Digestive-resistant carbohydrates affect lipid metabolism in rats

Digestion resistant carbohydrates (DRC) are complex carbohydrates that resist digestion and absorption in the small bowel. Diets high in DRC can have wide ranging impacts on the health of the host, which include changes to immunity and allergy, incidence of cardiovascular disease, and obesity. The aim of this study was to characterise the effects of DRC (inulin, konjac or resistant starch) on large intestinal short-chain fatty acid (SCFA) concentrations and serum metabolite and lipid profiles. A rat model was used to compare the effects of feeding a basal diet or the basal diet containing 5% inulin, konjac or resistant starch for 14 days. Of the three DRC, inulin had the greatest effect; 10 serum phospholipids differed significantly in abundance between inulin-treated and control rats. In particular phosphatidylcholines and lysophosphatidylcholines containing fatty acyl chains 22:5, 22:4, 20:4, 18:0 and 16:0 were increased in the inulin-fed group, whereas phosphocholines containing fatty acyls 20:5 and 22:6 were decreased. These results indicated an impact on both n-3 and n-6 fatty acid metabolism as a result of inulin dietary intake. Increased intestinal concentrations of SCFA were detected in rats fed DRC, but only inulin caused appreciable changes to serum lipid profiles.