Consumption of spirulina could help protect against hepatic inflammation in the elderly, according to the new animal research published in Nutrients.
Belgian researchers carried out tests on mice, which suggest that the algae Spirulina has an impact on the gut microbiota, which in turn activates the immune system in the gut and improves inflammation in the liver that is associated with ageing.
Led by senior author Professor Nathalie Delzenne from the Louvain Drug Research Institute in Belgium, the team said oral feeding of Spirulina was found to modulates several immunological functions involving, among others, the TLR4 pathway in old mice.
“The fact that its oral consumption can influence both gut immunity and systemic sites, such as the liver, suggests that its immune action is not confined to the gut immune system,” wrote the team – who said the findings open the way to new therapeutic tools “in the management of immune alterations in aging, based on gut microbe-host interactions.”
Furthermore, they suggested that improvement of the homeostasis in the gut ecosystem ‘could be essential’ during the aging process, “and, in this perspective, dietary manipulation of the gut microbiota of the elderly with Spirulina, may represent a tool for preserving a healthy gastrointestinal microbial community in addition to its beneficial effects on immune function.”
Delzenne and colleagues noted that while the possible cardiovascular and immune support benefits of Spirulina have been fairly widely reported, the new study brings a fresh approach by testing whether the effects could be related to a modulation of gut micrbiota.
In the trial, young mice aged three months were fed a standard diet, while older mice aged 24 months were fed a standard diet either with or without 5% Spirulina for six weeks.
Upton supplementation with Spirulina, the team reported several changes to gut microbiota composition, including an increase in Roseburia and Lactobacillus populations.
“Interestingly, parameters related to the innate immunity are upregulated in the small intestine of Spirulina-treated mice,” said the team. “Furthermore, the supplementation with Spirulina reduces several hepatic inflammatory and oxidative stress markers that are upregulated in old mice versus young mice.”
Expression of several genetic and biochemical markers of inflammation and immunity were altered by supplementation with Spirulina, said the team.
In particular, the transcription factor Foxp3 – involved in the differentiation of T cells into regulatory T cells (Tregs) – and MCP1 were increased due to Spirulina supplementation in old mice.
Old mice that consumed Spirulina also showed activation of several immune parameters including Foxp3 in the ileum – suggesting an improvement of the gut immune function upon Spirulina treatment in this segment, said the Belgian researchers. Furthermore, Spirulina supplementation upregulated both TLR2 and TLR4 expression in the ileum of aged mice.
“In accordance with these results, a solution of Spirulina (5%) exhibited a TLR4 agonist activity similar to the one reached in old-SP mice, suggesting a direct effect of the Spirulina, itself, on the TLR4 pathway,” they added.
While the positive effect of Spirulina on the microbiome and liver inflammation is clear, the team noted that the mechanism by which the algae could change the composition of the intestinal microbiota remains unanswered.
One possible mechanism could be the presence of antimicrobial substances produced by Spirulina, they said.
“On the other hand, antimicrobial peptides (AMPs) could be mediators of the nutritional modulation of the gut microbiota.”
“In the present study, RegIIIγ and Pla2g2 were increased by the supplementation with Spirulina, suggesting that the host contributes to the reduction and modification of the microbial community by modulating the production of specific AMPs,” they added.
Volume 9, Issue 6, 633, doi:10.3390/nu9060633
“Spirulina Protects against Hepatic Inflammation in Aging: An Effect Related to the Modulation of the Gut Microbiota?”
Authors: Audrey M. Neyrinck, et al