Background Alcohol consumption is associated with hyperuricemia and gout. Previous studies have indicated a role for green tea catechins in uric acid (UA) metabolism. This study aimed to elucidate the effect of green tea catechins in terms of enhancing urinary excretion of UA and xanthine/hypoxanthine (Xa/HX) after alcohol ingestion.
Methods In a randomized crossover study, 10 healthy subjects consumed test meals, including a Japanese distilled spirit (Shōchū) with water (SW) or Shōchū with catechin-rich green tea (SC), each containing 20 g of alcohol. The SC contained 617 mg of total catechin. Serum and urine UA and Xa/HX concentrations were measured. Blood samples were collected after 2.5 h, and urine samples were collected between 0 and 5 h after consuming the test meal.
Results Urine UA and Xa/HX excretions were significantly higher in the SC group than in the SW group ( P < 0.05). UA clearance and fractional UA excretion tended to increase more in the SC group than in the SW group. No significant differences in S-UA and S-Xa/Hx concentrations were observed between the SW and SC groups.
Conclusions Based on these observations, it was concluded that green tea catechins can enhance the excretion of UA and Xa/HX, even though alcohol is ingested.
Trial registration The protocol was approved by the Ethics Committee of the University of Shizuoka and registered with UMIN (University Hospital Medical Information Network in Japan). Trial registration number: UMIN000040076. Registered 7 April 2020 – Retrospectively registered, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000045687