Calcium Supplements: Too Much of a Good Thing?

PJ Hamel Health Guide
  • “Drink your milk.”

    It’s a refrain we started hearing years ago, when Mom would set a brimming glassful of milk in front of us two or even three times a day. Whether it was hot cocoa at breakfast, milk and cookies after school, or the beverage of choice at supper, for most of us milk was a key part of our childhood diet.

    Some of us carried that mantra through adulthood, dutifully switching to skim milk, and broadening our horizons to include cheese and yogurt, cottage cheese, even going so far as to seek out other forms of calcium beyond dairy: fortified orange juice, for instance. Breakfast cereal.

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    And, just to be sure, a calcium supplement, or daily multivitamin high in calcium.

    We patted ourselves on the back. A diet rich in calcium keeps your bones strong; we were living a bone-healthy lifestyle, warding off a possible future of widow’s humps and hip fractures.

    Or so we thought.

    We may have been wrong.

    A recent study reported in The Journal of Clinical Endocrinology and Metabolism concluded that men aged 59-70 who exercised regularly exhibited higher bone density than men who didn’t exercise, but took daily calcium (1000mg) and vitamin D (800IU) supplements.

    Men who exercised and took supplements didn’t show any increase in bone density over men who just exercised, leading researchers to conclude that those taking supplements were doing so needlessly; their regular diet included sufficient calcium and vitamin D.

    Well, that’s men; what about women?

    Dr. Walter Willett, chair of the Department of Nutrition at the Harvard School of Public Health, has been saying for years that there’s no relationship between calcium consumption and bone fracture. Willett draws his conclusions about calcium from the Nurses’ Health Study (NHS), an ongoing study of older women’s health begun in 1976, where he’s has been one of the lead researchers. 

    Willett has found that while we do need a certain amount of calcium to ensure strong bones, many of us may be overloading by adding supplements to a diet that already includes adequate amounts of calcium. Willett estimates that about 700mg of calcium daily is a sufficient amount to keep bones strong.

    The National Institutes of Health’s daily recommendation for calcium for women over age 50 is 1200mg.

    So, whether you believe Dr. Willett, or the NIH, you should be getting between 700mg-1200mg calcium daily. If you take a typical 1000mg supplement, though, you might very well be getting more. And not only might this extra calcium be unncessary; it might actually be hurting you.

    Dr. John Baron, a professor of medicine at Dartmouth Medical School in Lebanon, New Hampshire, co-authored an intriguing study released last summer. The study shows that older people taking a daily calcium supplement of at least 500mg showed a 30% increase in heart attacks over those taking no supplemental calcium.

    Baron stressed that results are preliminary, and that patients taking calcium supplements should consult their doctor before stopping. But the study does at least call into question the “more is better” approach many of us have been taking with regard to calcium, especially in supplemental form.

  • Bottom line: To protect both bones and heart, try for a daily intake of about 1200mg calcium. And, rather than popping a supplement or vitamin, try to get that calcium in the form of food.

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    Maybe that glass of milk is a good idea, after all.

Published On: March 07, 2011