The effect of Chlorella pyrenoidosa supplementation on immune responses to 2 days of intensified training

PURPOSE: Periods of intensified training are associated with immune disturbances, The aim was to investigate the effects of supplementation with Chlorella pyrenoidosa (Chlorella) on secretory IgA (sIgA) responses to 2 days intensified training. METHODS: Twenty-six subjects (age 29.1 ± 8.7 years; VO(2max) 53.7 ± 11.7 ml kg min(−1)) provided resting saliva samples for determination of sIgA, at baseline (week-0) and following 4, 5, and 6 weeks (weeks-4, -5, -6) of daily supplementation with 6 g/day Chlorella (n = 13) or placebo (PLA, n = 13). During week-4 a 2-day intensified training period was undertaken [morning and afternoon sessions each day, respectively: VO(2max) test; high-intensity interval training (HIIT, 3 × 30 s Wingate sprints); 90 min at ~60% VO(2max); 3 × 30 s HIIT]. RESULTS: Chlorella increased resting sIgA secretion rate (trial × time, P = 0.016: no change with PLA but increases with Chlorella at week-4, week-5 and week-6, P = 0.020, <0.001, and 0.016). PLA vs Chlorella: week-0 = 54 ± 33 vs 57 ± 37 µg/min; week-4 = 54 ± 35 vs 83 ± 57 µg/min; week-5 = 63 ± 46 vs 98 ± 47 µg/min; week-6 = 58 ± 35 vs 85 ± 59 µg/min. Minimal acute changes in sIgA were seen in response to individual exercise bouts, but it was higher at some times in the Chlorella group (for bouts 2 and 3). CONCLUSION: Supplementation with Chlorella has beneficial effects on resting sIgA, which might be beneficial during periods of intensified training. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00394-017-1525-9) contains supplementary material, which is available to authorized users.