An editorial discusses the results of this analysis and a linked paper which reviews the evidence for calcium intake and the risk of fracture.
The current analysis found small increases in BMD associated with extra dietary or supplemental calcium in adults aged >50 years, with no further gains beyond the first year, and no further benefit apparent from the addition of vitamin D at any dose. The related paper reports no effect of calcium supplements on fracture risk at any site when the analysis was limited to the four RCTs at lowest risk of bias. One study performed in women living in nursing homes with very low serum vitamin D, low serum calcium and low calcium intake did however report a benefit.
The authors of the editorial state that the currently available evidence gives a strong signal that calcium supplements with or without vitamin D do not protect older people in general from fractures. This view is shared by the United States Preventive Services Task Force after their recent meta-analysis. They say that the official recommendations in the UK of 700-800 mg/day of dietary calcium for adults seem at present to be enough; this can be achieved with a normal varied diet. They note that other guidelines (e.g. US National Osteoporosis Foundation) recommend higher intakes that are difficult to achieve through diet alone, leading to widespread supplement use by older women in the US. They say most will not benefit from this increased intake and they will also be exposed to a higher risk of adverse effects (e.g. constipation, cardiovascular events) and they consider it time to reconsider these ‘controversial recommendations’.