Nutrition Hotline

By Reed Mangels, PhD, RD

QUESTION: I'm a vegan and I want to know if I should be taking a daily multivitamin supplement.

S.A., via email.

ANSWER: As a vegan, you should be able to meet your needs for most nutrients from foods. Eating a variety of whole plant foods is a good practice, both because it's a simple way to get needed nutrients and because of the other benefits that go along with a plant-based diet. That said, there may be occasional days when your food choices aren't ideal; using a multivitamin/mineral supplement on those days can be better than nothing. Of course, supplements don't take the place of a healthy diet.

Supplements can be expensive, especially since many of the vitamins they supply are excreted if you already have enough of those vitamins in your diet. Also, sometimes you can get too much of a vitamin if your diet and supplement both supply generous amounts.

Vegans need to get vitamin B12 from either supplements or fortified foods. Vegan dietitians Jack Norris, RD and Virginia Messina, MPH, RD recommend that if vitamin B12 supplements are used, you should take either a 25-100 microgram supplement once a day or a 1000 microgram supplement three times a week.1

Taking a multivitamin that contains the suggested amount of vitamin B12 is another option. Supplemental vitamin D is recommended unless you live in southern California or Florida or another sunny spot and are out in the sun regularly. Those of us in the north in winter can't rely on sun for vitamin D. Even when vitamin D-fortified foods are used, it's challenging for most people to get the recommended amount of vitamin D each day. If iodized salt or sea vegetables are not something that you eat regularly, look for an iodine supplement or check that your multivitamin/mineral supplies the RDA of 150 micrograms daily (for adults).

Iron deficiency is a common issue for many premenopausal women, adolescent girls, and young children. Vegan diets can supply adequate amounts of iron. If you're in one of the groups at risk for iron deficiency, a registered dietitian or physician can help you decide if use of a low dose iron supplement or a multivitamin with iron is needed. All women who could become pregnant, whether vegan or not, should get 400 micrograms a day of folic acid from fortified foods or supplements to reduce the risk of having a child with spina bifida or other birth defects.

1 Norris J, Messina V. Vegan for Life. DaCapo Press, 2011.