Researchers agree that movement and exercise help to slow down the inevitable loss of bone with aging that increases risk for osteoporosis and fractures. Most studies show that maintaining normal levels of vitamin D and getting your calcium from food also help to prevent fractures, but almost all studies show that calcium pills by themselves may not help to prevent osteoporosis or fractures (European Society of Endocrinology, April, 2018;178(4):D13-D25). The same may apply to vitamin D pills. Studies show that high-dose vitamin D pills offer no protection against bone fractures or osteoporosis in middle-aged and older adults, regardless of factors such as sex, age, and race (N Engl J Med, July 28. 2022;387:299-309).
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 (BMJ, September 29, 2015;351:h4183 ). An editorial in the same journal issue states that in light of the strong evidence that extra dietary calcium does not prevent fractures, it is very puzzling that many medical and public health organizations still recommend taking calcium pills. Perhaps it is because of data showing that starting to take calcium pills before age 35 may help to reduce fracture risk (Elife, Sept 27, 2022;11:e79002) and starting to take calcium in later life may be too late to protect bones. The message is that most people should start to exercise and keep on moving at a young age. When you are older and already have developed osteoporosis, it may be too late for calcium and vitamin D to prevent many of the fractures associated with aging.
Potential Side Effects of Calcium Pills
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. The United States Preventative Services Task Force has presented the more evidence-based recommendation that post-menopausal women should not take daily calcium supplements.
Because of heavy advertising, many people believe that any amount of calcium is good and that it will cause no harm. However, too much calcium in pills can have dangerous side effects. Excess calcium can accumulate in:
• arteries to increase heart attack risk (BMJ, 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 and increased risk for pre-cancerous colon polyps (Gut, March 1, 2018;68(3):)
Calcium in foods does not cause high blood calcium levels, but calcium in pills can cause high blood calcium in susceptible individuals, which can cause nausea, vomiting, confusion, and seizures. 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 can reduce the benefits of drugs such as calcium-channel blockers and beta blockers.
Risk Factors for Osteoporosis
• aging
• Being thin or having a small body frame
• Being white or Asian
• Excessive alcohol intake
• Family history of osteoporosis
• Smoking
Food Sources of Calcium
Women ages 19 to 50 should consume 1,000 milligrams of calcium a day, and the target for women over 50 is 1,200 milligrams per day. Food sources of calcium include almonds, oranges, dried figs, soybeans, chick peas, beansand other legumes, dairy products such as milk and yogurt, and green vegetables such as kale and spinach.
Exercise to Strengthen Bones
Women who sit for more than nine hours a day are 50 percent more likely to have a hip fracture than those who are less sedentary (Am J Public Health, April, 2014;104(4):e75–e81). Weight-bearing exercises such as walking, jogging and weight training can help to slow bone loss.
My Recommendations
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 are 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
• 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.
