The effects of Lactobacillus and/or Bifidobacterium in fermented foods on cognitive health

Background: Psychobiotics are microorganisms that modulate brain function via the gut–brain axis and are increasingly studied for their cognitive benefits. Lactobacillus and Bifidobacterium species, widely present in fermented foods, are considered safe and may influence cognition by modulating neuroinflammation, neurotransmitters, and gut barrier integrity. This systematic review examined the effects of foods fermented with these species on cognitive performance in healthy adults and individuals with mild cognitive impairment. Methods: We conducted the systematic review following EFSA guidelines, Cochrane methodology, and a PROSPERO protocol, using CADIMA for study selection and data extraction. PubMed, Scopus, and Cochrane Library were searched (1 January 1970–31 August 2023) for human intervention and observational studies assessing cognitive outcomes after ingestion of foods fermented with Lactobacillus or Bifidobacterium. Eligible populations included healthy adults and individuals with mild cognitive impairment