Last week, one of my blogs focused on the association between cola consumption and weakened bones, and the fact that milk, contrary to popular perception, is actually not an ideal beverage for building bones click here. Further evidence for the uselessness of milk in this capacity has come from a study published in this week’s edition of the British Medical Journal [1]. This review, which amassed evidence from 19 studies involving children ranging from 3-18 years in age, found that calcium supplementation had no effect on bone density in the hip or spine, and very marginal benefits for bone density in the arm. The authors of this review conclude that calcium supplementation seems unlikely to be of ‘major public health importance’.
This edition of the BMJ contains an editorial which critiques this study, and goes on to review other evidence for the relationship between calcium, milk and bones [2]. This editorial highlights just how little evidence there is that calcium supplementation and milk drinking helps build strong bones. It cites three reviews, two of which concluded that it is not known whether the modest increments in rate of bone gain after supplementation with calcium or dairy produce will translate into clinically meaningful reductions in the risk of osteoporosis later in life [3,4], and the third of which concluded that increases in dairy or total dietary calcium intake did not reliably increase bone mineral density or reduce fracture rate in children or adolescents [5].
The editorial author also drew attention to the evidence exposing the fact that populations consuming the most cow’s milk and other dairy products have among the highest rates of osteoporosis and hip fracture in later life [6, 7].
The author concludes that: It is time to revise our calcium recommendations for young people and change our assumptions about the role of calcium, milk, and other dairy products in the bone health of children and adolescents. While the policy experts work on revising recommendations, doctors and other health professionals should encourage children to spend time in active play or sports, and to consume a nutritious diet built from whole foods from plant sources to achieve and maintain a healthy weight and provide an environment conducive to building strong bones.
Here, here.
References:
1. Winzenberg T, et al. Effects of calcium supplementation on bone density in healthy children: meta-analysis of randomised controlled trials. BMJ 2006;333:775-778.
2. Lanou AJ. Bone health in children. BMJ 2006;333:763-764
3. Bachrach LK. Acquisition of optimal bone mass in childhood and adolescence. Trends Endocrinol 2001;12: 22-8.
4. Wosje KS, et al. Role of calcium in bone health during childhood. Nutr Rev 2000;58: 253-68.
5. Lanou AJ, et al. Calcium, dairy products and bone health in children and young adults: a re-evaluation of the evidence. Pediatrics 2005;115: 736-43
6. Report of a Joint Food and Agriculture Organization of the United Nations/World Food Organization of the United Nations Expert Consultation. Human vitamin and mineral requirements. Bangkok, Thailand; September 1998. ftp://ftp.fao.org/es/esn/nutrition/Vitrni/vitrni.html
7. Abelow BJ, et al. Cross-cultural association between dietary animal protein and hip fracture: a hypothesis. Calcif Tissue Int 1992;50: 14-8
