Why essential fatty acids are vital for skin health

Essential fatty acids first became exposed for their role in achieving optimal skin health almost 100 years ago in 1929¹. The experimental scientists, Burr and Burr followed the effects of a diet devoid in fats and found that in this instance, skin became dry and scaly. When diet was subsequently corrected with essential fatty acids, skin symptoms lessened and in some cases completely reversed. The past 3 decades of fat-free diets and fat reduced foods have proven a great trial for the quest towards healthy, youthful skin. …but not all fats are equal. Not all fats have the same healthy skin effects and simply increasing your consumption of one essential fatty acid does not guarantee an individuals improved skin health. Balance is key.

What is an essential fatty acid?

Essential fatty acids are a type of fatty acid the body cannot create itself. The human body contains many enzymes which allow it to manufacture fatty acids and antioxidants from food sources that do not contain them i.e. rather than these nutrients having to be consumed directly, in times of scarcity, the body can manufacture them from alternate building blocks. However in the case of essential nutrients or essential fatty acids, the body lacks the needed enzymes to manufacture these ingredients from alternative food sources, therefore needing to be supplied a consistent and steady dietary stream. There are two families of essential fatty acids;

• Omega 3 fatty acids (eaten as alpha-linolenic acid)
• Omega 6 fatty acids (eaten as linoleic acid)

Both are referred to as polyunsaturated fatty acids and in the past their combination was also referred to as Vitamin F. Dietary intake of essential fatty acids as with all nutrients penetrate the gut lining to be up taken and redistributed through the blood stream. From here, essential fatty acids are transported into the epidermis² where they perform several roles vital to the maintenance of a healthy, youthful skin type.

The role of fatty acids in skin

When skin has an adequate supply and balance of essential fatty acids, it’s able to perform optimally in several ways; Essential fatty acids maintain the stratum corneum permeability barrier The top layers of skin are designed to form a barrier which locks in hydration and locks out irritants, allergens and bacteria. Essential fatty acids play a crucial role in this process³. Skin’s permeability barrier is formed by a brick wall structure of dead skin cells locked together with lipid glue – a natural mixture of fatty acids, ceramides and cholesterol. Fatty acids make up a 15% portion of this mixture⁴. Essential fatty acids serve as building blocks for the synthesis of complex lipids⁵ Ceramides are crucial to the maintenance of the skin’s barrier function, accounting for over 50% concentration in the lipid glue maintaining it. Linoleic acid and its breakdown products are required for the synthesis of stratum corneum ceramides⁶.   Essential fatty acids help to maintain epidermal homeostasis The epidermis, the first of 3 layers of skin (followed by the dermis and hypodermis) is in a constant state of renewal – a cycle lasting on average 30 days. Skin, similarly to hair and nails, is consistently being grown, matured and shed. Essential fatty acids help to regulate this 30 day cycle. When skin cells mature they evolve from cells called keretinocytes into corneocytes – the technically dead skin cells responsible for forming an effective skin barrier. This differentiation process is one of many regulated in part by essential fatty acids⁷. Essential fatty acids contribute towards maintenance of skins acid mantle Upon the top layer of the epidermis rests a thin film referred to as skins acid mantle. The acid mantle describes a biological mixture of sweat and sebum with a pH between 4.2-5.6⁸. This acidification assures skin is shielded against bacterial proliferation and therefore infection. At pH levels in excess of 5.6 pathogenic strains of bacteria are able to colonize skin. Essential fatty acids can be processed into free fatty acids which help maintain the acidification of skins acid mantle⁹.

Omega 3 vs. Omega 6

Although originally thought of as having similar effects, omega 3 and 6 essential fatty acids are now known to have very different benefits. Omega 3 essential fatty acids consumed in the diet as linolenic fatty acids act as immune modulators. They may exert anti-inflammatory effects helping to treat inflammatory skin conditions such as acne and eczema. Omega 3 fatty acids are most prolific in the western diet through foods such as;

• Fatty fish e.g. salmon, tuna and mackerel
• Nuts e.g. walnuts
• Chia, hemp and flaxseeds>
• Egg yolks

Omega 6 essential fatty acids (EFAs) consumed as linoleic fatty acids contribute to the formation of skins lipid barrier, its metabolism and ongoing health. Omega 6 EFAs help to prevent bacterial infection, hydration loss, irritation and dryness. The following foods are rich in omega 6 fatty acids;

• Vegetable oils e.g. sunflower
• Poultry e.g. pork and chicken
• Nuts e.g. almonds and brazil nuts
• Dairy e.g. cheese and butter

Increasing dietary intake of omega 3 and 6 fatty acids must be done in consideration of relative quantity. Western diets are often prolific in omega 6 fatty acids and relatively deficient in omega 3 fatty acids. Studies show the ideal ratio of EFAs is 3: 1 of omega 6: omega 3¹⁰¹¹.  Western diets on average follow a ratio in the order of 10: 1. Trans-fatty acids should also be limited, often found in margarine and pre-packed goods, trans-fatty acids can inhibit the metabolism of linoleic acid into long-chain products vital for skin health.

The effect of EFA deficiency or imbalance on skin health

With improper essential fatty acid balance or essential fatty acid deficiency, skin experiences noticeably different metabolism cumulating in 3 marked changes;

• Dryness/water loss

A regular supply of essential fatty acids are required for maintenance of the skin’s barrier properties. When dietary supplies dwindle, skin begins to metabolise oleic acid an omega-9 acid. This process creates mead acid which is unable to match the barrier properties of linoleic acid. As a result trans-epidermal water loss (TEWL) is increased and the appearance of skin is negatively affected¹² leading to or provoking vulnerability for contact dermatitis, a dry skin type, dehydration, eczema and psoriasis.

• Inflammation

Omega 3 fatty acids are involved in many immune mechanisms. Inflammation is the consequence of an activated immune system, when skin believes it has been damaged, the immune system is activated and inflammation is initiated. This process provides a healing supply of nutrients to the local area. Short term inflammation is useful, long-term inflammation is harmful. Omega 3 helps alleviate chronically switched on inflammatory mechanisms, therefore in modes of deficiency, inflammation can progress in an uncontrolled manner leading to skin disorders such as acne, psoriasis and atopic dermatitis¹³.

• Hyperkeratosis

Hyperkeratosis describes the abnormal shedding of dead skin from within hair follicles. In skin disorders such as acne hyperkeratosis allows dead skin cells to become trapped within hair follicles leading to the proliferation of acne causing bacteria, p.acnes. Studies show that those suffering with acne have a very low level of linoleic acid present in their sebum¹⁴. Conversely treatments prescribed for acne such as Isotretinoin, increase sebum levels of linoleic acid¹⁵. In controlled cases of essential fatty acid deficiency, hyperkeratosis is provoked alongside increases in TWEL.

Essential fatty acid supplementation: Does it work?

If an individual is suffering from acne, atopic dermatitis, chronic dryness, psoriasis or a similar inflammatory skin condition, will supplementation with essential fatty acids help to alleviate the condition? Studies have previously shown that essential fatty acid deficiency causes dry, scaly skin, however large scale clinical trials are still required to substantiate the role of supplementation in cases of acne, atopic dermatitis and dry, dehydrated skin. What however has been shown is that;

• Evening primrose oil supplementation can help relieve specific cases of atopic dermatitis

Evening primrose oil is a source of omega 6 fatty acids. Studies show patients with atopic dermatitis and elevated immunoglobulin levels when supplemented with evening primrose oil experience alleviated symptoms¹⁶.

• Daily consumption of 4g evening primrose oil increases sunburn threshold¹⁷

Additionally in a 20 year study of the Inuit population, a population having a markedly high fish consumption, extremely low rates of skin cancers were noted¹⁸.

• High doses of fish oil may help improve the symptoms of psoriasis

Fish oil is a rich source of omega 3 fatty acids and studies have shown that in hospitalised patients with psoriasis intravenously administered doses improved their clinical symptoms¹⁹. Small scale studies also confirm oral supplementation has a positive effect²⁰.

• Fish oil supplementation during pregnancy associated with decreased severity of atopic dermatitis

Atopic dermatitis is in part genetic therefore mothers suffering from the condition have an increased likelihood of passing the causing genetic mutation on to their children. Expectant mothers supplemented with fish oil capsules from week 20 gave birth to children with improved clinical outcomes at 1 year²¹. Additionally decreased intake of trans fatty acids and saturated fatty acids during pregnancy is positively correlates with a lower risk of atopic dermatitis²².

• Omega 3 supplementation may help improve inflammatory skin conditions such as acne²³

The balance between omega 3 and 6 fatty acids is extremely important. Omega 6 fatty acids may be synthesised into pro-inflammatory compounds whereas omega 3 fatty acids exert as anti-inflammatory effects. Supplementation with fish oil has been shown to reduce inflammation and therefore may be helpful in the treatment of chronic inflammatory conditions such as acne. Small scale studies show consumption of 3 fish oil capsules daily for 12 weeks helped improve the condition of moderate to severe acne²⁴.

 

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