The effect of L-theanine supplementation on the immune system of athletes exposed to strenuous physical exercise

Background

The 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.

Method

The 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.

Results

Supplementation 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.

Conclusion

Despite 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.

Prevalence of Helicobacter pylori infection in pediatric celiac disease

OBJECTIVE

A lower risk of celiac disease (CD) in patients with Helicobacter pylori (Hp) infection has been reported when Hp infection prevalence in CD patients was compared against CD-negative symptomatic persons with indications for diagnostic gastroduodenoscopy. Therefore, we aimed to determine Hp infection frequency in a group of pediatric CD patients at diagnosis and to compare obtained results to data coming from age-matched healthy population.

PATIENTS AND METHODS

The study population consisted of 74 CD subjects aged 3 to 12 years in whom the presence of Hp was diagnosed routinely in the course of differential diagnosis with the use of stable isotope breath test which is the gold standard. The control group consisted of 296 healthy age-matched subjects.

RESULTS

Hp infection was diagnosed in 4 CD patients and 20 healthy subjects. Its prevalence in CD patients and HS did not differ neither in the entire age group undergoing comparison (5.4% vs. 6.8%, p = 0.5713) nor in the selected age subgroups (3-6 years: 2.5% vs. 3.7%, p = 0.8551; 7-12 years: 8.8% vs. 11.0%, p = 0.8742).

CONCLUSIONS

The prevalence of Hp infection in CD patients does not seem to be different than that in general population. However, further studies are needed to assess the potential role of Hp in the pathogenesis of CD.