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. Vitamin C is required in all body tissues for optimal activity of a number of essential biosynthetic and regulatory enzymes. We are particularly interested in the role that vitamin C may play in immunity and fertility, through enhancement of white blood cell (neutrophil) and sperm function. Kiwifruit are an outstanding commonly available source of vitamin C. We have recently carried out human intervention studies investigating the bioavailability of kiwifruit-derived vitamin C. We found that two kiwifruit per day were required to saturate plasma and thus provide “optimal” vitamin C levels. Neutrophil and seminal vitamin C levels were also increased significantly with two kiwifruit per day. Furthermore, we have shown that kiwifruit-derived vitamin C has equivalent bioavailability to synthetic vitamin C supplements. The aim of our current study is to investigate the effects of kiwifruit-derived vitamin C on neutrophil and sperm function. We will supplement young men low in vitamin C with two kiwifruit per day for one month and measure neutrophil and sperm function before and after intervention. Specifically, we will determine the effects of the intervention on neutrophil cell death, bacterial killing, formation of extracellular traps and neutrophil chemotaxis. We will also determine the effects of the intervention on specific sperm parameters such as viability, motility, agglutination, mitochondrial function, markers of oxidative stress, and chromatin structure. The vitamin C status of the participants’ blood plasma will be monitored weekly for the duration of the study. Overall, the proposed study will provide valuable information as to how vitamin C affects neutrophil and sperm function and thus potentially impact on immunity and fertility.
Interventions
Participants will be supplemented with two export-grade gold kiwifruit/day for four weeks. Compliance will be monitored by measuring plasma vitamin C levels every week.
An extension period will comprise supplementation with 250 mg/d vitamin C tablets for two months. Compliance will be determined by counting remaining tablets.
Sponsors
University of Otago, Christchurch
Study design
Allocation
Non-randomised trial
Primary purpose
Educational / counselling / training
Eligibility
Sex/Gender
Male
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
Male aged 18-35 years Non-smoker Plasma vitamin C <50 umol/L Residing in Christchurch for the duration of the study
Exclusion criteria
allergy/intollerance to kiwifruit recent smoker (within previous year) taking vitamin C supplements (within past 3 months) taking prescription medication (within past 3 months) excessive alcohol consumption (>21 std drinks/week) high fruit and vegetable consumption (>5 servings/d) diabetes mellitus bleeding disorgers fainting due to fear of needles
Outcome results
None listed