Calcium has been seen as a cure-all for physicians, parents, and consumers alike. Have osteoporosis? There's calcium for that. Have PMS? There's calcium for that. Trying to lose weight? Some research has indicated that people with lower levels of calcium tend to be more likely to gain weight, have a higher body-mass index, and are more likely to be overweight and obese. Better take some calcium for that.

Federal guidelines recommend that people take 1,000 milligrams of calcium a day, advising some groups – 9- to 18-year-old teenagers, pregnant or lactating 14- to 18-year-old mothers, and women who are 51-years-old or older, and men who are over 70 years old – to take up to 1,300 mg a day. But any more than that can be dangerous.

In fact taking more calcium than those levels can lead to kidney stones, in a recent study published in the British Medical Journalheart attacks, and can cause hardened coronary arteries.

That is because the body can handle amounts of only 600 mg of calcium at the same time. Any more than that, and calcium can build up in the kidneys. Additional calcium can build up in the bloodstream and, when passed through the kidneys via urine, can lead to kidney stones.

The knowledge about kidney stones is old hat, but the research about heart problems is new – and potentially very problematic. Heart disease is the largest killer of Americans right now. With milk being the state drink of 21 states, and the love of supplements, the role that too much calcium could play could have dangerous ramifications for a lot of people.

However, the role that too much calcium can play in provoking heart attacks and in causing hardened coronary arteries is far from conclusive. In addition, research has indicated that these conditions are exacerbated in susceptible individuals, and may not be the case for everyone.

Regardless, the American Health Association is investigating calcium supplements that provide beyond what is recommended by federal guidelines.

In the meantime, researchers recommend that you continue eating calcium-rich foods – but be careful that you do not go overboard. Dairy is always an option, but if you do not eat dairy products, beans, tofu, broccoli, breads, cereals, kale, and soy are always options.