Postprandial bone turnover is independent of calories above 250 kcal

Background: The mechanisms causing bone turnover after food intake have not yet been elucidated. Several gut hormones are secreted in the postprandial phase, proportional to meal calorie content, and possibly one or more of these could influence bone turnover. The aim of this study was to investigate bone turnover in proportion to graded-calorie and fixed calcium containing meals. Methods: A group of healthy volunteers were given six meals with calories varying from 250 to 3000 kcal on different occasions. All the meals contained 500 mg of calcium. C-telopeptide type I collagen (CTX) was measured before and 180 min after each meal. Results: All meals significantly reduced CTX between 35.8 +/- 5.6% and 44.8 +/- 3.8%. No significant difference in CTX was however apparent for the different calorie containing meals. Observed differences suggest a trend to greater CTX suppression with lower protein and higher fat content of meals. Conclusion: Changes in CTX are not proportional to calorie contents when the meals contain 500 mg of calcium. Further studies should now determine whether patients with increased bone resorption would benefit from multiple small meals to slow down the rate of bone loss.