Brittle Bones or Increased Heart Risk?

Calcium supplements linked to increased heart attack risk

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Calcium supplements, often taken to maintain bone health and prevent osteoporosis, appear to be linked to an increased risk of heart attack, a large study revealed.

Calcium supplements are commonly taken by post-menopausal women and the elderly to prevent bone thinning that can lead to osteoporosis. Previous studies had suggested the supplements may lower the risk of hypertension, obesity and type 2 diabetes, which are risk factors for heart attack and stroke.

"Talk to your doctor about calcium-boosting methods."

Kuanrong Li, the lead researcher from the German Cancer Research Centre in Germany, also found that boosting calcium through calcium-rich foods offers no significant protection from heart disease and stroke.

During the large study researchers followed 24,000 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) study in Germany, which began in 1994. Patients between the ages of 35 and 64 filled out food frequency questionnaires and were interviewed about their use of vitamins and supplements in the previous year.

After 11 years of follow up, 354 reported heart attacks, 260 suffered strokes and 267 died from cardiovascular-related causes.

Researchers found that participants who included a moderate amount of calcium from both food and supplements, an average of 820 milligrams, were 31 percent less likely to suffer a heart attack compared to the lowest calcium consumers. Those that consumed more than 1,100 milligrams a day of calcium were not found to have a significantly lower heart attack risk.

However, individuals who regularly took calcium supplements were 86 percent more likely to suffer a heart attack compared to non-supplement users. Certain types of calcium supplements were found to double that risk.

The findings also showed that calcium did not protect against or reduce the risk of stroke, which is consistent with previous research.

In light of the findings, researchers advised that individuals use caution when deciding whether to take calcium supplements since it could increase their heart risk.

In an accompanying editorial, Ian Reid and Mark Bolland, professors from the Faculty of Medical and Health Science at the University of Auckland in New Zealand, noted that the protective benefit of taking calcium supplements to ward off brittle bones is modest -- only about 10 percent.

They wrote that small amounts of calcium consumed throughout the day are absorbed slowly, while supplements cause blood calcium levels to increase beyond the normal range, which could be harmful.

“It is now becoming clear that taking this micronutrient in one or two daily [doses] is not natural, in that it does not reproduce the same metabolic effects as calcium in food,” they wrote.

The study was recently published in medical journal Heart.

Reviewed by: 
Review Date: 
May 22, 2012
Last Updated:
August 3, 2012