When you may need more than 100 percent

Depending on your condition, your physician may ask you to take more than 100 percent of the DV. These high doses are advised to help people fight certain diseases or conditions. Higher doses are usually not needed for a person who is in good health, but there are exceptions. For example, a doctor may recommend extra vitamin D for breastfed babies, people who get little sun or people who are at risk for osteoporosis.

Pay attention to the labels on supplement bottles. Some vitamins and minerals require taking more than one pill a day. Take calcium, for instance. The recommendations for calcium vary based on age and sex. Women usually require more calcium than men and may have to take calcium supplements in addition to their multivitamin.

Ask your physician or RD about health claims you may have heard. Many of the "cure all" vitamin claims are not true. The vitamin industry is not regulated by the U.S. Food and Drug Administration (FDA). This is why seeing an RD will help you get the information you need to make the proper choices.

When it comes to vitamins, brand names are not important. They matter only to your pocketbook because they are more expensive but essentially offer the same benefit as less expensive generic brands. Using a store brand versus a popular brand does not change the quality or effectiveness of a vitamin.