Study on Prevention of Lifestyle Diseases by Regulating Fermentation in the Large Intestine using Luminacoids Naomichi NISHIMURA* Department of Nutritional Sciences, Faculty of Health and Welfare Science, Nayoro City University | An altered colonic environment including changes in gut microbiota and/or fermentation has been reported to lead to metabolic syndromes, which result in accumulation of cholesterol and oxidative stress. Modifying the colonic environments may therefore be an important strategy for preventing disease. This paper discusses the plasma cholesterol-lowering effect of dietary fiber via colonic fermentation, the enhanced production of colonic n-butyrate by supply of resistant protein, and the suppression of oxidative stress through colonic hydrogen (H2) derived from nondigestible saccharides (NDS). We demonstrated in rats that beet fiber, which is high in hemicellulose and pectin, increased colonic production of short-chain fatty acids (SCFA) and that the large intestine, especially the cecum, was an essential organ for manifesting the plasma cholesterol-lowering effect of beet fiber. Increased production of colonic SCFA production and increased excretion of bile acid into feces both contributed to this effect. Nitrogen is in short supply in the large intestine of monogastric animals. In rats fed pectin, the colonic supply of nitrogen by soy-resistant protein enhanced production of n-butyrate, the predominant energy source for colonocytes. In weaning rats, which have low digestibility, the administration of soy protein isolate formed stable colonic microbiota and enhanced production of colonic n-butyrate. Nitrogen is an important factor for the modification of colonic fermentation as well as carbohydrate. Fermentable NDS promotes the generation of H2, which has an antioxidant activity. We found that colonic H2 derived from fermentable NDS was absorbed into the portal vein, resulting in a reduction of oxidative stress and damage in hepatic reperfusion-ischemia models. Interestingly, colonic H2 was diffused into the abdominal cavity as well as into the portal vein, and became located in abdominal tissues, especially adipose tissues. The abundance of adipose Il6 mRNA was decreased by NDS feeding. Colonic H2 therefore acted as an effective supply of antioxidants in the system. Taken together these results show that modified colonic fermentation by luminacoids has potential preventive and therapeutic effects in metabolic syndromes by improving cholesterol metabolism and enhancing colonic n-butyrate and/or H2. Key words : colonic fermentation, short-chain fatty acid, hydrogen, nondigestible saccharides, luminacoid. |
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