Most of us understand or at least appreciate that omega-3s can confer benefits on our health.
But did you know that there are three types of omega-3 fatty acid, each associated with its own roles and actions in the body?
In this article we aim to focus our attention on EPA (eicosapentaenoic acid), a marine omega-3 well studied in the field of clinical nutrition.
Indeed there may be circumstances under which prioritising EPA becomes important, particularly in relation to mental health but also for pregnancy, cardiovascular health, joint problems and weight loss.
Eicosapentaenoic acid is a type of polyunsaturated fatty acid (PUFA) commonly found in the oils of cold-water fish such as sardines, herring, mackerel, trout and salmon.
However, it should be noted that most fish contain higher levels of DHA (docosahexaenoic acid) than EPA. The EPA molecule is made up of 20 carbon atoms and five double bonds.
Like us, fish are unable to effectively biosynthesise EPA and DHA, both of which are produced by plankton which the fish then eat.
However, the presence of these fatty acids in the systems of fish equips them for living in icy-cold waters, working as a kind of biological antifreeze. The oils also facilitate oxygen uptake.
To a large extent EPA and DHA work together, and therefore their roles – at least in some instances – are indivisible.
For example, both contribute to the maintenance of healthy blood pressure and blood triglyceride levels, and by extension healthy heart function.
It is this partnership between the Essential Fatty Acids – this artery-protecting, triglyceride-lowering teamwork – which makes omega-3 one of the most beneficial nutrients for cardiovascular health.
EPA, however, has many benefits on its own, and so it is worthwhile parsing out their effects a little. The precursor of series 3 prostaglandins, EPA has beneficial knock-on effects for our kidneys, platelets, immune system, arteries and triglyceride levels.
As well as blocking the production of pro-inflammatory series 2 prostaglandins made from omega-6 fatty acids, s3 PGs help prevent problems involving clot formation, such as pulmonary embolism.
Let’s look at some other specific examples where EPA can have a positive effect.
The anti-depressive effects of EPA were noted in a 2009 study published in the Journal of the American College of Nutrition.
Researchers learned that although the effect of pure DHA on depression scores was negligible, “symptoms of depression were reduced in 13 studies using supplements containing greater than 50% EPA and in 8 studies using pure ethyl-EPA.”
A separate study published two years later assessed 15 different trials with close to 1,000 participants and came to the same conclusion: that omega supplements comprised of 60% or more EPA were the most effective in reducing depression.
Finally, a 2012 study featuring 81 participants showed benefits for those who received 1,000 mg per day of EPA over a period of 12 weeks; in fact, six patients demonstrated a 50% or greater improvement on the Hamilton Depression Rating Scale, compared to zero for the DHA group!
One reason for this is that EPA is an essential hormonal component of brain cells, and as such has a clear influence on the way cells interact with one another via the bloodstream.
Depression is quite clearly tied to the way in which cells communicate with neurotransmitters such as dopamine and serotonin, which regulate the perception of emotions.
There’s even evidence that post-natal depression is linked to low levels of omega-3 in the brain and tissues of the mother.
If you are suffering from depression, you should strive to maintain a high intake of EPA and monitor the results; you might also consider using an EPA-rich fish oil supplement in conjunction with an antidepressant. Diet, as ever, can be helpful.
Anxiety has a relevant co-morbidity with depression, and indeed many doctors speculate that increased cellular inflammation in the brain is the root cause of both disorders. A therapeutic dose of EPA, therefore, may provide the same benefits for both conditions.
This topic was well explored by the biochemist Barry Sears, PhD, in an article for Psychology Today.
Dr. Sears references a 2008 study which showed decreases in anxiety among substance abusers who maintained a high EPA intake of 2,000mg per day. (Interestingly, a higher DHA intake correlated with lower end-of-trial anger scores.)
Though the study concluded that the topic should be further explored for various psychiatric conditions, there have been precious few conducted in the decade since.
The benefits of DHA fish oil for pregnancy are well understood, with omega-3s contributing to the normal visual development of infants up to 12 months.
Maternal intake also contributes to the normal brain development of the foetus and breastfed infant, as well as the normal development of the eye. DHA is an absolutely crucial nutrient for early life.
But what about EPA?
As it transpires, many of the studies showing omega-3 benefits for pregnant women used fish oil supplements containing both EPA and DHA.
While DHA provides more specific benefits, such as those mentioned above, the intake of general omega-3 supplements has been shown to correlate with larger birth weights, prolonged pregnancy without detrimental effects and healthy nervous system development in the foetus.
There is even some evidence to suggest that fish oil can reduce the risk of premature birth.
Clearly there are benefits to both EPA and DHA during pregnancy, and so the focus should be on obtaining a healthy ratio of EFAs in any supplement consumed during the period.
Because both EPA and DHA activate receptors in the body that speed up metabolic rate, fish oils have shown promise for weight loss.
That isn’t the only reason, though. Some studies show that fish oil increases satiety after a meal, thereby indirectly reducing your calorie intake.
However, other research outcomes have actually shown the opposite, with effects varying depending on health status, body weight, nutrition and who knows how many other factors.
While more investigation is needed, it is interesting to note that EPA has been identified as the PUFA which counters reductions in levels of leptin (the satiety hormone) which occur during weight loss. In other words, weight loss provokes a fall in satiety, leading to overeating (and weight gain) – and EPA can prevent this.
Omega-3 is especially useful for fat-burning when combined with aerobic exercise, because it improves the flow of blood to muscles during training. Indeed, researchers at the University of South Australia tested whether tuna oil – a rich source of omega-3s – could provide weight-loss benefits when used as an adjunct.
The group who followed the protocol lost an average of 4.5 lbs over the 3-month period, while those who took fish oil and did not exercise lost no weight.
Perhaps the take-home should be this: do not consume fish oil and expect the pounds to fall off. But if you are exercising, an omega supplement could yield better rewards for your efforts. An EPA-enriched diet could also help to preserve lean body mass.
As mentioned, EPA works with DHA to help maintain healthy blood pressure and triglyceride levels. However, it appears that EPA by itself has major benefits for cardiovascular health.
In a 2018 study, the prescription fish oil drug Vascepa was linked with a 25% reduced risk of heart attack and stroke. Vascepa is a pure EPA supplement, delivering 1g of EPA per capsule.
The high EPA fish oil was tested on 8,179 patients for a period of five years. Every volunteer had elevated levels of triglycerides at the outset, and they also had either established cardiovascular disease or Type 2 diabetes, plus a minimum of one other cardiovascular risk factor.
After the study ended, the patients who received Vascepa were shown to be 25% less likely to have a coronary event than those in the control group.
It seemed the drug’s effectiveness stemmed from its ability to decrease triglycerides without increasing LDL (‘bad cholesterol’) levels.
As mentioned, most fish contain a higher DHA content than EPA; hence why it is often necessary to use a highly concentrated EPA supplement to achieve a significant therapeutic dosage.
Certainly you do not want to have to eat the quantity of fish necessary to consistently hit such a daily target, both due to the risk of trace mercury and other heavy metals present in fish and also because chomping your way through that much seafood would be incredibly onerous!
That said, regularly eating 2-4 portions of oily fish per week will ensure a balanced intake of DHA and EPA – and so this should remain a priority.
If you do not eat fish, an EFA-rich oil such as flaxseed oil will do: it is the most omega-3 rich of all edible oils, though its main component is Alpha-Linoleic Acid (ALA), the precursor to EPA and DHA.
Many people may wonder how much EPA constitutes a ‘therapeutic dose’. Certainly there will be some therapeutic benefits to eating oily fish a few times per week, but in many of the aforementioned studies a higher daily dose was used: anywhere between 500mg and 2,000mg EPA. To put that in context, a can of white tuna provides just 200mg of EPA.
UnoCardio EPA 90% is a pharmaceutical-grade fish oil supplement from WHC, a Belgian company well known for the purity and quality of their products.
Unlike the vast majority of supplements which contain a roughly equal balance of EPA and DHA, this one is skewed heavily in favour of EPA: one serving of two softgels provides 1000mg EPA and just 5mg DHA.
Of course, if you require just 500mg EPA per day, simply take one softgel. In addition to the appreciable omega-3 content, UnoCardio EPA 90% contains both phosphatidylserine (100% PS) and astaxanthin, both of which have their own benefits – particularly for neurological conditions and metabolic syndrome.
UnoCardio EPA 90%, therefore, is an ideal supplement for those wishing to enjoy the flexible benefits of omega-3.
Like all WHC supplements, the product is third party certified, uses sustainably-sourced fish and cold and environmentally-friendly technology. It’s also unflavoured and free from beef gelatine, gluten and lactose.
Hopefully this article has been of value. Clearly there are very many health benefits associated with omega-3 fatty acids, but perhaps a closer look at eicosapentaenoic acid was long overdue.
Of course, we would recommend getting the synergistic benefits of fish oil by eating a few portions of sustainably-sourced fatty fish each week. However, a fish oil supplement is a great choice if you want a continuous therapeutic dosage.
As indicated, striving for a high intake of EPA in particular comes with a number of positives.
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Anxiety has a relevant co-morbidity with depression, and indeed many doctors speculate that increased cellular inflammation in the brain is the root cause of both disorders.