Get pretty skin with vitamin C
Do you know where your body stores vitamin C? Your brain, lungs, stomach? The answer is your skin!
Vitamin C is found at the highest levels in both the dermis and epidermis [1][2].
Let’s learn about how the role of vitamin C is related to skin health, especially in the condition of eczema, and how vitamin C can act as a skin-lightening agent.
Before we dive into the mystery of vitamin C and skin health, let’s begin with the structure of our skin.
SKIN STRUCTURE
Our skin contains two main layers, the epidermis and the dermis [3][4]. The epidermis is the upper layer that is
responsible for barrier functions, while the dermis is the underneath layer for structural and nutritive support.
The epidermis is 0.1mm to 0.6mm thick [5] and mainly contains keratinocytes (90-95%) that produce the structural protein keratin, making up the epidermal barrier [6]. Melanocytes are also present in this layer to produce melanin, a compound that absorb energy from UV light to
shield underlying tissues from damage [7].
The dermis is thicker, having a depth from 0.3mm to 4mm depending on body location, and is generally 10x thicker than the upper epidermis layer [8]. 75% of the weight of this layer is a matrix of collagen – an extracellular protein that provides structural support and elasticity for the skin. Fibroblasts are the cells that are responsible to synthesize this structural protein, collagen [6].
THE PHYSIOLOGY OF VITAMIN C IN SKIN
As we mentioned in the very beginning, our body stores most of the vitamin C in our skin – at a much higher concentration when compared to other body tissues [1][2]. Normal skin actively accumulates vitamin C from the circulation. More vitamin C is found in the upper epidermal layer than in the dermis, with differences of 2-5-fold [10].
However, aging causes a decline in vitamin C content in the skin (both the epidermis and dermis layer) [11][12][13].
Excessive exposure to UV light, pollutants such as cigarette smoke, and ozone, may also lower vitamin C content [1][2][6][14].
THE ROLE OF VITAMIN C IN SKIN
Vitamin C (Ascorbic Acid) is a renowned antioxidant to protect cells from oxidant stress and is a vital molecule for skin health because of its role in collagen synthesis [15][16].
1. Photoprotection
Although vitamin C cannot act as a sunscreen to block UVA or UVB, the antioxidant activity of vitamin C protects against UV-induced damage caused by free radicals and limits the damage induced by ultraviolet (UV) light exposure [17].
2. Reduce oxidative damage
In studies, researchers found that vitamin C and vitamin E work together to effectively scavenge radical species and reduce oxidative damage to the skin, thus protecting cell membrane structures [10][18][19].
3. Collagen Synthesis
Vitamin C is an essential cofactor for collagen synthesis by dermal fibroblasts and is crucial to the maintenance of healthy skin [20][21].
In damaged skin, vitamin C has been shown to stabilize collagen mRNA, thus increasing collagen protein synthesis [15] and helping recovery.
As we age, collagen synthesis activity decreases as the proliferative capacity of fibroblasts reduces. Study showed that vitamin C can help to increase the proliferation rate of fibroblasts and stimulate DNA repair in cultured fibroblasts [22][23].
4. Promote differentiation of keratinocytes
Vitamin C enhances the late differentiation of keratinocytes (the main cell type in the epidermis layer of the skin), ensuring the function of the skin barrier and preventing skin water loss, which in turn can lead to skin disorders [24].
HOW SUPPLEMENTATION OF VITAMIN C AFFECT SKIN CONDITION
Cosmetics products (especially those for skin-lightening purposes) are often marketed with vitamin C. Does oral consumption of vitamin C affect our skin? Studies found that oral intake of vitamin C can effectively increase vitamin C levels in the skin [25][26]! But how does such a level affect how our skin ‘look’ externally?
Vitamin C Deficiency & Skin
Researchers found that skin abnormalities could be related to vitamin C deficiency in the body. Symptoms such as skin
discoloration, abnormal hair growth, and poor wound healing may be associated with vitamin C deficiency disease, known as scurvy [15].
These symptoms appear once plasma concentrations of ascorbic acid drop below 10 micromolar (μM), a level that can be prevented by consuming as little as 10 mg of ascorbic acid daily [27].
If you eat vegetables and fruits every day, you don't have to worry too much about it. The best daily intake of vitamin C is 200 mg.
Oral vitamin C can...
Prevent UV-induced damage
As we learned above, when vitamins C and E work together, they can effectively remove radical species and reduce oxidative damage to the skin. It is proven to be true when vitamins C and E are consumed orally together, they can help in preventing UV-induced damage [15][28][29][30][31. This is particularly important for those who with dermal neoplasms and skin tumors.
Decrease Skin Wrinkling
As vitamin C is responsible for collagen synthesis, studies found that higher intakes of vitamin C from the diet can decrease skin wrinkling and give a better skin appearance [32][33].
Combat dry skin
Vitamin C promotes the differentiation of keratinocytes and the synthesis of barrier lipids. Higher intakes of vitamin C could help establish a functioning stratum corneum (top layer of the epidermis) with low water permeability, thus combating the problem of dry skin [32][34][35].
RELATIONSHIP BETWEEN VITAMIN C AND ECZEMA
Eczema (atopic dermatitis) is a chronic relapsing inflammation of the skin associated with allergies [36].
Studies found that eczema patients lack several nutrients, including vitamin A, vitamin C, and vitamin D [37].
Let’s first talk about the related nutrients apart from vitamin C. How are they related to the condition of eczema?
The severity of eczema is found to be associated with vitamin D deficiency and vitamin A deficiency [38][39][40][41][42][43][44][45]. When both are in deficient, the condition is most severe.
In addition, in patients with eczema, zinc levels are low in serum, hair, and erythrocytes. The lower the zinc level, also
the more severe the condition [46][47].
Intestinal permeability & microbiome
In eczema patients, intestinal permeability is increased. The leaky gut allows exogenous antigens to be transferred and
circulated around the body, thus resulting in chronic inflammation.
Apart from cutting off wheat from the diet (Wheat directly increases gut permeability and result in a leaky gut), taking
probiotics could be beneficial in modulating the intestinal microbiome, thus improving the intestinal barrier and regulating the intestine-skin immune response [48][49].
Gamma-linolenic acid (GLA)
Many people with eczema think we shall consume less, or even avoid food with omega-6 polyunsaturated fatty acids
(PUFAs). We have to be cautious that there are few types of omega-6: linoleic acid (LA), Gamma-linolenic acid (GLA), and dihommo-gamma-linolenic acid (DGLA).
Our body have enzymes to convert LA to GLA and DGLA. We only have problem when the ratio gone wrong.
Researchers found atopic children had higher levels of LA and low serum GLA and DGLA levels, possibly because of the impaired activity of the enzyme [50]. The lower the GLA and DGLA levels, the higher the transepidermal water loss and severity of the eczema condition [51].
Oral intake of GLA was found to be effective for the treatment of eczema [52] because of its anti-inflammatory effects and it may stabilize the physical structure of the skin [51].
Evening primrose oil, [53][54], black currant seed oil [55] and borage oil [56][57], sea buckthorn oil can be good source of GLA in improving eczema
condition.
High levels of vitamin C may improve inflammation and eczema
So how about vitamin C? How is this vitamin related to eczema?
Studies showed that in the patients with eczema, there were
high iron and low vitamin C concentration in the dermis
[58]. Intaking high levels of vitamin C was found to improve chronic inflammation and the condition of eczema [59][60][61][62].
In addition, vitamin C can promote collagen synthesis and help the recovery of damaged skin areas. The vitamin can also promote keratinocyte differentiation and the production of interstitial material [63][64].
Vitamin C acts as a co-factor with enzymes to produce ceramide, the most abundant lipid in the skin barrier materials in the stratum corneum (top layer of the epidermis) [65]. Thus, strengthening the overall epidermal barrier function [66] and retaining moisture.
Studies showed that the more severe the condition of eczema, the more vitamin C and ceramide levels were reduced [67].
This is why high levels of vitamin C intake are essential in the recovery journey of eczema patients.
VITAMIN C AS SKIN-LIGHTENING AGENT
In the epidermis, melanocytes produce melanin, a compound that absorbs energy from UV light to protect other cells from being damaged [7]. The result of melanin synthesis is
skin pigmentation [68] and this is why we got tanned after having a sun bath, or dark spots on our faces after exposure to sunlight.
Melanin act as a reservoir for reactive oxygen species (ROS), Cu, and calcium (Ca) within the cells [69]. Vitamin C interacts with copper ions and inhibits the action of the enzyme tyrosinase, thus reducing melanin formation which makes it an effective skin-lightening agent [69][70][71][72][73].
Vitamin C can be used s a treatment for the depigmentation of hyperpigmented spots on the skin by topical, transdermal, and intravenous methods [69].
CONCLUSION
Apart from having a healthy diet with less refined and processed food, daily intake of vitamin C-rich food from diet is crucial to maintain our body’s first line of defense – the epidermal barrier and to having healthy, beautiful skin.
Vitamin C is readily available in various vegetables and fruits.
Higher intakes of vitamin C can be beneficial to those who want to improve their skin condition from aging, skin
wrinkling, dry skin, hyperpigmentation, and even those with eczema.
Since the condition of eczema patients is related to nutrient deficiency, apart from reducing the intake of deep fried
foods, it is recommended to increase the intake of:
foods rich in vitamin D, such as salmon (salmon), tuna, eggs;
foods rich in vitamin A, such as liver, fish, eggs, carrots, pumpkin, broccoli;
foods rich in zinc, such as beef shoulder, lamb, seeds, spinach, mushroom;
and vegetables and fruits to replenish vitamin C, vitamin E, prebiotics, enzymes and antioxidants to help the body to recover.
Liposomal vitamin C is an efficient way to intake high levels of vitamin C and achieve higher plasma concentrations than
water-soluble vitamin C.
Try to eat more fresh food instead of shelf-stable prepackaged food. Try to explore the joy of cooking with wholefoods!