Multivitamins are not a ticket to optimal health. In fact, evidence that they improve health for most people is inconsistent. In some cases, they may even cause harm.

The U.S. Preventive Services Task Force concludes that there’s insufficient evidence to support any benefit from vitamin and mineral supplements for the prevention of cancer or cardiovascular disease.

While experts agree that most Americans don’t eat enough vitamin-rich foods, research shows that vitamin supplements might not be a great way to bridge the gap. And people who take higher doses of certain vitamin supplements actually have a higher risk of adverse health outcomes.

Dietary supplements may support good health, but are not replacements for a diet of nutrient-dense foods. Vitamin and mineral supplements should be only taken in addition to a healthy eating pattern, and only with the recommendation of your physician or dietitian.

The researchers concluded that multivitamins don’t reduce the risk for heart disease, cancer, cognitive decline (such as memory loss and slowed-down thinking) or an early death. They also noted that in prior studies, vitamin E and beta-carotene supplements appear to be harmful, especially at high doses.