Calcium Supplements Linked to Heart AttacksJan 16, 2008 | Parker Waichman LLP Older women who take calcium supplements to maintain bone strength may have an increased risk of heart attack, researchers in New Zealand said on Tuesday. The researchers cautioned that they do not consider their findings the definitive word on the subject, but said the potential side effect they saw merits further study. "This effect could outweigh any benefits on bone from calcium supplements," researchers led by Ian Reid of the University of Auckland wrote in the British Medical Journal.
Many women take calcium supplements to try to prevent osteoporosis and calcium has long been suggested for women with either a history of osteoporosis or for women in their post-menopausal years as this is when osteoporosis-related bone fractures tend to occur. Osteoporosis makes bones weak and more likely to break and while anyone can develop osteoporosis, it is common in older women. As many as half of all women and a quarter of men older than age 50 will break a bone due to osteoporosis. Risk factors for osteoporosis include: Aging, being small and thin, having a family history of osteoporosis, taking certain medicines, being a white or Asian woman, and having osteopenia, also known as low bone mass. Osteoporosis is a silent disease and is often undetected until a bone breaks.
The study involved 1,471 healthy post-menopausal women with a median age of 74 and who already had previously participated in a study on the effects of calcium on bone density and fracture rates. Of the nearly 1,500 women, 732 were given a daily calcium supplement and 739 were given a placebo each day. They followed the women’s progress for five years.
The study revealed that heart attacks were more common among the group of women taking the calcium supplements, with 31 women who took supplements experiencing a heart attack compared to 21 women who received the placebo treatment, the researchers said. The researchers also noted that previous research had suggested that taking calcium supplements might protect against vascular disease by lowering levels of bad cholesterol in the blood. They said that because calcium supplements raise blood calcium levels, this could accelerate the formation of deposits in the arteries that could then lead to heart attack. The new results "are not conclusive but suggest that high calcium intakes might have an adverse effect on vascular health," the researchers wrote. "In the meantime this potentially detrimental effect should be balanced against the likely benefits of calcium on bone, particularly in elderly women," they added.
About 99 percent of the calcium in our bodies is found in our bones and teeth and, in addition to building and maintaining healthy bones, calcium allows blood to clot, nerves to send messages, muscles to contract, and other body functions. Our bodies lose calcium through skin, nails, hair, sweat, urine, and feces; the human body cannot produce calcium on its own. When the diet does not have enough calcium for our body’s needs, calcium is taken from the bones.