Vitamin C 4 Care Homes: a Pilot and Feasibility Study to Assess Daily Vitamin C Requirement of Care Home Residents

This is a pilot dose-finding study comprising 20 older people ENRICH-listed care home residents (aged 65+). The feasibility of a larger study and a future trial recruitment will also be assessed.

The investigators will invite care homes to participate in the study by approaching care homes that have expressed interest in hosting research studies as research sites via care home network ENRICH (https://enrich.nihr.ac.uk/joining-the-network/). Flyers will also be provided (VitaC4Care_ V.3 14.09.21 Flyer) to raise interest.

Each participant, with the assistance of a care home staff member, will complete a two-part questionnaire at the beginning of the study and at the end. The first part of the questionnaire will include recordings of age, weight/height, date of admission to care home and date of completion of the present questionnaire, co-morbidities (specifically hypertension, diabetes, previous cerebrovascular accident or myocardial infarction, arthritis, Chronic obstructive pulmonary disease or asthma, active malignancy, and type), regular medication (specifically omeprazole, diabetic medication and type, aspirin, diuretics and type, and statins). The first-part questionnaire will include free text spaces for the addition of other comorbidities or medications not mentioned above. For the second part of the questionnaire, the participant will be required to complete a symptom record for the following symptoms: arthralgia (lay language as per patient questionnaire: sore joints), myalgia (sore muscles) ankle edema (puffy ankles), loss of appetite, peripheral paresthesia (pins and needles at hands or legs), dizziness, shortness of breath, malaise (tiredness), low mood, irritability. The participant will be required to state how often they experience these symptoms on a scale from 1 (Never) to 5 (All the time). The same questionnaire will be offered to the participants at the end of the study and symptom improvement, or deterioration will be recorded on a numerical scale. Furthermore, each participant (assisted by care home staff) will provide twelve urine samples over the course of up to four weeks which will be analysed for vitamin C content using a urine vitamin C test strip (VitaChek-C, Teco Diagnostics, USA) and creatinine/protein/Specific Gravity ((HomeHealth, UK). There will be six designated test days and the rest of the study period will be made up of break days when no samples will be collected. After each test day, three break days will be allowed to ensure participant comfort. If on a "testing" day, a second urine sample is not obtained, the same supplement concentration will be provided on the next "testing" day to ensure data completion.

On the test days, the participant will be asked to provide a urine sample before taking the supplement (Vitamin C 5000, NutriVital Food Supplement, made in UK by NutriVital Health, nutrivital.co.uk), this sample will be used as a baseline and assessed for Vitamin C and creatinine/protein and specific gravity, with the same testing strips as mentioned above. Once collected, the participant will be provided with a drink containing an increasing daily dose of vitamin C (0 - 500 mg; see study schedule in 3.2). The supplement will be encapsulated and either consumed as a pill or dissolved in a room temperature water drink prior to consumption.

A second urine sample will then be collected approx. 3 - 4 hours later to assess the extent of vitamin C excretion in urine with an increase in vitamin C supplement. Another urine test strip will also be used to determine creatinine concentrations (to standardize vitamin C values), presence of albumin/protein (to determine kidney function) and specific gravity (to determine urine concentration).