CALCIUM SUPPLEMENTATION FOUND NOT TO INCREASE RISK OF HEART DISEASE

New findings conclude that calcium supplements, widely prescribed for bone health in women, do not appear to be associated with increased cardiovascular risk.  This study offers strong support against a link between calcium supplementation and cardiovascular problems.

The potential for calcium supplementation to increase heart disease risk in women has been a subject of intense scrutiny in recent years after some studies uncovered an apparent association between calcium supplements and heart disease.  However the results of this most recent study, based on a landmark 20-year study that tracked more than 75,000 women found no link between calcium supplementation and heart disease, and that supplementation with calcium, if anything, slightly reduces the risk of heart disease.

 

In this study, Dr. Julie Paik from Harvard Medical School analyzed data from the Nurses' Health Study in the U.S., which began enrolling women in 1976 at ages 30-55.  Over the next 24 years participants’ lifestyle, diet, supplement intake, and medical records were tracked.  Researchers took into account other factors that are known to affect heart health risk including diet, weight, activity, smoking, family history, smoking, alcohol intake, and aspirin use as well as other patient characteristics.  Their analysis indicated that among participants who supplemented with 1,000 mg or more of calcium, risk of getting heart disease overall was slightly reduced.  And, participants’ risk of having a fatal heart attack or stroke appeared unaffected by supplementation.

The main previous work pointing to a possible link between calcium supplementation and heart health risk tracked more than 24,000 Swiss women over an 11-year period.  This research found that participants whose calcium intake from all sources was moderate -- 820 mg a day -- had a lower risk of heart attack than those whose intake was less than 820 or more than 1,100 mg.   And, when the researchers singled out those who supplemented with calcium, they found a significantly increased risk of heart disease. 

The researchers in the Swiss study postulated that unlike many dietary sources with small amounts of calcium, supplements could cause greater fluctuations in blood calcium and possibly contribute to hardening of the arteries.  Still, many experts felt that such an effect was unlikely because the body can only absorb about 500-600mg of calcium at a time.  And, supplements typically contain about 500mg, equivalent to the amount of calcium in 1 cup of milk plus 1 oz. of cheese.  There are other experts who advise that when calcium supplements are combined with vitamin D they are better utilized and therefore less likely to lead to a potential high blood calcium level.  This study did not address whether individuals were taking calcium alone or in combination with vitamin D.  In response to the findings from the Swiss study, Dr. Robert Recker, director of the Osteoporosis Research Center at Creighton University stated, "It's hard to understand why calcium in the diet can reduce the risk of heart attack, but supplements increase the risk."  He stated that he felt these findings could reflect a bias where those already at risk for heart attacks took supplements in hopes of reducing the risk, but some had heart attacks nonetheless.  Because the results of this study seem contradictory and the recent findings by Paik and colleagues found no association between supplementation and heart disease, most experts continue to recommend that adolescent girls and women over 50 who do not consume a diet rich in calcium take ~500 mg of calcium combined with ~200-600 IU of Vitamin D two times per day.

What to do:  Consume a diet rich in calcium as calcium rich diets have consistently been found to be good for bone health and blood pressure as well as other aspects of health.  Dairy products and fish that contain bones (such as sardines) are the richest food sources of calcium.  When choosing dairy always opt for nonfat or lowfat to avoid unhealthy saturated fats.  Dark green vegetables also have significant calcium but it is harder for the body to absorb the calcium they contain.  Many products such as soy milk, cereal, and orange juice are fortified with added calcium. During adolescence, when bone is built most rapidly, adequate calcium intake is essential to life-long bone health.  Talk with your doctor to determine if calcium with vitamin D supplementation is right for you.

Adapted from articles available at: http://www.nlm.nih.gov/medlineplus/news/fullstory_125506.html

http://www.consumer.healthday.com/Article.asp?AID=665054

Sources:

Paik J, et al "A prospective study of calcium supplement intake and risk of cardiovascular disease in women" ASBMR 2012; Abstract 1135.

Li K et al. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study (EPIC-Heidelberg). Heart 2012 Jun; 98:920.