Plain language summary
Euglena gracilis is a single cell algae which inhabits most garden ponds. Euglena is rich in several nutrients and produces paramylon, a type of carbohydrate known as β-glucan, which has been shown in animal studies to have several health benefits. This study looked at the effects of E. gracilis on the immune system and quality of life (QOL) in humans. Seven healthy men aged 30-70 completed the study. Subjects were split into two groups and instructed to take 500mg/day of either the E. gracilis or a placebo (cornstarch) for 4 weeks. After a break, the groups were swapped, and the experiment repeated for another 4 weeks. The researchers found that ingestion of the algae increased the amount of salivary s-IgA secretion, and was able to activate the mucosal immune system in such a way that could potentially enhance the immune response against microbial infections such as Candida and Aspergillus. Ingestion of the algae also improved scores in both mental and physical health. Due to the limited number and diversity of subjects, further studies with a larger number of more diverse subjects are needed. The researchers suggest that Euglena gracilis would be a useful functional food for humans.
undefined: EOD-1, a microalgal strain known for high yields of the β-1, 3-glucan paramylon, is suggested to function as a dietary fiber and enhance immunity. Here, we aimed to investigate the effects of EOD-1 biomass (EOD1BM) ingestion on immunoglobulin A (IgA) antibody titers in saliva, its reactivity, and the health-related quality of life (QOL) in humans. Reacting human immunoglobulin preparations and saliva with paramylon granules revealed the presence of anti-paramylon antibodies in the blood and saliva. We conducted a placebo-controlled, double-blind, crossover study involving 13 healthy subjects who ingested the placebo or EOD1BM for 4 weeks. Saliva was collected from each subject before and after ingestion, and IgA titers and EOD-1 paramylon (EOD1PM) reactivity were compared. In the EOD1BM Ingestion group, the anti-EOD1PM IgA content and titer increased after EOD1BM ingestion. No such change was observed in the Placebo group. Furthermore, the health-related QOL, especially mental health, increased in the EOD1BM Ingestion group. Thus, EOD1BM ingestion led to the production of paramylon (PM)-specific IgA antibody and increased salivary IgA antibody titers. We demonstrate that EOD1BM ingestion enhanced the immunity in the mucosal surface, evoked an antigen-specific response, and increased the health-related QOL, thereby contributing to health improvement.