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By Kathleen M. Zelman, MPH, RD, LD

Reviewed By Elizabeth Ward, MS, RD

Boost energy, lose weight, beat stress, improve performance, and reduce wrinkles! Do these phrases sound familiar?

These are just a few of the promises found on the labels of vitamin and mineral supplements.  But can vitamin and minerals really live up to these claims, or is it more hype than truth?  Is there evidence that a vitamin or mineral supplement really can turn a bad diet into a healthy one, melt pounds away, or put the zip back in your step?

Experts say there is definitely a place for vitamin or mineral supplements in our diets, but their primary function is to fill in small nutrient gaps.  They are "supplements" intended to add to your diet, not take the place of real food or a healthy meal plan.

WebMD takes a closer look at what vitamin and mineral supplements can and cannot do for your health.

Food First, Then Supplements

Vitamins and other dietary supplements are not intended to be a food substitute. They cannot replace all of the nutrients and benefits of whole foods. 

"They can plug nutrition gaps in your diet, but it is short-sighted to think your vitamin or mineral is the ticket to good health -- the big power is on the plate, not in a pill," explains Roberta Anding, MS, RD, a spokesperson for the American Dietetic Association and director of sports nutrition at Texas Children’s Hospital in Houston. 

It is always better to get your nutrients from food, agrees registered dietitian Karen Ansel.  "Food contains thousands of phytochemicals, fiber, and more that work together to promote good health that cannot be duplicated with a pill or a cocktail of supplements."

What Can Vitamin and Mineral Supplements Do for Your Health?

When the food on the plate falls short and doesn’t include essential nutrients like calcium, potassium, vitamin D, and vitamin B12, some of the nutrients many Americans don’t get enough of, a supplement can help take up the nutritional slack. Vitamin and mineral supplements can help prevent deficiencies that can contribute to chronic conditions.

Numerous studies have shown the health benefits and effectiveness of supplementing missing nutrients in the diet.  A National Institutes of Health (NIH) study found increased bone density and reduced fractures in postmenopausal women who took calcium and vitamin D.  

Beyond filling in gaps, other studies have demonstrated that supplemental vitamins and minerals can be advantageous. However, the exact benefits are still unclear as researchers continue to unravel the potential health benefits of vitamins and supplements. 

Anding offers these tips to guide your vitamin and mineral selection:

• Think nutritious food first, and then supplement the gaps.  Start by filling your grocery cart with a variety of nourishing, nutrient-rich foods.  Use the federal government's My Plate nutrition guide to help make sure your meals and snacks include all the parts of a healthy meal.
• Take stock of your diet habits. Evaluate what is missing in your diet. Are there entire food groups you avoid? Is iceberg lettuce the only vegetable you eat? If so, learn about the key nutrients in the missing food groups, and choose a supplement to help meet those needs. As an example, it makes sense for anyone who does not or is not able to get the recommended three servings of dairy every day to take a calcium and vitamin D supplement for these shortfall nutrients.
• When in doubt, a daily multivitamin is a safer bet than a cocktail of individual supplements that can exceed the safe upper limits of the recommended intake for any nutrient.  Choose a multivitamin that provides 100% or less of the Daily Value (DV) as a backup to plug the small nutrient holes in your diet.
• Are you a fast food junkie?  If your diet pretty much consists of sweetened and other low-nutrient drinks, fries, and burgers, then supplements are not the answer.  A healthy diet makeover is in order. Consult a registered dietitian.
• Respect the limits. Supplements can fill in where your diet leaves off, but they can also build up and potentially cause toxicities if you take more than 100% of the DV.
• Most adults and children don’t get enough calcium, vitamin D, or potassium according to the 2010 Dietary Guidelines.  Potassium-rich foods, including fruits, vegetables, dairy, and meat are the best ways to fill in potassium gaps. Choose an individual or a multivitamin supplement that contains these calcium and vitamin D as a safeguard.

What Can Vitamin and Mineral Supplements Do for Your Health? continued...

Keep these additional tips in mind when selecting a vitamin or mineral supplement:

• Iron and folic acid are also on the list of nutrients of concern for women in their childbearing years (14 to 50).
• The 2010 Dietary Guidelines recommend that people over the age of 50 get most of their vitamin B12 from synthetic sources, either from fortified foods or dietary supplements.
• Limit supplemental folic acid to 1,000 micrograms a day. Taking more than this amount increases the chance of developing nerve damage from vitamin B12 deficiency. Grains can be highly fortified with folic acid, with upwards of 100% of the DV in one serving.
• Women past menopause and men need a very low iron or no iron supplement.
• Women should be discouraged from getting excess vitamin A as it may cause birth defects if they become pregnant.

Remember to take your supplements. They won’t do you any good if you forget to take them. Set up a routine of taking them with meals or before bed.

What Supplements Can’t Do

If it sounds too good to be true, it probably is. It is unlikely a vitamin or mineral can deliver on a promise like helping you lose weight.  A promise like that goes beyond the function of a supplement. "Don’t expect a vitamin or mineral to do anything more than it does in food," says Anding.

Promises on labels can stretch the letter of the law by using carefully worded claims that suggest exaggerated results. Dietary supplements are not regulated by the FDA as drugs are, and some manufacturers may imply that their products have greater powers than the scientific evidence shows.

Multivitamins have long been considered a secret weapon to aid health and preventing chronic disease, but according to several studies, that may not be the case. The National Institutes of Health convened a group of experts to evaluate the evidence on multivitamins and the effect on chronic disease prevention. Researchers found few studies to make general recommendations for or against multivitamins to prevent chronic disease. 

An overall healthy diet and regular physical activity can help prevent chronic disease, not supplements, says Anding.

Who Needs Vitamin and Mineral Supplements?

Anyone whose diet lacks the 40-plus nutrients needed for good health may benefit from vitamin and mineral supplements. In general, the following groups can be helped, but they should consult their doctor or a registered dietitian when deciding if they need a supplement or choosing one:

• Pregnant and lactating women
• Vegans and some people on vegetarian diets
• Anyone on a low-calorie diet (intentional and unintentional)
• Certain disease states (including people with a history of cancer)
• People who suffer from food allergies or intolerances
• Picky eaters who limit food groups, or have limited variety within food groups
• Anyone with a poor diet
• People taking certain medications

Vitamins and minerals can be helpful when it comes to providing the missing nutrients in your diet, but don’t trust the clerk in the health food store to tell you what you need to take.