Inclusion Criteria:
* Aging between 60-80 years old
* Having normal vision and hearing
* Having a body mass index between 18.5 and 30
* Having mild to moderate subjective cognitive complaints
Exclusion Criteria:
* Smoking
* Having food allergies
* Following restrictive and/or unbalanced diets (Appendix 6: Are you vegetarian or vegan? Yes / No; Are you currently on a weight-reducing or other special diet? Yes/No If 'Yes', please give details.)
* Being diagnosed with any psychiatric or neurologic conditions (e.g. schizophrenia, depression, dementia) including eating disorders
* Being diagnosed with any cardiometabolic diseases (including type II diabetes and cardiovascular disease), or hypertension or thrombosis related disorders or suffer from thyroid disease
* Currently taking anticoagulants, antiplatelet medication, antidepressants, proton-pump inhibitors
* Currently consuming prebiotic or probiotic supplements
* Continuous antibiotic use for \> 3 days within 1 month prior to enrolment
* Continuous use of weight-loss drug for \> 1 month before screening
* Having a significant gastrointestinal (GI) condition affecting absorption including (but not limited to) inflammatory bowel disease; total colectomy or bariatric surgery; irritable bowel disease; end stage renal disease; active cancer, or treatment for any cancer, in last 3 years
* History of claustrophobia
* Fitted with a pacemaker or artificial heart valve
* Have active implants, such as cochlear, ocular, or penile implant
* Experience of metal fragments e.g. shrapnel in your eyes or any other part of your body
* Drug infusion pump installed
* Have any surgically implanted metal in any part of your body, other than dental fillings and crowns (e.g. joint replacement or bone re-construction)
* Have had any surgery that might have involved metal implants
* Current or historical experience of epilepsy
* Have stimulators for nerves, brain or bone installed
* Have an intrauterine contraceptive device installed (IUD)
* Wear transdermal patches containing metal
* Wear a filling, crown, dental post (entirely within the tooth) associated with root canal treatment, retainer, bridge or braces
* For scanning, would need to remove coloured contact lenses, nail polish and makeup.
* Hearing aid wearer
* Body piercings that you cannot or will not remove for the scanning session
* Have tattoos or permanent makeup
