An Investigation Into the Feasibility of Beetroot Juice Supplementation in People Living With Alzheimer's Disease.

Participants will be supported by a carer, friend or family member to complete a semi-structured interview to assess how feasible the trial was. Questions will be based around adherence (e.g. was the beetroot juice taken consistently and at the right times), acceptability/safety (e.g. was the beetroot juice tolerable and would they consider doing it daily if the benefits were proven and were there any adverse effects) and data collection feasibility (e.g. how easy was it to collect and post saliva samples themselves and how much of a burden was the pre and post-testing). Simple Likert scales will also be used to assess acceptability of the beetroot juice.

An oral swab will collect bacteria from the tongue to analyse changes in the relative abundance of bacteria (%). Particular interest will be paid to pathogenic and nitrate reducing bacteria. Higher abundances of pathogenic bacteria and lower abundances of nitrate reducing bacteria indicate poorer oral health.

Cognitive function will be assessed pre and post-intervention through the use of Montreal Cognitive Assessment. A different version of the questionnaire will be completed pre and post. Higher scores indicate better cognitive performance.

Blood will be collected and analysed for arginine levels (µM). Higher nitric oxide levels can mean better health however, the inclusion of iNOS measurements is to determine the source of the nitric oxide i.e. whether it's inflammatory based, or health based.

Saliva and blood will be collected and analysed for nitric oxide levels (µM). Higher nitric oxide levels can mean better health however, the inclusion of iNOS measurements is to determine the source of the nitric oxide i.e. whether it's inflammatory based, or health based.

Blood will be collected for arginase activity (µmol/min/mg protein). Higher arginase activity could mean better health however, the inclusion of iNOS measurements is to determine the source of the nitric oxide i.e. whether it's inflammatory based, or health based.

Blood will be collected to analyse inducible nitric oxide synthase (iNOS) activity (relative fold change). Higher iNOS activity indicates greater levels of inflammation.

Pulse wave analysis (augmentation index %) will be measured with lower scores considered better.

Body mass index (kg/m²) will be calculated by measuring height (m) and weight (kg).

Blood pressure (mmHg) will be measured with 120/80 considered normal.

Exercise capacity will be measured with a 2-minute step in place test (more steps indicates a higher fitness level).

The International Physical Activity Questionnaire will be used to determine whether their physical activity levels change over the course of the intervention.

Quality of life will be measured using Dementia Quality of Life questionnaire (DEMQOL). Higher scores indicate a higher quality of life.