By now it is safe to assume that we all know the health benefits of Omega 3 fatty acids. But how important are they really?
Well, pretty important.
People who have more Omega 3 in their system have larger, more functional brains. This is a scientific fact. In context, our brains have around 100 billion neurons, their total mass is comprised of approximately 8% Omega 3 fatty acids!
In 2007, researchers released the findings from a landmark study in the elderly which found that those who consumed Omega 3 had larger brain volumes and increased grey matter (the part of our brain that pretty much does everything; including controlling our muscles, interpreting sensory information, storing memories, making us think, talk and have emotions). But possibly the greatest finding of all was that the researchers noticed that Omega 3 increased cellular development in those parts of the brain associated with happiness! How amazing is that?
The common consensus used to be that pregnant women should limit their fish consumption during pregnancy. Then three years ago the medical journal Lancet published a study conducted in 12 000 pregnant women who obtained Omega 3 fatty acids through consuming fish versus those who hadn’t, and the results were staggering: They showed that the children of those women who hadn’t eaten fish, consistently scored lower on IQ tests than the children from the Omega 3 cohort. During the development of the foetus, Omega 3s accumulate in the brain and are vital in its development.
Our brains are literally dependent on Omega 3
These polyunsaturated fatty acids are important for healthy brain, heart and liver function as well as aiding other parts of our anatomy to operate optimally. They support the structure of brain cells, decrease the damage done by inflammation and oxidisation in the brain and also upregulate the production of important neurotransmitters (like serotonin – our happy molecule). In fact, Omega 3 consumption is so vital for human health, that according to a meta analysis conducted by Harvard University in 2009, it was estimated that nearly 100 000 mortalities in the US could be prevented if people ingested more Omega 3!
Our bodies cannot naturally make Omega 3 fatty acids. We obtain these from our diet. There are 3 different types of fatty acid used by the human body (this is where the ‘3’ comes from). These are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). EPA and DHA are the ones most widely used in the body, in fact, once ingested ALA is converted into EPA and DHA. ALA is the plant version of EPA and DHA.
Humans derive their essential Omega 3s from Krill oil, cod liver oil, phytoplankton, salmon oil, flaxseed oil, kelp and on and on. The shelves are now saturated with products containing this beneficial fatty acid.
But how do the different formulations/sources measure up against each other?
First, let’s take a closer look at what Omega 3 fatty acids actually are.
EPA and DHA – what’s the difference?
As mentioned, there are two types of Omega 3 fatty acids used by the body. Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA). Whilst these may be a mouthful to say, it is important to understand what makes them distinct from each other – as different sources contain varying ratios of these two fatty acids
Both EPA and DHA are the principal by-products of alpha linolenic acid (or ALA, the type of fatty acid itself- derived from seed consumption) metabolism, it appears that the conversion process happens at a more optimal rate (15% higher) in women than in men.
DHA is important. A deficiency in DHA has been linked with cognitive decline, as its absence promotes increased neuronal cell death (apoptosis.) Decreased levels of DHA have been observed in the brain tissue of severely depressed patients.
Humans obtain DHA naturally from their mother’s milk and throughout life by consuming certain food groups, mainly marine organisms (fish, krill and algae/phytoplankton) though flax seeds contain a high percentage of DHA.
The structural integrity of our cerebral cortex (the part of our brain that deals with information from our sensory organs and also controls all voluntary muscle movement) relies heavily on the presence of DHA (it makes up 40% of all polyunsaturated fatty acids in the cortex – half the weight of the plasma membrane of a nerve cell is made of DHA.) This fatty acid is also important for the development of sperm in the testes and also the retinal layer of the eye and the structure and make-up of our skin (our largest organ.) In the retina, DHA comprises up to 60% of all polyunsaturated fatty acids.
DHA helps modulate the synapses that communicate electrical pulses into chemical messages between neurons. It also facilitates the transport of the essential nutritional compounds taurine, choline and glycine.
As you can see from the above graphic, EPA has a longer chain than DHA. EPA is often referred to as a longer chain (20 carbon bases) Omega-3 fatty acid. Sometimes it is also called timnodonic acid. EPA is also a natural precursor to DHA, and is metabolically difficult for us to synthesise – so in many ways it is more important for us to get high concentrations of this fatty acid than DHA – because even though the EPA can be converted into DHA, the reverse is not true.
Clinical studies have shown that EPA has the ability to reduce symptoms in people with depression and schizophrenia. People who consumed Omega-3 with a higher EPA:DHA ratio showed greater reduction in the severity of their symptoms. It also has positive, measurable, effects on healthy liver functioning.
In our diet it EPA found mostly in fatty fish, in eggs, and in smaller amounts in seaweed and phytoplankton/algae.
Fish Oil Omega 3
In terms of Omega 3 supplementation, fish oil was what started it all off (the ‘alpha’). Omega 3 used to be derived from fish livers (most of us can probably remember being forced to ingest yucky cod liver oil as children) but the extraction techniques have now become so sophisticated, that modern fish oil derives it from the whole fish.
It has been measured that fatty fish (salmon, mackerel, and sardines) provide about 1 g of Omega-3 fatty acids (EPA:DHA ratios alter depending on species) for every 100 g of fish. Recently, suppliers of fish oil supplements are attempting to improve the purity of the Omega 3’s obtained from fish, as well as increasing the EPA:DHA ratio.
It is important to note that if you obtain your Omega-3’s from fish, that frying the fish in other oils has the ability to cancel the protective properties of the Omega-3 ingested. Nutritionists recommend that you either bake or boil the fish (or eat raw) as opposed to frying it.
As opposed to krill and phytoplankton (which have seasonal variations of Omega 3 concentrations,) fish oil has a standard concentration all year round.
Phytoplankton Omega 3
Phytoplankton (alternatively, algae) are marine microbes that live in nitrogen-rich parts of the sea. Usually phytoplankton live fairly close to the surface as they utilise UV radiation from the sun to manufacture many important nutrients (including EPA and DHA). Incidentally, phytoplankton are one of the longest surviving multicellular life forms on this Earth – they gave birth to all land plants about 500 million years ago.
Compared to fish, phytoplankton have a much higher Omega 3 content per gram of body weight. In fact staggeringly, in one species, the thraustochytrids, Omega 3 fatty acids make up over half of the body weight!
In general phytoplankton’s omega-3 content is nearly twice as high (per 100 g) as that of any species of fatty fish. Fish and all other marine organisms obtain their Omega-3 fatty acid content from ingesting phytoplankton.
So it appears that sourcing omega 3’s from phytoplankton makes sense from a sustainability point of view (getting it directly from the source.) However, phytoplankton has a much lower ratio of EPA:DHA than Omega 3’s obtained from fish oil.
Krill Oil Omega 3
Krill form the basis of the Antarctic food web. They are tiny marine crustaceans (resembling shrimp) that are found in all oceans of the world.
But because these smaller creatures are the main food source for larger fish (some whales and dolphins, for instance, feed exclusively on krill), harvesting these smaller varieties is depriving entire species of their food supply.
Krill oil offers some advantages over fish oil. Krill are much smaller than fish and as such they cannot store toxins such as mercury, hence krill oil is free from some of the contaminants found in larger fish. It also has a higher antioxidant content, including vitamins A and E and astaxanthin. Krill oil also has a higher ratio of Omega 3 to Omega 6 essential fatty acids, so can help redress the disproportionate level of Omega 6s often present in the modern diet.
Furthermore, krill contain phospholipid liposomes (natural pouches that bind cellular receptors and bring Omega 3 and antioxidants directly into the cells) and this enhances the absorption of these important nutrients when compared to triglyceride carriers found in standard fish oils.
Flaxseed Oil Omega 3
The first advantage of this formulation is that it is vegetarian. Flaxseed oil is sourced from the flax plant Linum usitatissimum, commonly known as Linseed. Flaxseed oil has the highest ALA content of any vegetarian source (plant). It is the most stable form of ALA because flaxseed oil contains high amounts of the protective antioxidant Vitamin E, compared with fish oil Omega 3s which do not.
One flax seed is made up of nearly 40% oil (by weight) and of this oil, 55% of it is Omega 3 fatty acid. Every tablespoon of flaxseed oil contains around 8 grams of ALA.
Interestingly, some clinical studies have shown that people who suffer from irritations in the gut (Crohn’s disease, irritable bowel syndrome, inflammatory bowel disorder) benefit from flaxseed oil as it appears to have a soothing effect on the mucosal lining of the gut.
How does the Food Chain factor into all this?
In biology class we learned that all animals on earth exist in a subtle interconnected ‘hierarchy’ organised via an intricate web of animals that are dependent on the presence of other animal species for survival (mainly as a food source). The relationship is complex and calling it a ‘hierarchy’ is a little misleading – even ‘chain’ does not describe what the reality looks like. A web would be the most apt descriptor. Let’s look at the ocean as an example:
Phytoplankton would be at the very base of the chain (or web – where it all starts) – Sharks and Orcas would sit at the top. They regulate the whole ocean food web. Reducing krill and fish populations to obtain Omega 3 removes a vital connection in this web and the knock on effects can be drastic.
Furthermore, taking the lifespan of a fish into account, we learn that fish can accumulate a lot of environmental contaminants and pollution in their life time, whereas phytoplankton and algae have a much shorter lifespan and hence don’t accumulate these toxins.
On top of this, our fish stocks have already been taxed the world over, due to their popularity in most cultures as a major food source. 1.4 billion hooks (laden with 1.4 billion fish) are cast every year by commercial fishermen. Trawl nets with catch depths of over 23 000 m² bring in over 500 tons of marine life (think 4 rugby pitches filled with marine life) with each haul – shockingly, most of the marine life is ‘unusable’ by-catch that just gets tossed over board again. Adding supplement derived omega-3 from fish to this industry is argued by some to be unsustainable.
In the USA alone, consumers spend over $1 billion dollars every year on fish oil! That’s a lot of fish.
So which Omega 3 to choose?
This depends on what you are trying to achieve, how highly you value sustainability and whether you are vegetarian or not. You can increase your Omega 3 naturally by ingesting foods with high concentrations. Besides fatty fish, great dietary sources of Omega 3s are chia seeds, walnuts, flaxseeds, canola oil, olive oil and pumpkin seeds.
Hopefully this article has helped outline the subtle differences between the varying Omega 3s out there. The ultimate choice remains yours however.
But choose. You must. For your brain, your heart, your liver – indeed, your whole body!
by Christopher von Roy BSc, MSc, DCP Immunology
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2667673 “The Preventable Causes of Death in the United States: Comparative Risk Assessment of Dietary, Lifestyle, and Metabolic Risk Factors”
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