LONG-TERM, HIGH-FAT-SUCROSE DIET ALTERS RAT FEMORAL-NECK AND VERTEBRAL MORPHOLOGY, BONE-MINERAL CONTENT, AND MECHANICAL-PROPERTIES

Short-term exposure to diets high in fat and sucrose can induce hyperi nsulinemia, affect calcium and magnesium metabolism, and alter bone mi neralization and mechanical properties. The current study focused on t he morphological and structural changes that result from long-term exp osure to a high-fat sucrose (HFS) diet. Inbred, female Fischer 344 rat s were assigned randomly to a low-fat, complex-carbohydrate (LFCC) die t group or a HFS diet for 24 months. At the end of the 2 years, each f emoral neck (FN) was tested to failure in cantilever-bending, the sixt h lumbar vertebra (L6) was tested in compression, and geometrical char acteristics of the bones were determined. Although the HFS rats were s ignificantly fatter and heavier than the LFCC rats, the HFS L6 had a s ignificantly smaller average cross-sectional area. When L6 structural properties were normalised with respect to body mass, the HFS L6 had s ignificantly lower loads, energies, and stiffnesses. The HFS L6 stress and strain energy density values were also significantly less than th e LFCC L6. Compared to the LFCC FN, the HFS FN had a smaller cortical shell and larger trabecular core. The HFS FN also had significantly lo wer mass-normalised loads, energies, and stiffnesses. These results su ggest that a long-term HFS diet has a significant adverse effect on ra t bone morphology and mechanics.