Feeding Soy Protein Isolate Prevents Impairment of Bone Acquisition by Western Diets as a Result of Insulin Signaling in Bone

Abstract

Excessive consumption of high fat/high cholesterol “Western” diets during postnatal life results in increased energy intake, development of obesity and systemic insulin resistance. However, how this diet impairs bone development and remodeling is not well understood, and no effective dietary interventional strategy has emerged. In the current study, male rats pair‐fed a Western diet (WD) for 7 wks start from post natal day 20 displayed obesity with significantly increased gonadal and abdominal fat mass and body weight compared to control (p<0.05). WD rats had increased in bone marrow adiposity, insulin resistance and impaired glucose tolerance. Supplementation of soy protein isolates (SPI) ameliorated the effects of WD. Inhibition of WD‐induced impairment of bone acquisition by SPI was associated with increased undercarboxylated osteocalcin secretion and increased IRS1/Akt insulin signaling in osteoblasts. SPI normalized non‐esterified free fatty acid (NEFA) levels in WD rats. These results suggest that the effects of SPI diet on metabolism and body composition in WD rats are due to increased of secretion of active osteocalcin and stimulated insulin signaling in bone. Supported in part by ARS CRIS #6251‐51000‐005‐03S.Grant Funding Source: USDA / ARS CRIS