MONDAY, Dec. 16, 2013 (HealthDay News) -- With three new studies finding that a daily multivitamin won't help boost the average American's health, the experts behind the research are urging people to abandon use of the supplements.

The studies found that popping a daily multivitamin didn't ward off heart problems or memory loss, and wasn't tied to a longer life span.

The studies, published in the Dec. 17 issue of the journal Annals of Internal Medicine, found that multivitamin and mineral supplements did not work any better than placebo pills.

Dietary supplements are a multibillion-dollar industry in the United States, and multivitamins account for nearly half of all vitamin sales, according to the U.S. Office of Dietary Supplements.

But a growing body of evidence suggests that multivitamins offer little or nothing in the way of health benefits, and some studies suggest that high doses of certain vitamins might cause harm.

As a result, the authors behind the new research said it's time for most people to stop taking them.

"We believe that it's clear that vitamins are not working," said Dr. Eliseo Guallar, a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

In a strongly worded editorial on the three studies, Guallar and his co-authors urged people to stop spending money on multivitamins.

Even a representatives of the vitamin industry asked people to temper their hopes about dietary supplements.

"We all need to manage our expectations about why we're taking multivitamins," Duffy MacKay, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, a trade group that represents supplement manufacturers, said in a prepared statement.

"Research shows that the two main reasons people take multivitamins are for overall health and wellness and to fill in nutrient gaps," MacKay said. "Science still demonstrates that multivitamins work for those purposes, and that alone provides reason for people to take a multivitamin."

However, Guallar said, it's not clear that taking supplements to fill gaps in a less-than-perfect diet really translates into any kind of health boost.