Effects of Dietary Supplementation of Taurine, Carnitine or Glutamine on Endurance Exercise Performance and Fatigue Parameters in Athletes

ABSTRACT

The effects of taurine, carnitine or glutamine supplementation on endurance exercise performance along with related fatigue factors were evaluated in male college students in the Department of Physical Education, who''s maximal oxygen consumption rates (VO2max) were equivalent to those of endurance athletes. Twenty four subjects were randomly divided into 4 groups (n=6), and given placebo, taurine (4 g/day), carnitine (4 g/day), or glutamine (4 g/day) tablets for 2 weeks. Subjects could run 6.9 min or 9.0 min longer until exhausted on a treadmill at the intensity of 75% VO2max following taurine or camitine supplementation for 2 weeks, respectively, compared to the value measured prior to each supplementation. Glutamine or placebo supplementation did not improve the endurance exercise performance based on the running time until exhausted on a treadmill. Serum lactate concentrations measured 1 hr after the initiation of the endurance exercise, as well as at all-out state tended to be decreased by taurine, carnitine, or glutamine supplementation, and were significantly lowered (43% decrease) by carnitine supplementation (p<0.05). Taurine supplementation significantly reduced the serum inorganic phosphorus concentration measured at all-out state (14% decrease, p<0.05), while carnitine supplementation significantly lowered the resting state serum inorganic phosphorus level (20% decrease, p<0.05). Taurine (32% reduction) or carnitine (23% reduction) supplementation significantly decreased serum ammonia concentration measured at all-out state (p<0.05). From these results, 4 g/day of taurine or carnitine supplementation appears to improve the endurance exercise performance and related human fatigue factors.