The alphabet soup of multivitamins and supplements loaded on drugstore shelves is overwhelming. The sheer number of options can have a toppling effect, creating a purchasing frenzy.
Dietary supplements have grown into a $122 billion industry, according to the Center for Responsible Nutrition, a lobbying group. But emerging research is casting doubt on just how effective those pills are. A new comprehensive meta-analysis of 277 clinical trials has found a wide range of nutritional supplements—and even some common diets—aren’t effective at preventing heart disease, the leading cause of death in the U.S. What’s more, they won’t help prolonging a person’s life either.
“The panacea or magic bullet that people keep searching for in dietary supplements isn’t there,” Erin D. Michos, M.D., M.H.S., senior author of the study, said in a press release.
The massive study culled data from 277 randomized clinical trials around the world, which evaluated the effectiveness of 16 vitamins and other supplements, as well as eight different diets. The researchers combed through that data to see how the supplements and diets affected the risk of heart conditions, like heart attacks and coronary heart disease, as well as how they affected mortality among the participants. In total, the meta-analysis incorporated data from over 992,000 people across the globe—an impressive sample size, to say the least.
The researchers assessed a wide range of supplements, including antioxidants, multivitamins, folic acid, iron, omega-3 fatty acid, and vitamins A, B3, B-complex, C, E, D, and more. They also honed in on several popular diets, including the Mediterranean diet, reduced-fat diet, and reduced-salt diet, among others. Strikingly, nearly every supplement and most diets were found to have no effect on heart health and no effect on mortality.
A few diets did show evidence of a positive impact on heart health. Among people with healthy blood pressure, the researchers discovered that a low-salt diet yielded a 10 percent decrease in the participants’ risk of death. They also found that when people with high blood pressure followed a low-salt diet, their risk of death by heart disease dropped 33 percent.
the vast majority of multivitamins, minerals, and different types of diets had no measurable effect on survival or cardiovascular disease risk reduction.
Of the 16 studied, two supplements stood out for their effectiveness. The first, omega-3 fatty acid, created a slight reduction in the risk of having a heart attack (by 8 percent) and developing coronary disease (7 percent). The second, folic acid, was linked to a 20 percent reduced risk of stroke, but the researchers hypothesized that this was because the participants were from China, where grains aren’t fortified with folic acid like they are in the U.S. Folic acid supplements likely wouldn’t be as effective in America, since most people already get folic acid from, say, a morning bowl of cereal.
The meta-analysis even revealed a combination of supplements that had a negative impact on health. Together, calcium and vitamin D supplements actually increased the risk of stroke by 17 percent, based on analysis of health data from over 42,000 research participants.
“Although there may be some evidence that a few interventions have an impact on death and cardiovascular health, the vast majority of multivitamins, minerals, and different types of diets had no measurable effect on survival or cardiovascular disease risk reduction,” Safi U. Khan, M.D., a lead author of the study, said in the press release.
The news comes as supplements enjoy continued popularity among people looking to stay healthy. According to a study published in the Journal of the American Medical Association, 52 percent of Americans take a dietary supplement, and the press release states that Americans spend $31 billion annually on over-the-counter supplements. But the data shows they have little to no effect on some of the biggest health risks that Americans face.
“People should focus on getting their nutrients from aheart-healthy diet,” said Michos, “because the data increasingly show that the majority of healthy adults don’t need to take supplements.”