DAIRY CALCIUM, BUT NOT CALCIUM SUPPLEMENTS PROTECT AGAINST CVD, DIABETES AND COLONIC CANCER A meta-analysis of RCTs that involved 28,072 participants found that calcium or calcium plus vitamin D supplementation increased the risk of myocardial infarction by 24% (RR = 1.24; 95% CI: 1.07, 1.45) and the composite of myocardial infarction or stroke by 15% (RR = 1.15; 95% CI: 1.03, 1.27) (2). These results were consistent with those of the WHI trial and other RCTs (2). The benefits and risks are summarized as follows: the treatment of 1000 women with calcium plus vitamin D for 5 y would prevent 5 breast cancers and 1 colorectal cancer, and might prevent 1 fracture and 2 deaths, but would cause 4 myocardial infarctions or strokes (1). Although it is difficult to know for certain whether both nutrients are required to achieve the benefits, it has been shown that the adverse cardiovascular effects are due to the calcium component of the supplement. However, it appears that this adverse effect can be prevented by supplying the calcium in the more complex chemical form found in dairy products (3). Current calcium supplements acutely increase serum calcium concentration and suppress parathyroid hormone concentrations, and these changes are positively associated with atheroclerosis and incidence of myocardial infarction and mortality. Ingestion of the same amount of calcium from dairy products has a much slighter effect on serum calcium concentrations than do calcium supplements (4), which might explain the absence of adverse vascular effects of dairy calcium in the observational studies reviewed. In this context, it is interesting that intake of high amounts of dairy products, despite high saturated fat contents, seems to protect against cardiovascular disease (5), diabetes, and colonic cancer (6). Therefore, a way to obtain the health benefits of calcium and vitamin D may be to obtain at least 1000 mg calcium from dairy products, which would not pose a problem for most individuals.
Posted on: Sun, 09 Jun 2013 13:53:16 +0000
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