The crossover intervention will include 60 participants. Another 40 participants will only complete the first (baseline) visit. primaryPurpose: BASIC_SCIENCE masking: SINGLE whoMasked: INVESTIGATOR count: 100 type: ESTIMATED name: Fermented dairy name: Non-fermented dairy measure: Difference in change from baseline in defecation frequency between the interventions measure: Difference in change from baseline in cognitive performance between the interventions measure: Difference in change from baseline in phase-amplitude coupling between gastric slow-wave activity and cortical alpha activity between the interventions measure: Difference in change from baseline in whole gut transit time between the interventions measure: Difference in change from baseline in stool consistency between the interventions measure: Difference in change from baseline in stool moisture between the interventions measure: Difference in change from baseline in fecal abundance of Lactobacillus acidophilus between the interventions measure: Difference in change from baseline in self-reported gastrointestinal symptoms between the interventions measure: Difference in change from baseline in gut microbiota between the interventions measure: Difference in change from baseline in fecal pH between the interventions measure: Difference in change from baseline in breath hydrogen and methane levels between the interventions measure: Difference in change from baseline in biomarkers of colonic fermentation between the interventions measure: Difference in change from baseline in fecal short-chain fatty acids (SCFAs) between the interventions measure: Difference in change from baseline in fecal zonulin levels between the interventions measure: Difference in change from baseline in plasma levels of lipopolysaccharide-binding protein (LBP) between the interventions measure: Difference in change from baseline in gut metabolome between the interventions measure: Difference in change from baseline in urine metabolome between the interventions measure: Difference in change from baseline in plasma metabolome between the interventions measure: Difference in change from baseline in inflammatory biomarkers between the interventions measure: Difference in change from baseline in plasma levels of cortisol between the interventions measure: Difference in change from baseline in biomarkers of glucose and lipid metabolism between the interventions measure: Difference in change from baseline in appetite hormones between the interventions measure: Difference in change from baseline in plasma level of Brain Derived Neurotrophic Factor (BDNF) between the interventions measure: Difference in change from baseline in self-reported stress and mood between the interventions measure: Difference in change from baseline in self-reported sleeping patterns between the interventions measure: Difference in change from baseline in resting-state cortical connectivity between the interventions measure: Difference in change from baseline in event-related potentials evoked by a cognitive task between the interventions measure: Difference in change from baseline in quality of life between the interventions measure: Difference in change from baseline in habitual diet between the interventions sex: FEMALE minimumAge: 45 Years maximumAge: 65 Years stdAges: ADULT stdAges: OLDER_ADULT facility: University of Copenhagen, Department of Nutrition, Exercise and Sports status: RECRUITING city: Copenhagen country: Denmark name: Henrik M Roager, PhD role: CONTACT email: hero@nexs.ku.dk name: Anke Karabanov, PhD role: SUB_INVESTIGATOR lat: 55.67594 lon: 12.56553 hasResults: False