Since metabolic syndrome associated with obesity is a risk factor for cerebral and myocardial infarction, the development of preventive methods is desired in the world. Our aim is to clarify the preventive effect and its molecular mechanism of marine lipids on obesity and metabolic syndrome.

We find that fucoxanthin, a marine carotenoid abundant in brown algae such as wakame, improves blood glucose level and suppresses weight gain in type II diabetes/obesity model mouse KK-A^y. As one of the mechanisms of those effects, it is suggested to promote membrane translocation of glucose transporter (GLUT) 4 in skeletal muscle and to increase energy consumption via upregulation of uncoupling protein (UCP) 1 expression in adipose tissue.

Recently, furthermore, it is becoming clear that inflammation in tissue is involved as the pathological basis of chronic diseases such as obesity. In adipose tissue of KK-A^y mouse, the number of infiltrated immune cells such as macrophages increases, exacerbating tissue inflammation. By contrast, in adipose tissue of mouse fed fucoxanthin-containing diet, immune cell infiltration and tissue inflammation are significantly suppressed. Since fucoxanthin metabolites exhibit anti-inflammatory action on macrophages and adipocytes in vitro, dietary fucoxanthin can effectively suppress tissue inflammation through its metabolism in body. In addition, we reveal that fucoxanthin administration has a preventive effect on the onset of non-alcoholic steatohepatitis model mice, which are chronic inflammatory diseases of the liver. These findings show that fucoxanthin regulates inflammation in each tissue including liver and adipose tissue, which is expected to apply for health maintenance and promotion.

In our laboratory, we will clarify the health functions of not only above-mentioned marine carotenoids but also various marine lipids.