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Are Calcium Supplements Safe?

Oct 29, 2016

There are a number of studies saying that calcium supplements may not be heart safe.

A recent study showed a link to poorer cardiovascular health from calcium pills, but can’t prove cause-and-effect.

This current study suggests that dietary calcium in the form of supplements, but not calcium-rich foods, might have a harmful impact on the heart. The study couldn’t prove the supplements help cause heart trouble, but its authors believe the finding should give consumers pause for thought.

Dr. Erin Michos, associate director of preventive cardiology at the school’s Ciccarone Center for the Prevention of Heart Disease and lead author of this study, in a news release stated that, “when it comes to using vitamin and mineral supplements, particularly calcium supplements being taken for bone health, many Americans think that more is always better.”  But she also added that the results of the study add to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system, and the important word here is “excess.”

We know through a number of surveys, and according to the U.S. National Institutes of Health, that about 43 percent of American adults now take a supplement that includes calcium, and more than half of women over 60 take calcium supplements to reduce their risk of osteoporosis.

In this new government-funded heart disease study, they analyzed data from 10 years of medical tests on more than 2,700 adults in the U.S. Participants ranged in age from 45 to 85, and they were questioned on their daily diet and the supplements they took.

They adjusted for factors that included exercise, education, weight and income. The research showed that people in the top fifth in terms of calcium intake had a 27% lower risk of heart disease, compared to those in the bottom one-fifth.

However, that statistic looked at total calcium intake in people who took in the nutrient from food and/or supplements. And what they discovered was that those who took calcium supplements had a significant increase in their odds for heart disease and plaque buildup in their arteries, compared to people who didn’t take the supplements.

The findings added to the growing concern about the possible harm in taking calcium supplements, as opposed to the calcium found in our foods.

According to the National Osteoporosis Foundation, foods rich in calcium include milk and many dairy products, broccoli, oranges and beans, among others.

Co-author John Anderson, professor emeritus of nutrition at the University of North Carolina, said in the news release, “What we do know is that there is clearly something different in how the body uses and responds to supplements versus intake through diet that makes it riskier. It could be that supplements contain calcium salts, or it could be from taking a large dose all at once that the body is unable to process them.”

Regarding telling patients, Dr. Michos added,, “Based on this evidence, that there doesn’t seem to be any harm in eating a heart-healthy diet that includes calcium-rich foods, and it may even be beneficial for the heart. But patients should really discuss any plan to take calcium supplements with their doctor to sort out a proper dosage or whether they even need them.”

In one other study in the British Medical Journal, participants who consumed calcium supplements on a regular basis were found to have a significantly higher risk of heart attack — 86% — compared to participants who took no calcium supplements. They found not only an increase in heart attacks, but also an increase in strokes and heart-stroke related death.

In addition, participants consuming only calcium supplements were also found to be two times more likely to have a heart attack than those participants who took no supplements at all.

Researchers concluded that taking calcium supplements may actually be harmful, since supplements raise the calcium levels in the blood well above normal range. Findings indicate that consuming calcium via supplements doesn’t have the same metabolic benefits as when calcium is consumed naturally in the diet.

Study authors believe that consumption of calcium supplements should be discouraged, and instead calcium should be consumed from natural, dietary sources.

Practice Pearls:

  • Coronary heart disease kills more than 370,000 Americans each year, according to the U.S. Centers for Disease Control and Prevention, 2016.
  • According to the National Osteoporosis Foundation, we should be getting our calcium from calcium-rich foods such as milk and other dairy products, broccoli, oranges, beans, among others.
  • Patients should really discuss any plan to take calcium supplements with their doctor to sort out a proper dosage, or whether they even need them

Dr. Erin Michos: Published in the Oct. 10 issue of the Journal of the American Heart Association.

BMJ-British Medical Journal (2012, May 23). Calcium supplements linked to significantly increased heart attack risk, study suggests.