Updated May 22, 2008

Choosing a Multivitamin

by Marie Spano, M.S., R.D.

Though magnesium seems to be related to insulin action, individual magnesium supplements should only be taken if a physician recommends it. Otherwise, a multivitamin–multimineral supplement with a bioavailable source of magnesium (see the chart "Minerals") and plenty of magnesium-rich foods is the safe option.

Potassium. Potassium helps regulate fluid and mineral balance, maintain normal blood pressure, and transmit nerve impulses and helps your muscles contract. The amount of potassium in multivitamin–multimineral supplements is minimal, and the majority of people should obtain enough from food sources. Many fruits and vegetables, including tomatoes, potatoes, oranges, strawberries, and melon, are high in potassium.

Zinc. Zinc is essential for cell reproduction, immune functioning, and tissue growth and repair. It is essential for growth and helps the body use carbohydrate, protein, and fat.

Iodine, manganese, molybdenum, chloride, boron. All of these minerals are found in food, and supplementation isn't necessary.

Individualized intake
Certain people have increased nutrient needs. These include women who are pregnant or breast-feeding, people with certain diseases, elderly people, vegans, people on restricted diets or low-calorie diets, and people who do not eat a healthy diet rich in fruits, vegetables, whole grains, and low-fat meat, poultry, and dairy products. If you have any questions about whether you should be taking additional vitamins or minerals, speak to your health-care provider. Though we know the general functions of each vitamin and mineral, research is ongoing, and scientists are continually learning more about how certain vitamins and minerals play many different roles in our body, preventing disease and promoting good health. In the meantime, do what you can to ensure your good health by following a healthy diet and taking a daily multivitamin–multimineral supplement with approximately 100% DV of most vitamins and minerals.

Marie Spano is a registered dietitian and exercise physiologist. She is a freelance writer, consultant, and speaker in the nutrition, fitness, and health industries. In addition, she is a spokesperson for the International Society of Sports Nutrition.

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