None listed
Conditions
Brief summary
Vitamin C is an essential nutrient which is not produced in humans and consequently must be obtained through dietary sources. Kiwifruit is an outstanding commonly available source of vitamin C, one serving providing about twice the recommended daily intake of the vitamin. We are proposing to investigate the uptake of vitamin C from kiwifruit compared with a vitamin C supplement using a randomised parallel groups study design. We will screen individuals for low vitamin C status and each participant will be randomised to receive either kiwifruit or a vitamin C supplement. The vitamin C status of the participant’s blood plasma will be measured regularly as an indication of dietary intake of the vitamin. Food and beverage records will also be filled out periodically to monitor the participant’s dietary intake of the vitamin. The vitamin C levels of urine, semen, white blood cells and muscle tissue will be measured at the beginning and end of the supplementation period to determine cellular accumulation and excretion of the vitamin. Overall, the proposed study will provide valuable information as to how the body accumulates and stores vitamin C, and whether or not a food source of the vitamin is preferred over a dietary supplement.
Interventions
Arm 1 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - gold kiwifruit (half/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 2 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - chewable vitamin C tablet (45mg/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 3 - baseline period (4 weeks) to monitor dietary int
Arm 1 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - gold kiwifruit (half/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 2 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - chewable vitamin C tablet (45mg/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 3 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - gold kiwifruit (two/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels.
Sponsors
Margreet Vissers
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
Male aged 18-30 years Non-smoker Low/below average plasma vitamin C levels (<40 uM) Residing in Christchurch for the duration of the study
Exclusion criteria
Recent smoker (within previous year) Allergy/intolerance to kiwifruit Taking vitamin C containing supplements (within past three months) Excessive alcohol consumption (>21 standard drinks/week) High fruit and vegetable consumption (>5 servings/day) Diabetes mellitus Bleeding disorders Obese (>35 kg/m2) Fear of needles
Outcome results
None listed