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.

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/m(2)) or placebo (n = 31; mean age 55.6 +/- 1.5 years; BMI 27.6 +/- 0.3 kg/m(2)) 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 better- controlled 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.