Effects of single and long-term administration of wheat albumin on blood glucose control: randomized controlled clinical trials.
OBJECTIVE: To examine the effects of single and long-term administration of wheat albumin (WA) on blood glucose levels and blood glucose control, respectively. DESIGN: Randomly arranged crossover trial for single administration in healthy subjects and double-blinded randomized controlled trial for long-term administration (3 months) in diabetic patients. In vitro alpha-amylase inhibitory activity of WA was also determined. SETTING: Central Research Laboratories of Nisshin Flour Milling Co. Ltd. (Saitama, Japan) for single administration and Aiwa Clinic (Saitama, Japan) for long-term administration. SUBJECTS: A total of 12 healthy adult male volunteers for the single administration and 24 type II outpatient diabetics with mild hyperglycemia for the long-term administration. INTERVENTIONS: Subjects took soups containing 0, 0.25, 0.5, and 1.0 g WA before test meals for single administration, and patients took soups with or without 0.5 g WA before every meal for the long-term (3 months) administration. RESULTS: In vitro alpha-amylase inhibitory activity of WA was 150 times that of wheat flour. In the single administration experiment, WA suppressed peak postprandial blood glucose levels in a dose-dependent manner: 31, 47, and 50% reduction after 0.25, 0.5, and 1.0 g administrations, respectively. In the long-term administration, 0.5 g of WA did not affect fasting blood glucose levels, whereas it reduced hemoglobin A1c levels. No significant adverse effects such as hypoglycemia or gastrointestinal disturbances were observed in the two experiments. CONCLUSION: In the treatment of type II diabetic patients, WA might be a useful functional food, which, with diet and exercise, could help to improve blood glucose control without any critical adverse effects.