Vitamins and supplements don’t protect you from heart disease. Johns Hopkins researchers (including Miller) reviewed randomized clinical trials involving hundreds of thousands of subjects, in which some were given vitamins and others a placebo. “We found no evidence of benefits to cardiovascular disease,” Miller says. “Supplements were ineffective and unnecessary.” One possible exception is omega-3 or fish oil capsules. This type of fatty acid, found in fish and marine algae, helps the heart. Two servings of fatty fish per week provides enough for most people. For those who don’t get enough omega-3 in their diet, supplements may be helpful, Miller says.

Vitamins and supplements can be unsafe. While research has turned up no clear benefit to supplements, consuming too much of certain vitamins can be harmful. Too much calcium and vitamin D are associated with an increased risk of cardiovascular disease, Miller says. Though studies are ongoing, there’s little evidence that any amount of a vitamin D supplement will protect the heart, he adds. Another risk is that what you see on the label isn’t always what you get. Investigations have shown that too often pills said to contain medicinal herbs are actually full of fillers like powdered rice or even dangerous substances. Some don’t even contain any of the herbs on the labels. “Supplement production is not regulated by the FDA nor does the industry need to prove health benefits, so they can use vague language like ‘good for heart health’—but they can’t say ‘will lower blood pressure,’ ” Miller says.