Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Calcium Intake and Bone Mineral Density

Dietary sources vs supplements

Publish date:: October 13, 2015

An increase in calcium intake either from dietary sources or from calcium supplements produced only small, non-progressive increases in bone mineral density (BMD) which is unlikely to translate into clinically significant reductions in fractures, according to a meta-analysis of 59 randomized controlled trials in participants aged 50 years and older. The study found:

• Increasing calcium intake from dietary sources increased BMD by 0.6% to 1.0% at the total hip and total body at 1 year and by 0.7% to 1.8% at these sites and the lumbar spine and femoral neck at 2 years.

• Calcium supplements increased BMD by 0.7% to 1.8% at all 5 skeletal sites at 1, 2, and over 2½ years, but the size of the increase in BMD at later time points was similar to the increase at 1 year.

• Increases in BMD were similar in trials of dietary sources of calcium and calcium supplements, in trials of calcium monotherapy vs co-administered calcium and vitamin D, in trials with calcium doses of ≥1000 mg/day vs <1000 mg/day, and ≤500 mg/day vs >500 mg/day.

Citation: Tai V, Leung W, Grey A, Reid IR, Bolland MJ. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ 2015;351:h4183. doi:10.1136/bmj.h4183.

Commentary: This meta-analysis of 59 randomized controlled trials of both dietary and supplemental calcium strongly suggests that the standard advice of increasing calcium intake is likely to yield little to any benefit on either BMD or risk of fracture in post-menopausal women. This low likelihood of benefit must be viewed in the context of reported increase in cardiovascular risk and the increased risk of kidney stones associated with increased calcium intake.^1,2,3 This is another example of an intervention that intuitively makes complete sense which turns out not to be so after careful examination under the scrutiny of randomized trials. —Neil Skolnik, MD

1. Bolland MJ, Barber PA, Doughty RN, et al. Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. BMJ 2008;336:262-266.

2. Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ 2010;341:c3691.

3. Jackson RD, LaCroix AZ, Gass M, et al. Calcium plus vitamin D supplementation and the risk of fractures. N Engl J Med 2006;354:669-683.

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