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Open Access Research

Salivary Secretory Immunoglobulin a secretion increases after 4-weeks ingestion of chlorella-derived multicomponent supplement in humans: a randomized cross over study

Takeshi Otsuki1*, Kazuhiro Shimizu2, Motoyuki Iemitsu3 and Ichiro Kono4

Author affiliations

1 Faculty of Health and Sport Sciences, Ryutsu Keizai University, Ryugasaki, Ibaraki, Japan

2 Sports Research & Development Core, University of Tsukuba, Tsukuba, Ibaraki, Japan

3 Faculty of sport and health science, Ritsumeikan University, Kusatsu, Shiga, Japan

4 University of Tsukuba, Tsukuba, Ibaraki, Japan

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Citation and License

Nutrition Journal 2011, 10:91  doi:10.1186/1475-2891-10-91

Published: 9 September 2011

Abstract

Background

Chlorella, a unicellular green alga that grows in fresh water, contains high levels of proteins, vitamins, minerals, and dietary fibers. Some studies have reported favorable immune function-related effects on biological secretions such as blood and breast milk in humans who have ingested a chlorella-derived multicomponent supplement. However, the effects of chlorella-derived supplement on mucosal immune functions remain unclear. The purpose of this study was to investigate whether chlorella ingestion increases the salivary secretory immunoglobulin A (SIgA) secretion in humans using a blind, randomized, crossover study design.

Methods

Fifteen men took 30 placebo and 30 chlorella tablets per day for 4 weeks separated by a 12-week washout period. Before and after each trial, saliva samples were collected from a sterile cotton ball that was chewed after overnight fasting. Salivary SIgA concentrations were measured using ELISA.

Results

Compliance rates for placebo and chlorella ingestions were 97.0 ± 1.0% and 95.3 ± 1.6%, respectively. No difference was observed in salivary SIgA concentrations before and after placebo ingestion (P = 0.38). However, salivary SIgA concentrations were significantly elevated after chlorella ingestion compared to baseline (P < 0.01). No trial × period interaction was identified for the saliva flow rates. Although the SIgA secretion rate was not affected by placebo ingestion (P = 0.36), it significantly increased after 4-week chlorella ingestion than before intake (P < 0.01).

Conclusions

These results suggest 4-week ingestion of a chlorella-derived multicomponent supplement increases salivary SIgA secretion and possibly improves mucosal immune function in humans.