Drug Profile

It is estimated that 40 percent of adults in the United States take vitamin and mineral supplements daily.[1] Is this necessary?

Vitamin deficiencies are rare in this country. Mineral deficiencies are more common, but taking a multivitamin supplement with minerals is often not the best way to get minerals. These products either do not supply enough of the mineral you lack, or they contain other minerals that reduce your body’s ability to absorb the specific mineral you need. Instead of taking such supplements, try changing your diet so that you get more of just the mineral you need, or take a specific mineral supplement. For example, if you have iron-deficiency anemia, you should be taking an iron supplement. Calcium deficiency is another example. Most multivitamin supplements with minerals do not supply enough calcium to meet the recommended dietary allowance (RDA), so taking these supplements may give you a false sense of security about your calcium intake. Changes in your diet, combined with a calcium supplement, may be the best way to increase your calcium intake. See the listings for individual minerals and vitamins for more details.

Who needs a multivitamin and mineral supplement? Research published in the August 6, 2005, British Medical Journal found that the daily use of a multivitamin with a mineral supplement by people over 65 years of age did not affect numbers of infections, use of health care services, quality of life, number of antibiotic prescriptions, or hospital admissions compared to an inactive placebo. These results support previous research from randomized, controlled clinical trials (the scientific “gold standard” for proving effectiveness) that found no benefit from vitamin and mineral supplements in preventing infections in older adults.[2] 

The following groups of older adults are at risk of vitamin deficiency and may need a supplement:

• those who eat fewer than 1,500 calories a day and may have a barely adequate vitamin intake
• those who live alone, are institutionalized, have recently been discharged from the hospital, or cannot shop for their food
• those who have certain medical problems (such as some intestinal disorders) or take certain drugs that interfere with their body’s ability to absorb nutrients
• those who drink too much alcohol, which can reduce the body’s supply of certain vitamins (thiamine, riboflavin, folic acid, and vitamins C and B₆)

The more of these groups you belong to, the greater your risk of having a low-calorie, unbalanced, and nutritionally deficient diet. If you have one or more of these factors, you should discuss the need for a multivitamin supplement with your doctor. Remember that a supplement will not completely make up for deficiencies in your diet, since vitamins are only a very small part of proper nutrition. Getting a good balance of protein, fat, carbohydrates, and fiber is also important, and you can only do this through a well-balanced diet.

If you don’t fit into the risk categories above, should you take a supplement for “insurance”? If you are eating a well-balanced diet, there is no reason why you need one.

If you take a multivitamin supplement, don’t take doses significantly higher than the recommended dietary allowance (RDA). Doses higher than the RDA will either be eliminated from your body in your urine (in the case of water-soluble vitamins such as the B vitamins and vitamin C) or will accumulate in the body tissues and cause harmful adverse effects (in the case of the fat-soluble vitamins A, D, E, and K).

When choosing a multivitamin, keep in mind that many manufacturers use the same general trademark for several products that have different formulas. Some make drastic changes in the formula of a product and keep the name the same. Read the labels and compare the contents of several products. Compare the label with the recommended dietary allowances for older adults (see Vitamins and Minerals). There is not much logic in a formula that contains less than 50 percent of the RDA for some vitamins and more than 500 percent for others. Choose a supplement that comes as close as possible to 100 percent of the RDA for each ingredient.

Buy the least expensive supplement that meets your needs, and buy a generic version if you can. Generic products are cheaper and are just as effective as the brand-name products.

A recent Journal of Parenteral and Enteral Nutrition (JPEN) systematic review revealed that, with a few possible exceptions, dietary supplements offer no benefits to well-nourished adults eating a Western diet and, in many cases, may be harmful. The results of this study reinforce Worst Pills, Best Pills News’ longstanding view that there is little evidence that dietary supplements are either safe or effective.

The study authors concluded that with the possible exception of vitamin D in elderly patients and omega-3 fatty acids in patients with a history of cardiovascular disease, no data support the widespread use of dietary supplements in the U.S. and other Western countries. Indeed, the data suggest that certain commonly used dietary supplements, including beta-carotene, vitamin A and vitamin E, may be harmful. We agree.[3]