Kiwifruit Intake Enhances Skin Vitamin C Levels and Strengthens Dermal Structure: Study - Video

Vitamin-C is more than just an immunity booster-it's one of the skin's most powerful natural defenders. A new study in the Journal of Investigative Dermatology reveals how dietary vitamin C directly changes the skin from within, reshaping both its structure and function. The research shows that eating vitamin C–rich foods like kiwifruit can increase ascorbate concentration across all skin layers, subtly improving skin density and cellular renewal.

Vitamin C (ascorbic acid) is essential for collagen production, antioxidant defense, and skin repair. It exists in both the dermis (the collagen-rich inner layer) and the epidermis (the outer layer where new cells form). While topical serums are popular, they struggle to deliver stable and active vitamin C across the skin’s tough outer barrier. The human body instead relies on active transport proteins—SVCT1 and SVCT2—to absorb vitamin C from the bloodstream into the skin. Until now, however, there has been little data on how dietary intake influences vitamin C levels in different skin compartments.

To fill this gap, researchers measured vitamin C levels in dermal and epidermal tissue samples from healthy adults and then ran a dietary intervention where participants consumed about 250 mg of vitamin C daily through kiwifruit. Blood and skin samples were analyzed using advanced chromatography and imaging to track changes in ascorbate distribution and skin physiology.

Results showed striking differences between skin layers. Dermal fibroblasts contained roughly seven times more vitamin C than epidermal cells, similar to levels found in the brain and adrenal glands—suggesting an intense need for the nutrient in collagen production. After supplementation, participants with initially low plasma vitamin C reached full saturation, and skin density increased by 50%, reflecting better structural protein content. These increases were confirmed through both biopsy samples and noninvasive blister-fluid analysis, showing synchronized rises in plasma and skin ascorbate.

While elasticity dropped slightly and no measurable jump in collagen peptides was seen, the study confirmed a key takeaway: dietary vitamin C effectively reaches all skin compartments, boosting renewal and structure. The authors conclude that maintaining steady vitamin C intake—through fruits like oranges, kiwifruit, or peppers—supports healthy skin from the inside out, offering real biological benefits beyond the cosmetic aisle.

REFERENCE: Pullor, J. M., Bozonet, S. M., Segger, D., et al. (2025). Improved Human Skin Vitamin C Levels and Skin Function after Dietary Intake of Kiwifruit: A High-Vitamin-C Food. Journal of Investigative Dermatology. doi: 10.1016/j.jid.2025.10.587, https://www.jidonline.org/article/S0022-202X(25)03509-2/fulltext