Efficacy of Ipomoea batatas (Caiapo) on diabetes control in type 2 diabetic subjects treated with diet.

OBJECTIVE — To investigate the tolerability, efficacy, and mode of action of Caiapo, an extract of white sweet potatoes, on metabolic control in type 2 diabetic patients. RESEARCH DESIGN AND METHODS — A total of 61 type 2 diabetic patients treated by diet were given 4 g Caiapo (n = 30; mean age 55.2 ± 2.1 years; BMI 28.0 ± 0.4 kg/m²) or placebo (n = 31; mean age 55.6 ± 1.5 years; BMI 27.6 ± 0.3 kg/m²) once daily for 12 weeks. Each subject underwent a 75-g oral glucose tolerance test (OGTT) at baseline and after 1, 2, and 3 months to assess 2-h glucose levels. Additionally, fasting blood glucose, HbA_1c, total cholesterol, and triglyceride levels were measured. RESULTS — After treatment with Caiapo, HbA_1c decreased significantly (P < 0.001) from 7.21 ± 0.15 to 6.68 ± 0.14%, whereas it remained unchanged (P = 0.23) in subjects given placebo (7.04 ± 0.17 vs. 7.10 ± 0.19%). Fasting blood glucose levels decreased (P < 0.001) in the Caiapo group (143.7 ± 1.9 vs. 128.5 ± 1.7 mg/dl) and did not change in the placebo group (144.3 ± 1.9 vs. 138.2 ± 2.1 mg/dl; P = 0.052). A decrease in body weight was observed in both the placebo group (P = 0.0027) and in the Caiapo group (P < 0.0001), probably due to a bettercontrolled lifestyle. In the Caiapo group, body weight was related to the improvement in glucose control (r = 0.618; P < 0.0002). Two-hour glucose levels were significantly (P < 0.001) decreased in the Caiapo group (193.3 ± 10.4 vs. 162.8 ± 8.2 mg/dl) compared with the placebo group (191.7 ± 9.2 vs. 181.0 ± 7.1 mg/dl). Mean cholesterol at the end of the treatment was significantly lower in the Caiapo group (214.6 ± 11.2 mg/dl) than in the placebo group (248.7 ± 11.2 mg/dl; P < 0.05). No significant changes in triglyceride levels or blood pressure were observed, and Caiapo was well tolerated without significant adverse effects. CONCLUSIONS — This study confirms the beneficial effects of Caiapo on plasma glucose as well as cholesterol levels in patients with type 2 diabetes. For the first time, the long-term efficacy of Caiapo on glucose control was demonstrated by the observed decrease in HbA_1c. Thus, the neutraceutical Caiapo seems to be a useful agent in the treatment of type 2 diabetes.