synbiotic supplementation and its effects on cognition in alzheimer’s patients: a double-blind study

Introduction: dementia is a progressive neurodegenerative disorder and a significant healthcare concern increasing worldwide. the modulation of the gut-brain axis by gut microbiota might have favorable effects on ameliorating cognitive decline. we aimed to investigate whether synbiotics administration could enhance cognition and function in older adults with non-severe alzheimer’s disease (ad). methods: this study was designed as a randomized, placebo-controlled, double-blind clinical trial to test the effects of synbiotic supplementation for 90 days (between august 2019 and february 2021). a synbiotics formulation or placebo was randomly allocated to older outpatients with mild to moderate ad. the intervention group took two capsules daily containing a mixture of 7 bacterial strains as probiotics and a prebiotic for 12 weeks. mini-mental state examination (mmse) and barthel index evaluated participants’ cognition and functional status. pre-intervention and post-intervention fasting blood samples were obtained to compare their serum albumin (alb), fasting blood sugar (fbs), 25(oh) vitamin d, and lipid profile.results: a total of 60 patients with a mean age of 77 years were recruited. after 12 weeks of synbiotic supplementation, no significant improvement was detected in the mmse score (p=0.53) and barthel index (p=0.43). furthermore, metabolic parameters including fbs (p=0.92), triglyceride (p=0.48), total cholesterol (p=0.74), high-density lipoprotein (hdl) (p=0.54), low-density lipoprotein (ldl) (p=0.79), serum alb (p=0.28) and 25(oh) vitamin d levels (p=0.67) were not different before and after synbiotic administration. conclusion: this study does not support the idea that short-term synbiotic supplementation could enhance cognitive and physical function in older patients with mild to moderate ad.