Effects of Soy Protein Isolate and/or Omega‐3 Polyunsaturated Fatty Acid Supplementation on Bone Health in Female Rats with Polycystic Kidney Disease

Abstract

Polycystic kidney disease (PKD) is a genetic disorder resulting in multiple cysts that can alter kidney function leading to mineral imbalance and bone loss. In healthy female rats, soy protein isolate (SPI) and omega‐3 polyunsaturated fatty acids (n‐3 PUFA) increased bone mineral density (BMD), bone mineral content (BMC), and bone formation markers. The study objective was to investigate the effect of soy protein isolate and/or n‐3 PUFA supplementation on bone mass and strength in rats with PKD. Growing female pck rats (n=12/group) were randomly assigned to be fed soy protein isolate + corn oil (Casein + CO), casein + soybean oil (Casein + SO), soy protein isolate + soybean oil (SPI + SO) or soy protein isolate + 1:1 soybean/salmon oil (SPI + BLEND) for 12 wks. Urinary calcium (Ca) decreased (P=0.003) in the order of Casein + SO >; Casein +CO >; SPI +SO >; SPI + BLEND. Urinary phosphorus (P<0.001) decreased in the order of Casein + SO >; Casein CO >; SPI + BLEND >; SPI + SO. There were no significant differences in bone Ca, P, BMD and BMC among the diet groups. There were also no dietary effects on peak force, ultimate stiffness, ultimate bending stress, or young's modulus. Serum alkaline phosphatase was higher (P=0.003) in rats fed SPI + BLEND and SPI + SO compared to Casein + CO and Casein + SO. The SPI + BLEND group had the highest (P=0.001) femur length. Based on the study results, diet had little impact on the bone mass or strength of female rats with PKD.