Dietary supplements: Do we need them, or can we get all our nutrients from food?

In an ideal world, no one would need dietary supplements. Our balanced diets would provide all the vitamins, minerals and other nutrients our bodies need.

Alas, the world of American eating is far from ideal. And that, some nutrition experts and supplement advocates argue, is why we need dietary supplements.

Jennifer LaRue Huget

Writes the Eat, Drink & Be Healthy column and Lean & Fit e-newsletter, and blogs for The Checkup.

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Four nutrients most people need more of

The latest federal data show that more than half of U.S. adults use dietary supplements, mostly multivitamins. But do we really need all those pills?

Depends on whom you ask. The latest version of the federal Dietary Guidelines for Americans urges us to get our nutrients primarily from food:

“A fundamental premise of the Dietary Guidelines is that nutrients should come primarily from foods. Foods in nutrient-dense, mostly intact forms contain not only the essential vitamins and minerals that are often contained in nutrient supplements, but also dietary fiber and other naturally occurring substances that may have positive health effects.”

This “food first” approach is based on the emerging understanding that our bodies may process nutrients in food differently from those supplied by supplements and that foods contain scores of compounds whose synergy may be what makes them good for us.

The document also points out that “sufficient evidence is not available to support a recommendation for or against the use of multivitamin/mineral supplements in the primary prevention of chronic disease for the healthy American population.”

But, as I wrote in 2009, meeting your daily dietary needs without using supplements is a challenge, even when you’re choosing ultra-healthful foods under a professional dietitian’s guidance.

It’s a widespread challenge. Society has “invested a lot in the science behind the Dietary Guidelines for Americans,” says Duffy MacKay, vice president for scientific and regulatory affairs for the Council for Responsible Nutrition, a dietary supplement trade group. “When you think about people and what they’re eating, a significant number are not meeting those benchmarks.”

Robert Post, deputy director of the U.S. Department of Agriculture’s Center for Nutrition Policy and Promotion, says too few Americans are meeting all their nutritional requirements and that dietary supplements, used sensibly, can help fill gaps in our diets. In particular, he notes, the guidelines single out four “nutrients of concern” that most of us need more of to maintain good health: potassium, Vitamin D, calcium and fiber (see chart).

But Post, like the guidelines, calls for people to get their fill of those four nutrients from food and to consider supplements only for a handful of dietary deficiencies related to our stage of life and dietary preferences. Those include:

Iron: Women who are able to become pregnant need more iron, especially heme iron, which the body absorbs more readily than non-heme iron. Heme iron is found in lean meat and poultry; non-heme iron is in white beans, lentils, spinach, enriched breads and cereals. Foods rich in Vitamin C can aid iron absorption. Adult males need just 8 mg of iron per day; women need 18 mg, and pregnant women need 27 mg.