Can a multivitamin a day keep ailments away? Many people think so. According to the National Institutes of Health, more than one-third of Americans take a multivitamin or mineral supplement every day. These products promise to improve health in various ways, including boosting energy, strengthening the immune system and increasing sleep. But do multivitamins and supplements live up to their claims or are they a waste of money?

There’s little scientific evidence to support the idea that multivitamins and supplements dramatically improve health. The U.S. Food and Drug Administration doesn’t regulate these products, meaning they don’t test the accuracy of these claims. So a supplement claiming to boost energy might be stretching the truth.

Health experts do agree it’s OK to take a multivitamin daily. It helps avoid vitamin deficiencies, but it’s not a cure-all or replacement for eating healthy. People who eat a well-rounded diet full of protein, fruits and vegetables should receive all the nutrients their bodies require. Multivitamins and mineral supplements are designed to fill in any nutritional gaps.

For example, postmenopausal women may benefit from calcium and vitamin D supplements, as studies have shown these nutrients help bone density. Vegans and vegetarians may consider taking vitamin B12 supplements because the nutrient is found in animal foods. Women who are or may become pregnant should take folic acid supplements to protect against specific birth defects.

Before taking a multivitamin or any supplements, talk with your doctor about your dietary plan. Together, you can ensure any supplements you take are good for your health.