However, there are certain times in life, such as during pregnancy, breast-feeding or an illness, that your nutrient requirements may increase. At those times, you may want to take a supplement to ensure you're getting all the nutrients you need. You may also want to take a multi or other supplement as you get older, because people sometimes start to have problems absorbing vitamins from food as they age. And if you're on a restricted diet -- if you avoid animal products, for instance -- you may need a supplement, because your diet may not provide adequate amounts of some nutrients.
More than one-third of Americans take multivitamins, according to the National Institutes of Health Office of Dietary Supplements. Ask your doctor whether you could benefit from taking multivitamins and, if so, what type of multivitamin would be best for you.