Good Skin Barrier
Why maintaining a good skin barrier is vital for everyone
When you understand how your skin works, you will know that the stratum corneum (the outer layer of our epidermis) is our first line of defence against the outside world. It is absolutely vital to every one that good skin barrier is maintained. Sufferers of chronic dry skin conditions often have compromised skin barrier and it is even more crucial to them that a good skin barrier is properly maintained at all times (even in between flare ups, when the skin is in a state of homeostasis - ie normal condition). Weakness in the stratum corneum allows invasion by pathogens and allergens and loss of moisture (trans-epidermal-moisture-loss). Once moisture is lost more cracks appear and on a microscopic level the skin will look like the cracked, baked surface of a dried-up river bed. The dryness, inflammation and consequent scratching cause further damage to the barrier, perpetuating a vicious cycle. Once you re-seal that lipid barrier moisture is sealed in. For people with normal skin, compromised skin barrier causes loss of moisture, which leads to premature wrinkling.
For those with chronic skin conditions, good skin barrier function is essential to breaking the scratch cycle. Healthy skin makes natural oils that seal the stratum corneum keeping moisture in and pathogens out. This concoction is 50% ceramide, 10-20% free fatty acids and 25% cholesterol. It has been proven that plant oils, particularly those containing linoleic acid, linolenic acid and lauric acid improve skin barrier and can even have an anti-inflammatory effect without side effects.
Sunflower Oil, Shea Butter, Rosehip Oil and Borage Oil are all rich in Linoleic acid (an Omega-6 fatty acid). This is an essential fatty acid (EFA), your body cannot synthesise EFA's so you need to gain it through diet or topically. Linoleic acid is used by the skin to synthesise ceramide no 1. Ceramides are synthesised by your body and are a vital component of your skin structure, these compounds act as the cement in the outer layer of your skin with skin cells being the bricks. Ceramides keep the skin barrier strong to keep out pathogens and allergens. If the ceramide content of the skin decreases then the cement starts to crumble leaving your body open to the elements and in a constant state of disrepair.
In colder months and as you age skin ceramide levels reduce. Maintaining a good skin barrier becomes more difficult, due to age-related ceramide decrease. Ageing skin is more delicate and potentially prone to infection and drying out. This can become more noticeable during and after menopause in women as it is linked to the drop in Oestrogen levels. Oestrogen also plays an important role in sebum production and skin lubrication so when these levels drop the skin becomes drier and wrinkles become more visible.
Shea butter and calendula contain plant compounds (eg triterpenes, tocopherol, phenols, and sterols) that are also precursors to ceramides (this means your body uses these compounds to make ceramides). Borage oil is rich in GLA (Gamma-Linoleic Acid) which is synthesised in the body from linoleic acid by the enzyme delta-6-desaturase, however, those with atopic skin are often deficient in the enzyme and are unable to synthesise GLA so it is advisable to have an additional source of GLA in Patients with Atopic Dermatitis
Inflammation is a vital part of the body's immune response but just like wine too much of a good thing can be bad for you. Linoleic acid acts as an anti-inflammatory Anti-inflammatory and skin barrier effects of topical Linoleic acid Chronic inflammation causes your skin to become exhausted, it gets stuck in a cycle of inflammation and fire fighting, it is then unable to normalise to maintain good skin barrier function.
Emulsifiers on the skin
Emulsifiers are agents that enable water and oil to mix together without separating, great if you are making water-based skincare but not so good when it gets to your skin. The emulsifiers cause the lipids in your stratum corneum to mix freely with water, this weakens the skin barrier as it reduces the amount of protective lipids. This in turn causes the Stratum Corneum to dry out (trans-epidermal-water-loss) and be at risk of pathogens and allergens entering the body.
Soap detergent and bubble baths contain emulsifiers and will be detrimental to good skin barrier and studies have shown using soap-free cleansers are preferable, so employing the oil cleansing method may be helpful to those suffering from eczema who want to treat it naturally.
What you eat can help to maintain a good healthy skin barrier, eating a healthy balanced diet containing lots of fruit, vegetables and unprocessed foods will support good skin barrier function. Most importantly drink plenty of water as it will be drawn through the dermis into the outer layer of the skin to keep it hydrated and healthy.