6.7 Essential Fatty Acids

There are two essential fatty acids that our body needs to get from the diet and are vital to health. These are omega 3 and omega 6 fatty acids. If they are important for health, what’s the problem with those oils mentioned above? Well, omega 6 is only needed in very small amounts. When consumed in these small amounts it plays some very important roles in our body. Once we get past this amount, this once beneficial compound becomes incredibly problematic.

Dietary fatty acids play many roles in the body. One of their biggest functions is to be the metabolic building blocks for the body’s production of a group of communication compounds called prostaglandins. Essential fatty acids are incorporated into our cell membranes and are liberated by an enzyme called phospholipase, for use in daily metabolic processes – i.e. the formation of prostaglandins.

Prostaglandins regulate several important responses in the body, including the inflammatory response. There are 3 types of prostaglandin – series 1, series 2, and series 3. Series 1 is mildly anti-inflammatory, series 2 is powerfully pro-inflammatory (i.e. switches on and exacerbates inflammation), and series 3 is powerfully anti-inflammatory.

Omega 6

Omega 6, when consumed at a level above our daily needs, is converted into a substance called arachidonic acid. This can then be rapidly converted into series 2 prostaglandins (the powerfully pro-inflammatory variety). On average here in the UK, we are consuming 23 times more omega 6 than we need per day. The end result of this is that we are essentially force-feeding metabolic pathways that manufacture prostaglandins, and our body’s expression of the pro-inflammatory series 2 goes into overdrive. It is pretty logical what’s going to happen here. This leads to a state of sub-clinical (i.e. isn’t immediately obvious, like your big toe swelling up), chronic (ongoing, long-term) inflammation. In its most obvious manifestation, this can exacerbate inflammatory conditions such as arthritis, eczema etc. Probably of more sinister consequence are the small subtle changes that this makes within body tissues when inflammation is present long term. Continual inflammation within tissues can lead to damage to tissues, such as the damage found in cardiovascular disease, when the blood vessel walls become damaged by inflammation, and plaques then form. Inflammatory changes in tissues have also been linked to the instigation of cancer. The other thing this long-term exposure to inflammation can do is affect cell receptor function. The fatty acid content of our cell membranes has a massive effect on the cell and its functioning, and the functioning of the membrane and membrane-bound structures. The cellular structure of great importance here is the insulin receptor. Our fatty acid intake does affect the performance of this.

Omega 3

On the flip side, the other big dietary fatty acid, one you have probably heard a great deal about. Omega 3 fatty acids. These amazing fatty acids are literally like the antidote to the above. There are 3 main types of omega 3 fatty acids – ALA, EPA, and DHA. EPA is a powerful natural inflammatory mediator; DHA is more of a structural fatty acid and is vital for the production and maintenance of the myelin sheath, the fatty outer membrane of nerve cells; ALA is the plant form of omega-3, and is nowhere near as metabolically active as EPA and DHA, so it needs to be converted into these. Humans are not good at doing this, which is why it’s best to get omega-3 from fish.

EPA omega 3 fatty acids are considered the Rolls Royce of natural inflammatory mediators. It’s basically the metabolic building block of the body’s own inherent anti-inflammatory chemicals, a group of very powerful compounds called prostaglandins. Some prostaglandins switch inflammation on and enhance pain signaling and muscle contraction (think menstrual or digestive cramps), whereas others reduce inflammation and pain signaling. They require fatty acids for their manufacture, and different fatty acids will deliver a different end product- a different class of prostaglandins known as series 3, which are powerfully anti-inflammatory. By increasing our intake of EPA, we greatly encourage the body to produce series 3 prostaglandins, thus helping manage inflammatory episodes within the body. You’ll find oily fish is the best source for EPA omega 3 fatty acids.

DHA doesn’t have the potent anti-inflammatory activity of EPA, but a new class of compounds called resolvins, which are metabolites of EPA and DHA, have been discovered (metabolites are substances produced by metabolism). These compounds can actually cause a local reversal of inflammatory events, and so may help to resolve the issue. You’ll find DHA in algae, seafood and oily fish.

ALA is the plant-derived form of omega-3, found in foods such as flaxseeds, chia, hemp, soya, and walnuts. While there are some health benefits associated with ALA, it’s really the poor cousin of EPA and DHA. Why? Because we need to convert it into EPA and DHA first, using a whole selection of enzymatic processes. Some animals, such as salmon, are fabulous at doing this. Human beings are not, in fact, we’re dreadful at it. We manage to convert a tiny percentage of dietary ALA into EPA and DHA- perhaps 12% if that. Many people, usually those defending dietary ideals or commercial interests, will tell you that many of the properties associated with EPA and DHA (such as anti-inflammatory activity, effects on mood and neurological functions) can be gained from ALA. Alas, this simply isn’t the case. We just don’t convert it effectively enough. To get those effects, you need EPA and DHA.