Protein intake and bone mineral density in active older adults

Click on the link to access this abstract at the publisher's website.Recently, there has been a renewed interest in the relationship between protein intake and bone health. Several cross-sectional studies have reported a positive influence of protein intake on bone mineral density (BMD). However, few studies have focused on protein consumption with regards to protein quality (essential amino acids/total amino acids) and distribution throughout a day. PURPOSE: To determine the association between consumption of total protein, quality protein, and quality protein distribution and bone mineral density in active older adults. METHODS: Thirty-three healthy male (n=11) and female (n=22) active older adults (60.1 ± 7.1 years, 168.1 ± 8.4cm, 68.4 ± 12.5kg) participated in this cross sectional study. Total protein, quality protein, and daily quality protein distribution were determined from a seven-day food record. Seven-day food records and amino acid profiling were analyzed using a computer software program (Nutribase, v.11, Cybersoft Inc., Phoenix, AZ). Daily food records were averaged across seven-days to give an average representation of total protein intake, quality protein intake, and quality protein distribution. Specifically, quality protein distribution was defined as consumption of a meal offering at least 10 grams of essential amino acids. Areal BMD (g/cm2 ) of the non-dominant proximal femur (total hip and femoral neck) and lumbar spine (L1-L4) were determined by Dual Energy X-Ray Absorptiometry (Discovery A, Hologic Inc., Bedford, MA). Self-reported physical activity level of the participants was determined using the Godin Leisure-Time Exercise Questionnaire. Data were analyzed using Pearson Partial Correlation Coefficients controlling for body mass and physical activity level with an alpha level of 0.05. RESULTS: Neither average 24 hour total protein intake (89.9 ± 28.7g), quality protein intake (0.67 ± 0.06g), or quality protein distribution throughout a day (1.02 ± 0.6g) was significantly (p > 0.05) associated with aBMD at any bone site. CONCLUSION: In contrast to other cross-sectional studies, our findings suggest that, after controlling for physical activity level and body weight, total protein intake, quality protein intake, and quality protein distribution is not associated with aBMD in active older adults