What’s a Girl to Do? Calcium Supplementation: Good for Our Bones, Bad for Our Hearts?


Ever since we were kids we were told that calcium is important for our bones – and it is! It is also important for many other physiologic functions: vascular contraction and vasodilation, muscle function, nerve transmission, intracellular signaling and hormonal secretion. For many years now, adult women have been encouraged to supplement calcium to prevent osteoporosis. Results of recent studies, however, have raised questions about whether regular calcium supplementation may increase the risk of cardiovascular disease.

A meta-analysis by Dr. Mark Bolland and his colleagues at the University of Auckland, New Zealand, of 15 randomized blinded placebo-controlled trials, found that in 12,000 patients who had taken at least 500 mg of calcium daily, there was a 30% increase in the risk of heart attack as well as an increased tendency to stroke and sudden death. In fact, the authors suggest that while supplementing with 1000 mg of calcium daily over 5 years would prevent 26 fractures, this would be at the cost of causing 14 heart attacks! Of note, these studies did not include calcium taken with vitamin D.

So What’s a Girl to Do?

Well, it’s still very important to keep our bones healthy and strong to prevent fractures as we age and to enjoy mobility and activity well into our golden years. Getting back to the basics of diet and exercise appear to be the safest way to protect our bones – at least for most women without significant bone loss already. And while starting to protect our bones in our 30’s is optimal, research shows it is never too late to start.

Calcium in the Diet

Dietary Allowance (RDA) for calcium for women aged 19-50 years is 1000 mg/day; women over age 50 are encouraged to get 1200 mg/day. Milk, yogurt, and cheese are significant natural sources of calcium; organic dairy products are recommended whenever possible. Nondairy sources of calcium include dark green leafy vegetables, such as kale, collards, broccoli, and Chinese cabbage. Tofu, salmon, and sardines are also very calcium-rich. Almonds and sesame seeds also contain calcium and blackstrap molasses is quite a rich source. Think of it this way; if you need to get 1000 mg/day of calcium into your diet, you would need to select from the following in an appropriate amount:

Food/Serving Size

Mg Calcium/Serving

Yogurt, plain, low fat, 8 oz

415

Milk, non fact, 8 oz

296

Cheddar cheese, 1.5 oz

306

Cottage cheese, 1% fat, 1 cup unpacked

138

Sardines, canned in oil, 3 oz

324

Tofu, firm; ½ cup (made with calcium sulfate)

253

Kale, cooked, 1 cup

94

Sesame seeds, whole roasted, 1 oz

280 mg

Almonds, 1 oz

80 mg

Blackstrap molasses, 1 tbs

135 mg

Many other foods also contain calcium. See http://ods.od.nih.gov/factsheets/calcium/

Dietary factors can also block calcium absorption or increase the rate at which our bodies eliminate it. Diets high in sodium, protein, and potassium, caffeine intake, alcohol consumption, and phosphorous in sodas, can all contribute to calcium loss.

Shake Them Bones

Exercise is critical for building and maintaining bone density and strength, and for reducing bone loss. Regular weight bearing exercise at any age, even in the very elderly, can increase muscle strength, balance, and functional capacity. All of this can lead to a significant reduction in falls and fractures. Recommended types of exercise include walking, jumping, running, and weight training – 30 to 45 minutes of exercise, 5 or more times per week. Tai chi is the only form of exercise that has been proven in studies to reduce the number of falls in the elderly and is strongly recommended.

So ladies, not too complicated. A healthy diet and a brisk walk after dinner are good for your your bones. And the good news? Great for your heart, too!

Bolland MJ, Avenell A, Baron J, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010; 341:c3691.

Dietary Supplement Fact Sheet, Calcium: health professional fact sheet. Available at: http://ods.od.nih.gov/factsheets/Calcium_pf.asp
Accessed September 22, 2010.

Proctor, DN, Melton III, LJ, Khosla S, et al. Relative Influence of Physical Activity, Muscle Mass and Strength on Bone Density Osteoporosis International 11(11), 944-952.

Voukelatos A, Cumming RG, Lord SR, Rissel C. A randomized, controlled trial of tai chi for the prevention of falls: the Central Sydney tai chi trial.Journal of the American Geriatrics Society 55(8):1185-91 Aug, 2007.

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