According to a new research, calcium pills intake could increase chances of heart attack.

The research team found that people who took calcium pills were at more risk of heart attack than people who did not take any supplements.

The study group involved some 24,000 German men and women who were asked to fill out a questionnaire describing their lifestyle, food and supplements taken.

All the participants were followed for 11 years. During this period 354 people suffered from heart attack.

The team found that people who took supplements and especially calcium supplements were 86 percent or more likely to have a heart attack than people who did not take any supplements.

"Their [calcium supplements] use in osteoporosis had caused concern with respect to the risk of renal calculi, which is increased by about 20%. There has also been a longstanding awareness that they cause gastrointestinal symptoms, particularly constipation, but it is more alarming to find that they double the risk of admission to hospital with an acute abdominal condition," write Ian Reid and colleagues in an editorial accompanying the study.

Some experts say that this research does not give a cause and effect relation between calcium intake and heart disease.

"This research indicates that there may be an increased risk of having a heart attack for people who take calcium supplements," said Natasha Stewart, a senior cardiac nurse with the BHF, to BBC. "However, this does not mean that these supplements cause heart attacks."

"Calcium is an important mineral. However, we probably do not need mega-doses of calcium, and the current recommendation can be met by a balanced diet that includes (low-fat) milk and dairy products," says Sabine Rohrmann, the senior author of the new study, epidemiologist at the University of Zurich, reports CNN.

Another study published in the journal BMJ in 2007 found increased rates of heart attack in postmenopausal women who were on calcium supplements. The study followed 1417 postmenopausal women for 5 years. The participants were randomly divided in two groups that received either calcium or placebo.

Yet another study says that calcium/vitamin D supplements did not have any effects on postmenopausal women. This particular study was based on 36,282 women who were assigned in to random groups; one group received calcium pills while the other group was kept on placebo. After a period of about 7 years, the number of heart attacks/strokes among the participants was found to be almost same in both groups.

"People who take supplemental calcium have a surge in [blood] calcium levels, and we know that surge increases calcium uptake in atherosclerotic plaques," said Dr. Christopher Cove, assistant director of the cardiac catheterization lab at the University of Rochester Medical Center, reports CNN.