LOS ANGELES, CA (Catholic Online) - Hundreds of thousands of adults take the supplements, prescribed by either their doctor against osteoporosis or bought over the counter as "bone insurance."

Osteoporosis is a disease, usually found in the elderly in which the bones become thinner and increasingly fragile.

The study, involving 388,000 people, found men taking calcium supplements of more than 1,000 milligrams a day had a greater chance of suffering heart disease and dying from it.

Interestingly, those achieving high-calcium diets solely through food or drink were not at extra risk, according to researchers from the National Cancer Institute in the U.S. It was the way supplements increase the levels of calcium circulating in the blood which appeared to have a negative effect on the cardiovascular system.

Experts believe higher blood levels lead to hardening of the arteries, which can cause heart attacks.

Experts recommend adults have 700 milligrams of calcium a day, which should come from dietary sources including milk, cheese and green, leafy vegetables.

According to a report in the JAMA Internal Medicine, women had no such extra risk, although some previous trials have found a link. Researchers followed men and women aged 50 to 71 over an average of 12 years. They recorded 7,904 deaths in men from cardiovascular disease and 3,874 deaths in women.

Supplements containing calcium were used by 51 percent of men and 70 percent of women.

Men taking 1,000 milligrams or more in calcium supplements a day had an almost 20 percent higher rate of heart disease and death than those who did not take supplements.

"Whether there is a sex difference in the cardiovascular effect of calcium supplements warrants further investigation," the report said.

"Given the extensive use of calcium supplements in the population, it is of great importance to assess its use beyond bone health."

It must be noted that older women are more at risk of osteoporosis because the rate of bone loss is accelerated by the menopause. One in two women and one in five men over the age of 50 will break a bone mainly because of the disease.

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