Kiwi increases vitamin C levels and improves skin structure

The scientists measured the concentration of ascorbate in the dermis, epidermis and whole skin samples from healthy volunteers. The participants then received about 250 mg of vitamin C per day in the form of kiwi fruit. These actions allowed us to assess whether the level of vitamin C in the skin increases with an increase in plasma levels, and whether these changes are associated with an improvement in skin functions.

The analysis showed that dermal cells contain about seven times more vitamin C than epidermal cells. This concentration is comparable to levels in the adrenal glands and brain, where ascorbate acts as an important cofactor for enzymes, and probably plays a critical role in the synthesis of collagen by fibroblasts.

The main conclusion of the study is that the level of vitamin C in the blood is directly reflected in the level of vitamin C in the skin. After regular consumption of kiwi fruit, low-baseline participants achieved plasma saturation, and skin biopsies confirmed ascorbate growth in both the dermis and epidermis. Additional measurements using the bubble method (suction blister) showed that the skin actively captures vitamin C using specialized SVCT transporters.

Such physiological changes were accompanied by an improvement in the skin structure. During the intake of kiwi, the density of skin tissues increased from 0.15 to 0.23 conventional units, which indicates an increase in the content of structural proteins. The rate of renewal of epidermal cells has also increased. However, the elasticity of the skin decreased slightly, the UVA protection indicators did not change, and the level of procollagen I in skin fluids remained the same. The data suggest that the effect of vitamin C on collagen synthesis may be more subtle and is not always reflected in standard markers.

Overall, the study demonstrates that a diet rich in vitamin C really increases its concentration in all layers of the skin and supports its function.Regular intake of ascorbate with food can actually help strengthen the dermis, improve cell renewal and overall skin condition, although its capabilities in terms of anti-UV protection and direct increase in collagen synthesis are limited.