Introduction:
Human and animal studies have demonstrated that some of the deleterious health consequences of obesity such as insulin resistance and hypertension can be reversed by weight loss. The effects of weight loss through dietary modification on bone health are unclear.
Aim:
Assess the effects of weight loss on bone health in a mouse model of diet induced obesity.
Method:
C57Bl/6J mice were divided into 3 groups: 1)Mice fed high fat diet for 16 weeks (HH); 2)Mice fed low fat diet for 16 weeks (LL); 3) Mice fed high fat diet for 8 weeks and then switched to low fat diet for 8 weeks (HL). Bone density was monitored with DXA. Tibia was collected for ex vivo microCT analysis of trabecular architecture
Results:
After switching from high fat to low fat diet at 8 weeks the body weight of the HL group returned to the weight of LL group within 2-3 weeks. DXA analysis at 8 weeks showed high-fat fed mice had reduced bone density (79.9±1.1 vs 75.3±1.1 g/cm2, p<0.01). At 16 weeks the HL and LL groups had significantly higher bone density than the HH group (LL=81.9±1.2, HL=82.5±1.1, HH=72.8±1.3g/cm2). The change in bone density over this 8 week period was significantly higher in the HL group compared to HH group(p<0.01) and between the HL and LL groups(p=0.02).
MicroCT analysis of tibia collected at 16 weeks showed that the HL and LL groups had significantly higher trabecular bone volume (BV/TV) compared to the HH group but there was no significant difference between HL and LL groups.
Conclusions:
These data suggest that deterioration in bone quality and density caused by high-fat feeding are reversible after returning to a healthier diet.