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

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.

Figure 1

Effects of supplementation with chlorella-derived multicomponent supplement on mucosal immune function. These figures show salivary secretory immunoglobulin A (SIgA) concentrations (A), saliva flow rates (B), and salivary SIgA secretion rates (C) before and after 4-week placebo (n = 15)/chlorella (n = 15) ingestion. While no difference was observed in salivary SIgA concentrations and secretion rates between before and after placebo supplementation, these indices significantly increased after chlorella intake compared to baseline. The saliva flow rates did not change after supplementation with placebo or chlorella compared to those before intervention. Data are expressed as mean ± SE. *, significant change compared to before ingestion.