“This study suggested the beneficial effects of synbiotic supplementation on immune parameters, which were correlated with synbiotics-induced microbial changes and modified by microbial enterotypes,” the researchers wrote in the journal Gut Microbes.
The research was funded by China’s Major International (Regional) Joint Research Project; the Young Scientists Fund of the National Natural Science Foundation of China, and BYHEALTH Nutrition and Health Research Foundation. Life-Space Global Microbiome Center donated the synbiotic and placebo used in the study.
Synbiotics for immunity
Previous studies have investigated the role of synbiotics – a mixture of probiotic live microbes and prebiotic substrates – in combatting systemic inflammation, which is associated with the progression of chronic conditions.
As this inflammation leads to the persistent activation of the immune system and the release of proinflammatory mediators including C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α) and interleukins (ILs), synbiotics are drawing increasing attention as potential modulators of gut microbiota and immunity. However, “evidence regarding the immunity-regulating effects of synbiotic products in healthy individuals is limited and yields inconsistent results,” the researchers noted.
To expand the evidence, they set out to evaluate the effects of of synbiotics on immune factors among healthy adults, whether changes are linked to resulting variations in gut microbiota, and if synbiotic effects are affected by gut microbiota type (microbial enterotype). The primary outcome was the change in plasma CRP, with other immune factors and gut microbial alterations as secondary outcomes.
The double-blind, randomized, placebo-controlled study assigned 106 healthy adults to receive either synbiotics (containing Bifidobacterium lactis HN019, Lactobacillus rhamnosus HN001 and fructooligosaccharide) or a maldodextrin placebo for 8 weeks. These probiotic strains are known for possessing immunomodulatory properties. Fasting blood samples, stool samples and saliva samples at baseline, week 4 and week 8 of the study to evaluate immune factors and gut microbiota composition.
“In the current study, we found that daily supplementation of synbiotic supplements for 8 weeks altered systemic inflammation markers (plasma CRP, IFN-γ, and IL-10) and mucosal immunity markers (stool sIgA) in healthy adults,” the study concluded, noting a correlation of IL-10 and stool sIgA with microbial variations in the synbiotics group.
In addition, supplementation enhanced beneficial bacterial (Collinsella, Lactobacillus, Bifidobacterium, and Clostridium_sensu_stricto_1), as well as several functional pathways related to the biosynthesis of amino acids and short-chain fatty acids. Potential pro-inflammatory Parabacteroides were reduced compared to baseline.
Variations in responses
The research team also highlighted the variation in outcomes among participants, notably a sex-specific response and heightened effects among individuals with a higher pre-treatment Prevotella-to-Bacteroides (P/B) ratio.
“The use of basal P/B ratio holds great promise for personalized supplementation of synbiotics for immunomodulation, but additional randomized controlled trials with larger numbers of participants are needed to confirm these findings,” they wrote, also calling for more gender-focused research in this area to understand underlying mechanisms.
Source: Gut Microbes
“Effect of synbiotic supplementation on immune parameters and gut microbiota in healthy adults: a double-blind randomized controlled trial”
Authors: Xiaoqin Li et al.