Effects of Gynura bicolor on Glycemic Control and Antioxidant Ability in Prediabetes

There exists an intermediate group of individuals whose glucose levels do not meet the criteria for diabetes yet are higher than those considered normal (prediabetes mellitus (preDM)). Those people have a higher risk of developing diabetes in the future. Gynura bicolor (GB) is a red-purple-colored vegetable, which is common in Taiwan. GB has shown antioxidant, anti-inflammatory and anti-hyperglycemic effects in previous studies. The aim of this study was to assess the effects of serving two serving sizes of GB every day on the glycemic control and antioxidant ability of preDM subjects. According to the age and anthropometry data of the participates, we assigned them into a control or GB group for the 8-week intervention and 4-week washout period. Data of anthropometry and biochemical analysis were collected at 0, 8 and 12 weeks. Oral glucose tolerance tests were performed, and we collected dietary records on the baseline and Week 8. Both groups received nutrition education and a diet plan individually. After intervention, the fasting glucose and malondialdehyde (MDA) values were significantly decreased in the GB group. HOMA-IR and QUICKI values were improved, and antioxidant activity was increased in the GB group. GB could improve glycemic control and decrease oxidative stress because of its large amounts of polyphenols.