MORE THAN 60 percent of American women older than 60 take calcium on a regular basis believing that it strengthens bones and improves health. But that may change with the publication of new research that suggests that not only is calcium ineffective at preventing bone fractures, it may be harmful to your health.
After decades of believing in the benefits of calcium supplements for women, most doctors were surprised and skeptical when in 2010, researchers reviewed data from the famous Women's Health Initiative study and found that calcium might be associated with heart attacks and strokes. Soon after, an article from Australia contradicted those findings, suggesting that calcium was safe to take.
But now a new study, published Feb. 13 in the British Medical Journal, looked at a population of nearly 62,000 Swedish women over a long time frame — nearly 20 years. The women were closely surveyed for their dietary calcium intake as well as calcium supplements (in pill form). Their intake of calcium was then correlated to a number of important outcomes — the risk of death from all causes, cardiovascular disease, heart attacks and stroke.
After an average of 19 years of follow-up, women who took 1,400 milligrams of calcium per day (about 3 calcium pills per day), had a 40 percent higher risk of death from all causes and nearly 50 percent higher risk of cardiovascular disease. Most importantly, women
The authors of this study concluded that high intake of calcium in women is associated with higher death rate and cardiovascular disease. They postulate a number of reasons why calcium may be harmful, but the bottom line is that we just don't know.
What is clear is that the body regulates calcium blood levels very carefully, and it will absorb as much as needed. Taking extra calcium seems to overwhelm the normal calcium regulatory system in the body, causing a number of dangerous effects. This does not apply to women with very low calcium intake who may still need calcium supplementation.
Beyond being dangerous, there is increasing evidence that calcium supplements have minimal effect on bone strength.
This week, the U.S. Preventative Services Task Force, the most influential national guideline group, issued a press release stating it no longer recommends calcium supplements for women. This new finding had nothing to do with the risk of calcium causing heart disease and death. The recommendation was issued because a comprehensive review of the medical literature suggests that calcium doesn't work to prevent bone fractures in otherwise healthy women. The task force also suggested that vitamin D supplements are not needed for most women as well.
In the words of the task force: "The USPSTF concludes that the current evidence is insufficient to assess the balance of the benefits and harms of daily supplementation with greater than 400 IU of vitamin D3 and greater than 1,000 milligrams of calcium for the primary prevention of fractures in "... postmenopausal women."
This does not apply to women with known bone disease including women with documented osteoporosis who may need calcium supplements along with other osteoporosis medications. It also does not apply to women with documented low vitamin D levels who may require supplementation.
But for the average healthy postmenopausal woman, popping two or three calcium plus vitamin D pills per day should not be considered a routine recommendation anymore. Talk to your doctor about it and assess your risk. If you are at the age where you need a bone density test, get that done before you take unnecessary and perhaps harmful supplements.
This also doesn't apply to a diet high in calcium — which most experts continue to recommend for healthy women. Calcium rich foods include dairy products, dark leafy greens (spinach, kale, turnips, collard greens), soy products, and enriched breads and cereals. Weight bearing exercise including walking, hiking, jogging, weight training, dancing, aerobics, jumping, and tennis stress the bones (a good thing) and make them stronger. Active women tend to have much better bone density than sedentary women. Healthy women who are a bit above their ideal weight also have stronger bones than thinner women.
Eat right and exercise — sometimes we sound like broken records but when it comes down to it, the message is the same: lead a healthy natural life. Be active, eat good foods and avoid any unnecessary pills or supplements.
Dr. Bill Elliott is an internist at Kaiser Novato and an assistant clinical professor of medicine at UCSF. His column appears every third Monday.