A review of 33 studies shows that calcium and vitamin D pills do not prevent fractures, regardless of dose (JAMA, Dec 26, 2017;318(24):2466). Other reviews of 59 studies and 50 studies showed that neither calcium pills nor foods rich in calcium prevent bone fractures (British Medical Journal, September 29, 2015;351:h4183 ). An editorial in the same issue of JAMA states that the evidence is so overwhelming that extra calcium does not prevent fractures that we have to ask ourselves why these products are still so widely used.
Why so Many Calcium Pills? In 1994, Congress passed a law that allows manufacturers of calcium and vitamin D pills to advertise and sell their pills without having to supply evidence that their products have any health benefits whatsoever. Today, more than $6 billion of calcium pills and $2.5 billion of vitamin D are sold each year. The Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies recommends 1200 mg of calcium each day for people over 50, even though they have little data to support the recommendation. In 2013 the United States Preventive Services Task Force reviewed 135 studies and recommended that postmenopausal women refrain from taking supplemental calcium and vitamin D.
Side Effects of Calcium Pills Calcium from supplements can accumulate in:
• arteries, to increase heart attack risk (British Medical J, 2011;342:d2040; JAMA Intern Med, 2013;173:639-46; NEJM, October 17, 2013; Heart, 2012;98:920-925; JAMA Internal Medicine, February 2013; Endocrine Practice, published online August 19, 2011; The Oncologist, 2012;17:1171–1179). However, researchers at Harvard found no association between calcium pills and increased risk for heart attacks (Osteoporosis International, May 2014)
• kidneys, to increase kidney stone risk (NEJM, 2006;354:669-83)
• stomach, to cause acid rebound and increase hospital admissions for acute stomach ulcer bleeding (J Bone Miner Res, 2012;27:719-22)
• colon, to cause constipation
• blood, to cause high blood calcium levels that can cause nausea, vomiting, confusion and seizures
• eyes, linked to macular degeneration (JAMA Ophthalmology, April 2015)
• prostate, to possibly increase risk for prostate cancer (Ann Epidemiol, 2009;19:96-102)
Calcium from pills can also bind to other drugs, such as antibiotics or osteoporosis medications, to prevent them from being absorbed into your bloodstream, and it can block the benefits of drugs such as calcium-channel blockers and beta blockers.
My Recommendations More than 75 percent of North Americans spend 12 billion dollars a year on supplements that are largely unregulated by the government to check whether they work or are even safe. Calcium and vitamin D pills are particularly popular because people believe that they strengthen bones, yet this recent study shows this is not true. More than 54 million North Americans have osteoporosis that causes more than 30 percent of the women over 50 to break their bones. I recommend that people who have weak bones or suffer fractures should:
• lift weights if they are able
• do weight-bearing exercise such as walking, jogging, dancing and playing tennis
• restrict alcohol
• avoid smoking and second-hand smoke
• get calcium from foods, not from pills. Calcium-rich foods include milk, cheese, yogurt, tofu, nut milks, leafy green vegetables, nuts and fish such as salmon and sardines.
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