1. Introduction
cognitive impairment, inflammation, dementia, Alzheimer’s disease, cognitive impairments, AD
DEGENERATION, INFLAMMATION, NEURODEGENERATIVE DISEASES, OXIDATIVE STRESS, PATHOGENESIS
These authors contributed equally to this work.The role of neurotrophic factors, oxidative stress, and inflammation in the pathogenesis of Alzheimer’s disease (AD) has been explored. Animal studies have reported the positive effects of probiotics on these factors. Some clinical studies also support the potential role of probiotics in improving cognitive function via the gut–brain axis in older adults. However, clinical experimental studies evaluating the efficacy of probiotics targeting the neurotrophic factors and inflammatory biomarkers, particularly among AD patients, remain very limited. In this randomized, double-blinded, active-controlled trial, we used multi-strain probiotic supplements, including Population aging is a global concern. According to estimations by the United Nations, the global population aged 65 or older will double from 700 million in 2019 to 1.5 billion by 2050. Aging can affect the nervous system, and may lead to cognitive impairments, potentially resulting in dementia. Alzheimer’s disease (AD) is the most common form of dementia and may contribute to 60–70% of cases [In recent years, numerous studies have highlighted the relationship between the human gut microbiota and neurodegenerative diseases [In addition to the effects on BDNF, probiotics may also have other beneficial effects regarding the inflammation and oxidative stress which contribute to brain degeneration. Our previous study has shown that multi-strains of Most of the previous randomized controlled trials using probiotics as intervention were performed either among community-dwelling older adults, or subjects with mild cognitive impairment and dementia without specifically focusing on people clinically diagnosed with AD [Based on the aforementioned evidence and our previous study, we chose the multi-strain probiotics 