Today, more than half of American adults say they take some sort of vitamin supplement regularly. But in a recent editorial published in the journal Annals of Internal Medicine, a group of physicians stated that findings from a multitude of studies show that most supplements don’t prevent chronic disease or death, CNN reports.

The scathing editorial was based on three studies (also published in the same issue of the medical journal) that looked at the effects of multivitamins on preventing heart attacks and cancer, as well as improving cognitive function in men older than 65.

The first study reviewed 27 research papers that covered more than 450,000 participants. This study found that taking vitamins had no preventive effect for either cardiovascular disease or cancer. In addition, findings also showed that taking vitamins didn’t prevent death. What’s more, the findings suggested that smokers who only took beta-carotene supplements could actually increase their risk of developing lung cancer.

The second study attempted to look at vitamin use in 1,700 heart attack patients. But because more than 50 percent of them stopped taking their vitamins, researchers were unable to conclude anything from this study.

The third study followed nearly 6,000 older men who took either a placebo or a multivitamin for 12 years and then had their cognitive skills tested. The result? Researchers found no discernible differences between the two groups.

“The message is simple,” said the editorial’s authors. “Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.”

But the doctors did reserve judgment on several supplements: vitamin D and omega-3 fatty acids including DHA and EPA. They believe more research must be done to determine these supplements’ long-term health effects.

Other researchers disagreed with the study authors. “There’s always a nontrivial minority that’s actually getting a questionable level of some micronutrients,” said Gladys Block, PhD, a professor of nutrition and epidemiology at the University of California, Berkeley. “So multivitamins are a backstop against our poor diet.”

In general, African Americans are three times more likely to be vitamin D deficient than their white counterparts. Click here for more information.