The use of dietary supplements has increased in the United States in recent decades . Folic acid , vitamin C , magnesium , zinc and copper pose an increased risk . However , the increases in death risk ( or decrease , in the case of calcium ) were extremely small and may not be clinically meaningful , says Mary L. Chavez , a professor of pharmacy practice at the Texas A & M Health Science Center , in Kingsville . Iron was most strongly linked to an increased risk of earlier death -- calcium was the least . Increases in mortality risk were extremely small and may not be clinically meaningful .
The use of dietary supplements has increased in the United States in recent decades . Folic acid , vitamin C , magnesium , zinc and copper pose an increased risk . Iron was most strongly linked to an increased risk of earlier death -- calcium was the least . Increases in mortality risk were extremely small and may not be clinically meaningful .