Protein Intake and Bone Health
A meta-analysis looking at protein intake and bone health was published this month in the American Journal of Clinical Nutrition (1).
In terms of bone mineral density (BMD), the authors reported:
“Overall, there was very little evidence of a deleterious influence of protein intake on BMD, with most cross-sectional surveys and cohort studies reporting either no influence or a positive influence. Thus, 15 cross-sectional surveys found a statistically significant positive relation between protein intake and at least one BMD site. However, 18 studies found no significant correlation between protein intake and at least one BMD site.
“The cohort studies also identified little evidence of any deleterious influence of protein intake on bone. … [N]o studies showed a significant increase in BMD loss with increased protein intake, and only one study showed a significant decrease in BMD loss with increased animal and total protein intakes.”
In terms of bone fracture rates, the authors reported:
“Overall, the [seven] cohort studies indicated either a benefit or no effect of protein intake on hip fracture relative risk, with only one study reporting a significant increase in risk with increasing animal protein intake and increasing animal to vegetable protein ratio. Three studies found a decreased relative risk of hip fracture with increasing animal, total, and vegetable protein intakes. Two studies found no significant association of animal protein with fracture risk, whereas 2 studies found no association of total protein with fracture risk. Last, 2 studies found no relation between fracture risk and vegetable protein.”
“Overall, the weight of the evidence shows that the effect of dietary protein on the skeleton appears to be favorable to a small extent or, at least, is not detrimental. However, the long-term clinical importance of the effect is unclear, and a reduction in fracture risk was not seen. More research is required to resolve the protein debate. In the meantime the protein intakes and balance of different protein sources as indicated in the current healthy eating guidelines represent appropriate dietary advice.”
1. Darling AL, Millward DJ, Torgerson DJ, Hewitt CE, Lanham-New SA. Dietary protein and bone health: a systematic review and meta-analysis. Am J Clin Nutr. 2009 Dec;90(6):1674-92. Epub 2009 Nov 4.