Dietary supplements include vitamins and minerals and can also include herbs and other plant extracts, probiotics, fish oil and other substances. This month, we will focus on supplements containing essential nutrients. About 60% of Americans indicate that they take at least one dietary supplement. Should you?

The Academy of Nutrition and Dietetics (formerly the American Dietetic Association) says, “The best nutrition-­based strategy for promoting optimal health and reducing the risk of chronic disease is to choose a wide variety of foods wisely.” It adds: “Additional nutrients from supplements can help some people meet their nutrition needs as specified by science-based nutrition standards such as the Dietary Reference Intakes.”

Unfortunately, the second part of the academy’s position is frequently ignored, leading many people to believe that if they can consume adequate amounts of whole foods and stay away from processed foods, their bodies will have adequate nutrients to promote health and prevent disease.

Does your diet measure up?

Consuming adequate nutrients can be a challenge. In fact, the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey database shows that most people’s diets are inadequate in one or more essential nutrients. Nutrient requirements depend on age, gender, health, amount of exercise, adequate calorie intake, numerous prescribed or over-the-counter medications and more.

Iron deficiency affects about 20% of the population. Blood donors and women with heavy blood loss, for instance, have increased iron needs. B12 supplements or B12-fortified foods are recommended for those over age 50.

For people who choose a plant-based diet, absorption of iron and zinc is significantly lower, requiring nearly double the typical recommendation. In addition, since vitamin B12 comes from animal products, like eggs, meat and milk, B12 supplements are needed.

For those on a paleo diet or a diet too low in plant foods, nutrients such as vitamins C, A and E may be too low.

Beneficial supplements

A beneficial supplement provides all essential nutrients that are inadequate in your diet. Therefore, taking a daily low-level multivitamin- multimineral supplement may benefit health — but taking more than your body needs is not likely to help you and may be harmful.

FDA regulation of dietary supplements is limited, so choosing a major brand offers the best quality control. Also, keep combined nutrients from supplements and fortified foods to no more than 150% of the daily value; this serves as a safety net from taking in excessive nutrients. The Office of Dietary Supplements website provides additional information on upper safe levels. Go to ods.od.nih.gov.

Joannie Dobbs, Ph.D., C.N.S. and Alan Titchenal, Ph.D., C.N.S. are retired nutrition faculty from the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa.