Enhanced human neutrophil vitamin C status, chemotaxis and oxidant generation following dietary supplementation with vitamin C-rich SunGold kiwifruit.
Level 4 - case-series / case-control
Uncontrolled single-arm before-and-after interventional study
PubMed 25912037 · doi:10.3390/nu7042574
What was done
Fourteen young men aged 18 to 30 years with suboptimal plasma vitamin C concentrations (<50 μmol/L) consumed two SunGold kiwifruits per day for four weeks. Plasma vitamin C status was measured weekly. Neutrophil vitamin C content and four neutrophil functional parameters (chemotaxis, oxidant generation, extracellular trap formation, and spontaneous apoptosis) were assayed ex vivo at baseline and after four weeks of supplementation.
What was found
Plasma vitamin C levels increased from suboptimal baseline levels to >70 μmol/L within one week (p < 0.001). Neutrophil vitamin C status rose significantly after four weeks (p = 0.016). Post-intervention neutrophil chemotaxis increased by 20% (p = 0.041), and oxidant generation increased by a comparable magnitude (p = 0.031). Neutrophil extracellular trap formation and spontaneous apoptosis were unchanged.
Why it matters
This study demonstrates that consuming whole vitamin C-rich fruit can normalize intracellular vitamin C in immune cells and enhance key neutrophil defensive functions in individuals with suboptimal baseline status.
Limits
The study is limited by a very small sample size (n = 14) and a single-arm, uncontrolled design with no placebo or non-supplemented comparator group. The cohort was restricted entirely to young adult males with low baseline vitamin C. Outcomes were measured ex vivo, leaving clinical effects on infection rates or immune resilience unassessed.
Cited by
- supports Human studies have shown that vitamin C can enhance neutrophil function in young men aged 18 to 30 as well as in older women.