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How well does calcium intake really protect your bones?

September 30, 2015
  • By Beverly Merz, Executive Editor, Harvard Women's Health Watch

About the Author

photo of Beverly Merz

Beverly Merz, Executive Editor, Harvard Women's Health Watch

Beverly Merz is Executive Editor of Harvard Women’s Health Watch, a publication she helped start in 1993. Before coming to Harvard she was an Associate Editor of JAMA, Managing Editor with the Union of Concerned Scientists, … See Full Bio
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October 2, 2015

Thanks for this information.

sham gawande
October 2, 2015


Linda T.
October 1, 2015

Calcium by itself is not indicated to increase bone density. Weight bearing exercise is essential. Magnesium and Vit D prevent calcium from ending up in the wrong place (in heart arteries) instead of in bones. In addition, adding manganese, boron, Vitamin K, and other nutrients keep the bones happy.

Harold Byerly
October 1, 2015

I am 76 years old and have no calcium deposits in my heart’s arteries. I have taken 600 mg calcium and 300 mg magnesium daily for twenty years and enough vitamin D to reach an optimal blood level of Vitamin D. I also do aerobic exercise 4 to 5 days a week. I have very dense bones. I had to have a bone marrow assay and the doctor broke two needles trying to penetrate my hip bone. I agree with Stan that the amount needed is different for different people and is best determined by blood analysis. As I have aged I had to increase the amount of vitamin D to remain at the optimal level. Currently I am up to 7,000 units of Vitamin D daily.

Stan Bass
October 1, 2015

I’m a 71-year-old Vietnam Era Vet, retired Sr. H.R./Safety Director, and lifelong (since 1977) long-distance runner and racer, including marathons. (Not a big shot, in fact, pretty slow, but constant, including up/down hills and mountain trails.)

One thing I’ve learned about these studies, as well as a myriad of studies about diet (e.g. “China Studies,” is that no matter how good or thorough they are, they rarely if ever look at the subjects’ exercise habits. I have learned (for example, after a near-health disaster just months after trying a vegan diet without adding several important supplements) that it is evident that a whole different nutrition regime applies, or should apply, to regular exercises. For example: what is the effect of calcium/magnesium supplements for people who regularly run distance and/or lift heavy weights? I believe the effect of supplements is different, and possibly more positive, in effect for those who exercise and use their body as the Great Spirit intended it to be utilized and cared for.

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