A recent study involving around 2,000 postmenopausal women found no benefit from a calcium and vitamin D supplement treatment for women who do not have a vitamin or mineral deficiency. Study participants were a randomly selected subset of the larger Women’s Health Initiative study, a set of clinical trials and observational studies on a sample of healthy postmenopausal women between the ages of 50 and 79. Participants reported their health behaviors, and completed a survey of demographic and other relevant personal information, and were randomly assigned to receive either a supplement with calcium carbonate and vitamin D3 or a placebo for a two-year period. (There were no significant demographic or health behavior differences between the two groups.)
Participants were asked to record their diet in the weeks leading up to the study and at the two-year mark, so that the investigators could estimate the amount of dietary vitamins and calcium that participants were consuming. In both groups (supplement and placebo), around one-third of participants used daily multivitamins or other supplements, which they were allowed to continue using throughout the study. Participants who developed kidney stones or other conditions associated with excessive mineral or vitamin intake were removed from the study.
The investigators compared the participants’ joint pain (reported by participants) and joint swelling (objectively measured in-clinic) before the study and after two years of receiving either supplement or placebo. To assess the effects of the calcium and vitamin D supplement, the researchers compared the changes in joint pain and swelling while factoring in a variety of relevant characteristics (such as related health, dietary, demographic, and behavioral variables).
After two years of daily supplements or placebo, there were no significant differences in the frequency of joint pain or joint swelling between the two groups. In other words, the addition of the calcium and vitamin D supplements did not improve the joint health of the study participants. In a subsequent analysis, investigators found that women in the supplement group who also used non-study-related calcium supplements at the beginning of the study appeared to have slightly less joint pain than those who had not been supplementing with calcium. This finding, paired with the lack of benefit from the supplement protocol across the study, might suggest that individuals who use calcium and other supplements may be more likely to engage in other health-supportive behaviors, and may warrant further study on calcium in the general population.
Chlebowski RT, Pettinger M, Johnson KC, et al. Calcium plus vitamin D supplementation and joint symptoms in postmenopausal women in the Women’s Health Initiative Randomized Trial. Journal of the Academy of Nutrition and Dietetics. (2013). DOI: 10.1016/j.jand.2013.06.007