By Joyce Hendley, July/August 2007
Every time the body makes new cells, it needs folate, the B vitamin that’s abundant in beans, fruits and vegetables—leafy greens in particular. Folate is essential for processing vitamin B12, and recent studies suggest it might help protect against Alzheimer’s disease, colorectal cancer and strokes. Folate also helps prevent neural-tube birth defects (NTDs), such as spina bifida. In fact, since 1998 when the U.S. Food and Drug Administration began requiring enriched cereal grain products (including white flour, pasta and white rice) to be fortified with folic acid—the form of the vitamin used in supplements—the incidence of NTDs has dropped by about 25 percent.
However, new research published last January in the American Journal of Clinical Nutrition provides the first inkling that folic-acid fortification may be a problem for older people. The trouble stems from the vitamin’s close relationship with vitamin B12, which your body becomes less able to process as it ages. If you are deficient in B12—a problem more common after age 55—folic-acid megadoses can mask the early symptoms that warn of the B12 deficiency. Left undetected and thus untreated, B12 deficiency can lead to irreversible nerve and brain damage.
When Martha Savaria Morris, Ph.D., and her colleagues at Tufts University reviewed data from 1,459 elderly people (average age 70) who participated in a recent federal nutrition survey, they found that about one-quarter of them were low in vitamin B12. Within this group, those who also had the highest blood levels of folate were five times more likely to have symptoms of advanced B12 deficiency—including slower responses on a standardized test that measured ability to combine numbers with symbols—than those with lower folate levels.
Ironically, some of the worst problems were seen in health-minded folks who took supplements on top of eating a variety of folic-acid enriched foods. Breakfast cereals, some fortified with 100 percent of the daily recommendation of 400 micrograms (mcg), were a particularly potent source—especially for people who, like many of us, poured themselves a bigger serving than what was specified on the cereal box. “Some people got around 1,000 mcg of folic acid from breakfast alone,” says Morris.
Unless you’re a woman of childbearing age, eating plenty of vegetables, fruits and beans is all the folate insurance you’ll likely need; 1⁄2 cup of pinto beans or 1 cup of orange juice or romaine lettuce supplies about one-fifth of the daily requirement. Without even trying, most of us meet our needs with fortified grains like cereals and rice. If you’re over 55, it’s OK to take a basic multivitamin, but don’t take a specific folic-acid supplement, says Morris. “You’re unlikely to need it and it may be harmful.” Women capable of becoming pregnant should consume 400 mcg from supplements or fortified foods in addition to intake of food folate from a varied diet.