In a massive new analysis of findings from 277 clinical trials using 24 different interventions, Johns Hopkins Medicine researchers say they have found that almost all vitamin, mineral and other nutrient supplements or diets cannot be linked to longer life or protection from heart disease.

Although they found that most of the supplements or diets were not associated with any harm, the analysis showed possible health benefits only from a low-salt diet, omega-3 fatty acid supplements and possibly folic acid supplements for some people. Researchers also found that supplements combining calcium and vitamin D may in fact be linked to a slightly increased stroke risk.

Results of the analysis were published on July 8 in Annals of Internal Medicine.

Surveys by the Centers for Disease Control and Prevention show that 52% of Americans take a least one vitamin or other dietary/nutritional supplement daily. As a nation, Americans spend $31 billion each year on such over-the-counter products. An increasing number of studies — including this new one from Johns Hopkins — have failed to prove health benefits from most of them.

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