Table 1.

Influence of tea on the urinary excretion of mutagens in human volunteers

Volunteer
Water

Black tea
Overnight post-mealMorning post-mealAfternoon post-mealTotalTotal ingested as beefburgerOvernight post-mealMorning post-mealAfternoon post-mealTotalTotal ingested as beefburger
F12,966 ± 3051,055 ± 8728 ± 2204,38912,2335,920 ± 1981,446 ± 222662 ± 887,16413,817
M25,129 ± 665793 ± 91153 ± 765,81762,7335,730 ± 574587 ± 88192 ± 686,21853,300
M3979 ± 237256 ± 15216 ± 01,01516,2174,704 ± 81270 ± 167326 ± 1214,99736,000
M41,186 ± 45669 ± 100 ± 01,25512,689600 ± 300 ± 00 ± 06006,222
M51,477 ± 30110 ± 4124 ± 201,28218,033746 ± 14745 ± 4827 ± 4767614,333
F6678 ± 6014 ± 2529 ± 507217,133196 ± 9243 ± 520 ± 021110,306
F94,578 ± 283608 ± 91330 ± 635,00036,2003,024 ± 151378 ± 46226 ± 873,39730,183
F105,680 ± 614886 ± 36479 ± 1256,25683,0002,450 ± 114413 ± 51432 ± 512,42558,567
M115,890 ± 1942,962 ± 535297 ± 1318,99044,3675,080 ± 7481,198 ± 210413 ± 836,37640,778
M123,405 ± 407612 ± 81403 ± 624,11118,7081,247 ± 41182 ± 244139 ± 411,34313,000
  • NOTE: Mutagenic activity is expressed as histidine revertants (mean ± SD for triplicate plates) per urine pool from each volunteer. Total mutagenic activity is presented after subtraction of baseline mutagenicity, i.e. urinary mutagenicity prior to ingestion of the beefburger meal. Mutagenic activity in each sample was determined in the Ames test in the presence of an activation system, and utilizing S. typhimurium strain YG1024. Volunteers drank 10 cups of tea or the equivalent volume of water, and consumed three well-cooked beefburgers during the evening. Three urine voids were collected for each volunteer.