The A, B, C, D + E of hair, skin and nail health

Like drinking plenty of water and protecting our skin from the sun, consuming plenty of vitamins has been long established as essential to optimal health but what’s becoming more apparent is the impact that good nutrition can have on our skin, hair and nails.

To understand more about the function of vitamins when it comes to these areas, it helps to know a little more about the biological make up of our skin. Providing an interface between our vital organs and the external environment, the skin as our largest organ and operates to provide protection from aggressors such as pollution and UV light. Our skin is comprised of two layers – the epidermis, which provides the barrier function, the dermis (or inner dermal layer) which is responsible for giving nutritional support to the epidermis and the hypodermis (fat layer). * Disruption of the skin barrier and immunity has been associated with several skin diseases, namely atopic dermatitis, psoriasis, and acne.

As one of the most important micronutrients, research has found that vitamins have multiple antioxidant, anti-inflammatory, and anti-microbial effects. Studies have also shown that the immunomodulatory action of vitamins can disrupt the progression of certain skin diseases. This is particularly evident if you think about the large number of vitamin deficiency diseases that result in dermatological disorders. One example of this is scurvy, a skin disease caused by vitamin C deficiency and characterised by fragile skin, impaired wound healing and bleeding gums. ‘We all know vitamins and minerals are essential for bodily functions such as helping to fight infection, wound healing, making our bones strong and regulating hormones,’ explains Dr Justine Jordan, a Dublin based GP. ‘They are particularly important for our skin hair and nails. Some vitamins - also known as beauty supplements work to combat deficiencies and have grown in popularity of late. We have known for some time that deficiencies in certain vitamins and minerals can cause hair thinning, brittle hair and nails, can be linked to some forms of alopecia, and can cause nail and skin disorders.’

Considering the 360-degree impact that vitamins can have on wellbeing, The SKINday Times thought it appropriate to make the focus of our very first blog post of 2024 on the role of vitamins in maintaining skin immunity and health...

Vitamin A

Key benefits

* Stimulate collagen production
* Stimulating cell turnover
* Reducing hyperpigmentation and sun damage

When vitamin A is consumed orally, the liver converts dietary retinyl esters and beta-carotene to retinol – a game-changing active ingredient, renowned for its ability to treat photo-aged skin (amongst many other skin benefits). But vitamin A’s powers do not end there – it has even been proven to have beneficial effects in the prevention of various skin diseases.

To get nerdie, retinoic acid plays an intricate role in regulating mast cells and is commonly used in the treatment of several inflammatory skin conditions. An example of this is in the case of atopic dermatitis (AD), where a growing number of studies indicate that sufferers are deficient in vitamin A and further studies have illustrated that supplementation of vitamin A could reduce inflammation in AD.

Sources of vitamin A: Eggs, sweet potato, carrots, butternut squash, and other orange and yellow fruits and vegetables. When topically applied, vitamin A works at a cellular level, meaning that it is able to feed the upper layers of the epidermis, and reinforcing why it is important from both internal and external sources.

Vitamin B3

Key benefits

* Antioxidant
* Antibacterial
* Anti-inflammatory
* Photo-protective effects

Niacinamide is a water-soluble derivative of niacin and part of vitamin B3 group. Niacinamide has become a popular addition to many skincare and cosmetics products thanks to an extensive number of effects it can have on the skin. The potential benefits of niacinamide have been highly researched, with many studies focusing on niacinamide’s ability to fight inflammation and acne. The anti-inflammatory properties of niacinamide have also been found beneficial in the treatment of skin diseases, such as acne vulgaris. Additionally, B vitamins such as niacin and biotin are involved in hair growth and preventing hair loss

Nicotinamide has also been tested against Atopic Dermatitis. A clinical study was undertaken for eight weeks to investigate the moisturising impact of nicotinamide in patients with atopic dry skin. The study concluded that the topical application of niacinamide helped to sustain the skin barrier, decreasing trans-epidermal water loss (TEWL) and increasing the production of skin proteins and ceramides.**

Sources of vitamin B3: Fish, poultry, avocado and mushrooms

Nerdie note: Atopic means: ‘Of, relating to or caused by a hereditary predisposition to develop allergic reaction such as hayfever or urticaria, after exposure to specific antigens including pollen.*** A common example of an atopic skin disease is eczema (atopic dermatitis).

Vitamin C

Key benefits:

* Provides antioxidant protection
* Assists collagen formation
* Anti-inflammatory

Vitamin C has been recognised for its role in skin health since it was discovered as a remedy for scurvy in the 1930s. Normal skin contains high concentrations of vitamin C, which, alongside supporting crucial biological functions, provides antioxidant protection against UV induced photodamage and stimulating collagen synthesis. UV exposure and ageing have been found to deplete our natural levels of vitamin C and so optimising dietary intake of vitamin C is the most scientifically supported way to gain maximum benefit from the vitamin, however vitamin C is also added to many topical products, particularly those claiming to provide antioxidant protection and brighten the skin.

Vitamin C’s impact on the skin has been the topic of much research, where it has been found to limit the damage induced by UV exposure and enhance the production of barrier lipids, helping to protect against water loss. Vitamin C also supports the endothelial cells, the cells that line the capillaries supplying oxygen and nutrients through the blood supply to the skin. By supporting these cells, it assists in reducing the damaging effects of over dilation of the capillaries. Additionally, research has indicated that improved vitamin C status could protect against wrinkle formation through improved collagen synthesis but of all effects of vitamin C on skin health, its beneficial effect on wound healing is thought to be the most significant, with provision of vitamin C to the skin greatly assisting wound healing and minimises raised scar formation. Vitamin C turnover at wound sites, due to both local inflammation and the demands of increased collagen production, means that supplementation is useful, and both topical application and increased nutrient intake have been shown to be beneficial.

Sources of vitamin C: Citrus fruit, broccoli and tomatoes.

Vitamin D

Key benefits

* Keratinocyte differentiation
* Antibacterial
* Anti-inflammatory

Vitamin D plays a key role in many disorders and diseases including autoimmune disorders, skeletal disorders, central nervous system diseases and infections. Vitamin D also affects multiple functions in the skin ranging from keratinocyte proliferation to barrier maintenance. Many factors affect an individual’s vitamin D status; and a growing number of dermatologic disorders have been linked to vitamin D levels such as atopic dermatitis (AD), psoriasis and cutaneous cancers. Getting an appropriate intake of vitamin D can be difficult as very few foods naturally contain vitamin D; and so, most sources of vitamin D derives from skin exposure and oral intake, including supplementation.

Sun exposure can also help the skin produce vitamin D, but the amount produced varies depending on factors such as skin colour, time of day, season, and location. It has been found that there is an increased likelihood of developing AD in individuals with insufficient vitamin D levels. When it comes to treating psoriasis and AD, therapeutic interventions (topical and systemic) based on vitamin D have been proved beneficial. What is problematic is the debate around the benefit of UV exposure for vitamin D and the risks that come from exposure to the sun. To mitigate this, many people choose to take vitamin D supplements.

Sources of vitamin D: Salmon, eggs and mushrooms.

Vitamin E

Key benefits:

* Skin immunity
* Antioxidant
* Anti-inflammatory
* Antibacterial

Vitamin E is an essential fat-soluble vitamin and another antioxidant that is often obtained from diet. Vitamin E is the first line of defence against damage caused by free radicals on cell membranes and can prevent lipid peroxidation by quenching free radicals. It has been found that vitamin E levels in the skin decline with age and exposure to UV light can diminish the levels of vitamin E in the skin, particularly within the stratum corneum – the outer layer of the skin.

Studies have shown that supplementation with vitamin E has demonstrated improvements in skin conditions associated with AD. Supplementation of vitamin E in patients with acne vulgaris also showed positive results in reducing acne.

Sources of vitamin E: Oils, nuts and seeds.

Topical v dietary delivery of vitamins

At The Skin Nerd, we always recommend a food-first approach to nutrition, and encourage a healthy, balanced diet including lots of fruit and vegetables. We also know that sometimes lifestyle and food intolerances can prevent us from getting our recommended intake of fruit and vegetables and this can be a good time to consider a supplement. Supplementation has seen many positive results when it comes to supporting skin health. Both vitamin C and vitamin E have been found to improve the rate of wound healing in children with extensive burns, and plasma vitamin C levels in smokers, abstaining smokers and non-smokers were positively associated with the rate of wound healing.

Vitamin skincare has been trending for the past few years, providing topical ways to get your nutrient fix, but although more accessible, this method isn’t always as effective. As the epidermis does not have the blood vessels that would normally deliver nutrients to the cells, it is regarded as a problematic environment for the delivery of nutrients. The stratum corneum also functions as an effective barrier, preventing many substances from getting to the deeper layers of the skin** This doesn’t mean that vitamin infused skincare is of no use at all, in fact, several studies have shown many benefits of topical application. L-ascorbic acid is one of the most potent and recommended forms of vitamin C in skincare, whilst vitamin E’s lipophilic properties enable it to penetrate both the epidermis and dermis. The topical application of vitamin C, in combination with vitamin E has also been shown to have an impact on skin health, reducing damage due to UV irradiation.

The SKINday Times Verdict

As The Skin Nerd champions a 360-degree approach to skin health, it probably comes as no surprise that we view vitamins as vital for the health of your skin and general wellbeing. The best way to get your vitamins is undoubtably via a food source, but if this isn’t possible it is worth considering a food supplement. Always do your research before taking a supplement – this involves speaking to a pharmacist or nutritionist if you are unsure of which to take and your GP if you have any medical conditions or concerns.


*Pullar JM, Carr AC, Vissers MCM. The Roles of Vitamin C in Skin Health. Nutrients. 2017 Aug 12;9(8):866. doi: 10.3390/nu9080866. PMID: 28805671; PMCID: PMC5579659.

** Soma Y, Kashima M, Imaizumi A, Takahama H, Kawakami T, Mizoguchi M. Moisturizing effects of topical nicotinamide on atopic dry skin. Int J Dermatol. 2005 Mar;44(3):197-202. doi: 10.1111/j.1365-4632.2004

*** Miller-Keane Encyclopaedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. (2003).