The vast majority of studies on calcium supplements show that taking in extra calcium does not prevent bone fractures and that the extra calcium in pills may form plaques in arteries and stones in kidneys. People who take in low amounts of calcium on a plant-based diet are not at any higher risk for fractures than those who take in much larger amounts of calcium (Journal of Bone and Mineral Research, May 23, 2016). Furthermore, a review of the world’s literature shows that neither a high calcium diet nor calcium pills strengthen the bones of people over 50 (British Medical Journal, published online Sept 30, 2015). An earlier study showed that dietary calcium has no effect on the rate of fractures in postmenopausal women (Nutrition, June, 2009;25(6):647-54).
Calcium in Pills, Not Foods, May Increase Risk for Heart Attacks
Researchers at Johns Hopkins followed 2700 people who took calcium pills for at least 10 years and found that they had a 22 per cent increased risk of calcium plaques forming in the arteries leading to their hearts, compared to those who do not take calcium pills (Journal of the American Heart Association, October 11, 2016). On the other hand, people who took in large amounts of calcium from food (more than 1400 milligrams per day) were 27 percent less likely to have this buildup of plaques. This suggests that calcium in pills is processed differently from calcium in foods to accumulate in body tissues, rather than in bones. Food sources of calcium include dairy products, broccoli, leafy green vegetables, beans and some fruits. Calcium content of foods list
Limitations of Studies Supporting Calcium Pills
This month, a study from Tufts University reviewed 27 studies and found no difference in heart attack rates between those who took:
• calcium pills,
• calcium pills plus vitamin D, or
• placebo pills (Ann Intern Med, October 25, 2016).
However, the study limited calcium intake to 2500 mg per day, the amount that you can get from two to three daily servings of high-calcium foods such as dairy products, tofu and leafy greens. An editorial accompanying the article states that, “Calcium supplements may increase kidney stone formation, whereas dietary calcium intake reduces the risk for kidney stones, a painful condition that affects 10-20 percent of adults. No evidence exists that consuming more calcium than the recommended dietary allowance will result in better bone health or any other health benefits.”
More than 50 percent of women over 60 take calcium pills, and more than 50 percent of all North Americans take vitamins and/or mineral pills (JAMA, 2016;316(14):1464-1474), heavily influenced by advertising from the $32 billion supplement industry.
My Recommendations
• I believe that you should not take calcium pills unless your doctor prescribes them for a particular reason such as a condition that decreases your ability to absorb or retain calcium. Calcium from pills has been associated with increased risk for heart attacks and kidney stones.
• You can meet your needs for calcium by eating calcium-rich foods as part of a varied diet. The safe upper limit for healthy people is about 2000 mg of calcium per day.Â
Dr. Gabe Mirkin is a Villager. Learn more at www.drmirkin.com
