Calcium, Vitamin D, and Bone Health

It is difficult to figure out whether or not one should take calcium supplements. It seems that the media prefers headlines that scream out that supplements are bad for you. A very large trial, the Women's Health Initiative, involved 36,000 postmenopausal women aged 50-79 years. They were randomly assigned to treatment with calcium carbonate (not the most absorbable form of calcium, and not paired with magnesium, which would have been better) 1000 mg/day, plus vitamin D3 400 IU/day (the current conservative recommendation is 600-800 IU/day) or placebo. Even though the intervention wasn't ideal, the women who actually took at least 80% of their supplements showed a statistically significant 29% reduction in the risk for hip fracture after 12 years. In addition, after 12 years, but not after fewer years, a significant 13% reduction in vertebral fracture was noted in the active treatment group. These are significant findings. Don't be confused when the headlines say that no significant reduction in hip fracture was noted. That conclusion is reached when the women who did not take the supplements are also included. Of course calcium supplements won't help if they're sitting on the shelf! 

No increased risk in heart disease or breast cancer was noted. A slight decrease of in situ breast cancer was noted.