Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 401
Objectives: Polylactose is a novel dietary fiber, synthesized by extrusion of lactose. To evaluate its potential as a prebiotic, we determined its fermentability, and its effects on adiposity and glycemic control in a diet-induced obesity animal model.
Methods: 72 male Wistar rats were fed normal fat (NF) or high fat (HF, 50% fat by kcal) diets containing various fibers (6% fiber of interest and 3% cellulose, by weight); including cellulose (NFC and HFC), polylactose (HFPL), matched lactose (HFML), matched to the residual lactose in the HFPL diet, and two established prebiotic fibers, polydextrose (HFPD) and fructooligosaccharides (HFFOS). During weeks 8 and 9 of feeding the experimental diets, rats underwent oral glucose, insulin (by intraperitoneal (i.p.) injections), and pyruvate (by i.p. injections) tolerance tests. At the end of week 10, blood and organs were harvested and cecal contents collected.
Results: There were no significant differences in final body weights among the groups, nor did average daily food intake differ significantly among the HF-fed groups. Rats fed the HFPL diet had improved glycemic control when compared to the positive control (HFC) animals, as indicated by a strong trend for a lower area under the curve (AUC) for the oral glucose tolerance test (OGTT) (p=0.051), and lower blood glucose at 60, 90, and 120 min. There were no significant differences among the groups in the insulin and pyruvate tolerance tests. Epididymal fat pad weight was significantly decreased in the HFPL animals compared to all other HF groups (p < 0.05), and did not differ from the normal fat control (NFC). HFPL animals had greater cecal weight (empty) and lower cecal contents pH when compared to all other groups, suggesting that polylactose is much more vigorously fermented than the other prebiotic fibers.
Conclusions: Polylactose is a vigorously fermentable fiber, suggesting that it will elicit a change in the gut microbiome. We also demonstrate that consuming polylactose, in the context of a high fat diet, prevents the accumulation of body fat normally seen with this diet, as well as improves glycemic control. As these effects of polylactose were greater than those of two established prebiotics, fructooligosaccharides and polydextrose, this suggests that polylactose may be a potent prebiotic.
University of Minnesota - Twin Cities
St. Paul, Minnesota