Study Title:

Chlorella intake attenuates reduced salivary SIgA secretion in kendo training camp participants.

Study Abstract

BACKGROUND:

The green alga Chlorella contains high levels of proteins, vitamins, and minerals. We previously reported that a chlorella-derived multicomponent supplement increased the secretion rate of salivary secretory immunoglobulin A (SIgA) in humans. Here, we investigated whether intake of this chlorella-derived supplement attenuated the reduced salivary SIgA secretion rate during a kendo training camp.

METHODS:

Ten female kendo athletes participated in inter-university 6-day spring and 4-day summer camps. They were randomized into two groups; one took placebo tablets during the spring camp and chlorella tablets during the summer camp, while the other took chlorella tablets during the spring camp and placebo tablets during the summer camp. Subjects took these tablets starting 4 weeks before the camp until post-camp saliva sampling. Salivary SIgA concentrations were measured by ELISA.

RESULTS:

All subjects participated in nearly all training programs, and body-mass changes and subjective physical well-being scores during the camps were comparable between the groups. However, salivary SIgA secretion rate changes were different between these groups. Salivary SIgA secretion rates decreased during the camp in the placebo group (before vs. second, middle, and final day of camp, and after the camp: 146 ± 89 vs. 87 ± 56, 70 ± 45, 94 ± 58, and 116 ± 71 μg/min), whereas no such decreases were observed in the chlorella group (121 ± 53 vs. 113 ± 68, 98 ± 69,115 ± 80, and 128 ± 59 μg/min).

CONCLUSION:

Our results suggest that a use of a chlorella-derived dietary supplement attenuates reduced salivary SIgA secretion during a training camp for a competitive sport.

Introduction.

Salivary secretory immunoglobulin A (SIgA) plays a crucial role in mucosal immune function and is the first line of defense against pathogenic microbial invasion in humans [1]. Rounds of heavy exercise depress salivary SIgA secretion, which results in an increased risk of infection [2,3]. In particular, athletes appear to require infection control during training camps because of the high-intensity physical activity and group living. Yamauchi et al.[4] demonstrated that the secretion rate of salivary SIgA decreased by approximately 25% during a rugby football training camp, and this decrease was inversely related to the number of upper respiratory symptoms. Akimoto et al.[5] also reported that the salivary SIgA secretion rate decreased by approximately 45% during a 3-day soccer competition involving 6 games. These reductions in salivary SIgA secretion in athletes may be preventable with dietary supplements. Indeed, various dietary supplements (e.g., vitamins, bovine colostrum, and probiotics) have been tested for their effects on attenuating or suppressing the intensive exercise-related declines in immune function. However, the recently published position statement of the International Society of Exercise and Immunology noted that no adequate dietary supplements for SIgA secretion have been proposed for athletes [6].

Chlorella is a unicellular green alga that grows in fresh water and contains high levels of proteins, chlorophylls, vitamins, minerals, and dietary fibers. Previous studies showed that chlorella-derived dietary supplements improved SIgA concentrations in breast milk [7] and antibody responses to influenza in subjects aged 50–55 years [8]. Based on these findings, we conducted an intervention study and demonstrated that a 4-week chlorella supplementation program increased the salivary SIgA secretion rate by 40% in healthy humans [9]. However, it is not known if chlorella intake can attenuate reduced salivary SIgA secretion during a training camp for a competitive sport.

Discussion.

We investigated the effects of placebo and chlorella intake on salivary SIgA secretion in the participants of a kendo training camp. Although the scores for physical well-being before the camp were slightly lower than a usual level (3.0), all of our subjects participated in nearly all of the training programs. Body mass changes and subjective physical well-being scores during the camp were comparable between the placebo and chlorella groups. Based on these results, we consider that there were no intergroup differences in the physical requirements of this training camp. However, with respect to the baseline levels, salivary SIgA secretion rates decreased only with placebo intake but not with chlorella supplementation. These changes in the salivary SIgA secretion rate were comparable to the changes in the saliva flow rate. There were no changes in salivary SIgA concentrations during the camp. These results suggest that using a chlorella-derived dietary supplement attenuates the reduced salivary SIgA secretion during a training camp for a competitive sport like kendo.

Study Information

Otsuki T, Shimizu K, Iemitsu M, Kono I.
Chlorella intake attenuates reduced salivary SIgA secretion in kendo training camp participants.
Nutr J.
2012 December
Faculty of Sport and Health Sciences, Ryutsu Keizai University, Ryugasaki, Ibaraki, Japan.

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