Glycaemic and Appetite Suppression Effect of a Vegetable-Enriched Bread

Bread, a frequently consumed food, is an ideal vehicle for addition of ingredients that increase nutrient density and add health benefits. This experimental cross-over study sought to test the effect of a vegetable-enriched bread (VB) in comparison to commercial white bread (WB) and wheatmeal bread (WMB) on serum glucose, insulin response and subjective appetite suppression. On three separate occasions, 10 participants (23 +/- 7 years) visited the laboratory and consumed after an overnight fast, in random order, a 75 g serve of WB, WMB or VB. Venous blood samples drawn twice before (0 min) and at 15, 30, 45, 60, 90 and 120 min after consumption of the bread were analysed for glucose and insulin. Participants rated their subjective feelings of hunger, fullness, satisfaction and desire to eat on a 150 mm Likert scale. The mean glucose iAUC over 120 min was not different among the breads. The mean insulin iAUC for the VB was significantly lower than the WB and WMB; difference VB and WB 12,415 pmol/L*minutes (95% CI 1918, 22,912 pmol/L*minutes, p = 0.025) and difference VB and WMB 13,800 pmol/L*minutes (95% CI 1623, 25,976 pmol/L*minutes p = 0.031). The VB was associated with a higher fullness feeling in the participants over the 120-min period. The consumption of VB was associated with less insulin release and higher satiety over 120 min which may be related to the higher fibre content and texture of VB. The role of vegetable and fruit fibres such as pectin in bread and insulin response should also be further explored.

Automated summary

This experimental study compared the effects of different types of bread on serum glucose, insulin response, and subjective appetite suppression. The results showed that vegetable-enriched bread (VB) could reduce insulin release and increase satiety over 120 minutes compared to commercial white bread (WB) and wheatmeal bread (WMB). Further exploration into the role of vegetable and fruit fibers in bread and insulin response is warranted.