Effects of resistant starch ingestion on lipidmetabolism in rats

Kumiko OKUMURA, Tomoyuki NAKAGAWA and TakashiHAYAKAWA*

Gifu University, Faculty of Applied Biological Sciences, GraduateSchool of Agriculture

 Rats were fed a diet of 28.6% high-amylose starch (HAS, 70%amylose) or heat-moisture-treated starch (HTMS) for 3 weeks, andthe effects of these diets on lipid profiles, fatty acid syntheticactivity and cecal fermentation were examined. Resistant starch(RS) content in the HAS and HMTS diet was 16.5% and 15.0%,respectively. Plasma cholesterol concentrations were lower in theRS fed groups than in the control diet group, with a significantdecrease observed in the HMTS group. Plasma triglycerideconcentration, liver triglyceride content and total lipids contentwere lowest in the HMTS group, and glucose-6-phosphatedehydrogenase [EC] was decreased significantly in thisgroup. Fecal lipid excretions in the RS fed groups weresignificantly lower compared to that in the control group. Theweights of the epididymal and abdominal fatty pads were decreasedsignificantly in the HMTS group. Cecal short-chain fatty acidcontent increased in the RS fed groups, however, propionate contentwas increased only in the HMTS group. The difference in thefermentation pattern is a tentative factor in the lipid loweringeffect of the HMTS diet as compared to the HAS diet.

Key words: resistant starch, high-amylose starch,heat-moisture-treated starch, lipid metabolism, propionic acid,shortchain fatty acids