Cubes of butternut squash

A new Tufts University study involving more than 27,000 Americans is the latest research to show that most supplements may not do much to improve health—or at least can’t compete with the benefits of a healthy diet. The researchers found that taking supplements didn’t lower the risk of death during the study follow-up period, while those who got the recommended amount of certain nutrients from foods had a lower risk of death in that time frame.

“These results are consistent with current dietary recommendations,” says study author Fang Fang Zhang, M.D., Ph.D., associate professor in the Friedman School of Nutrition Science and Policy at Tufts University. “The general U.S. population should aim to get adequate nutrition from healthy foods, and a healthy diet.”­­­

What the Study Found

The researchers analyzed National Health and Nutrition Examination Survey (NHANES) data on supplements such as multivitamins, vitamin C, and calcium—which the study participants took—along with info on the foods they ate. Taking supplements, the study authors found, didn’t translate to a lower risk of death from cardiovascular disease, cancer, or any cause for that matter. Getting adequate amounts of vitamin K and magnesium from food, however, reduced the risk of dying overall by more than 20 percent. And those whose diet had enough of vitamins A and K, copper, and zinc cut the risk of death from cardiovascular disease by half.

More On Supplements

When the researchers analyzed the data, they found that in supplement takers, nutrients from the foods they ate were protective, but nutrients from the supplements were not. In fact, they didn’t need supplements at all to meet their daily requirements for vitamins and minerals.

The study also highlighted the negative effects of overuse of supplements: For example, getting 1,000 mg per day of calcium in pill form was linked to a 62 percent increased risk of cancer. However, when people got that much calcium from food, it didn’t increase cancer risk, Zhang says.

Stephen Fortmann, M.D., senior director of science programs at the Kaiser Permanente Center for Health Research, who worked on a systematic review of supplements for the U.S. Preventive Services Task Force in 2013, says the results from this new study are in line with the findings from that report. “There’s not a lot of evidence that these supplements do any good.”

When Are Supplements Needed?

More than half of American adults take multivitamins or another supplement, according to the NHANES data, perhaps in part because of what they are—or aren’t—already eating. It’s no secret that many Americans don’t follow a healthy diet; for example, about 90 percent of people don’t eat the daily recommended 1½ to 2 cups of fruit and 2 to 3 cups of vegetables, according to the Centers for Disease Control and Prevention.

But can supplements make up for those shortfalls? Supplement proponents argue that it can be challenging for Americans to stick to dietary guidelines. “The majority of U.S. adults do not get the recommended amount of nutrients," says Andrew Shao, interim senior vice president for scientific and regulatory affairs at the Center for Responsible Nutrition (CRN), a trade association for the supplement industry. “It is a health benefit to get the nutrients you need.”

Still, experts say that eating healthfully is a preferred way to stay healthy. “Using dietary supplements shouldn’t be a substitute for a healthy, balanced diet,” Zhang says. What’s more, when you get nutrients from food, you are also getting a variety of other compounds, such as phytochemicals, that interact with one another in myriad ways, some of which scientists may not even understand yet.

“It’s possible that these particular benefits we’ve seen here could reflect the complex interaction among multiple nutrients from food,” Zhang says. “We don’t eat isolated nutrients.”

Another concern with supplements is that the Food and Drug Administration classifies them differently from drugs. So the companies that make and sell them aren’t required to prove that they’re safe for their intended use, that they work as advertised, or even that their packages contain what the labels say they do, according to Chuck Bell, programs director at Consumer Reports, who is involved in CR’s advocacy work on supplement safety.

There are times when supplements are recommended, such as if a patient is deficient in a certain nutrient due to a health issue, Zhang says. In some cases, a doctor might also suggest taking prescription supplements, which are subject to FDA regulations for drugs.

People who may need supplements include:

Women planning to become pregnant within a month. Folic acid supplements are recommended to reduce the risk of brain and spinal-cord abnormalities (called neural tube defects) that can occur in the first months of pregnancy.

Pregnant women. Folic acid is needed to protect against neural tube defects, and vitamin D is needed to help prevent pre-eclampsia.

Strict vegans who consume no meat, fish, eggs, or dairy. A daily vitamin B12 supplement can be recommended; B12 is found only in animal foods.

People over age 60. At this age, you may need vitamin B12, because with age, some people lose the ability to absorb vitamin B12 from food.

A person who rarely gets out in the sun. He/she may need vitamin D3. Our bodies make vitamin D from sunlight.

Those taking certain drugs. Vitamin B12 and magnesium supplements may be needed for people taking diabetes medication such as metformin (Glucophage and generic) and long-term users of heartburn drugs, such as lansoprazole (Prevacid and generic) or famotidine (Pepcid and generic).

Eating a Healthier Diet

One main takeaway from the study, Zhang says, is that if your diet is made up mostly of nutritious foods, supplements won’t necessarily offer any additional benefits.

You can get the nutrients highlighted in this study from many foods. For example, dark green vegetables such as broccoli and kale have vitamins A and K. Butternut squash, carrots, sweet potatoes, and egg yolks are rich in vitamin A. Leafy greens, nuts, and whole grains supply copper and magnesium. "But it is best not to focus on specific nutrients, but rather trust that a balanced diet of healthy foods will meet your nutritional needs," says Charlotte Vallaeys, M.S., Consumer Reports' senior food and nutrition policy analyst. "When you eat a variety of healthy whole foods—whole grains, fruits and vegetables, nuts, legumes, and lean meats—you get the vitamins and minerals you need."