{"id":221086,"date":"2025-12-08T02:07:13","date_gmt":"2025-12-08T02:07:13","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/221086\/"},"modified":"2025-12-08T02:07:13","modified_gmt":"2025-12-08T02:07:13","slug":"kiwifruit-intake-boosts-vitamin-c-in-skin-and-supports-dermal-structure","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/221086\/","title":{"rendered":"Kiwifruit intake boosts vitamin C in skin and supports dermal structure"},"content":{"rendered":"

By directly measuring vitamin C inside human skin, researchers show that diet can boost skin vitamin C content and influence skin structure, while also revealing clear limits to its effects on collagen formation and UV protection.<\/strong><\/p>\n

\"Letter<\/a><\/p>\n

Letter to the Editor: Improved Human Skin Vitamin C Levels and Skin Function after Dietary Intake of Kiwifruit: A High-Vitamin-C Food<\/a>. Image Credit: Meomeow \/ Shutterstock<\/p>\n

Vitamin C (ascorbic acid) is widely promoted for supporting collagen production and skin health, yet little is known about how oral intake changes dermal or epidermal ascorbate concentrations. A new study in the\u00a0Journal of Investigative Dermatology<\/strong><\/a> directly examines how skin compartments respond to dietary ascorbate and whether these changes translate into measurable improvements in skin function.<\/p>\n

Distinct Roles of Dermal and Epidermal Vitamin C<\/p>\n

Vitamin C is present in both skin layers: the collagen-rich dermis and the highly cellular epidermis. As an antioxidant, ascorbate neutralizes ultraviolet-induced free radicals, protects against oxidative stress, and stimulates both fibroblast collagen synthesis and keratinocyte proliferation, processes central to skin thickness and anti-aging benefits.<\/p>\n

Challenges of Topical Delivery and Dependence on Active Transport<\/p>\n

Topical products must stabilize dissolved ascorbate and deliver it across the stratum corneum, an effective barrier that complicates absorption. Systemically, the skin relies on sodium-dependent vitamin C cotransporters (SVCT1\/SVCT2) to actively import circulating ascorbate. Prior research has offered almost no data on dermal vs. epidermal ascorbate content or on functional consequences of dietary supplementation.<\/p>\n

Study Goal: Mapping Skin Ascorbate Across Compartments<\/p>\n

Researchers quantified ascorbate concentrations in dermis, epidermis, and whole skin from healthy adults. They also conducted a pilot dietary intervention using kiwifruit, providing ~250 mg\/day of vitamin C, to test whether increasing plasma ascorbate levels elevate skin ascorbate content and alter skin function outcomes.<\/p>\n

Dermal Cells Contain Far More Ascorbate Than Epidermal Cells<\/p>\n

Using per-cell measurements of DNA content, investigators found that the epidermis had 11-fold more DNA than the dermis, enabling cellular-level concentration estimates. Dermal fibroblasts contained ~6.4 mM ascorbate, whereas epidermal keratinocytes contained ~0.9 mM, a seven-fold difference. High dermal ascorbate parallels levels in adrenal and brain tissue, where ascorbate acts as an enzymatic cofactor, likely supporting robust collagen synthesis in fibroblasts.<\/p>\n

Plasma Vitamin C Strongly Predicts Skin Compartment Levels<\/p>\n

Whole-skin, dermal, and epidermal ascorbate concentrations rose proportionally with blood ascorbate. In the kiwifruit supplementation cohort, participants with below-average baseline levels achieved plasma saturation (>60 \u03bcM), accompanied by higher dermal ascorbate in biopsy<\/a> samples. At a second study site, suction-blister sampling showed that increases in plasma ascorbate were mirrored in blister fluid and epidermal blister-roof tissue, confirming active epidermal uptake via SVCT transporters.<\/p>\n

Vitamin C Intake Improves Skin Density and Epidermal Proliferation<\/p>\n

Kiwifruit supplementation increased skin density from ~0.15 to ~0.23 scanner units, an indicator of greater dermal structural protein content. Epidermal cell proliferation also increased. However, skin elasticity declined by a small (~7%) amount, and UVA-induced oxidative stress protection did not improve. Procollagen type I peptides in blister fluid also did not increase, suggesting that changes in collagen synthesis may be subtle or not captured by this biomarker<\/a>, despite rising skin density.<\/p>\n

Implications for Skin Health and Dietary Supplementation<\/p>\n

Findings suggest that dietary vitamin C effectively elevates ascorbate levels across all skin compartments through active transport mechanisms. Improvements in skin density and epidermal renewal may reflect enhanced collagen support or TET-mediated transcriptional regulation, as observed in prior in vitro work. The authors conclude: \u201cIncreasing dietary ascorbate intake will result in effective uptake into all skin compartments and will benefit skin function.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"By directly measuring vitamin C inside human skin, researchers show that diet can boost skin vitamin C content…\n","protected":false},"author":2,"featured_media":221087,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[78],"tags":[119327,5505,7917,2906,2368,3286,18,110394,518,135,19,17,18556,8803,14919,5822,173,5931],"class_list":{"0":"post-221086","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-ascorbic-acid","9":"tag-cell","10":"tag-collagen","11":"tag-dermatology","12":"tag-diet","13":"tag-dna","14":"tag-eire","15":"tag-epidermis","16":"tag-food","17":"tag-health","18":"tag-ie","19":"tag-ireland","20":"tag-oral","21":"tag-oxidative-stress","22":"tag-proliferation","23":"tag-skin","24":"tag-stress","25":"tag-vitamin-c"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115681509232266888","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/221086","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=221086"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/221086\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/221087"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=221086"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=221086"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=221086"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}