The Important Role of Skin Barrier Function for Optimal Skin Health: Maintaining the Skin's Protective Barrier System

Our skin’s main function is protection. It also regulates body temperature and contains nerve endings responsible for sensation. This blog post will discuss the function and role of the skin barrier defence system and provide some insight into some contributing factors that may lead to impaired skin barrier function.

The skin forms our first 3 lines of defence against the outside world. These defence systems include

1. The Acid Mantle (The skin’s pH and microbiome).

2. The Stratum Corneum (The top layer of skin cells).

3. The Lipid Bilayers (The oil and water phase in the skin).

Each of these defence systems plays a different role in maintaining skin health.

● The acid mantle maintains an acidic pH of 4-5.5 and it contains a diverse variety of microorganisms, including bacteria, fungi, mites, viruses and archea. It is the skin’s first line of defence and its acidic nature protects the skin from pathogenic invasion, keeps the microbiome balanced, communicates with the immune system and modulates inflammation.

● The second line of defence is the stratum corneum, which consists of skin cells called keratinocytes/corneocytes that are held together by protein bonds and natural skin lipids. These cells are arranged in a brick and mortar like structure to protect against physical trauma and prevent the entry of harmful substances. The keratinocytes within the stratum corneum are often referred to as “dead cells.” However, these cells are alive until they are no longer attached to the skin and become house dust. They play an incredibly important role in communication, as they inform the deeper skin cells of what is happening in the external environment through a process called cytokinesis.

● The third line of defence is the lipid bilayers in the skin, which also form the skin’s natural moisturising factor. These lipid layers consist of cholesterol, fatty acids and ceramides, which are all synthesised and secreted by keratinocytes. This defence system is important for maintaining skin hydration levels, preventing trans-epidermal water loss keeping the natural enzymes within the skin active to support natural exfoliation, and slow down the penetration of substances entering the skin.

A healthy skin barrier requires these layers to be intact and functioning optimally. We often describe the skin as a house, with the barrier being your tightly packed roof tiles. Its function is to protect us from anything entering or exiting the house. If your roof tiles are cracked, the inside of the house will gradually start to deteriorate and things would become damaged.

The same thing happens with your skin, and this is what we refer to as an impaired skin barrier. It means the skin is allowing the invasion of pathogenic microbes, irritants and allergens, causing disruption of the skin’s microbiome and leading to inflammation. Products and substances are also able to penetrate the skin quickly, which can lead to irritation and sensitivity. The lipid bilayers then become imbalanced, leading to dehydration and impaired enzyme activity.

CONTRIBUTORS TO AN IMPAIRED SKIN BARRIER

● Genetics and health conditions: The genetic makeup can determine a person’s ability to produce a healthy natural moisturising factor and acid mantle. This is why some people have naturally dry or oily skin; these clients will always need support to protect their skin. Additionally, conditions such as PCOS, asthma, allergies and endometriosis can cause imbalances within the skin.

● Incorrect products (skin care, hair care and hygeine products): Products containing sodium lauryl sulphate (SLS), emulsifiers, excessive perfume or fragrance, harsh preservatives and high levels of alcohol will interfere with the acid mantle by breaking down the surface lipids and altering the skin’s pH and microbiome.

● EFA deficiency: Essential fatty acids are important for a healthy functioning cell membrane to ensure effective nutrient absorption occurs and waste is excreted. EFAs also contribute to the natural moisturising factor and acid mantle, which provide the skin with hydration and protection.

● Diet + Caffeine: Excessive caffeine consumption interferes with the stress response, increases insulin resistance, and in turn, results in inflammation. Pro-inflammatory foods such as fried foods, sodas, refined carbohydrates, alcohol and highly processed seed/vegetable oils also increase inflammation, impacting the skin’s ability to produce a healthy barrier.

● Medications: Some pharmaceutical drugs, such as antibiotics, roaccutane, anaesthetics and cholesterol medications, can result in changes to the skin’s oil production, skin microbiome and slow down metabolism temporarily or permanently.

● Stress: Lowers our immune system response and disrupts other hormones within the body, such as insulin. The stress hormone cortisol impacts the oil production in the skin and allows for water evaporation, resulting in dehydration and inflammation. It also contributes to fast cell turnover.

● Age: As we get older and hormonal fluctuations start to take place, our ability to produce good quality and quantity of oil is reduced, resulting in dryness.

An impaired skin barrier is often at the forefront of all skin conditions. Holistic Skin Co.’s philosophy in treating skin is always respecting and repairing the skin barrier systems. It should be the first thing addressed when trying to correct skin that is presenting with any condition. In our opinion and experience, there is no point in trying to correct a skin that isn’t functioning at its best, as the results will always reflect that. Always focus on repair before correction.