Q: I eat a healthful vegetarian diet. Do I still need a multivitamin?
A: Not if you get your nutrients in other ways. But multivitamins are handy. They help ensure complete nutrition when your diet might be less than perfect, and they are convenient sources of important nutrients. Two, in particular:
Vitamin B12 Unfortified plant foods are essentially devoid of vitamin B12, which you need for healthy blood and nerves. Moreover, the Institute of Medicine now recommends that everyone over age 50 take a B12 supplement (or eat fortified foods) due to problems with B12 absorption. The recommended dietary allowance is 2.4 micrograms daily for adults, with slightly more for vegetarian women who are pregnant or nursing. All common multivitamins have more than these amounts.
Vitamin D The natural way of getting vitamin D is through exposing the skin to sunlight. Vitamin D helps the body absorb calcium and appears to help prevent cancer. For people who do not get regular direct sun exposure, multiple vitamins are a good source. The recommended daily amount of vitamin D is 600 IU (15 micrograms) for adults up to age 70, and 800 IU (20 micrograms) if you're over 70. Because vitamin D may also help prevent cancer, some authorities recommend much higher intakes. Daily doses up to 3,000 IU (75 micrograms) are safe for healthy adults.
Q: So how do I choose a good multiple vitamin?
A: Here are some things to look for:
Vegetarian formulas, which skip the gelatin capsule.
Vitamin D comes in two common forms: Vitamin D3 (cholecalciferol) is derived from the lanolin in wool. Vitamin D2 (ergocalciferol) is derived from yeast. Although some authorities have questioned the absorbability of D2, recent evidence puts it on par with D3.
Vitamin-only brands omit added minerals and are good choices for people who get their minerals from foods, as most do.
Iron can be an issue for women in their childbearing years, and multiple vitamin formulas with added iron may be helpful if food sources alone prove inadequate. However, women after menopause and adult men of any age often accumulate more iron than their bodies need, and would do well to choose an iron-free brand.
Calcium is abundant in green leafy vegetables and some legumes, making supplements unnecessary for those with healthful diets. For men, recent research linking calcium supplements to prostate cancer suggests favoring supplements without added calcium. However, the prescription might be different for women with osteopenia or osteoporosis who are using calcium as part of a bone-rebuilding regimen.
Q: How about if I just choose vitamins individually?
A: That's a perfectly fine approach. Supplementing with vitamin B12 and vitamin D (unless you get plenty of sun exposure) and getting everything else from food is a sensible strategy.