Aqueous Components of Tomato Accelerate Alcohol Metabolism by Increasing Pyruvate Level

Abstract

Consumption of food while drinking alcohol has been suggested to play important roles in alleviating the physiological and pharmacological influences of alcohol. Vegetables are believed to provide health benefits, but there is little evidence for their influence on the effects of alcohol consumption. The present study aimed to investigate the effect of a common vegetable, tomato, on alcohol metabolism. In a randomized, controlled, crossover study with12 Japanese healthy men aged between 24 and 56 years, drinking tomato juice containing 5% (v/v) alcohol (TJAlc) significantly attenuated the elevation of blood ethanol level and subsequently increased the level of acetate compared with a water-based alcoholic beverage with an equal dose of alcohol (0.4 g/kg body weight). Significantly higher levels of blood pyruvate and lactate were also observed in subjects who had consumed TJAlc compared with those consuming the water-based beverage. Additionally, a biphasic alcohol effects scale method showed that subjective feelings for alcohol-induced stimulant effects were significantly enhanced by drinking TJAlc. Animal experiments using male Sprague Dawleyrats suggested that the effect on blood biomarkers was attributable to the serum fraction of tomato (TS), which largely consisted of aqueous compounds, but not lipophilic compounds such as the carotenoid lycopene. Furthermore, it was suggested the TS possibly included potent compound(s) in addition to alanine, glutamine, and citric acid, all of which have previously been reported to affect alcohol metabolism. Administration of TS clearly increased the activity of NAD (H)-dependent enzymes such as lactate-(LDH), alcohol-, and aldehyde-dehydrogenase in rat liver cytosols. These findings suggest that aqueous compound(s) in tomato promote alcohol metabolism, probably through increasing pyruvate level, enhancing LDH activity, and improving the ratio of NAD to NADH.