IDDF2020-ABS-0203 Investigating the evidence of prebiotic supplementation in the attenuation of age-related neurodegeneration in in vivo studies: a systematic review and meta-analysis with bayesian inference

Background Prebiotics, as non-digestible substances that stimulate the growth and activity of beneficial bacteria, is hypothesized to improve neurocognitive function through the Gut-Brain axis. This review therefore, investigates whether the administration of prebiotics is efficacious in attenuating age-related neurodegeneration. Methods 2675 studies from MEDLINE, Embase, Scopus, Web of Science and Cochrane library were searched for in vivo studies using equivalent combinations of ‘prebiotics’ and ‘age-related neurodegeneration’ in concordance with PRISMA guidelines. Quantitative outcomes such as Morris Water Maze (MWM), a cognitive-behavioural task, were examined and pooled with Forest Plots for overall effect (95% CI) and heterogeneity (I2). Weighted meta-regression of the prebiotic-neurodegeneration association with other continuous parameters such as treatment duration, study sample size and year of publication were assessed for potential confounding associations. Risk of Bias (RoB) for animal studies was assessed by the SYRCLE tool. Publication bias was analysed by the Begg-Mazumdar funnel plot. The potential conflict of interest in the source of funding was examined by subgroup analysis. Results 5 human studies on aged healthy volunteers were found. 23 animal studies were identified, with 9 animal studies having comparable quantitative results (149 subjects). Overall results in figure 1 demonstrate a 17.69 sec (11.71–23.67; I2: 96.8) improvement in MWM Escape Latency, suggesting an improvement in neurocognitive function in animal models. Meta-regression revealed that prebiotic-neurodegeneration association is independent from duration of treatment (p=0.202), year of publication (p=0.184); and sample size (p=0.0685). RoB analysis of animal studies on prebiotics shows that there is a risk for bias in terms of study personnel blinding and random housing and outcome assessment of subjects. An asymmetric distribution that is largely beyond the 95% CIs was observed in the Begg-Mazumdar funnel plot. 4 privately-funded studies had significantly weaker association of 12.67s (3.18–22.17) than 5 government-funded studies 21.61s (15.26–27.97). Conclusions Weak evidence suggests that prebiotic supplementation is useful in attenuating age-related neurocognitive decline, thus requiring more clinical trials to evidence its true efficacy.