Inclusion Criteria:  Aged between 65 - 80 Agree not to not consume probiotic or prebiotic supplements or live yoghurt throughout the course of study. Proficient in the English language  Exclusion Criteria:  Already a habitual user of probiotics Antibiotic treatment within last 3 months Current diagnosis of and not currently receiving treatment for mental health disorder Gastrointestinal disorder Allergic to any ingredient of the active or placebo treatment Regular smoker Diabetes mellitus