Dietary Protein and Bone Health
Associate Professor, Department of Allied Health Sciences University of Connecticut
Bone is a dynamic tissue that changes throughout life, with peak bone mass attained by 30-40 years of age. Loss of bone with advancing age is a universal phenomenon in both women and men.
Because nutrition is well known to play a key role in skeletal health, it is very important for both primary (during childhood) and secondary (adulthood) prevention of osteoporosis. While the roles of calcium and vitamin D are well recognized in this regard, the impact of dietary protein on bone health is less well understood. The traditional hypothesis is that high-protein diets are detrimental to bone because they increase urinary calcium, generally believed to be due to the loss of calcium from bone. However, most cross-sectional studies with bone mineral density or rates of bone loss as the principal outcome indicate that high-protein diets are associated with higher (not lower) bone mineral density and slower (not faster) rates of bone loss.
Three recent diet-controlled, isotopic calcium studies1-3 showed no net loss of calcium from bone in humans following high-protein diets. In one of these studies, our own research group showed that a high-protein diet increased urinary calcium, not via losses of calcium from bone, but by increasing intestinal calcium absorption. Therefore, strong data are emerging showing that a high-protein diet is actually beneficial to the skeleton, whereas adults who normally consume a moderately low-protein diet are at risk for accelerated bone loss. This presentation will summarize the latest research on the impact of dietary protein on the skeleton, the hypothesis being that a high-protein diet has beneficial effects on the skeleton at least in part because it increases intestinal calcium absorption.
Sources
- Kerstetter JE et al. The Impact of Dietary Protein on Calcium Absorption and Kinetic Measures of Bone Turnover in Women. J Clin Endocrinol Metab 2005;90(1):26-31
- Kerstetter JE, et al. Meat and Soy Protein Affect Calcium Homeostasis in Healthy Women. J Nutr 2006;136:1890–1895
- Kerstetter JE et al. High Protein Diets, Calcium Economy, and Bone Health. Top Clin Nutr 2004;19(1):57-70
