Calcium Pills may Increase the Risk of Heart Attack

Heart attack, stroke, and sudden death — side effect warnings you don't see on the back of a calcium bottle. If you did, you might not purchase the product. Indeed, if this warning was listed, supplement manufacturers would certainly suffer a great loss. At the same time, many health-conscious individuals don't hesitate to take supplements — just in case their diet is lacking. After all, since they don't require a prescription, they must be safe, right? Who would have thought that taking something considered to be so natural may actually be harmful? The truth is, health benefits from taking supplements are many times over-exaggerated; some supplements don't even contain what they list on the label, and others contain ingredients that could be potentially dangerous. Recently, researchers have questioned the validity of taking calcium supplements since emerging evidence has linked their consumption to an increased risk of cardiovascular disease — creating considerable uncertainty.

I appreciate Doctors John McDougall and Michael Greger for digging into the scientific literature concerning this topic and would like to share their discoveries with you. In Dr. McDougall's article, Calcium Supplements are Harmful, he cites a medical study published in the British Medical Journal showing that calcium supplements were associated with a "30% relative increase in the incidence of myocardial infarction and small increases in the risk of stroke and overall mortality."

Dr. Greger reports his findings in the video below, Are Calcium Supplements Safe? Greger writes, "In 12 short years, government panels have gone from suggesting widespread calcium supplementation — which may be necessary to protect our bones — to DO NOT SUPPLEMENT." He credits a study conducted in 2008 by New Zealand researchers who noted that women taking calcium supplements suffered more heart attacks that those not taking the supplement.

To gain a better understanding of this phenomenon, the researchers then examined the data collected by the Women’s Health Initiative, which was the largest and longest randomized controlled trial of calcium supplementation. Greger reports that the group of women who had not previously taken supplements showed a significant increase in heart attacks and strokes once they began supplementation. "High dose or low dose," says Greger, "any calcium supplementation seemed to increase cardiovascular disease risk."

According to Dr. Greger, "Researchers went back, digging through other trial data for heart attack and stroke rates in women randomized to calcium supplements with or without vitamin D added, and confirmed the danger, and most of the population studies agreed — users of calcium supplements tended to have increased rates of heart disease, stroke, and death." 

Greger emphasizes that taking calcium supplements increases the risk of heart attack, stroke, and death, but not the calcium we consume in our diet: 

Perhaps because when you take calcium pills, you get a spike of calcium in your bloodstream that you don’t get just eating calcium rich foods. Within hours of taking supplemental calcium, the calcium levels in the blood shoot up and can stay up as long as eight hours. This evidently produces what’s called a hypercoagulable state, your blood clots more easily, which could increase the risk of clots in the heart or brain. And, indeed, higher calcium blood levels are tied to higher heart attack and stroke rates. So, the mechanism may be calcium supplements lead to unnaturally large, rapid, and sustained calcium levels in the blood, which can have a variety of potentially problematic effects.

 He concludes by saying:

Calcium supplements have been widely embraced on the grounds that they are a natural and, therefore, safe way of preventing osteoporotic fractures. But, it is now becoming clear that taking calcium in one or two daily doses is not natural, in that it does not reproduce the same metabolic effects as calcium in food. And furthermore, the evidence is also becoming steadily stronger that calcium supplementation may not be safe. That’s why most organizations providing advice regarding bone health now recommend that individuals should obtain their calcium requirement from diet in preference to supplements.

The Starch-Smart® System that I recommend to my patients supplies adequate levels of calcium for every stage of life — without any adverse side effects. When consuming a wide variety of whole grains, beans, nuts, seeds, legumes, unprocessed non-GMO (organic) soy, fruits, and especially green leafy vegetables, it would be difficult not to obtain adequate calcium.

You may also enjoy reading:

(1) Calcium and Dairy Products - by Dr. John McDougall

(2) How the Calcium Paradox Baffles Bone Beliefs

(3) Calcium in Plant-Based Diets - by PCRM

(4) Calcium and Strong Bones - by PCRM

Additional medical studies:

• Does Widespread Calcium Supplementation Pose Cardiovascular Risk? Yes: The Potential Risk Is a Concern "In both of our meta-analyses, calcium supplementation was more likely to cause vascular events than to prevent fractures."
• Calcium Supplements and Cardiovascular Risk "...calcium supplements increased the risk of myocardial infarction [heart attack] and stroke by 25% to 30%."