Tomato juice preload has a significant impact on postprandial glucose concentration in healthy women: A randomized cross-over trial.

ABSTRACT

BACKGROUND AND OBJECTIVES: Our aim was to evaluate the effect of consuming tomato juice before carbohydrate on postprandial glucose concentrations in healthy women. METHODS AND STUDY DESIGN: In this randomized controlled cross-over study, 25 healthy women (age 21.6±3.8 years, HbA1c 5.3±0.2 %, mean±SD) consumed either 200 g of tomato juice, tomato, or water (control) at 30 min before consuming 200 g of boiled white rice at 900 and consumed identical lunch at 1300 for 3 days. The blood glucose concentrations were measured by selfmonitoring blood glucose at 0, 30, 45, 60, 90, 150, and 210 min pre- and post-breakfast, and at 0, 30, 60, 120, 150, and 180 min pre- and post-lunch. The concentration of postprandial glucose, incremental glucose peak (IGP), and incremental area under the curve for glucose after the test meals were compared among 3 days. RESULTS: Incremental blood glucose concentrations at 60 min (2.32±0.16 vs 2.97±0.19 mmol/L, p<0.05, mean±SEM), 90 min (2.36±0.23 vs 3.23±0.24 mmol/L, p<0.01), and IGP (2.77±0.19 vs 3.68±0.22 mmol/L, p<0.001) in consuming tomato juice 30 min before carbohydrate were all significantly lower than those of water, while IGP of consuming tomato was tended to be lower than that of water (2.82±0.19 mmolL, p=0.023). No significant difference was observed in glycaemic parameters after consuming lunch among 3 days. CONCLUSIONS: Consuming tomato juice half hour before carbohydrate ameliorates the postprandial blood glucose concentrations, although total amounts of energy and carbohydrate of tomato juice are higher than those of water.