A study by the Journal of the American College of Cardiology says most popular supplements such as multivitamins, vitamin D, calcium and vitamin C do not prevent heart disease or stroke. Natural health experts and some nutritionists believe a healthy diet eliminates the need for supplements. However, one exception may be folate or other B vitamins which may reduce the risk for heart disease or stroke. It is estimated that 50 percent of Americans take some sort of supplement and the vitamin industry reports billions of dollars in sales. The American College of Cardiology says eating vitamin-rich foods is more effective than taking supplements.