Exotic and protective: kiwi increases vitamin C in the skin
Daily kiwi intake increases ascorbate levels in the skin, improving skin density and cell proliferation
A new study reveals the direct connection between kiwi intake, rich in vitamin C (ascorbic acid), and an increase in this vitamin in human skin. This finding highlights the importance of considering diet in skin health, opening avenues for new skincare practices and slowing the visible effects of aging. Vitamin C is found in the dermis and epidermis, fulfilling antioxidant functions and playing a role in collagen synthesis. The difference in concentration between the two layers suggests a more efficient approach for skin treatments. Topical products face obstacles in delivering vitamin C into the skin, underscoring the need for dietary methods to maximize its benefits. Previously, numerous nutritional intervention studies had monitored the effect of oral ascorbate intake on skin function, but without measuring ascorbate content in the skin. Dietary supplementation with kiwifruit: Research demonstrates that daily kiwifruit intake increases ascorbate levels in the skin, improving skin density and cell proliferation, although some benefits such as elasticity do not show significant improvements. The study confirms that dietary ascorbate is absorbed through transporters in the skin, highlighting the ability of diet to influence skin health at a cellular level. In vitro studies indicate that ascorbate promotes collagen synthesis by fibroblasts and eliminates... free radicals generated by ultraviolet radiation and stimulates the proliferation and differentiation of keratinocytes, processes fundamental to skin thickness and its anti-aging benefits.
Clinical Implications
The findings suggest that incorporating kiwi into the diet could serve as an effective strategy to improve skin health.
A holistic approach combining diet with skin care practices is recommended.
Kiwifruit Compared to Other Supplements
Kiwifruit offers skin effects comparable to vitamin C supplements, primarily due to its high vitamin C content (up to 250 mg in two kiwifruits daily), which promotes collagen production and cell regeneration, increasing epidermal thickness after eight weeks of consumption.
Vitamin C supplements raise plasma levels rapidly (within two weeks), saturating them similarly to kiwifruit, but they lack the fruit's synergistic compounds, such as vitamin E in the peel, which enhance skin repair. Both maintain optimal levels with 250 mg daily, but kiwifruit promotes natural and multifaceted absorption for firmer skin. Other sources such as citrus fruits or peppers achieve similar effects, although kiwi stands out for its concentration.
Amount of kiwi needed
Consuming 1 to 2 kiwis daily is the recommended amount to obtain optimal benefits for the skin, according to studies on their high vitamin C and antioxidant content.
Studies show that 2 kiwis a day raise plasma levels of vitamin C to optimal levels (around 200 mg), improving DNA protection and reducing lipid peroxidation, with visible effects in 3-4 weeks. A smaller amount, such as half a kiwi, does not achieve these benefits.
Among the practical tips, it is recommended to include fresh kiwis in breakfast or as a snack, and avoid exceeding 3 units to prevent digestive effects in sensitive individuals.
Combine them with a balanced diet to maximize hydration and your skin's natural glow.
The kiwi (Actinidia deliciosa) is considered an exotic fruit, not widely cultivated. It originated in China, specifically the Yangtze River Valley, and was introduced to New Zealand in 1904, where it became popular and was commercialized starting in the 1930s. There, it adopted its current name due to its similarity to New Zealand's national bird.
Although its cultivation has spread to countries like Italy, Greece, Chile, and Spain since the 1960s and 70s, it is still classified as exotic due to its distant origin, sweet-and-sour tropical flavor, and characteristic fuzzy skin. In Europe, local producers, such as those in the Atlantic, have increased its accessibility, but it retains that exotic perception.