The Skin: Our Protective Barrier

Our skin is amazing. It is our protective shield, our first line of defence to the outside world, keeping things that may be harmful such as bacteria, viruses and other infectious agents along with toxins and pollution out, while keeping the things our body needs to function properly, such as water and nutrients in. 

It has 6 main functions:

  • Barrier protection; as a physical barrier that is enhanced by the skin microbiome (more on this later)
  • Thermoregulation; maintaining core body temperature through blood vessel dilation when it’s cold and vasoconstriction when it’s warm to cool us down.
  • Excretion; of waste and toxins from the tissues
  • Sensation; allowing us to touch and feel including things that may cause pain
  • Absorption
  • Vitamin D production; from the action of sunlight on the skin we are able to synthesise the precursor cholecalciferol that is converted in to active vitamin D through the liver and kidneys. 

 

Our skin has 3 layers

  • The Epidermis - the thin outermost layer, provides a protective shield to the outside world.
  • The Dermis - the thick elastic middle layer where the blood capillaries, lymph vessels, hair follicles, nerve endings, sebaceous and sweat glands reside along with the matrix of collagen and elastin fibres that form the connective tissue. It is this layer which gives the skin its mechanical strength.
  • The Subcutaneous Layer - contains fat to keep us warm, larger blood vessels and dense connective tissue.

 

The Epidermis

Let’s take a closer look at the Epidermis where our inner body meets the outer world. 

The Epidermis is itself composed of several layers. The innermost layer known as the basal layer is where the plump round fluid filled basal keratinocytes (type of skin cell) are produced. These cells divide and slowly migrate upward towards the surface. On their way towards the surface they begin to loose the cellular fluid within and are transformed in to flat protein producing cells. 

Once they reach the surface the keratinocytes form the stratum corneum. These flexible cells overlap like armour and are coated with a thin layer of sebum (fatty acids, waxes, and salts) that form the acid mantle or lipid layer.

Together the flat keratinocytes and the fatty acids form the protective shield, creating a barrier against microbial, viral, fungal and parasitic invasion; to protect against UV radiation; and to minimize heat, salt, water and nutrient loss from the deeper layers of the skin.

Before forming the stratum corneum, the young keratinocytes can produce chemical messengers that regulate the immune system. If you get a scratch, cut or develop a spot, these cells trigger an immune response that attacks the pathogens, bacteria or viruses that may be present. 

Part of this natural immune response is inflammation, as more immune defence cells are called to respond and mount and an attack on the foreign invader.

But it isn’t only pathogens that can trigger an immune response, toxins and synthetic chemicals (in skin care) have the potential to trigger an immune response too, causing irritation and or allergic response. Not only that but these synthetic substances can increase the permeability of the skin, in essence poke holes in the epidermis, allowing more undesirable agents to penetrate the skin.

When our skin feels constantly under threat our immune system is in constant alert mode, ie a constant state of low inflammation. This long term inflammation of the skin tissues unfortunately results in more rapid ageing. 

The epidermis also contains cells called melanocytes that provide pigment which gives our skin its colour. When our skin is subjected to harsh abrasives, chemical peels, acids and retinol, these specialist cells become deformed resulting in irregularities in skin colour (hyperpigmentation) and a reduced ability to respond in a healthy way to UV rays.

 

The Microbiome
Skin
The epidermis is also home to our skins microbiome. A whole eco system resides on the surface and in the multilayers of the skin. They play a significant role in immune response, inflammation, wound healing and many skin disorders. A dysregulated skin microbiota is seen in all chronic skin conditions. A healthy, diverse skin microflora is needed maintain the integrity of the skin’s barrier.

When the skin is ‘injured’ our ‘native’ microbes offer us protection by migrating to the area to defend against non-native pathogens. 

We need bacterial diversity on the skin, when microbial diversity mutates or plummets, pathogenic bacteria breeds and contributes to skin issues. To avoid a state of skin ‘dysbiosis’ (dysregulated microbiota) we need to nurture and ‘feed’ the friendly bacteria.

 

Gut  
The health of the gut microbiota can affect our skin microbiome through several potential pathways both positively and negatively. 

These include: 

  • the migration of microbes to the skin disrupting the balance of the skin microflora. 
  • increasing the susceptibility of systemic inflammation, due to a leaky gut lining allowing undigested food particles or toxins to gain access to the blood stream activating the immune system.
  • short chain fatty acids, produced by the gut microbiota (when fibre is consumed) in the digestive tract can affect the composition of skin microflora to positively influence the skin’s immune response. 

 

Research suggests that by supporting healthy gut flora you can modulate our body’s immune responses and improve skin pathologies.

 

The Skin Barrier Function

Our skin has an inherent intelligence, an ability to know how to function exactly to give us beauty and vitality. We can work with this intelligence, assisting the skin to do what it was always meant to do for long term skin health and vibrant ageing, or we can confuse the skin with mixed messages in our skin care, injuring the skin and its protective barrier.

A skin care routine that supports the epidermis will support the health and beauty of our skin, slowing the ageing process for vibrant healthful skin, and diversifying our unique and beneficial microbiome. 

Conversely substances that injure or remove the outer layers of the epidermis, are affecting not only its ability to provide protection, but are accelerating the ageing process and affecting our inherent natural beauty.

 

Acids and Retinols
Acids such as AHA’s (alpha hydroxy acid) and BHA’s (beta hydroxy acid) and retinol containing products work by stripping the top layers of the epidermis, exposing the young immature, plump, fluid filled cells beneath. This is why after the redness (which is injured inflamed skin) has subsided the skin can initially appear more plump and youthful.

But the cells of these epidermal layers are not yet dead or ready to be removed, but rather are still within their life cycle. Not only do we lose the protection they are giving but these cells are still communicating with our immune system and they send distress signals to the dermis. The dermis responds by sending its nutrient reserves to the epidermis for repair.

This is why after the redness has subsided the skin can initially appear more plump and youthful. However this is an inflammatory, immune response, essentially a healing crisis of the skin that over the long term depletes the dermis of nutrients, leading to limited, substandard cell proliferation that ultimately accelerates the ageing process.

An intact epidermis and a thriving dermis are responsible for skin health and vitality.

This stripping of the cellular layers of the epidermis will of course also harm the microbiome, the natural lipid barrier and as I said earlier affects the melanocytes of our skin, leaving us vulnerable to infection, water loss (dehydrated and dry skin) and sun damage.

 

Surfactants and Emulsifiers
Surfactants and emulsifiers, chemicals from petroleum and other toxic ingredient in many skin care products (even those labeled ‘natural’or ‘organic’), also strip not only the epidermal protective layers but also affect the native beneficial microbes, reducing diversity and creating a circumstance that allows pathogenic bacteria to flourish. 

Surfactants are used for cleansing, foaming, thickening, penetration enhancement, antimicrobial effects and emulsifying (enable water and oil to combine in creams and lotions), with their key property being they are compatible with both water and oil. 

Examples of emulsifiers include cetearyl alcohol, benzalkonium chloride, stearic acid, glyceryl stearate. Synthetic surfactants include ammonium lauryl sulphate, sodium lauryl, sodium laureate sulfate (SLES) and sodium stearate. 

There are also ‘naturally derived' surfactants, these include lauryl glucoside, decal glucoside, caprylyl glucoside, cocamidopropylbetaine. While many of these have been approved for use in organic skin care and have 'plant origins’ they need to undergo a degree of chemical processing that alters their nature, in order for them to offer the properties required for use in skin care.

Studies show surfactants (even the ones deemed suitable for use in natural and organic products) dissolve our hydro-lipid barrier (causing irritation) and our natural ceramides. Ceramides are important for retaining our skin’s moisture and preventing the entry of germs through the skin. 

It’s interesting that Ceramides have become such a buzz word ingredient in the skincare industry, with many companies advertising the addition of them (usually synthetic) to their products. My feeling is this is to replace the natural ceramides in our skin that they’ve damaged with surfactants!!

Surfactants insert themselves into the stratum corneum and initiate chronic degradation to this delicate layer. They cause oxidative stress which in turn can clog pores resulting in inflammation and friendly microbial elimination.

 

Positively Supporting the Skin Barrier For Long Term Skin Health

Our skin care routines don’t need to be complicated and our daily rituals can be as short or as long as our time allows, but what is important is choosing ingredients that support not harm the skin.

Choosing to nourish the skin with ingredients to support healthy cell renewal and barrier function, that work with our lymphatic system for efficient detoxification, reducing toxic burden and inflammation, ingredients that work with every aspect of our skin to truly nurture and enable our skin to find balance, harmony and it’s true radiance.

Nature has given us these things in abundance. Plants are rich in vitamins, minerals essential fatty acids, antioxidants and nutrients such as flavonoids, polyphenols and even ceramides, that provide the skin with the necessary building blocks for healthy skin cell production, a strong and robust barrier function, a balanced healthy microbiome and immune regulation.

Using whole plants and their cold pressed oils, with minimum processing, not only retains all the beneficial nutrient components in a highly bioavailable (easily absorbed) form, it also ensures the naturally present cofactors that work synergistically, ensure maximum efficacy of the vitamin and mineral content, to offer effective support for long term skin health and results that, rather than giving short term benefits, last a lifetime.

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