Natural Skin Collagen Support Through Vitamin C-Rich Diets

A landmark study led by researchers at the University of Otago, Faculty of Medicine – Christchurch Ōtautahi, has demonstrated that skin collagen production and renewal are directly influenced by the amount of vitamin C consumed through diet.

Published in the Journal of Investigative Dermatology, the research reveals a strong relationship between vitamin C levels in the blood (plasma) and the concentration of the vitamin in the skin. The findings confirm that increasing dietary intake—particularly through fruit—can significantly raise vitamin C levels within skin tissue.

The study involved 24 healthy adults from Aotearoa New Zealand and Germany and showed that consuming two vitamin C–rich SunGold™ kiwifruit daily led to higher plasma vitamin C levels. This increase was mirrored in the skin, resulting in improved skin thickness, enhanced collagen synthesis, and accelerated regeneration of the outer skin layers.

Lead author Professor Margreet Vissers, from Mātai Hāora – Centre for Redox Biology and Medicine within the Department of Pathology and Molecular Medicine, described the relationship between vitamin C intake and skin thickness as particularly striking.

The researchers observed an unusually strong correlation between plasma and skin vitamin C levels—stronger than what has been previously identified in other organs. Notably, the study is the first to show that vitamin C circulating in the bloodstream is absorbed into all layers of the skin, contributing to improved skin structure and function.

Professor Vissers explained that the findings reinforce the idea that skin health is supported from within. While vitamin C is widely used in topical skincare products to stimulate collagen, its ability to penetrate the skin barrier is limited. In contrast, the study shows that the skin efficiently absorbs vitamin C delivered through the bloodstream, with priority uptake into the outer epidermal layer.

The research was supported by Zespri International and a University of Otago Research Grant and was conducted in two phases. The first phase established the relationship between plasma and skin vitamin C using healthy skin tissue collected during elective surgical procedures at Te Whatu Ora Canterbury, with assistance from the He Taonga Tapu – Canterbury Cancer Society Tissue Bank.

The second phase involved an eight-week dietary intervention conducted in Christchurch and Germany, with 12 participants at each site. All participants consumed two Gold kiwifruit per day, providing approximately 250 mg of vitamin C daily. Skin samples were collected before and after the intervention to assess changes at different skin depths.

In Germany, participants were recruited and assessed by the SGS Institute Fresenius in Hamburg, which has specialized expertise in collecting outer dermal skin layers. Comprehensive skin function testing included ultrasound-based measurements of skin thickness and elasticity, UV protection, and epidermal cell renewal.

One of the most significant outcomes was a marked increase in skin thickness, indicating enhanced collagen production, along with increased regeneration of epidermal cells—clear evidence of improved skin renewal.

Although SunGold™ kiwifruit was selected due to its exceptionally high vitamin C content, the researchers anticipate that other vitamin C–rich foods—such as citrus fruits, berries, capsicum, and broccoli—would deliver similar benefits.

The study concludes that raising dietary vitamin C intake supports efficient delivery of the nutrient to all layers of the skin. Maintaining optimal plasma vitamin C levels—around 250 mg per day—is key, as the body does not store the vitamin. For this reason, the researchers recommend consuming five or more servings of fruits and vegetables daily, including at least one high–vitamin C food, to consistently support skin health.

Source: University of Otago
ImageCredits: Freepik