Recently, the number of people with diabetes has been increasing. Furthermore, metabolic syndrome in which diabetes co-exists with obesity, hyperlipidemia and hypertension, has become the most significant cause of redusing healthy life expectancy among Japanese, as it promotes progression of atherosclerosis and increases the risk of developing cardiac infarction and stroke.

}This department undertakes research to elisidate the mechanisms involved in developing diabetes and progression of atherosclerosis at the molecular level, and develops innovative diagnosis and treatment methods based on the above findings, which can be applied to the clinical field.

• Section of Metabolic Syndrome
  

  It is recognized tat lifestyle-related diseases (e.g. diabetes) develop by a combination of genetic and environmental factors. One hypothesis is that the rapid increase of diabetes among Japanese may be due to the lower insulin secretion capacity of the pancreatic beta cells among Japanese, compared to Westerners, making Japanese more lifely to accummurate energy at fat (genetic predisposition). Consequently, it is likely that obesity and insulin resistance induced by changes in environmental factors (e.g. westernized diet, reduced physical activity) can not be fully compensated.

  This section, therefore, investigates how genetic and environmental factors would interact to develop obesity, diabetes and metabolic syndrome.
  

• Section of Nutritional Therapy
  

  Excess energy intake, especially increased fat intake, is one of the major causes of diabetes and obesity. However, physiological free fatty acid concentrations are essential for insulin secretion, which would increase, in the short term, the secretion of glucose-responsive insulin. On the other hand, prolonged excess fat intake results in triglyceride accumulation in pancreatic beta cells, leading to decreased insulin secretion. It has been reported that fat intake contributes to obesity more than carbohydrate and protein intakes. Individuals with higher fat intakes are, therefore, more prone to obesity than those with lower fat intakes, even if total energy intakes are the same.
  
  This section examines the impacts of diets with different nutrient compositions on insulin secretion, glucose tolerance, insulin resistance, and obesity in genetically modified diabetes-, insulin resistant- and obesity-model animals. In this way, we aim to identify novel clinical applications by developing the optimal nutritional therapy, in terms of nutrient-to-energy ratio, for preventing lifestyle-related diseases.