Resistant starch in the diet of rodents promotes an increase in fermentation and a reduction in body fat in an animal model of dietary obesity

Abstract

In previous studies, in has been observed that the addition of resistant starch (RS) in the diet of rodents, a non-digestible fermentable fiber, promotes increases in markers of fermentation and improvements in body weight and body fat analysis when incorporated into low to moderate fat diets. This study investigated whether the same beneficial effects observed with RS addition in these lower fat diets could be obtained in a high fat diet, and if the type of fatty acid consumed in the diet makes a difference in markers of fermentation and body fat. Sprague Dawley rats (n=96) were fed as weight of diets, RS (27%), and Hi-fat (20%) or low fat (7%), for 12 weeks. Fish oil (4%) was given to half of the groups in order to assess the effects of fatty acid composition. The results revealed that markers of fermentation (pH and SCFA) were significantly decreased and increased, respectively, in RS fed groups (p<0. 05), but the high fat diet partially interfered with these improvements by reducing the amount of fermentation when compared to low fat groups. Gut hormones glucagon like peptide-1 (GLP-1) and peptide YY (PYY) were also significantly increased (p<0.05), but high fat diet demonstrated partial interference with PYY levels by reducing the level of this hormone when compared to low fat fed groups. The results of the abdominal fat analysis also revealed that RS significantly reduced body fat in RS fed animals (p<0.05), but the reduction was reduced from 24% in low-fat fed animals to 9% in high –fat fed animals. In conclusion, RS promotes benefits in fermentation and body fat reduction, but the fat content of the diet moderated the level of improvement observed.