We really are what we eat.
Vitamin C from food, particularly vitamin C-rich SunGold kiwifruit, boosts collagen levels in skin, a new study suggests.
Researchers at the University of Otago in New Zealand looked at how increasing fruit intake affects blood levels of the vitamin C in 24 healthy adults in New Zealand and Germany. They found that boosting plasma levels by consuming two SunGold kiwifruit per day increases the amount of the vitamin in the skin, improving collagen production and stimulating renewal and regeneration of the skin’s outer skin layer.
“We were surprised by the tight correlation between plasma vitamin C levels and those in the skin – this was much more marked than in any other organ we have investigated,” says Lead Author Margreet Vissers,
BSc(Hons)(Cant), MSc, PhD(Otago), a Professor at the Centre for Redox Biology and Medicine within the Department of Pathology and Molecular Medicine at the University of Otago, in a news release. “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.
“We know that vitamin C is required for collagen production. This fact has inspired the addition of vitamin C to many skin cream formulations. However, vitamin C is highly water soluble and poorly absorbed through the outer skin barrier. Our study shows that the skin is extremely good at absorbing vitamin C from the blood circulation. Uptake into the outer epidermal skin layer also seems to be prioritized,” she continues.
The study comprised two stages. The first stage established the association between plasma and skin vitamin C levels, using healthy skin tissue from patients undergoing elective surgical procedures. The second stage involved a before-and-after, dietary vitamin C intervention study at two sites each with 12 healthy participants.
“All were instructed to consume two Kiwi Gold kiwifruit daily – the equivalent of 250 micrograms of vitamin C – for eight weeks. We then collected skin samples before and after the intervention, with separate analyses allowing us to look at the skin basal layers in Christchurch and the outer dermal skin layer and skin function tests in Germany,” Vissers explains.
The German participants were recruited and tested by the SGS Institute Fresenius in Hamburg. The Institute measured skin sample regeneration – including ultrasound tested measures of skin thickness, elasticity UV protection and renewal of epidermal cells – for a full picture of skin function.
“We suggest that increasing your dietary vitamin C intake will result in effective vitamin C uptake into all compartments of the skin,” Vissers says. “The important thing is to keep your plasma levels optimal, which we know can be easily achieved in a healthy person with a vitamin C intake of around 250mg per day. The body however does not store the vitamin, so we recommend five+ a day, every day, with one of those five being a high vitamin C food, as a good habit to cultivate.”
The study is published in the Journal of Investigative Dermatology.
