Green tea polyphenols benefit bone health in obese female rats fed with high‐fat and restricted diets

Abstract

This study investigated the effects of green tea polyphenols (GTP) on the bone health in obese rats fed with a high‐fat (HFD) diet or a restricted diet (RD). Forty‐eight 3‐month‐old SD rats were fed with a HFD at libitum for 4 months. After 4 months, the animals were assigned to a 2 (HFD vs. RD with 35% caloric deficit) × 2 (no GTP vs. 0.5% GTP in drinking water) factorial design for additional 4 months. Body composition [fat mass (FM) and fat‐free mass (FFM)] was measured by bioimpedance spectroscopy. Bone parameters [femoral bone area, bone mineral content (BMC) and bone mineral density (BMD)] were measured by dual‐energy x‐ray absorptiometry. Bone strength was determined by 3‐point bending test. Serum leptin, adiponectin and insulin‐like growth factor‐I (IGF‐I) levels were determined. The results of two‐way ANOVA show that the RD lowered FM, BMC, BMD, bone strength, serum leptin and IGF‐I, and increased FFM and serum adiponectin. GTP supplementation resulted in an increase in FFM, BMC, BMD, and bone strength, a decrease in FM, serum letpin and IGF‐I, and no change in serum adiponectin. There was a significant interaction between caloric intake level and GTP supplementation in FM and FFM. This study demonstrates that GTP supplementation in drinking water for 4 months improved bone parameters in obese rats fed with a HFD or a RD diet through modulating fat hormones.