| Background. Osteoporosis is a disease of low bone density and increased fragility that can result in fractures, frailty, and death. Preventing bone loss in adults is vital to reducing the risk for osteoporosis and preventing fracures. Nutrition is an essential component of building bones and maintaining bone strength. Much of the nutrition research has focused on vitamin D and calcium. Other aspects of diet, such as macronutrient (i.e., protein, carbohydrate, and fat) content, are not well understood. Bone health can be assessed with biochemical indicators of bone turnover (i.e., formation and resorption). Research regarding nutrition and bone turnover could provide clinically significant information regarding the delay, or prevention, of osteoporosis.; Methods. The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OMNI-Heart Trial) was a three period, randomized, crossover feeding study designed to test the effects of a carbohydrate-rich diet, a diet higher in protein, and a diet rich in unsaturated fat. Participants ate all three diets in random order. Cross-sectional (pre-dietary intervention) associations between bone turnover, participant characteristics, and nutritional factors were explored. The effect of macronutrient intake was investigated by determining the effects of the three diets on the biochemical indicators of bone turnover.; Results. Cross-sectionally, there were differences in bone turnover in females by menopausal status but not race. There were no significant differences in males by age or race. Serum vitamin D was low in most participants and average serum parathyroid hormone was high. In multivariate linear regression analyses of the association between bone turnover and demographic and nutritional factors, no clear patterns emerged. In longitudinal analyses, all three diets increased bone formation and decreased resorption compared to baseline, which was a positive result. The most favorable overall effect on bone turnover was the protein diet.; Conclusion. It is difficult to determine which nutritional factors are associated with bone turnover in an uncontrolled study. We found a positive affect of all three diets on bone turnover, resulting in increased formation and decreased resorption. This information could facilitate the establishment of recommendations for dietary patterns that benefit bone health. |
