Healthcare (Commonwealth Union) – A new study from the University of Otago’s Faculty of Medicine in Christchurch Ōtautahi has revealed that the body’s ability to produce collagen and renew skin is directly influenced by how much vitamin C a person consumes.
Published in the Journal of Investigative Dermatology, the research reports that vitamin C levels in the skin closely mirror the amount found in the bloodstream — and can be raised simply by eating more fruit.
The project, involving around two dozen healthy adults in both Aotearoa New Zealand and Germany, found that lifting plasma vitamin C levels by eating two SunGold kiwifruit a day significantly increased the vitamin’s concentration in the skin. This boost supported thicker skin through enhanced collagen production, and promoted faster regeneration of the outer skin layer.
Professor Margreet Vissers, lead author and researcher at Mātai Hāora – Centre for Redox Biology and Medicine in the Department of Pathology and Molecular Medicine, indicated that the link between vitamin C intake and skin thickness is striking.
Professor Vissers further indicated that they were astonished by the tight correlation between plasma vitamin C levels and those in the skin – this was much more marked compared to any other organ they had looked into.
“We are the first to demonstrate that vitamin C in the blood circulation penetrates all layers of the skin and is associated with improved skin function. I am very proud of my team and excited about what the data is telling us.”
Professor Vissers says the findings indicate that healthy skin truly starts from within, as vitamin C supports skin processes by reaching the skin through the bloodstream — the way the body naturally transports it.
She indicated that they are already aware that vitamin C is essential for making collagen, which is the reason it is included in so many skincare products, the problem is that vitamin C dissolves easily in water and doesn’t pass through the skin’s outer layer very well. Professor Vissers further indicated that their research demonstrates that the skin is actually very efficient at drawing vitamin C from the blood instead and it even appears that the outer layer of the skin, the epidermis, is given priority when absorbing it.
The study was funded by New Zealand company Zespri International and a University of Otago Research Grant, and it was carried out in two phases. The first phase looked at how vitamin C levels in the blood relate to levels in the skin, using healthy tissue donated by patients undergoing planned surgeries at Te Whatu Ora Canterbury, with help from the Otago campus’s He Taonga Tapu – Canterbury Cancer Society Tissue Bank.
The second phase was a before-and-after dietary trial in which participants increased their vitamin C intake. This stage was conducted at two locations — Christchurch and Germany — and included 12 healthy volunteers at each site.
Professor Vissers indicated that all participants were asked to eat two Gold Kiwi fruit each day—providing about 250 micrograms of vitamin C—for a period of eight week. She indicated that the skin samples were taken both before and after this phase, with different laboratories examining different layers: researchers in Christchurch focused on the deeper basal layers of the skin, while a team in Germany studied the outer dermal layer and carried out various skin function assessments.
The German group was recruited and assessed by the SGS Institute Fresenius in Hamburg, whose facilities enable them to collect the outer dermal layer (the blister ‘roof’). The Institute evaluated how well the skin samples repaired themselves—using ultrasound to assess thickness, elasticity, UV resilience, and the renewal of epidermal cells—offering a thorough view of overall skin health.
