Caloric Substitution of Diets with Apple Pomace was Determined to be Safe for Renal and Bone Health Using a Growing Rat Model

Aims: To determine the safety of caloric substitution with 10% (g/kg) apple pomace to a healthy or Western diet.

Study Design: Growing (age 22-29 days) female Sprague-Dawley rats were randomly assigned (n=8 rats/group) to consume a purified standard rodent diet (AIN-93G), AIN-93G/10% g/kg apple pomace (AIN/AP), Western diet, or Western/10% g/kg apple pomace (Western/AP) diets for 8 weeks.

Results: Histological evaluation showed renal interstitial hypercellularity in rats fed AIN/AP, Western, and Western/AP diets. However, there were no effects on renal expression of oxidative stress and inflammatory genes or serum measures of kidney damage and function among diet groups. Apple pomace was also high in calcium which can affect calcium balance. Dietary calcium consumption was highest (P < .001) in rats consuming Western/AP. However, there were no significant differences in calcium absorption and retention among diet groups. Further, there was no evidence of renal calcification. There were also no impacts on femoral calcium, total mineral content, size or strength.

Conclusions: Based on the results, apple pomace consumption was safe for renal and bone health in a rodent model, regardless of diet quality. Future preclinical studies should be conducted to further determine the efficacy and safety of apple pomace.