Vitamin and mineral supplements do not prevent death or chronic diseases, according to a new scientific article, but some groups can still benefit.

Multivitamin and mineral supplements are virtually universal in America. You can find them in pharmacies, supermarkets, and boutique nutrition stores.

Each year Americans spend billions of dollars on nutritional supplements, but according to a new editorial published this week in Annals of Internal Medicine, most people are wasting their money. The authors write that there is no scientific evidence to show that these daily pills prevent chronic diseases like cancer or heart disease, or reduce the risk of death.

Does this mean it’s time to clean out your medicine cabinet and dump the vitamins down the drain? Not necessarily.

“What people have to understand, and what that editorial really didn’t mention,” says Robert Berberian, D.O., an Integrative Medicine specialist in Los Angeles, “is that the role of vitamins is not to cure chronic illnesses like diabetes, high blood pressure, heart disease, or even cancer. The role of vitamins is to supplement some of the nutritional gaps in our diet.”

The typical American diet is far from the nutritious buffet envisioned by public health officials. Our busy lives mean that we grab whatever food we can while on the go, including processed or junk foods.

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“That’s why it’s helpful to supplement your diet with a good multivitamin,” says Berberian.

However, taking a daily pill—no matter how large it is—doesn’t give you a free pass to snack.

“The most important source of nutrition for your body is going to be through whole foods, especially fruits and vegetables,” says Berberian. “Vitamins should never act as a replacement for food, but rather as a supplement to fill in some of these deficiencies in our diet.”

Expecting vitamins to prevent chronic diseases may be overreaching, but Berberian says that certain groups of people can definitely benefit from taking nutritional supplements.

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Vitamin D, which the body needs for absorbing calcium in the gut and building strong bones, shows up in very few foods people eat—unless it is added during processing. The bulk of this vitamin is produced by the body when the skin is exposed to sunlight.

“A lot of people are low in vitamin D in America,” says Berberian, “because not a lot of people get enough sun exposure—they’re working in an office setting all day long and hardly get enough sun.”

People who think they are deficient in vitamin D should check with their doctor. A simple blood test can show whether you are lacking, and your doctor can recommend a supplement, if needed.

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Vitamin B12 is required for making red blood cells and for proper brain function. Because it mainly shows up in animal products like meat, milk, and other dairy foods, vegans are at risk of being deficient.

“In the typical vegan food, there really isn’t much vitamin B12,” says Berberian, “unless you are eating certain foods that are fortified with vitamin B12.”

Foods enriched with vitamin B12 include cereals and soy products. Another option for vegans is nutritional yeast, a flaky product that can be mixed with oatmeal or sprinkled on salads or entrees.

Vegans who don’t eat nutritional yeast or fortified foods regularly can develop low blood levels of vitamin B12. Likewise, elderly people sometimes have difficulty absorbing vitamin B12 from food, which can also lead to a deficiency.

If you are concerned about your vitamin B12 intake—or often feel tired—check with your doctor, who can test your blood and recommend a supplement.

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Folic acid, which appears in vegetables, grains, meat, and dairy products, is essential for proper prenatal development. In the U.S., most grain products—such as breads, cereals, flours, pastas, and rice—are enriched with folic acid.

Because of the importance of this vitamin for unborn babies, doctors routinely prescribe folic acid supplements to pregnant women, usually in the form of standard prenatal vitamins. Folate deficiency in other people, however, is rare.

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