| The purpose of this study was two fold: (1) to investigate the physiological and performance responses to chronic (24d) supplementation with thiamin tetrahydrofurfuryl disulfide (TTFD), also known as allithiamin, and (2) to investigate the physiological and performance responses to chronic (28d) supplementation with TTFD in conjunction with carbohydrate loading. Utilizing a randomized, double blind, matched-pair design, 20 recreationally trained endurance athletes ingested either 300 mg·day-1 of TTFD (n = 10) or a placebo (PL) (n = 10) for 28 days. On day 0 and 23 (TTFD1, TTFD2, PL1, PL2), participants performed a progressive cycling test to volitional exhaustion for the determination of VO2peak and lactate threshold (La TH). Twenty-four hours after the second test for VO2peak (TTFD24, PL24) participants were measured for resting metabolic rate (RMR) and then performed a 60-min ride at ∼80% of VO 2peak followed by a 5-km time-trial (TT). Following this 60-min ride and TT, a 3-d high dietary carbohydrate intake regimen was initiated. Following the 3-d high carbohydrate dietary regimen (TTFD28, PL28) subjects were again measured for RMR and then performed a final 60-min ride and TT. Serial measures of respiratory gases, heart rate, rating of perceived exertion (RPE), and [La-] were made during each 60-min ride. Five-km cycling time to exhaustion was also recorded. A univariate factorial analysis of variance (ANOVA) with repeated measures was used to determine significant differences between trials and across time. In response to the 24-d TTFD supplementation, there were no statistically significant differences observed between the TTFD or PL groups (VO2peak (TTFD1 4.11 +/- 0.16, TTFD2 4.27 +/- 0.19, PL1 4.30 +/- 0.17, PL2 4.76 +/- 0.18) (F(3,4) = 6.73, p > 0.05), LaTh (TTFD1 218 +/- 13, TTFD 2 230 +/- 15, PL1 219 +/- 8, PL2 230 +/- 9) (F(1,18) = 3.34, p > 0.05). In response to chronic TTFD supplementation in conjunction with a 3-d high carbohydrate intake there were likewise no significant differences in any physiological or performance parameters. Though there were no treatment effects, HR, RPE, and VO2 demonstrated a progressive drift across time. Other variables measured included La- (TTFD24 3.89 +/- 0.06, TTFD 28 4.11 +/- 0.27, PL24 3.72 +/- 0.06, PL28 3.95 +/- 0.06 mM), 5-km TT (TTFD24 12.83 +/- 0.40, TTFD28 12.24 +/- 0.48, PL24 12.97 +/- 0.60, PL28 11.97 +/- 0.42 min) and mean power output during the TT (TTFD24 220 +/- 12, TTFD28 238 +/- 15, PL24 225 +/- 14, PL28 254 +/- 10 W). The results of this study suggest that neither chronic TTFD supplementation, nor chronic TTFD supplementation in conjunction with carbohydrate loading, provides any physiological or performance benefits to trained athletes performing high-intensity exercise. |
