The effects of chitosan on blood glucose levels have been contradicting. Hypoglycemic effects of high molecular weight chitosan are related to diabetic models with hypoinsulinemia but have shown little effect on the blood glucose levels in hyperinsulinemia related diabetic models. Based on previous reports, high molecular weight chitosan either directly or indirectly related to insulin secretion in pancreas but has little effect on insulin resistance. In the present study, the effect of GO2KA1 (low molecular weight chitosan oligosaccharide) on blood glucose levels in Korean pre-diabetic adults, will be evaluated. The changes in postprandial blood glucose levels will be investigated in subjects with impaired fasting glucose or glucose tolerance.

In the detailed description we believe that it will be wise to discuss about the long-term study of the effect of GO2KA1(Chitosan oligosaccharide: oligosaccharides derived from chitosan) on pre-diabetic individuals (in addition to the postprandial blood glucose levels). In the present study, we will investigate the effects of GO2KA1 on the level of postprandial blood glucose in adult Koreans with impaired fasting glucose or impaired glucose tolerance. Postprandial blood glucose levels will be tested for 2 hours at every 30 min interval after 75g-OGTT and the experimental group will be pre-fed with 500 mg of GO2KA1. Primary outcomes will be included change in HbA1c, insulin, glycemic AUC, and lipids(total cholesterol, triglyceride, and HDL).

This clinical study will be conducted with 60 subjects after explanation and accommodation about experimental protocols and model. To test under same condition, smoking and drinking water will be completely prohibit from 1 hour before and during the experiment. At first day, control experiment will be conducted without oral take of GO2KA1 or placebo.

Inclusion Criteria:

• males and females 20-75 years old
• impaired fasting glucose (FPG 100~125 mg/dL) or impaired glucose tolerance (PPG-2h 140~200 mg/dL)
• able to give informed consent

Exclusion Criteria:

• having received a diagnosis of diabetes or receiving treatment for diabetes
• having a history of ischemic heart disease, stroke, liver cirrhosis, chronic pancreatitis, pituitary disease, thyroid disease, adrenal gland disease, mental illness, gastrectomy, or advanced malignant tumor
• receiving corticosteroid or thyroid hormone medication
• being judged by the responsible physician of the local study center as unfit to participate in the study
• abnormal liver or kidney function tests (ALT or AST > 2 times the upper limit of normal
• elevated creatinine, males > 125 umol/L, females > 110 umol/L)