Khuyến cáo sử dụng vitamin B
• For most people, a reasonably balanced diet combined with a multivitamin-multimineral supplement is the best source of RDA-appropriate levels of B vitamins.
• B6: Avoid supplements that contain more than the RDA for this vitamin, as excess amounts can cause nerve damage.
• Folic acid: Beware of getting too much of this
micronutrient from supplements and forti ed foods (see “B bonanza: Boon or bust?” above). Most multivitamins contain 400 mcg, but many forti ed breakfast cereals also contain that much. Add a few other enriched grain products (10 pret- zels adds 172 mcg, and a cup of spaghetti, 166 mcg) and you’re over your daily limit. If you take a daily multivitamin, avoid foods forti ed with 300 to 400 mcg of folic acid.
• B12: Vegans, who avoid all animal-based foods, and elderly people, who may have trouble absorb- ing vitamin B12 from food, should consider eating a vitamin B12–forti ed breakfast cereal or taking a supplement.