Calcium supplements treble heart attack risk--study

Researchers from University of Auckland, New Zealand, University of Aberdeen, University of Leeds and University of Hull in England together with researchers from the US found that people taking excessive calcium supplements to improve bone strength might be putting their heart at risk.

Reuters quoted Ian Reid, professor of medicine, University of Auckland as saying, “People regard calcium supplements as natural but they are really not natural at all.”

The research was funded by Health Research Council and University of Auckland School of Medicine Foundation, New Zealand.

Meta-analysis of 11 studies
Researchers conducted a four-year long meta-analysis of 11 randomized-controlled-trials of calcium supplements.

The analysis to assess the likelihood of harm, involved nearly 12,000 patients who were taking supplements equal to 500mg or more per day.

Under the trial, half of the people received calcium supplements without vitamin D, which otherwise are often given in combination for the body to absorb calcium.

The other half was given placebo or dummy pills with no curative properties.

Results of the meta-analysis
Analysis revealed that people taking calcium supplements were at a greater risk of suffering a heart attack than those who did not take the supplements. The risk was calculated to be thirty percent.

Furthermore, it was known that treating about 1,000 people with calcium for a five-year period could cause 14 heart attacks, 10 strokes and 13 deaths in addition. It could however, prevent 26 fractures, stated researchers.

Nonetheless, researchers clarified that diets rich in calcium do not increase heart attack risk. The risk might aggravate with supplements, which are known to increase the levels of calcium circulating in the blood.

Higher blood serum levels lead to coagulation in the arteries, which can cause heart attacks, researchers further stated.

Study authors were quoted by The Press Association as saying, “Serum calcium levels have been positively associated with an increased incidence of (heart attack) in large observational studies.”

“Ingestion of equivalent doses of calcium from dairy products has a much smaller effect than calcium supplements on serum calcium levels,” they noted.

Daily Mail further quoted study researchers as saying, “Given the modest benefits of calcium supplements on bone density and fracture prevention, a reassessment of the role of calcium supplements in the management of osteoporosis is warranted.”

The study appears online in the British Medical Journal.