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.