EFFECTS OF HIGH-FAT DIET ON MATURE BONE-MINERAL CONTENT, STRUCTURE, AND MECHANICAL-PROPERTIES

Diets with a high saturated fat content can produce deleterious effect s on the absorption of dietary calcium and consequently an adverse eff ect on bone mineralization in growing animals. Hence dietary fat may h ave long-term consequences for skeletal health and skeletal pathologie s such as osteoporosis. Whether a diet high in saturated fat has simil ar negative effects on adult bone, however, remains unresolved. Thus, we investigated effects of a high-fat diet on mature bone structure an d mechanics. Adult (40-week-old) roosters were maintained for 20 weeks on either a diet high in saturated fat (HF) or a low-fat (LF) diet, C ortical bone samples (tarsometatarsus) were tested mechanically in thr ee-point bending, and cancellous bone cores from the femoral condyles and tibial plateau (four sites per knee) were tested mechanically in c ompression. Cortical bone cross-sectional areal data were also compare d among the groups, and bone mineral content (BMC) was determined (by ashing) for both cortical bone and cancellous bone samples. There were no significant high-fat diet effects on mature cortical bone mechanic al properties, geometric structure, or mineral content. Diet, however, did affect cancellous bone composition. For example, LF cancellous BM C was significantly greater than HF. Mechanical properties of the canc ellous bone showed similar trends such that LF cancellous bone strengt h was consistently greater than HF. The potential for adverse effects of a HF diet on intestinal calcium absorption in the mature animal may be more apparent in cancellous bone, with its faster rate of turnover , than in cortical bone. Changes in cancellous bone structure and mech anical properties, related to dietary saturated fats, may have implica tions for understanding the role of nutrition in skeletal health and p revention of pathological bone loss (osteoporosis).