Researchers from the University of Otago’s Faculty of Medicine in Christchurch Ōtautahi have uncovered a strong link between dietary vitamin C consumption and the skin’s ability to generate collagen while promoting its own renewal processes. These discoveries indicate that the condition of the skin can be tangibly improved through higher vitamin C intake from food sources, extending beyond the effects of merely applying it topically.
Elevating Vitamin C Through Diet Increases Skin Density and Vitality
The investigation, detailed in the Journal of Investigative Dermatology, revealed that vitamin C concentrations in the skin align closely with those measured in the bloodstream, known as plasma levels. By incorporating more vitamin C-packed foods into their diets, participants successfully elevated both their blood and skin vitamin C levels.
This study tracked 24 healthy individuals from Aotearoa New Zealand and Germany. Those who boosted their plasma vitamin C by consuming two SunGold kiwifruits daily experienced a noticeable rise in skin vitamin C. Such elevations correlated with enhanced skin thickness, signaling boosted collagen synthesis, and accelerated turnover in the outermost skin layer.
Professor Margreet Vissers, the lead researcher from the Mātai Hāora Centre for Redox Biology and Medicine in the Department of Pathology and Molecular Medicine, called these outcomes remarkably impressive. She highlighted the persuasive nature of the connection between vitamin C consumption and skin thickness improvements.
Vitamin C Travels Efficiently from Bloodstream to Skin Layers
Professor Vissers pointed out that the synchronization between vitamin C in the blood and in the skin was more pronounced than in other tissues examined. “We were taken aback by how closely plasma vitamin C levels matched those in the skin—this linkage was far stronger than what we’ve observed in any other organ,” she noted.
The team further demonstrated that vitamin C present in the circulation effectively permeates every stratum of the skin, fostering superior skin performance. “Our work is pioneering in showing that circulating vitamin C infuses all skin layers and correlates with better skin health. I’m immensely proud of my team’s efforts and thrilled by the insights from this data,” she added.
Why Nutritional Sources Outperform Topical Applications
These results underscore Professor Vissers’ view that optimal skin wellness originates from within, nourished by nutrients transported via the bloodstream. As a critical component for collagen formation—often why it’s included in cosmetics—vitamin C’s water-soluble nature hinders its penetration through the skin’s protective barrier. Yet, the study illustrated that skin cells excel at taking up vitamin C directly from the blood, prioritizing absorption into the epidermis.
Details of the Research Methodology
Supported by Zespri International from New Zealand, a University of Otago Research Grant, the project unfolded in two distinct stages. Initially, scientists analyzed the interplay between plasma and skin vitamin C using healthy skin biopsies from patients in elective surgeries at Te Whatu Ora Canterbury, aided by the Otago campus’s He Taonga Tapu Canterbury Cancer Society Tissue Bank.
The subsequent stage was a meticulously controlled dietary trial conducted in Christchurch and Germany, each site involving 12 healthy volunteers.
An Eight-Week Commitment to Kiwifruit Consumption
Over eight weeks, participants incorporated two Kiwifruit Gold kiwis into their daily routine, delivering approximately 250 milligrams of vitamin C. “Everyone followed the protocol of eating two Kiwifruit Gold kiwis each day—equating to 250 milligrams of vitamin C—for the full eight weeks. We gathered skin samples at the start and end, conducting specialized analyses: basal skin layers in Christchurch, and outer dermal layers plus functional tests in Germany,” Professor Vissers elaborated.
In Germany, volunteers were enlisted and assessed by the SGS Institute Fresenius in Hamburg, equipped to harvest samples from the outer dermal layer via a blister technique. They measured skin regeneration through ultrasound for thickness and elasticity, alongside UV protection and epidermal cell turnover rates to gauge comprehensive skin health.
Significant Improvements in Collagen Synthesis and Epidermal Turnover
A standout result was the documented thickening of participants’ skin, a clear marker of heightened collagen production paired with quicker epidermal cell regeneration. “Another key discovery was the substantial uptick in skin thickness among participants, which points to enhanced collagen creation and a marked acceleration in epidermal cell renewal—essentially, revitalized skin,” Professor Vissers stated.
Broader Food Options for Comparable Skin Advantages
The choice of SunGold kiwifruit stemmed from its reliable high vitamin C levels. Nonetheless, the researchers anticipate parallel advantages from various vitamin C-abundant foods, particularly fresh produce like citrus fruits, berries, bell peppers, and broccoli.
“We believe that ramping up your vitamin C through diet will ensure its effective delivery to every part of the skin,” Professor Vissers affirmed.
Consistency in Daily Vitamin C Consumption Is Crucial
Sustaining consistent blood vitamin C levels is vital, given the body’s inability to stockpile it over extended periods. Professor Vissers advises that healthy people can attain ideal plasma concentrations with roughly 250 milligrams daily. “The key is maintaining optimal plasma levels, achievable for healthy individuals with about 250 milligrams of vitamin C each day. Since storage isn’t possible, we advocate for five-plus servings of fruits and vegetables daily, including one rich in vitamin C, as an excellent ongoing practice.”
