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Effect of synbiotic supplementation on immune parameters and gut microbiota in healthy adults: a double-blind randomized controlled trial.
Li, X, Hu, S, Yin, J, Peng, X, King, L, Li, L, Xu, Z, Zhou, L, Peng, Z, Ze, X, et al
Gut microbes. 2023;15(2):2247025
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Plain language summary
The gut microbiota is involved in regulating immunity and synbiotics, that is combinations of pro- and prebiotics, may therefore modulate immunity via the gut microbiota. The aim of this randomised, double-blind, placebo-controlled trial was to evaluate the immune-modulatory effects of a synbiotic supplement (containing Bifidobacterium lactis HN019, Lactobacillus rhamnosus HN001 and fructo-oligosaccharide) in healthy adults. Outcome measures included C-reactive protein (CRP, an inflammatory marker), various pro- and anti-inflammatory cytokines, stool and salivary secretory IgA (sIgA), leukocytes, microbial stool analysis and occurrence, duration, and severity of upper respiratory tract infections (URTI). Compared to the control group, a significant reduction in the inflammatory markers CRP and interferon-gamma and an increase in the anti-inflammatory interleukin-10 and stool sIgA were observed in the supplementation group. There were no differences in types of leukocytes or URTIs between groups. Significant favourable changes in microbiome analysis were observed in the supplemented group which correlated with the observed improvements in inflammatory markers. These changes were dependent on the baseline composition of the microbiome. No adverse events were reported. The authors conclude that the data show that synbiotics are of benefit to healthy adults and support the concept of personalised supplementation.
Abstract
Synbiotics are increasingly used by the general population to boost immunity. However, there is limited evidence concerning the immunomodulatory effects of synbiotics in healthy individuals. Therefore, we conducted a double-blind, randomized, placebo-controlled study in 106 healthy adults. Participants were randomly assigned to receive either synbiotics (containing Bifidobacterium lactis HN019 1.5 × 108 CFU/d, Lactobacillus rhamnosus HN001 7.5 × 107 CFU/d, and fructooligosaccharide 500 mg/d) or placebo for 8 weeks. Immune parameters and gut microbiota composition were measured at baseline, mid, and end of the study. Compared to the placebo group, participants receiving synbiotic supplementation exhibited greater reductions in plasma C-reactive protein (P = 0.088) and interferon-gamma (P = 0.008), along with larger increases in plasma interleukin (IL)-10 (P = 0.008) and stool secretory IgA (sIgA) (P = 0.014). Additionally, synbiotic supplementation led to an enrichment of beneficial bacteria (Clostridium_sensu_stricto_1, Lactobacillus, Bifidobacterium, and Collinsella) and several functional pathways related to amino acids and short-chain fatty acids biosynthesis, whereas reduced potential pro-inflammatory Parabacteroides compared to baseline. Importantly, alternations in anti-inflammatory markers (IL-10 and sIgA) were significantly correlated with microbial variations triggered by synbiotic supplementation. Stratification of participants into two enterotypes based on pre-treatment Prevotella-to-Bacteroides (P/B) ratio revealed a more favorable effect of synbiotic supplements in individuals with a higher P/B ratio. In conclusion, 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. These findings provided direct evidence supporting the personalized supplementation of synbiotics for immunomodulation.
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Effect of an enzyme-containing mouthwash on the dental biofilm and salivary microbiome in patients with fixed orthodontic appliances: a randomized placebo-controlled pilot trial.
Hoffstedt, T, Skov Hansen, LB, Twetman, S, Sonesson, M
European journal of orthodontics. 2023;45(1):96-102
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Fixed orthodontic appliances are associated with dysbiosis in the oral cavity which may result in demineralisations of the enamel. Antiseptic mouthwashes have been shown to control the formation of cariogenic biofilm but may have negative effects on the salivary microbiome. The aim of this 8-day double-blind, randomised, placebo-controlled trial, including 35 adolescents with fixed orthodontics, was to evaluate the effect of an enzyme-based mouthwash (EBM), used twice daily, on dental biofilm (plaque) formation and salivary microbiome. At 8 days, a statistically and clinically significant decrease in the orthodontic plaque index was seen in the EBM group, whilst no change was seen in the placebo group. There were no statistically significant changes in microbiome between groups but a trend to increased richness in the placebo group. The authors concluded that the use of an enzyme-based mouthwash alongside regular toothbrushing reduced dental biofilm in adolescents with orthodontics without affecting the salivary microbiome.
Abstract
BACKGROUND Mouthwashes containing oral antiseptics or enzymes are suggested suitable for controlling biofilm accumulation in patients with fixed appliances and thereby limiting unwanted side effects during the orthodontic treatment. OBJECTIVES To evaluate the effect of an enzyme-based mouthwash on the amount of dental biofilm and the composition of the salivary microbiome in patients undergoing treatment with fixed orthodontic appliances. TRIAL DESIGN Randomized double-blind placebo-controlled trial. MATERIAL AND METHODS In total, 35 young adolescents (14-18 years) under treatment with fixed appliances were consecutively enrolled and randomly allocated to an experimental or a placebo group by opening a computer-generated numbered envelope. The subjects were instructed to rinse twice daily during an intervention period of 8 days with experimental mouthwash or placebo without active enzymes. Unstimulated whole saliva samples were collected at baseline and after 8 days. The participants and examiner were blinded for the allocation. The primary outcome was the Orthodontic Plaque Index (OPI) and the secondary was the composition of the salivary microbiome. RESULTS In total, 28 adolescents (21 females and 7 males) completed the trial and there were no differences in age, clinical, or microbial findings between the test (n = 14) and the placebo group (n = 14) at baseline. We found a decreased OPI in the test group after 8 days and the difference was statistically significant compared with the placebo group (P < 0.05). There were no significant treatment effects on the richness and global composition of the salivary microbiome. HARMS In total, one participant in the test group claimed nausea and abandoned the project. In total, two participants did not like the taste of the mouthwash but used it as instructed. No other adverse events or side effects were reported. LIMITATIONS Short-term pilot trials may by nature be sensitive for selection and performance biases and are not designed to unveil persisting effects. CONCLUSION Daily use of enzyme-containing mouthwash reduced the amount of dental biofilm in adolescents under treatment with the fixed orthodontic appliances, without affecting the composition of the salivary microbiota. ETHICAL APPROVAL Approved by the Regional Ethical Board, Lund, Sweden (Dnr 2020-05221). CLINICAL TRIAL REGISTRATION NCT05033015.