Trial reportJournal of the International Society of Sports Nutrition2019
The effect of L-theanine supplementation on the immune system of athletes exposed to strenuous physical exercise.
Trial report in Journal of the International Society of Sports Nutrition, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers.
What it found
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
9 citing papers in PubMed.
- Performance-enhancing effects of caffeine and L-Theanine among Iranian elite wrestlers: a focus on cognitive and specific physical performance.Journal of the International Society of Sports Nutrition · 2025Trial
- Effect of single or combined caffeine and L-Theanine supplementation on shooting and cognitive performance in elite curling athletes: a double-blind, placebo-controlled study.Journal of the International Society of Sports Nutrition · 2023Trial
- Acute effects of combined and isolated caffeine and theanine supplementation on physical and cognitive performance in competitive athletes: a randomized, double-blind, placebo-controlled crossover study.Frontiers in nutrition · 2025Article
- A single 2000-meter exercise test to assess exercise adaptation in elite rowers during the preparatory phase.Frontiers in physiology · 2025Article
- L-Theanine and Immunity: A Review.Molecules (Basel, Switzerland) · 2023Review
- Paraxanthine Supplementation Increases Muscle Mass, Strength, and Endurance in Mice.Nutrients · 2022Article
- Protein and Sport: Alternative Sources and Strategies for Bioactive and Sustainable Sports Nutrition.Frontiers in nutrition · 2022Review
- L-Theanine: A Unique Functional Amino Acid in Tea (Frontiers in nutrition · 2022Review
- Impairment between Oxidant and Antioxidant Systems: Short- and Long-term Implications for Athletes' Health.Nutrients · 2019Review
Corrections and comments
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Authors and funding
9 authors.
Funding
Abstract
backgroundThe aim of this study was to analyze the response of selected components of the immune system in rowers to maximal physical exercise, and to verify if this response could be modulated by supplementation with L-theanine.
methodThe double-blind study included 20 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group (n = 10), receiving 150 mg of L-theanine extract for 6 weeks, or to the placebo group (n = 10). The participants performed a 2000-m test on a rowing ergometer at the beginning (1st examination) and at the end of the supplementation period (2nd examination). Blood samples were obtained from the antecubital vein before each exercise test, 1 min after completing the test, and after a 24-h recovery. Subpopulations of T regulatory lymphocytes (Tregs) (CD4+/CD25+/CD127-), cytotoxic lymphocytes (CTLs) (CD8+/TCRαβ+), natural killer (NK) cells (CD3-/CD16+/CD56+) and TCRδγ-positive (Tδγ) cells were determined by means of flow cytometry. The levels of interleukin 2 (IL-2), interleukin 4 (IL-4), interleukin 10 (IL-10), interferon gamma (INF-ɤ) and total antioxidant capacity (TAC) were determined with commercially available diagnostic kits.
resultsSupplementation with L-theanine contributed to a significant post-exercise decrease in IL-10 concentration, which was reflected by higher values of IL-2 to IL-10 and IFN-γ to IL-10 ratios. Moreover, a significant post-recovery decrease in CTL count, Treg to NK and Treg to CTL ratios was observed in the supplemented group.
conclusionDespite the decrease in the number of some cytotoxic cells (CTLs) and an increase in the proportion of Tregs to CTLs, supplementation with LTE seems to exert a beneficial effect on a disrupted Th1/Th2 balance in elite athletes, as shown by the decrease in IL-10 concentration.
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