Skin Conditions and Nutrition

Introduction

The skin is known to be the first line of defence in our body, being the most external organ covering an area of over 1.5 meters squared. This organ, in addition, is the largest organ of the body, as it constitutes nearly 15% of our body weight.¹ It includes several integrated layers such as the outer layer (epidermis), the skin proper or middle layer (dermis), and the innermost layer (subcutaneous tissue).² Nutrition is a major factor in supporting the skin’s ability to perform its functions in an optimal manner.

What are the most common skin conditions?

Eczema and psoriasis are common types of long-lasting, inflammatory conditions that affect a large population worldwide. Research is increasingly providing evidence for the link of these conditions with a previous family history.³ Eczema or atopic dermatitis is known for dry skin with reddened scaly areas or vesicles that may ooze liquids on their crust. Itching and redness are major signs of eczema.⁴ Eczema appears as a flare-up in the acute phase or thickened, scaly skin with white elevations that measure more or less 1 cm in diameter in the chronic phase.⁵ Eczema has variable phases throughout one’s lifespan.⁶ 

The word ‘psoriasis’ may represent to many people an itching, burning sensation, and even easily bleeding skin with greyish/white scales. Although psoriasis may have large elevations similar to chronic eczema, its presentation on the skin is totally dry without any oozing fluid. These elevations may appear on the scalp, elbow, knees, and lower back.⁷ This may also extend to the nails and even genitals in some cases of acne vulgaris.⁸

The gut-skin axis

The connection between the gut and skin microbiomes

Some recent studies highlighted the possibility of such skin diseases developing due to an immune disruption, where the immune system attacks one’s own cells instead of foreign bodies, which is known as an autoimmune attack. These studies focused on the skin being a structural cover against different microorganisms, in addition to possessing defensive white blood cells in its layers. This integrative system would work perfectly if it attacked the foreign microorganisms that may pass through skin cracks, but sometimes it misses its target and attacks normal bacterial inhabitants that live inside the gut such as E.coli, or on the skin such as cutibacteria.⁹ In fact, findings show fewer numbers of these types of bacteria inside the psoriatic or eczematous area of the skin, representing one form of immune disruption. 

Another form of disruption would happen upon the internal secretion of anti-stress hormones from the brain. Primarily, the aim of this is to reduce the severity of the inflammation that results from the killing of the immune cells instead of the foreign organisms that invade the skin.¹⁰

What you eat indirectly affects skin health

Early prophylaxis has always been better than treatment, therefore, the maintenance of skin health for better structure and function is much more worthwhile than treating skin disorders after they occur. This considers skin integrity not only as a building structure but also as a defensive role. Prophylaxis begins from your meal, as a means to support one’s overall health. A Mediterranean meal could be a healthy plan with its traffic lights-like colours of leafy green vegetables, seeds, nuts, fruit, and fish.¹¹ 

Foods that are high in carbohydrates can impair the tolerance of the glucose transporters on the gut's internal surface, with an increase in the levels of insulin secreted. This is what happens in individuals with diabetes when subsequent skin infections occur due to fungi and bacteria. Dry itchy skin is a recorded feature with diabetes mellitus.¹² A high-fat diet can result in the impairment of the function of absorptive receptors, causing fatty skin tags over the eyelids.¹³ Food species and allergens in nuts and berries may cause allergic dermatitis and urticaria.¹⁴ Dermatitis can also occur as part of a disease called pellagra. This may occur on exclusive dependence on corn in food due to a deficiency of vitamin B3 (niacin) in corn.¹⁵ A kind of inflammation of the skin around the oral cavity, as well as oral aphthous ulcers, can occur due to the deficiency of leafy green vegetables with vitamins B1 and B2, and bran with vitamin B6.¹⁶

The skin-friendly diet

Plenty of water

Foods rich in vitamins C, D, and E

Foods rich in flavonoids

Starting with red-coloured foods like tomatoes, the latter contain lycopene which protects the skin against the ultraviolet rays of the sun. Five tablespoons of tomato paste have been shown to increase protection against sunburns by one-third.¹⁷ Watermelon is considered another example of healthy food for the skin. It keeps the skin moist because it is rich in water, whilst its  low sugar content reduces the glycation process, the products of which result in the formation of wrinkles and abnormal collagen line marks upon ultraviolet ray exposure.¹⁸  This highlights the importance of drinking sufficient water throughout the day (up to 3-5 litres/day) to maintain skin moisture, especially for individuals with eczema. The nature of the water and its solute content highly affect skin density and thickness.¹⁹ Additionally, frequent intake of watermelon and tomatoes may save you from spending a fortune on sunblock creams and anti-aging pharmaceuticals. 

Moving on to yellow-colored foods, the flavonoids (from the Latin ‘flava’, meaning ‘yellow’) in vegetables and fruits vary in their contribution to skin health. Carrots are among those vegetables that contain carotenoids that include vitamin A, the level of which was found to be decreased in people with psoriasis.²⁰ It is worth mentioning that Vitamin A can decrease the oil secretion in the skin by guaranteeing normal shape and function of the superficial cells of the skin (keratinocytes), which are related to the production of the skin scales in psoriasis.²⁰  Yellow-coloured foods include citrus fruits such as lemons and oranges. Their vitamin C content aids wound healing by increasing vascularity and regulating collagen synthesis. Furthermore, vitamin C has antioxidant effects, and protects the skin from the harmful ultraviolet sun rays.²¹ Thus, lemons and carrots can hinder ageing, with the added benefit of protection against skin cancer.

Finally, the colour green is very abundant amongst a variety of fruits and vegetables. Olive oil has anti-ageing properties and is low in saturated fat. Avocados have vitamin D, the activation of which takes place in the skin and acts either locally or generally. This vitamin D has been related to regulating the differentiation of the skin cells to functional skin cells without shape alteration, a function that is lost in psoriasis and eczema cases. Vitamin D has been effective in controlling the natural immune cell response to different microorganisms in addition to its ability to kill some bacteria such as Mycobacterium tuberculosis.²² Green tea also has polyphenols, which act as antioxidants and anti-inflammatories, in addition to vitamin K which can treat dark circles under the eyes.²³ Additionally, there are multivitamin fruits like avocados that contain vitamins A, D, and E, as well as broccoli which has vitamins K, A, and C.

Summary

In conclusion, we cannot rely on the expected development of dermatological therapeutics without having a solid understanding of several skin issues. In the meantime, we should be revising our lifestyle habits, starting with our gut health. We should guarantee our gut health before looking at what external factors may be responsible for the increase in skin diseases.