Harvard Heart Letter

Calcium supplements and heart attack

Opposing studies sound a note of caution on too much calcium.

Your body needs calcium to build bones, contract muscles, send nerve signals, help enzymes and genes do their jobs, and much more — including making your heart beat. How much calcium you need to take in each day to fulfill these tasks, and in what form, are two controversial questions.

The average adult carries around two pounds or so of calcium. About 99% of it resides in bone. But calcium is a restless mineral. Some time in middle age, it seems to start moving from bones to the cardiovascular system, where it stiffens arteries and heart valves.

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