Effect of vegetable juice consumption prior to eating rice on postprandial blood glucose and insulin levels.

Vegetable juice has been demonstrated to attenuate the elevation of postprandial blood glucose when consumed prior to meals. The present study aimed to investigate the effect of pre-meal consumption of vegetable juice on blood glucose and insulin levels. A total of 10 healthy volunteers aged 20-29 years ingested 200 ml of either water, a sugar solution with the same sugar composition as the vegetable juice or vegetable juice 30 min prior to consuming the cooked rice, and their blood glucose and insulin levels were measured. At the time of rice consumption and 15 min thereafter, blood glucose and plasma insulin levels tended to be lower in the vegetable juice intake group compared with those in the sugar solution intake group. However, there were no significant differences in the kinetic parameters (incremental area under the glucose curve and maximum change in glucose concentration) between these two groups. These results suggest that the sugars contained in vegetable juice account for the suppression of postprandial hyperglycemia.

Effect of low glycemic index food and postprandial exercise on blood glucose level, oxidative stress and antioxidant capacity.

Low glycemic index (GI) food and postprandial exercise are non-drug therapies for improving postprandial hyperglycemia. The present randomized, crossover study investigated the effect of low GI food combined with postprandial exercise on postprandial blood glucose level, oxidative stress and antioxidant capacity. A total of 13 healthy subjects were each used in four experiments: i) rice only (control), ii) salad prior to rice (LGI), iii) exercise following rice (EX) and iv) salad prior to rice and exercise following rice (MIX). The blood glucose level, oxidative stress and antioxidant capacity were then measured. At 60 min after the meal, the blood glucose level was observed to be increased in the MIX group compared with that in the LGI group. Furthermore, at 180 min, the antioxidant capacity was found to be reduced in the MIX group compared with those of the LGI and EX groups. These findings suggest that low GI food combined with postprandial exercise does not improve postprandial hyperglycemia. It may be necessary to establish optimal timing and intensity when combining low GI food with postprandial exercise to improve postprandial hyperglycemia.