María Monterrubio

Our body cannot make essential fatty acids, yet they are indispensable for our health. Thus, we have to ingest them. The requirements of omega 6 and 3 essential fatty acids in the skin differ from those in other organs. Discover how they work within your skin. And whether you need an extra supply of any of them through dietary changes or topical treatments.

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Last updated: March 26, 2022

Hi everybody! Follow along and learn what Essential Fatty Acids (EFAs) are, whether you have any EFA deficiency, why that would impact your skin, and how to solve it.

What are essential fatty acids?

The Essential Fatty Acids (EFAs) for humans are alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). They are Poly-Unsaturated Fatty Acids (or PUFAs). And comprise a short chain of 18 carbons with several double bonds (thus, they are called poly-unsaturated).

Linoleic acid (omega-6) is also called 18:2 (n-6), which denotes that it contains two consecutive double bonds from carbon 6 [when you count from the omega end]. Take a look at the image below.

Following the same pattern, alpha-linolenic acid (omega-3) is also named 18:3 (n-3). It contains three consecutive double bonds starting at the carbon 3 [again when you count from the omega end]. 

When they are inside our cells, both essential fatty acid molecules undergo the elongation of their hydrocarbon chain (via enzymatic processes) and give rise to other non-essential long-chain Poly-Unsaturated Fatty Acids (see the images below). Specifically, alpha-linolenic acid is a precursor of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). And linoleic acid gives rise to gamma-linoleic acid (GLA) and araquidonic acid (AA).

The mentioned long-chain PUFAs, albeit non-essential, play key roles in our bodies (including the skin). I will go through that in an upcoming article. We will focus now on how the deficiency or imbalance of the EFAs can affect your skin. And how to solve that!

Can you become Essential Fatty Acid Deficient? How would that impact your skin?

Essential Fatty Acid deficiency is rare, but it can happen. And, both in children and adults, you would quickly see skin symptoms. Mainly dermatitis with dry, flaky, or cracking skin (or scalp). And, often, skin with a bumpy texture on the back of the arms. You may also see signs of eczema, slow healing, and even hair loss. 

You can restore essential fatty acids in the skin (and any other organ) by ingesting adequate amounts of alpha-linolenic acid (high in walnuts, wild salmon, or chia seeds, for instance) and linoleic acid – present, for example, in poultry or vegetable oils –.

Yet, not all vegetable oils are good food choices to replenish your linoleic acid. One of the best, due to its far superior health benefits, is extra virgin olive oil. It has linoleic acid (omega-6) and omega-3 fatty acids (in lower amounts). Besides, it contains other healthy fatty acids (such as oleic acid, an omega-9 fatty acid). 

A swifter way to recover any cutaneous signs of low essential fatty acids involves the application of vegetable oil to the skin, such as virgin, cold-pressed sea buckthorn oil, or rosehip oil, both packed with linoleic acid, alpha-linolenic acid, and other PUFAs. If you don’t have any of those available or need to cover a broad skin area, you can also apply common cooking oils such as sunflower oil or corn oil.

Why is it crucial to keep an adequate omega 3 to omega 6 ratio?

Many of us have a more or less pronounced imbalance between omega 3 and 6 (essential) fatty acids. The modern western diet usually is much richer in omega-6 than omega-3 fatty acids (partly due to excessive amounts of lower-quality vegetable oils).

Does that mean that linoleic and other omega-6 fatty acids are not as good as the omega 3s? Not at all, they are both indispensable, and physicians recommend the intake of a 1:1 omega-3 to omega-6 ratio. It is the excess in omega-6s that is problematic. Let me explain that!

The elongation of linoleic acid (omega-6 EFA) yields arachidonic acid (a long chain PUFA). Arachidonic acid is the precursor of prostaglandins, which are key signaling molecules. They ensure the well-functioning of the immune system and trigger required healing processes throughout the body. However, prostaglandins should work at low levels and degrade quickly after doing their job. Otherwise, they promote too much inflammation within us. Thus, high levels of prostaglandins are pro-inflammatory.

The same enzymes act upon alpha-linolenic and linoleic acids to give rise to the long-chain PUFAs I mentioned before (including arachidonic acid). Therefore, if there’s not enough alpha-linolenic acid (omega-3) or too much linoleic acid (omega-6), those enzymes yield more arachidonic acid than required.

Those high arachidonic acid levels will lead to too many prostaglandins and hence too much inflammation, which generates or exacerbates so many cutaneous and non-cutaneous diseases. We don’t want that!

So, keep an eye on your supply of omega 3s since they keep non-required inflammatory processes at bay – in the skin and other organs –. 

However, the skin must have a steady and significant supply of linoleic acid (omega-6 EFA) to be a barrier between the internal organs and the external environment.

Why can the skin not make a barrier without linoleic acid?

The skin has a constant demand for omega-6 essential fatty acids. Without adequate linoleic acid availability, we could not develop a functional top layer of the skin (and waterproof permeability barrier). 

The lack of a proper epidermal barrier would promote water evaporation first from the skin and afterward from other organs. Thus, we would end up dehydrated and unprotected from the external environment. And that would lead to serious health issues (not just skin troubles).

Linoleic acid enables the adequate formation of the stratum corneum (the top, dead layer of the skin).

First, what entails a healthy stratum corneum?

The epidermis comprises various layers of cells (called keratinocytes; see the image below):

· the basal layer (SB, or stratum basale): the most internal. It contains highly proliferative cells that continuously duplicate, providing a constant supply of new keratinocytes. Those replenish the outer skin layers (as they move across the different epidermal levels towards the skin surface). See the image below.

· the spinous layer (SS, or stratum spinosum): the oldest keratinocytes in the basal layer eventually migrate upwards and become part of the stratum spinosum. The stratum spinosum is composed of several layers of slowly proliferating keratinocytes.

· the granular layer (SG, stratum granulosum): where keratinocytes prepare to die. They get ready for that by synthesizing two primary types of granules. Those granules release their contents at the skin surface to help form the stratum corneum.

There, the keratinocytes generate keratohyalin granules on the one hand. Take a look at the image below. And granules called lamellar bodies (which contain mainly lipids and lipid- and protein-processing enzymes).

· the stratum corneum (SC, see the image above): made up of flattened, dead keratinocytes (known as corneocytes). It also comprises the intercellular cement, intercellular lipids released from the lamellar bodies. And natural moisturizing factors liberated from the keratohyalin granules.

The keratinocytes in the stratum corneum (SC) are continuously shed off at the skin surface by the action of several enzymes (and that’s why the skin constantly peels off).

Then why is linoleic acid indispensable?

The intercellular cement at the stratum corneum comprises various lipid types: 50% ceramides, 27% cholesterol, 10% fatty acids, and a small number of cholesterol derivatives.

Linoleic acid is required for the synthesis and metabolism of essential ceramides at the stratum corneum (called acyl-glucosylceramides). 

Acyl-glucosylceramides arise at the skin surface from the lamellar bodies. And contribute to building a specialized structure around the dead keratinocytes, the corneocyte lipid envelope. That corneocyte lipid envelope enables the binding of cells with the intercellular cement around them.

That is mandatory for the formation of a compact stratum corneum. But it only occurs when the acyl-glucosylceramides comprise linoleic acid (and are thus called linoleyl-glucosylceramides – see the image below).

Then the stratum corneum is not impermeable enough when there is a linoleic acid deficiency. That results in too much water loss through the skin, and it becomes dry and flaky. So, if your skin feels like that, you might have some degree of cutaneous linoleic acid deficiency.

That situation can quickly improve after spreading a source of linoleic acid on top of the skin (such as sunflower oil). The applied molecules of linoleic acid will rapidly embed within the stratum corneum, generate linoleyl-glucosylceramides, form a quality epidermal barrier, and restore dry skin.

In addition, people with acne-prone oily skin often have lower linoleic acid on the skin and scalp surface. That seems to be related to the quality and quantity of their sebum. Moreover, the omega-6 essential fatty acid shortage is more pronounced in comedones. And the size of those can diminish significantly with the topical application of linoleic acid. You can find scientific evidence of all that within the references at the bottom of this article. 

Thus, you may also want to optimize your cutaneous EFAs if your skin is oily and acne-prone. Even if you are eating enough omega-6 and -3 fatty acids, you might want to spread one or two rosehip oil drops on your skin at nighttime. That might sound counterproductive for oily skin but may well work.

Nowadays, so much health advice highlights the importance of ingesting higher quantities of omega-3 fatty acids. And there is nothing wrong with that. But let’s not forget that we also need a decent amount of quality omega-6 essential fatty acids. That means healthy sources of linoleic acid (orally and perhaps topically too).

I hope you have liked this article. Please leave any questions below or send me a message on Instagram (@drmariamonterrubio). And if you like the content I create, I would love it if you subscribed to this blog and followed me on Instagram!

See you soon,

María

For your reference:

The permeability barrier in essential fatty acid deficiency: evidence for a direct role for linoleic acid in barrier function. Elias PM et al., J Invest Dermatol, 1980; 74 (4): 230-3.

Acylceramide is a key player in skin barrier function: insight into the molecular mechanisms of skin barrier formation and ichthyosis pathogenesis. Akiyama M, FEBS J, 2021; 288 (7): 2119-2130.

Octadecadienoic acids in the skin surface lipids of acne patients and normal subjects. Morello AM et al., J Invest Dermatol, 1976; 66 (5): 319-23.

The composition of the ceramides from human stratum corneum and from comedones. Wertz PW et al., J Invest Dermatol, 1985; 84 (5): 410-2.

Digital image analysis of the effect of topically applied linoleic acid on acne microcomedones. Letawe C et al., Clin Exp Dermatol, 1998; 23 (2): 56-8.

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