Two research reports, one reviewing 59 studies and the other reviewing 50 studies, found 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 journal issue states that in light of the overwhelming evidence that extra dietary calcium does not prevent fractures, it is very puzzling that many medical and public health organizations still recommend extra calcium. The author says, “The profitability of the global supplements industry probably plays its part . . . Manufacturers have deep pockets, and there is a tendency for research efforts to follow the money (with accompanying academic prestige), rather than a path defined only by the needs of patients and the public.”
For example, 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, an unreasonably high amount at any age. Three years ago, the United States Preventative Services Task Force presented the more evidence-based recommendation that post-menopausal women should not take daily calcium supplements. Studies in Sweden show that people who drink the most calcium-rich milk are at increased risk for bone fractures and premature death (British Medical Journal, October 28, 2014).
Side Effects of Calcium Pills
Because of heavy advertising, many people believe that any amount of calcium is good and that at the very least, it will cause no harm. However, too much calcium can have dangerous side effects; Excess calcium can accumulate in:
• arteries to increase heart attack risk (British Medical J, 2011;342:d2040; JAMA Intern Med, 2013;173:639-46)
• kidneys to increase kidney stone risk (N Engl J Med, 2006;354:669-83)
• the stomach to cause acid rebound and increased risk for acute stomach ulcer bleeding (J Bone Miner Res, 2012;27:719-22)
• the colon to cause severe constipation
High blood calcium levels can cause nausea, vomiting, confusion, and seizures. Calcium from pills can bind to other drugs, such as antibiotics or osteoporosis medications, to prevent them from being absorbed into your bloodstream and can reduce the benefits of drugs such as calcium-channel blockers and beta blockers.
What Is a Coronary Calcium Score?
Coronary Calcium Score is a test that shows the extent of calcium deposits in plaques the inner lining of the arteries leading to your heart, measured by a special X-ray called computed tomography (CT or cat scan). Plaques that cause heart attacks are full of calcium that is seen on X-rays. So the thicker your plaque, the more likely you are to have coronary heart disease. However, the test can miss “soft plaques” that can’t be seen by X-rays and you can be incorrectly diagnosed as having no plaques.. Your score can range from 0 to more than 400. A score over 100 suggests that you are at increased risk for a heart attack. The higher the score, the greater the risk for a heart attack.
I do not recommend this test because it exposes you to radiation equal to more than 150 chest X-rays, and radiation from any source increases your risk for cancers. Your doctor can get far more useful information about your risk for a heart attack from blood tests and questions about your lifestyle. I only mention the test because it shows the presence of calcium in arterial plaques which may be linked to excess calcium in the diet or from supplements. The association is not clear, but I believe it is a concern.
More than 54 million North Americans have osteoporosis, which causes more than 30 percent of women over 50 to have bone fractures. In the United States more than 12 billion dollars is spent each year on supplements that are largely unregulated so there is no way to know whether they are effective or safe. Calcium supplement advertising is notorious for its cure-all promises and unsupported claims.
If you have osteoporosis or have evidence that your bones are fragile (a fracture with little or no trauma), check with your doctor. The best non-prescription ways we have to strengthen bones are:
• exercise against resistance (lifting weights or using strength-training machines), and
• do plenty of weight-bearing exercise such as walking, running or dancing.
To keep your bones healthy, do not smoke and avoid being around smokers, restrict alcohol, and get enough vitamin D (blood levels of hydroxy vitamin D over 20 ng/ml). Sunlight is the best source of vitamin D.