Obihiro University of Agriculture and Veterinary Medicine

In research for health promotion, it's important to clarify intestinal flora and the characteristics of fermentation in the intestines. Research on probiotics and prebiotics is progressing with particular rapidity. I've worked on pioneering experiments and research on their health functionality.

Concerning the health functionality of probiotics, I've discovered that the administration of complex bacterial preparations made with several bacteria and yeasts reduces serum cholesterol in rats, and I've clarified the mechanism behind this, which involves decreased hepatic cholesterol synthesis, increased cholesterol in excreta due to the inhibition of micelle formation, and increased bile acid secretion due to bile acid binding. These results show that complex bacteria may cause fermentation that leads to increases in short-chain fatty acids in the appendix of rats.

Concerning the health functionality of prebiotics, I've clarified the intestinal improvements afforded by the numerous unavailable carbohydrates in food. I've found that dietary fiber from mushrooms reduces serum cholesterol by increasing the gene expression of LDL receptors in the liver. I've clarified the possible mechanism of action whereby mushroom fiber promotes intestinal fermentation. Regarding beans, the resistant starch in adzuki beans and kidney beans helps to increase the excretion of cholesterol in line with increases in short-chain fatty acids in the appendix. I've also clarified that potato starch has a high phosphorus content and stimulates the production of intestinal flora or short-chain fatty acids, thereby improving the intestinal condition. In addition, I've discovered that rice flour improves intestinal fermentation and enhances the barrier function of the intestinal mucosa, which includes mucin and secretory IgA. Recently, I built an in vitro intestinal fermentation model to take the place of in vivo intestinal fermentation testing, identified the characteristics of intestinal fermentation, and clarified through a fermentation test of inulin with different degrees of polymerization that inulin with a lower degree of polymerization has a higher fermentation rate and inhibits the production of ammonia.

As noted above, improvements to the intestinal environment afforded by probiotics and prebiotics contribute to enhanced lipid metabolism and intestinal mucosa barrier function. I present these results to the world, including at academic conferences. Currently, I'm pursing research on how the characteristics of intestinal fermentation differ for different combinations of food.

• Probiotics are microorganisms ingested from the mouth, reaching the intestine alive, and helping the health of the body. And Prebiotics are compounds inducing the growth of benefit microorganisms, especially lactic acid bacteria and bifidobacteria. I'm pursing research on the relationship between food ingredients and improvement of intestinal environment, especially antiobesity effect, antioxidant effect, detoxification effect and intestinal immune effect.