Anything you put into your body has an effect.

Supplement Choices

Many people do not receive all of the nutrients they need from their diets. Some groups, like pregnant women and older adults, have special nutritional needs and may benefit from dietary supplements. Though supplements do not replace the nutrients and benefits of eating whole foods, they can complement the diet.

Vitamins and minerals are substances your body needs in small but steady amounts for normal growth, function, and health. Your body cannot make these nutrients, so you must get them from the foods you eat or from supplements. (For recommendations about nutrients needed in the diet).

In general, choose a multivitamin-mineral supplement that provides about 100% daily value (DV) of all the vitamins and minerals, instead of one that supplies, for example, 500 % DV of one vitamin and only 20% DV of another. The exception is calcium. You may notice that calcium-containing supplements do not provide 100% DV. If they did, the tablets would be too large to swallow.

If you are already taking individual vitamins or mineral supplements and have not told your doctor, discuss it at your next checkup. Before taking anything other than a standard multivitamin-mineral supplement of 100 % DV or less, check with your doctor, pharmacist, or registered dietitian.

Supplements can lose potency over time, especially in hot and humid climates. If a supplement does not have an expiration date, do not buy it. If your supplements have expired, discard them.

Supplement Risks

Many supplements contain active ingredients with strong biological effects. If you have certain health conditions and take these products, you may be placing yourself at risk. These products have the greatest effect on children, women who are pregnant or nursing, or those who have chronic medical conditions such as diabetes, hypertension, or heart disease.

• Consumers cannot be sure that the product label matches the actual contents of the product.  Studies have shown a wide variation in the content of active ingredients in dietary supplements. For example, in an analysis of 24 ginseng products, one-third had no active ingredient. Worse, there have been reported cases of herbal products testing positive for arsenic, lead, mercury, and pesticides. 
• Some supplements can be toxic.  High doses of some vitamins or minerals may cause health problems. For example, high doses of vitamin B-3 (niacin) can create or worsen liver problems. Over time, too much vitamin A may cause liver problems or weaken bones in women.
• Some supplements may interact with prescription and over-the-counter (OTC) medicines. Taking a combination of supplements and medications (whether prescription or OTC drugs) could produce adverse effects, some of which could be life threatening. Be alert to advisories about these products, whether taken alone or in combination. For example: Coumadin (a prescription medicine), ginkgo biloba (an herbal supplement), aspirin (an OTC drug), and vitamin E (a vitamin supplement) can each thin the blood, and taking any of these products at the same time can increase the potential for internal bleeding. Combining St. John's Wort with certain HIV drugs significantly reduces their effectiveness. St. John's Wort may also reduce the effectiveness of prescription drugs for heart disease, depression, seizures, certain cancers, or oral contraceptives.
• Some supplements can have unwanted effects during surgery. It is especially important before elective surgery to fully inform your doctor about any supplements you are taking. Supplement/drug interactions can cause changes in heart rate and blood pressure and increased bleeding, which could adversely affect the outcome of your surgery. You may be asked to stop taking these products at least 2 to 3 weeks prior to the procedure.