary.
- If you want to try folic acid supplements because of folate’s yet-to-be- proven protective benefits, it is acceptable to take more than the recommended RDA -- folic acid is water soluble, which means it’s not stored in the body but must be replaced every day. But -- and this is a big but -- taking too much folate can exacerbate vitamin B12 deficiency. Older people are at a greater risk for vitamin B12 deficiency because over time the body becomes less efficient at absorbing essential vitamins. If vitamin B12 deficiency becomes severe, it can cause cognitive impairment and anemia. This fact makes some experts critical of folate fortification and also explains why European nations have resisted fortification. However, severe vitamin B12 deficiency is relatively rare.
Still, be sure to talk to your doctor about your vitamin B12 levels before taking folic acid. A safer bet is to eat a folate-rich diet. Foods high in folate include:
- Fortified breakfast cereals 3/4 of a cup has 100–400 mcg;
- Cooked frozen spinach 1/2 of a cup has 100 mcg;
- Cooked asparagus 4 spears have 85 mcg; and
- Cooked frozen green peas 1/2 of a cup has 50 mcg.
Folate warning: The following medications are known to interfere with the body’s capacity to utilize folate. If you are taking one of these drugs, you may want to ask your doctor about folate supplements.
- Anticonvulsants (dilantin, phenytoin, and primidone): for the treatment of epilepsy or other neurological disorders.
- Metformin: a type 2 diabetes drug.
- Diuretics: these blood pressure-lowering agents increase the excretion of fluids and, in turn, essential vitamins like folate.
- Methotextrate: used long term to treat cancer and rheumatoid arthritis and is commonly prescribed along with folate supplements.
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Medical Disclaimer: This information is not intended to substitute for the advice of a physician. Click here for additional information: Johns Hopkins Health Alerts Disclaimer
Posted in Nutrition and Weight Control on October 10, 2007
