A recent study investigated whether increased calcium intake is an appropriate strategy to prevent bone loss and risk of osteoporotic fractures in men.
Osteoporosis is a medical condition characterized by low bone mass and deteriorating bone tissue, which increases the risk of subsequent fractures in men and women. Current recommendations to reduce bone loss are based primarily on studies in women since they have the highest risk of osteoporosis and osteoporotic fractures. For men, however, there is a lack of evidence-based strategies, which is a concern considering the ageing population and increased life expectancies.
Increased calcium intake, via diet or supplementation, is one of the most common strategies recommended by health professionals for reducing bone loss and osteoporosis. One study found that in men a 1,200mg calcium supplement per day, for a total of 2 years, increased bone mass density (BMD) by 1-1.5%, compared to placebo. This may suggest some beneficial effect of calcium intake, but researchers argue that long-term effects of calcium supplementations on bone density have not been thoroughly investigated and warrant further attention.
A recent study, published in the British Journal of Nutrition, investigated the relationship between calcium intake and bone loss. Researchers utilized data from a previous study in men (n = 323), where participants were given calcium supplements and bone density was monitored over the course of 2 years. The authors also recruited additional healthy men to serve as a placebo-control group (n = 99) for longitudinal studies.
The authors found that, like previous studies in women, increased calcium intake did not significantly reduce bone loss in men. More precisely, at baseline, no correlation was found between dietary calcium intake and BMD, before and after adjusting for confounding factors. Furthermore, no correlation was observed between calcium intake and BMD during and at the end of the 2-year study period. Researchers did find that dietary calcium intake was inversely correlated with parathyroid hormone levels at baseline. This hormone plays a vital role in bone homeostasis by stimulating osteoclast cells, which induce bone degradation. Interestingly, however, there was no correlation between dietary calcium intake and markers of bone turnover. In other words, although there was an elevated level of parathyroid hormone with lower calcium intake, this did not translate into higher rates of bone degradation.
The authors conclude that calcium intake is not associated with bone loss and is not a good predictor of fracture risk in men. The beneficial effects of calcium supplementation observed in previous clinical trials occur during the first year of supplementation with no long-term effects thereafter. Therefore, increased calcium intake may not be an effective long-term strategy for reducing bone loss and preventing fractures in men. Researchers must continue to investigate novel therapeutic strategies and prophylactic measures for reducing the risk of osteoporosis and fractures in both men and women.
Written by Haisam Shah, BSc
Bristow, S. M., Gamble, G. D., Horne, A. M., & Reid, I. R. (2017). Dietary calcium intake and rate of bone loss in men. British Journal of Nutrition, 1-7.