None listed
Conditions
Brief summary
There is widespread belief in the general population that vitamin C supports the immune system, and claims along this line are frequently encountered, including on marketing promoting commercially available dietary supplements. One of the main drivers of this interest is that leukocytes accumulate the vitamin to high intracellular concentrations, signalling an important role for it in these cells. We will recruit individuals with low vitamin C status as indicated by a plasma vitamin C level <40 µmol/L. Participants will be randomised to be supplemented with two Sungold kiwifruit per day or a placebo tablet per day for four weeks. Two kiwifruit is equivalent to ~250 mg vitamin C per day and is sufficient to achieve plasma saturation within one week of beginning supplementation. Blood samples will be taken before and after the intervention period to monitor plasma vitamin C status, white blood cell vitamin C levels and white blood cell immune functions.
Interventions
This trial is a randomised human intervention study to determine the effect of dietary supplementation with 2 SunGold kiwifruit per day or placebo tablet on the function of mononuclear immune cells (monocytes and lymphocytes). We will screen prospective participants for low plasma vitamin C status (likely due to low daily fruit and vegetable intake) and will randomly allocate the enrolled participants to either a daily kiwifruit intervention or a placebo tablet. The period of the intervention is
This trial is a randomised human intervention study to determine the effect of dietary supplementation with 2 SunGold kiwifruit per day or placebo tablet on the function of mononuclear immune cells (monocytes and lymphocytes). We will screen prospective participants for low plasma vitamin C status (likely due to low daily fruit and vegetable intake) and will randomly allocate the enrolled participants to either a daily kiwifruit intervention or a placebo tablet. The period of the intervention is 4 weeks. Adherence to the assigned condition will be monitored by laboratory testing of blood plasma vitamin C status at baseline, mid-point at end of the intervention period, and by quantifying fruit/tablet return.
Sponsors
University of Otago, Christchurch
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
Inclusion criteria (all required): Males or females 18-65 years; Plasma vitamin C levels <40 µmol/L at baseline.
Exclusion criteria
Exclusion criteria (one required); Taking prescription medication (within past three months); Allergy/intolerance to kiwifruit; Daily smoker: Taking vitamin C supplements (within past three months); High fruit/juice & vegetable consumption (5 or more servings/day); Excessive alcohol consumption (more than 21 standard drinks/week); Diabetes mellitus; Bleeding disorders; Fear of needles.
Outcome results
None listed