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Eating for Vitamins: Do You Need Supplements?

Nancy Clark, MS, RD


Confusion abounds about vitamin supplements for active people: Should you take them? Which ones are best? When should you take them? Will they enhance sports performance? Here is information to help clear up any confusion and show you how to meet your vitamin needs without wasting money on unnecessary supplements.

What Are Vitamins?

Vitamins are food substances that assist essential biochemical reactions within your body. There are 13 known vitamins:

  • Four fat-soluble vitamins— A, D, E, and K— which your body stores in amounts large enough to last for months; and
  • Nine water-soluble vitamins: C (ascorbic acid), and the B-complex vitamins—B1 (thiamin), B2 (riboflavin), B6 (pyridoxine), B12, niacin, folic acid, biotin, and pantothenic acid. Your body is able to store enough of these vitamins to last for several weeks.

The Best Source: Food

Most people can get an adequate supply of vitamins from a 1,200- to 1,500-calorie-per-day diet consisting of a variety of wholesome foods. For athletes who get 2,500 to 4,000 or more calories a day, the task is relatively simple. For example, a thirsty teenage athlete who needs over 4,000 calories per day can easily get almost three times the recommended 60 milligrams (mg) of vitamin C from 16 ounces of orange juice. And that's just from one beverage there's even more in food.

The trick to getting enough vitamins is to choose foods that are nutritional powerhouses. Fresh fruits and vegetables are the ultimate natural vitamin sources. Unlike supplements, fruits and vegetables offer far more than just the vitamins—they also contain fiber and various other compounds that are important to health. If you eat a balanced diet you'll get these important nutrients and you won't need vitamin supplements to correct nutritional deficiencies. Unfortunately, most Americans eat fewer than the recommended 5 servings of fruits and vegetables per day.

Who Needs Supplements?

To date, no evidence suggests that extra vitamins will enhance athletic performance, increase strength or endurance, increase energy, or build muscles. Certainly, a vitamin deficiency can impair performance, but deficiencies are generally related to conditions such as anorexia, unhealthy weight loss, malabsorption, or poor eating habits. Deficiencies are unlikely in active people with robust appetites.

For very active people, vitamin E is a possible exception to the "eat your vitamins" rule, because even though a hungry athlete eats a lot of food, diet is unlikely to provide large enough amounts of this nutrient. Vitamin E is an antioxidant, which means it helps fight damage to body cells. It may help reduce the tissue damage associated with intense exercise. Researchers are still trying to determine if extra vitamin E offers benefits for athletes.

Although outright vitamin deficiencies are rare, some people are at risk for marginal vitamin shortages. Supplements can be appropriate for:

  • Dieters. People who restrict their food intake to less than 1,200 calories per day may miss out on important nutrients. This also includes people who eat only a few types of foods or have anorexia.
  • People who are lactose intolerant. Active people who are unable to digest the milk sugar found in dairy foods commonly eliminate milk and other dairy foods from their diets. Lack of dairy foods can result in a deficiency of riboflavin (as well as calcium, a mineral).
  • People who have food allergies. If you can't eat certain types of foods, such as wheat or fruit, you may have a harder time getting certain nutrients.
  • Vegans. Active people who eat no animal foods may become deficient in vitamins B12, D, and riboflavin (as well as the minerals iron and zinc).
  • Women who might become pregnant or are already pregnant. Before becoming pregnant, women should eat a diet that is rich in folic acid. This means eating generous amounts of spinach, broccoli, oranges, and lentils, and also taking 400 micrograms of folic acid daily. This vitamin, when taken at the time of conception, helps to prevent neurologic problems in the fetus, and can reduce certain types of birth defects.
  • Active people who are at risk for heart disease and cancer. Although the evidence is preliminary and controversial, 100 to 400 international units (IUs) of vitamin E is unlikely to cause harm, and its antioxidant properties may be beneficial (1).

Some people simply like to take a multiple vitamin pill for health insurance. This is practical as long as the pill just supplements healthy eating. People who take handfuls of pills in hopes of finding a cure-all are likely to feel better if they improve their diet instead. No amount of pills can compensate for a deficient diet.

Choosing Supplements

Prompted by persuasive advertising, many active people have developed a big appetite for vitamin pills. Here are some tips to help you sort through the hype and get the most from a vitamin supplement:

  • Choose a multiple vitamin with approximately 100% of the daily values (or DV—formerly known as the recommended dietary allowance, or USRDA); this will provide a safe and adequate balance of vitamins. It is highly unlikely that you need more. "High potency" vitamins enhance manufacturers' profits more than they enhance your health.
  • Because a person is rarely deficient in just one vitamin, a multiple vitamin is preferable to large doses of single vitamins (unless the vitamin is prescribed by a physician for a medical condition).
  • Claims about "natural" vitamins in pills tend to be false, given the prohibitive costs of extracting vitamins from natural sources. In reality, almost all vitamins in supplements are synthetic. Besides, naturally occurring and manufactured vitamins have identical chemical structures. The one exception is vitamin E, which, in its natural form, is slightly better absorbed and used. But for long-term use—and people generally take vitamin E for chronic conditions—the price of natural vitamin E may be too high to justify the slight advantage.
  • Store brands are likely to be identical to name brands, only much lower in price. Ten dollars a month is more than enough for vitamin supplements.
  • The label "stress tablets" is a marketing ploy. There is little evidence that the stresses of daily living deplete the body of vitamins. Evidence about the connection between stress and vitamin depletion pertains mostly to physical stress from surgery, burns, or fever, not psychological stress.
  • Supplements made without sugar or starch offer no advantages.
  • Taking beta-carotene is better than taking vitamin A, which is described on labels as palmitate, acetate, or fish oil. Beta-carotene, from which the body makes vitamin A, acts as an antioxidant and is safer than vitamin A. If taken for several months in doses greater than 25,000 IUs per day, vitamin A can be toxic.
  • Taking a supplement with or after meals optimizes absorption. Vitamins tend to work together with other nutrients.

Many active people are already getting abundant vitamins from fortified foods such as breakfast cereals, energy bars, sports drinks, and snack foods. You don't even need to take a vitamin pill if, for example, you eat a big bowl of a cereal fortified with 100% of the DVs for breakfast or as a snack.

Invest in Nutrition

If you don't know whether you're getting adequate vitamins in your food, consult with a registered dietitian who specializes in sports nutrition. He or she can evaluate your diet and teach you how to optimize your food intake. To find a local sports nutritionist, you can call the American Dietetic Association's referral network (800-366-1655). Investing in personalized nutrition education is better than buying myriad mysterious pills.


  1. Greenberg ER, Sporn MB: Antioxidant vitamins, cancer, and cardiovascular disease. N Engl J Med 1996;334(18):1189-1190

Remember: You, your physician, and your nutritionist need to work together to discuss nutrition concerns. The above information is not intended as a substitute for appropriate medical treatment.

Ms Clark is director of Nutrition Services at SportsMedicine Brookline in the Boston area. She is a fellow of the American College of Sports Medicine, a fellow of the American Dietetic Association, and a member of its practice group, Sports and Cardiovascular Nutritionists (SCAN).



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