CHIBA, Japan—Providing a combination of the amino acids cystine and theanine may help endurance athletes avoid exercise-induced immunosuppression and inflammation, according to a new study (J Intl Soc Sports Nutr. 2010;7:23. DOI: 10.1186/1550-2783-7-23).
Researchers from Jutendo University recruited 16 long-distance runners at a training camp; the subjects received either the combination supplement (700 mg cystine plus 280 mg theanine daily) or placebo for seven days prior to and during a nine-day training camp. Daily run training averaged 19.9 km/d prior to the camp and 28.6 km/d during the camp. Blood samples were collected before and after morning interval running workouts on the first and last days of the camp.
The relative change in exercise-induced blood neutrophil count (percent of pre-exercise values) was significantly lower in the supplemented group than the placebo group on the initial day of camp, but not on the last day. Similarly, the decline in lymphocyte counts was significantly less in the runners taking the combination supplement on the first day of camp, but not at the end. Researchers concluded supplementation significantly attenuated the increase in neutrophil count and reduction in lymphocyte count induced by intense endurance exercise, suggesting a combination of cystine and theanine could reduce exercise-induced immunosuppression.
