Green Tea Is a Poor Contributor to Tissue Folate in a Folate Depletion-Repletion Rat Model

Green tea contains folate and epigallocatechin gallate (EGCg), which is suggested to be an antifolate. In this study, we examined whether green tea was a good source of folate in a folate depletion/repletion rat model. Rats fed a folate deficient diet for 4 weeks were supplied with folate for 7 days, and then folate repletion effects were evaluated in terms of increase in total folate level in plasma, liver, and bone marrow and decrease in plasma homocysteine level. In this model, the folic acid treatment effect was observed to be dose-dependent and an appropriate dose of folic acid was 40 μg/kg/day or greater. Based on this finding, green tea as well as spinach, chicken liver, and folic acid as a reference were applied to this model. Increase in tissue folate level in response to the food samples varied among tissues, with bone marrow showing the smallest response. Increase in tissue folate level was in the order of spinach > chicken liver > green tea, which produced only a slight increase in tissue folate level and further diminished bone marrow folate level. EGCg administered by intragastric gavage at an approximate dose of 8 mg/kg did not attenuate the increase in tissue folate level when repletion was performed with folic acid. These results suggested that green tea is a poor source of food folate, but EGCg in green tea at a low dose has little effect on folic acid absorption.