<i>Koji</i> glycosylceramide commonly contained in Japanese traditional fermented foods alters cholesterol metabolism in obese mice

<i>Koji</i>, which is manufactured by proliferating non-pathogenic fungus <i>Aspergillus oryzae</i> on steamed rice, is the base for Japanese traditional fermented foods. We have revealed that <i>koji</i> and related Japanese fermented foods and drinks such as amazake, shio-<i>koji</i>, unfiltered sake and miso contain abundant glycosylceramide. Here, we report that feeding of <i>koji</i> glycosylceramide to obese mice alters the cholesterol metabolism . Liver cholesterol was significantly decreased in obese mice fed with <i>koji</i> glycosylceramide. We hypothesized that their liver cholesterol was decreased because it was converted to bile acids. Consistent with the hypothesis, many bile acids were increased in the cecum and feces of obese mice fed with <i>koji</i> glycosylceramide. Expressions of CYP7A1 and ABCG8 involved in the metabolism of cholesterol were significantly increased in the liver of mice fed with <i>koji</i> glycosylceramide. Therefore, it was considered that <i>koji</i> glycosylceramide affects the cholesterol metabolism in obese mice. Koji glycosylceramide commonly contained in Japanese traditional fermented foods alters cholesterol metabolism in obese mice.