Inclusion Criteria:  be aged 55 years or over, voluntarily agree to participate in the study in accordance with the Helsinki declaration, not be participating in another study that could interfere with the results.  Exclusion Criteria:  suffer from any serious mental illness other than depression and anxiety, score below 10 on the Mini-Mental State Examination (MMSE) (severe cognitive impairment) be using medications that affect cognition, taking anti-inflammatory drugs, antipsychotics, antibiotics and/or anxiolytics, have a serious illness (e.g. cancer, Parkinson's or Alzheimer's).