New B Vitamin Recommendations


From the publishers of the New England Journal of Medicine



       As part of the newly updated Recommended Dietary Allowances (RDAs) for the B vitamins, the RDA for folate has increased to 400 micrograms (mcg) for all adults, up from 180 mcg for women and 200 mcg for men.
       The recommendations also address the frequently confused terms "folate" and "folic acid." The two are often used interchangeably, but they're not the same thing: Folate comes from plants, while folic acid is the man-made form used in vitamin pills and to fortify grains. Moreover, folic acid is about twice as potent as folate, so you need to consume only 200 mcg of folic acid to get the equivalent of 400 mcg of folate.
       This difference is particularly important when considering the new RDA for women who could become pregnant: 400 mcg of folic acid to prevent birth defects that can happen even before a woman knows she's pregnant. This is in addition to whatever folate a woman gets through diet. The folic acid can come from vitamin supplements or any grains (such as breads, rice, or cereals), which are now fortified with at least 140 mcg of folic acid per 3-ounce serving.
       Conversely, people over 50 years old need to worry about getting too much folic acid. They should be sure to get no more than 1,000 mcg per day (the new upper intake level), because they're at greater risk of having a vitamin B12 deficiency, which can be masked by high amounts of folic acid. The new RDA specifies that people over 50 should consume the synthetic form of B12 (from vitamin supplements or fortified foods) because their bodies tend not to absorb the natural form. All adults need at least 2.4 mcg of B12 a day.
       The new RDA for folate does not take into account recent studies suggesting that folate can prevent heart disease. A study in the April 9 New England Journal of Medicine adds to the heart disease research, suggesting that people who already have heart disease should get 400 mcg of folic acid per day—twice the new RDA. In the study, people with heart disease who ate cereal with about 400 mcg of folic acid per 1-ounce serving had an 11 percent decrease in homocysteine, an amino acid linked with increased risk of heart disease. But those who ate typical breakfast cereal (with about 100 mcg of folic acid per ounce) had no significant drop in homocysteine.




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