In scientific terms Omega 3 fatty acids are long chain polyunsaturated essential fatty acids (PUFAs) with three cis double bonds, with the first double bond located at the Omega end of the chain on the third carbon atom from the end. You might also see Omega 3 fatty acids written as w-3 or n-3.
Think of the Omega chain as a bit like a backbone with connections all the way along it and like the first letter of the Greek alphabet the beginning of the Omega 3 chain is called the alpha end of the chain, and this happens to be the carboxylic acid end of the chain, and the end of the chain is the Omega end of the chain or methyl end.
Omega 3 has a long chain, or backbone, compared to some other fatty acid chains and because in their configuration they have more than one cis double bond, separated by a single methylene bridge, they are classed as polyunsaturated fatty acids or PUFAs. Cis means ‘on the same side’ as opposed to Trans, which means ‘across from’. Omega 3 is called Omega 3 simply because of the position of the first double bond.
Just for clarification, fatty acid chains with only one double bond are called monounsaturated so Olive oil for example. Monounsaturated fats or MUFAs tend to be liquid at room temperature but would start to solidify a bit if they are chilled. They are fairly stable but you can’t heat them to high temperatures in cooking or their structure will change and they can become unhealthy for humans to eat.
PUFAs are much more unstable than other fats and highly susceptible to going rancid so shouldn’t be used for cooking and should be stored in the fridge.
If there are no double bonds at all then the fat is called saturated fat. It is stable so ideal for cooking and is usually solid at room temperature. This type of fat mostly comes from animal fats.
Within all fats there are fatty acids. Essential fatty acids like the ones in Omega 3 fats are called essential in that the body needs them to maintain and promote good health but the body cannot make them so they need to be sourced from the diet. To explore Omega 3 a bit more, there are in fact many different types of Omega 3 fatty acids but the three types which are most important as far as human health is concerned are ALA, EPA and DHA.
Alpha Linolenic Acid or ALA is an Omega 3 fatty acid with an 18 carbon chain and three cis double bonds with of course the first double bond located at the third carbon atom from the n- end of the chain. You will sometimes see it written as 18:3(n-3). ALA is found in some plant oils and vegetables.
Eicosapentaenoic Acid or EPA has a 20 carbon chain with five cis double bonds so may be written as 20:5(n-3) and like the other Omega 3 fatty acids it has its first double bond situated at the third carbon atom from the Omega end of the chain. EPA is commonly found in oily fish, marine oils, and algae.
Docosahexaenoic Acid or DHA, also written as 22:6(n-3) in the nomenclature of fatty acids, has a 22 carbon chain with six cis double bonds, the first at the third carbon atom from the end. Like EPA, DHA is commonly found in marine oils and algae.
WHY IS OMEGA 3 SO IMPORTANT?
Omega 3 fatty acids are important because our bodies need Omega 3 for the metabolism to work properly and these EFAs play an important role in many physiological functions within the body and the brain; however, as we cannot produce them or synthesize them we have to source them from the diet.
Theoretically, if we get enough ALA in our diets, our bodies should be able to convert this into EPA and DHA. However, our ability to do this has been significantly impaired in recent decades, more than likely because of changes in our diet with the introduction of vegetable oils, cereals and grains and processed foods.
There is also evidence that ageing reduces our ability to convert ALA into EPA and DHA and there appears to be differences between men and women too regarding how efficiently they are able to do this.
The bottom line though, is that most studies agree that the ability to convert ALA into the longer chain more important fatty acids of EPA and DHA is severely limited and in most cases much lower than 5 percent.
This means that most of us are not getting enough Omega 3 in our diets in order to maintain health and some experts believe that the decline of Omega 3 in the diet along with an increase of another Essential Fatty Acid called Omega 6, is the single most common reason for the rise in diseases like cancer, heart disease and depression that we have seen over the past few decades, and that is despite advances in medical science and understanding.
What is Omega 6?
Omega 6 is another family of polyunsaturated fatty acids except that this time they have a common double bond located at the sixth carbon atom from the Omega end of the chain. Just like Omega 3 fatty acids, Omega 6 fatty acids are essential for good health and yet our bodies cannot make them so we have to get them from the diet. Unlike Omega 3 though, Omega 6 is not difficult to find in our diets, particularly Western diets as these fatty acids are abundant in processed foods, vegetable oils, cereals, bakery items, dairy produce and meats.
Omega 3 fatty acids help to regulate many physiological functions in the body and the brain and also play a role in the production of something called eicosanoids. Eicosanoids can be described as messenger molecules in the body and are produced from either Omega 3 or Omega 6 fatty acids and as such can either be pro-inflammatory if coming from Omega 6 or less inflammatory if coming from Omega 3.
It is the interplay of these two different types of Omega fatty acids that can have such a profound effect on our health.
Omega 3 Omega 6
Reduces inflammation Increases inflammation
Helps to inhibit tumour growth Helps to promote tumour growth
Thins the blood Thickens the blood
Helps keeps cell membranes fluid Reduces fluidity in cell membranes
Long ago, before the introduction of processed foods, grains, cereals and vegetable oils into our diets, we had a ratio of Omega 6 to Omega 3 of roughly 1:1. Now that ratio is more like 10:1 or even in some cases as much as twenty five to thirty times higher in favour of Omega 6.
Bearing in mind the role that these fatty acids play in the body it isn’t hard to see how this imbalance might have a devastating effect on our health and the evidence suggests that it is.
Omega 6 isn’t the bad guy though, because we need Omega 6 as much as we need Omega 3. Take something as important as blood clotting for example, we need our blood to be able to clot in order to stop us from bleeding to death, however, we also need our blood to be thin enough not to cause excessive clotting and possible thrombosis. This is only one example of the interplay of Omega 3 and Omega 6 but it gives you an idea of how important balance is.
Inflammation – Omega 3 applies the brakes
When the two fatty acids exist together they basically compete to be transformed into Eicosanoids and we need this to be roughly equal. However, when one is completely dominant, then eventually the body and health is going to suffer.
Many experts now believe that inflammation in the body, caused by an imbalance of Omega 3 to Omega 6, is the main cause of most health problems today.
Doctor Michael Roizen, a former Chair of a Food and Drug Administration advisory committee and a former editor for several medical journals as well as a best selling author, a co founder of RealAge Inc, and a world expert on preventative medicine, is one of them. He says:
“The ratio of omega-6 to omega-3 is important, the higher the ratio, the more omega-6, or the less omega-3, the more inflammation”
Another world expert, a Dr Andrew L Stoll says in his book The Omega 3 Connection:
“High levels of Omega 6 are almost always associated with inflammation; omega 3 applies the brakes.”
Essential Fatty Acid Deficiency
An Omega 6 deficiency is not common due to the fact that it is so abundant in our diets. An Omega 3 deficiency would be much more common and some of the signs that you are not getting enough Omega 3 in your diet include feeling tired a lot of the time, having wounds that are slow to heal, experiencing mental fog, low moods or depression, possibly dry scaly patches on the skin, dull and lifeless hair, and poor circulation.
Interestingly, according to Smit et al, a biological marker of an essential fatty acid deficiency is synthesis of an Omega 9 fatty acid known as Mead acid as the body shows a preference for Omega 3 first, then Omega 6 and therefore synthesis of Omega 9 mead acid or eicosatrienoic acid increases when the amount of Omega 3 and Omega 6 in the diet is very low.
It’s quite incredible really that it is not that long ago that we discovered Omega 3 and it is only in the past few decades that we have come to understand the importance of Omega 3 fatty acids and the implications for our health. So how did it all begin?
HISTORY OF OMEGA 3
The health properties of Omega 3 were only really discovered just over forty years ago by Danish researchers studying the Eskimos (Inuit) in Greenland. Scientists H. O. Bang and J. Dyerberg couldn’t understand why the Inuit didn’t seem to suffer from heart attacks or other inflammatory diseases in the same way that Danish people did despite the Inuits eating a diet that was extremely high in fat.
The Inuits tended to eat massive amounts of fatty fish such as salmon, whale and seal. Further investigation revealed that the one thing these fish had in common was a high quantity of a type of fatty acid which of course was Omega 3.
This led to the discovery that a diet rich in Eicosapentaenoic acid, an Omega 3 fatty acid, and lower in Arachidonic Acid, an Omega 6 fatty acid, promoted good health and inhibited disease.
Now most of us have been told by health professionals that eating a diet that is high in fat is not ideal. The reality though is that fats in general are not bad, in fact they are absolutely essential, but it is important to eat the right kinds of fats.
Most people who are trying to lose weight or improve their health think about reducing the amount of fat they have in their diet. In the light of all the evidence from numerous studies this would now seem to be the wrong way of going about it, in fact, this could even prove disastrous to health. The body absolutely needs fats to survive but the idea of eating a diet that is high in fat is controversial to say the least. What most health professionals now agree on is that eating Polyunsaturated and Monounsaturated fats are ok, but eating too much of the wrong kinds of fat is detrimental to health, the wrong kinds being saturated fats or the really nasty ones, hydrogenated or Trans fats. Omega 3 is obviously one of the good fats but what sort of quantities are we talking about?
How much Omega 3?
No one has come out and said exactly how much Omega 3 we need to consume in order to promote and maintain good health. It isn’t that straightforward either because if our conversion rates from ALA to EPA and DHA is not very efficient, that means we would have to get our Omega 3 primarily from fish, in particular oily fish.
Unfortunately this isn’t ideal either as we have effectively polluted all the fish in the oceans and rivers, especially predatory fish which happen to be the fish with the highest Omega 3 content.
On saying that, most health professionals agree that the benefits of eating fish outweigh the risks of avoiding it so although they advocate that we continue to eat oily fish, they also tell us we shouldn’t eat too much. Most would agree that two portions of fish a week (one of them oily) is better than eating no fish at all or going to the other extreme and eating too much fish.
The American Heart Association recommend that people with heart disease eat fish at least twice a week and include in their diet plenty of plant based Omega 3 fatty acids too.
MARINE AND PLANT BASED SOURCES OF OMEGA 3
The following fish contain high quantities of Omega 3 fatty acids EPA and DHA:
The following foods/vegetable oils contain high quantities of the Omega 3 fatty acid ALA:
- Flaxseed or linseed
- Chia seed
REPORTED HEALTH BENEFITS OF OMEGA 3
There have been countless studies carried out now looking at the health benefits of Omega 3 fatty acids. Some of the results of these studies have been more conclusive than others. However, the most significant have been in the area of Cancer, Cardiovascular Disease and Mental Health although new studies are being carried out all the time.
.Omega 3 and cancer
Whether or not long chain Omega 3 fatty acids can inhibit cancer tumours or help to prevent cancer from developing in the first place still isn’t really clear. On the one hand there have been plenty of randomised double blind trials showing that Omega 3 fatty acids can help to reduce inflammation and inhibit tumour growth, there equally have been plenty of studies showing no difference between the control group and the study group.
Groundbreaking Study – Omega 3 and Cancer
A ‘National Institute of Environmental Health Science’ (NIEHS) funded study carried out by a team of researchers from the University of California, UC Davis, have found a way that Omega 3 might help combat cancer.
Dr Guiodong Zhang from the Department of Entomology at the UC Davis centre who led the study discovered that Cytochrome P450 epoxygenase metabolites of 22:6(n-3) could help block the supply of blood and nutrients to a tumour and in doing so help prevent the tumour from growing or spreading.
Although the results of many studies have indicated that Omega 3 fatty acids could inhibit tumour growth, how it actually did this has not been clear.
“Many human studies have shown that omega-3 fatty acids reduce the risks of cancers, but the mechanism is poorly understood,” said Zhang,
“Our study provides a novel mechanism by which these omega-3 lipids inhibit cancer.”
This research was published in the Proceedings of the National Academy of Sciences in April 2013.
Jonathan Lindner, a renowned scientist from the Oregon Health and Science University who was not involved in the research study had this to say:
“The study by Zhang and colleagues has uncovered a previously unrecognized anti-cancer effect of omega-3 fatty acids which are an important lipid component of diets that have been developed to prevent heart disease and cancer. The authors have demonstrated that metabolites of these lipids can act to suppress the growth of new blood vessels that are necessary to feed tumor growth. By shutting off the tumor’s blood supply, these compounds can act to dramatically slow tumor growth and prevent metastasis. The results from this suggest that new drug strategies for fighting cancer could emerge from knowledge of how the body uses nutrition to promote health.”
Omega 3 and Heart Disease
Undoubtedly a condition where the benefit of Omega 3 fatty acids is most well known is Cardiovascular Disease. However, even there, the exact mechanisms as to how and why Omega 3 is beneficial are not entirely clear. It is postulated that Omega 3 may help to keep arteries clear and unclogged, and of course reduce inflammation.
Evidence has also shown that although Omega 3 can help prevent sudden death from a heart attack in people who have already suffered a heart attack, a diet rich in Omega 3 will not necessarily prevent heart disease.
A study by Zhang et al, that spanned more than 35 countries, found that a diet that included regular amounts of fish was associated with a reduction in death from heart disease and stroke.
There have also been studies by Kromhout et al, Shekelle et al and Dolecek et al that have reported a lower incidence of heart disease in those who regularly included fish in their diet.
Omega 3 and Mental Health
Although many studies have shown that Omega 3 can help protect mental health and alleviate depression, there has been some debate as to which Omega 3 fatty acid is most beneficial. A number of scientists claim that Docosahexaenoic Acid or DHA is most beneficial, whereas others claim it is Eicosapentaenoic Acid or EPA that is most effective. Most would agree that DHA is important for the structure of the brain and that EPA is important for brain function.
What is interesting is that in cases of depression and other mental health problems including childhood disorders such as Attention Deficit Hyperactivity Disorder (ADHD) blood tests reveal a low level of Omega 3 fatty acids.
What has been shown in some studies across the world is that there appears to be a direct association between the amount of seafood consumed and the incidence of depression and other mental health problems. The more that a country eats fish, the lower the rate of depression, although no one really knows why this is the case. The results suggest that eating seafood in some way helps to prevent depression.
Some studies have also revealed that supplementation with Omega 3 fatty acids in the form of fish oil have helped to alleviate the symptoms of depression although other studies have found no significant benefit at all.
One major randomized double blind placebo controlled study carried out by Frangou et al over 3 months found that individuals diagnosed with bipolar depression who took either 1 or 2 grams of Ethyl EPA a day experienced an improvement in the symptoms of their depression, however there appeared to be no effect on mania.
Taking all the evidence, both anecdotal and from studies into account, there is little doubt that Omega 3 fatty acids do have a role to play in promoting and maintaining mental health and efficient brain function, even in more serious mental diseases.
Studies carried out by Peet at al looking at EPA as a possible treatment for Schizophrenia revealed that EPA in addition to standard therapy was superior to DHA or a placebo. Other studies using EPA have had mixed results. In another study by Peet and Horrobin, it was found that ethyl EPA helped alleviate symptoms in Schizophrenic patients who were taking the antipsychotic medication Clozapine, but it didn’t help those on other types of medication.
Alzheimer’s disease is a particularly devastating form of dementia characterized by progressive brain degeneration and cognitive decline. Initially the symptoms include memory loss and confusion which deteriorates over time. Some studies, including those carried out by Kalmijn et al have been able to make a connection between increased omega 3 consumption and a reduced risk of cognitive decline and dementia. Others have associated lower amounts of DHA as a risk factor for cognitive decline and dementia. This isn’t really surprising if we consider that the human brain is composed largely of fat and in particular the Omega 3 fatty acid DHA.
Lower levels of Omega 3 fatty acids have also been implicated in postpartum depression. The implication is that if a woman does not get enough Omega 3 during pregnancy, what she does get will be used up by the baby and she will suffer from a lack of Omega 3 as a result and this could potentially trigger low moods and depression.
Omega 3 during pregnancy and lactation
Nutrition is obviously of particular importance during pregnancy, not only so that the mother can remain healthy at a time when her body is under a lot of pressure, but also to ensure that the developing baby has enough nutrients to develop properly. An adequate intake of Omega 3 fatty acids is essential during pregnancy for baby’s healthy brain and vision development.
Many women take supplements during the time as opposed to increasing the amount of fish in the diet in order to get enough Omega 3. However, it is important to discuss the prospect of taking supplements with a doctor or health care provider before starting to take them.
It is during the final three months of pregnancy that is the most important regarding getting an adequate amount of Omega 3 in the form of DHA in the diet. DHA will help the baby develop a healthy brain and will also help vision as not only is there an accumulation of DHA in the brain but in the retina too.
After pregnancy the baby will rely completely on the mother for nutrients if being breast fed. Breast milk also contains DHA, but how much will depend on whether the mother has enough in her diet. Infant formulas now contain added Omega 3.
A number of studies have been carried out on whether maternal Omega 3 levels had an impact on the cognitive ability of the child later on. One randomised placebo controlled study by Dunstan et al found that children whose mothers were given Omega 3 fish oil during pregnancy showed better eye and hand coordination when they were two years old than those children whose mothers received olive oil instead.
Although getting enough Omega 3 during pregnancy is important, it is also wise to be cautious as pregnant women need to avoid fish with high levels of mercury and shouldn’t take Cod Liver Oil either as that can contain high amounts of Vitamin A which is inadvisable during pregnancy due to the association between high levels of Vitamin A and birth defects.
SAFETY OF OMEGA 3
Omega 3 is without a doubt perfectly safe for the majority of people most of the time.
It has always been an important part of the human diet and it is only in recent years that there has been such a decline in the consumption of Omega 3.
People are eating more processed foods and meat and dairy produce and that combined with the fact that fish can contain high levels of toxins and heavy metals, means that the ratio of Omega 6 to Omega 3 has changed so dramatically in favour of Omega 6.
When we consider the roles that Omega 3 and Omega 6 play in the body then it isn’t hard to understand why some experts basically blame an overdose of Omega 6 for the increases in heart disease, cancer and depression. In order to redress this imbalance we would either have to lower the amount of Omega 6 in the diet or increase the amount of Omega 3. One way of increasing Omega 3 is to supplement.
One of the benefits of supplements is that they can be free of mercury and other toxins. There are also very few side effects, if any, for most people. The most commonly reported side effects are fishy burps, a fishy aftertaste in the mouth, and mild gastrointestinal upset. This can be eliminated by choosing a high quality oil. Some people may experience nausea and loose stools. More serious side effects are quite rare.
Bearing in mind the anticoagulant effect of Omega 3 then bleeding times could potentially be increased and there may also be an increased risk of hemorrhagic stroke, however, the amount of Omega 3 ingested would have to be extremely high. According to the FDA, up to 3 grams a day of EPA and DHA is unlikely to cause any problems whatsoever and most people would be taking less than this.
There are some contraindications too. Those who are taking anticoagulant medication to thin the blood should avoid Omega 3 supplements unless under the supervision of a doctor.
Caution is also advised for people who have compromised immune systems as it is possible that the anti inflammatory effect of Omega 3 could dampen down the immune system and subsequently impair the body’s ability to fight off pathogens.
We’ve come so far in our understanding of the potential health benefits of Omega 3 yet at the same time we have as yet barely scratched the surface. Future studies will no doubt reveal more about how and why Omega 3 is beneficial for health in so many different ways and this can only help to improve intervention strategies, treatment options, and also the way nutrition can play a part in disease prevention.