The effect of tea consumption on the steroid profile

Abstract

Green tea (GT), along with its flavonol epigallocatechin-3-gallate (EGCG), has shown to inhibit the UGT2B17 isoenzyme, which is highly involved in the glucuronidation of testosterone (T) and its metabolites. Since the steroid profile (SP) is composed of urinary concentrations of T and related metabolites excreted in both the free and the glucuronide fractions, GT consumption could alter the SP, leading to misunderstanding in doping controls. The aim of the present work was to study the effect of GT consumption on the SP. This study was performed with 29 male volunteers, which could be classified in 2 arms depending on their T/E values (0.12 ± 0.02, n = 12; 1.64 ± 0.90, n = 17). The clinical protocol was designed to evaluate the effect of GT administration on the SP biomarkers. Participants were asked to consume GT with a high content of EGCG for 7 days (5 GT beverages along the whole day for days 1-6 and 9 GT beverages on day 7, corresponding to 520 and 936 mg/day of EGCG, respectively). Urine samples were collected before and during GT consumption at different time periods. The SP was measured using gas chromatography-mass spectrometry. The excretion rates of the SP metabolites did not change after GT consumption. Moreover, the individual evaluation of the subject's steroidal biological passport resulted in normal sequences. The results obtained show that GT consumption does not distort the establishment of normal ranges of SP parameters. Therefore, GT consumption does not need to be considered a confounding factor in the SP evaluation.

Current Insights into the Steroidal Module of the Athlete Biological Passport

“…In principle, all compounds administered to the human body such as food, beverage or medication can act as a confounding factor if they encompass the ability to act on steroid genesis or metabolism 74 75 76 77 . A class of compounds with a straightforward and well investigated action on steroid metabolism are 5α-reductase inhibitors like for example finasteride 78 .…”

An in vitro assay approach to investigate the potential impact of different doping agents on the steroid profile

“…5,6 In order to maintain the integrity of the SP, all samples showing the presence of any CFs should be excluded when justified. Whereas several CFs have already been identified, for instance, ethanol, selective estrogen receptor modulators (SERMs) or glucocorticoids, [5][6][7][8][9] for many doping agents, nutritional supplements, and nonapproved substances, their possible impact has not been investigated; and therefore, samples containing them are not currently excluded.…”