Omega-3: Properties, Foods and Benefits

Omega-3: Properties, Foods and Benefits
In recent years, constant and increasing attention has been paid to omega-3s , essential substances for the well-being and proper functioning of the body. To better understand what they are, what their properties are and what roles they play, we turned to Doctor Giovanni Scapagnini , MD, PhD. Full Professor of Clinical Nutrition, Department of Medicine and Health Sciences, University of Molise, Campobasso and Vice President of the Italian Nutraceutical Society (SINUT).

What are Omega-3s?

«Omega-3s are a type of polyunsaturated fatty acids » explains Professor Scapagnini. They are defined as polyunsaturated because «they have many unsaturation groups; this means that their chemical structure is characterized by the presence of many double bonds between the carbon atoms». This fact, which may seem a pure question of chemistry, is far from trivial: as Professor Scapagnini states, in fact, “this peculiarity of the chemical structure of polyunsaturated fatty acids makes them very fluid”. Fluidity is a very important characteristic, especially when it comes to cell membranes, within which there is, not surprisingly, the presence of many polyunsaturated fatty acids. In this regard, Professor Scapagnini explains that “the presence of many polyunsaturated fatty acids in the structure of cell membranes ensures fluidity, which means having motility of the structure, better quality of the signal and interaction with the environment”.

The presence of many double bonds also gives polyunsaturated fatty acids another important property, namely “preserves them from changing state with temperature”. In other words, polyunsaturated fatty acids do not freeze, remaining liquid both at room temperature and at low temperatures , exerting what can be defined as an anti-freeze action.

Why are they called Essential Fatty Acids?

Professor Scapagnini explains that polyunsaturated fatty acids such as omega-3 are defined as essential as «not only are they fundamental for our life since without these molecules we could not live, but above all they are essential as we are unable to produce them with our biochemistry; therefore, we are obliged to obtain them with food » .

The Professor points out, however, that omega 3 are not the only essential fatty acids for the body. In fact, there is another type of polyunsaturated fatty acids defined as follows: they are omega-6s, which also have structural roles in cell membranes but have almost opposite functions.

Essential Fatty Acids and Inflammation: What’s the Relationship?

To this question, Professor Scapagnini answers first of all by specifying that «inflammation is a fundamental physiological phenomenon for survival: without inflammation we would not be able to defend ourselves from bacteria , viruses or other dangerous situations for our body. Conversely, if we lose control of inflammation, inflammation itself becomes a harmful element. In fact, it is no coincidence that all chronic or degenerative pathologies linked to aging – as well as many other pathologies – are associated with a loss of control of inflammatory processes”.

In the context of inflammation, however, “we cannot talk about omega 3 without talking about omega-6 because these two categories of molecules perform almost opposite functions, functioning as a switch: one part turns inflammation on and the other turns it off”.

In fact, we recall that the progenitor of all omega-6s is alpha linoleic acid (or AL); from it, arachidonic acid (or AA, the main type of omega-6 accumulated in cell membranes) is produced . Other types of substances are obtained from arachidonic acid: prostaglandins , leukotrienes and thromboxanes which, taken together, are called prostanoids. The prostanoids obtained from arachidonic acid, as Professor Scapagnini tells us, «regulate very important physiological functions which, however, are connected to the activation of the inflammatory process, to vasoconstriction and platelet aggregation , therefore to the formation of thrombi . Give himomega-3 fatty acids , on the other hand, prostanoids with practically opposite action are obtained: the prostaglandins, thromboxanes and leukotrienes that derive from omega-3 are in fact able to resolve inflammation ». This action of prostanoids derived from omega-3s is so established and demonstrated that, in the scientific literature, they are not called by the names of prostaglandins, leukotrienes and thromboxanes but by the names of “resolvins, protectins and maresins”.

However, it should be emphasized that omega-6s are as fundamental as omega-3s but, in order for the body to function properly, they must be present in adequate quantities since “the omega-6 /omega-3 ratio is essential in controlling the physiology of the ignition and extinction of inflammation.

EPA and DHA: what they are and differences

Polyunsaturated fatty acids are produced by plants; or rather, as Professor Scapagnini explains to us, the first double bond in the chemical structure of what will become polyunsaturated fatty acids can only be built by vegetable organisms; while animal organisms are unable to do so. On the other hand, however, animals can modify the structure of fatty acids once the first double bond in the carbon chain has been formed.

In this regard, Professor Scapagnini tells us that “plants usually produce short-chain omega-3 fatty acids, such as alpha-linolenic acid or ALA”; the latter is the precursor of all fatty acids of the omega-3 series. 3. Once introduced in the diet, “the biochemistry of the animal world processes it, lengthening its chain and inserting further double bonds to give rise to EPA – or eicosapentaenoic acid – and DHA – or docosahexaenoic acid “. EPA and DHA, therefore, “They are long-chain omega-3 fatty acids that constitute our body’s favorite form for accumulating and using omega-3s, both in terms of their structural role within cell membranes and in terms of their functional role in our biochemistry”.

It should be noted, however, that even if EPA and DHA can be synthesized by our body through the conversion of ALA, this is rather limited; for this reason, taking these omega-3s through food or supplementation is the only way to increase their quantity in our body.

From a chemical point of view, EPA and DHA are structurally different: EPA consists of a chain of 20 carbon atoms with 5 double bonds; DHA consists of a chain of 22 carbon atoms with 6 double bonds. Also from the point of view of distribution in the body, Professor Scapagnini explains, EPA and DHA differ: for example, the brain is richer in DHA, while in other areas of the body it is more probable to have higher concentrations of EPA.

Furthermore, EPA and DHA «are substrates from which molecules that control inflammation in a resolution sense are produced», but even in this case, there is a difference between the molecules obtained from EPA and those derived from DHA.

What are the Benefits of Omega-3 on the Body?

Omega-3s not only play a structural role within our body, but also a functional role: they are substrates from which it is possible to produce molecules useful for solving the inflammatory process , but not only.

«Let’s not forget that omega-3s are fats» explains Professor Scapagnini «therefore – like all fats – they are also an energy source. However, omega-3s also have the ability to stimulate fat utilization, i.e. to stimulate beta-oxidation at the level of various cell types , such as those of skeletal muscle . The most important muscle in our body, however, is the heart which – unlike skeletal muscle which prefers glucose to function – only works with fat”. Omega-3s, therefore, are beneficial for the heart «because – in addition to being a source of energypotentially usable – have the ability to stimulate the use of fat by the heart muscle ».

To all this, we also add the well-documented triglyceride -lowering action of omega-3s. In this regard, Professor Scapagnini informs us that «their effectiveness is so strong that they have received recognition from the EFSA (European Food Safety Authority) and, this year for the first time, the use of omega -3 has entered the guidelines of the European Society of Cardiology for the treatment of hypertriglyceridemia”. To do this, the guidelines indicate that it is necessary to take high doses of omega-3 equal to 4 grams of EPA per day, to be taken in two divided doses. Clearly, such dosages are not achievable with diet alone.

What are the Benefits on Brain and Brain Development?

The cell membranes of neurons , Professor Scapagnini informs us, are “rich in polyunsaturated fatty acids, in particular DHA”; in the light of what has been said so far, therefore, it appears clear how the correct lipid composition of the brain depends on the adequate intake of this molecule with food. In addition to the important structural role, many studies have shown how important DHA is in maintaining cognitive functions, in the functioning of the brain itself – at the level of which it plays a very important role in the transmission of nerve impulses – and in the correct functioning of the retina ( where, again, high levels of this type of omega-3 are present).

Furthermore, the right amount of omega-3s is essential for the brain development of the fetus and child, therefore it is essential during pregnancy and breastfeeding . Professor Scapagnini also explains that “on the one hand, omega 3s allow for the correct development of the nervous system of the fetus, on the other they have been shown to have a positive effect on the quality of the birth as well “.

What are the Benefits of Omega-3 in sports?

Professor Scapagnini conducted an interesting study with his research group that investigates the correlation between physical activity and omega-3. «This is a study that we carried out in Italy on amateur runners connected to the federations, not professionals but regular and not occasional» explains Professor Scapagnini «we collected blood samples from 1000 runners to measure the levels of polyunsaturated fatty acids, discovering that there is a very strong correlation between the amount of kilometers run and omega-3 levels. Basically, the more you run and the more kilometers you cover, the more you deplete yourself of omega-3s».

In the advancement phase of the study that the Professor is currently conducting, it was also discovered that «a reduction in omega 3 levels increases the risk of inflammatory events in the muscle. We have developed a hypothesis according to which physical activity induces inflammation in a physiological way; when it is very protracted, omega-3s are consumed which are used to manage the resolution of inflammation. Therefore, if the right quantity of omega 3 is not reintroduced in an adequate manner – with food or with supplementation – we are more exposed to their impoverishment “, with all the consequences of the case.

What are the richest sources and foods of Omega-3?

Unfortunately, our diet is not very rich in omega-3s; in fact, most of the foods – including vegetables – that arrive on our tables contain above all omega-6 fatty acids.

Vegetable sources particularly rich in omega-3 fatty acids, explains Professor Scapagnini, «are flax and the oil obtained from its seeds, purslane , algae ; the latter are an extraordinary source of omega-3 fatty acids. However, these are products that do not fall within our food tradition; the percentage of these foods introduced is, in fact, minimal compared to other types of vegetables».

As far as the animal world is concerned, however, ” fish and in particular oily fish such as anchovies , sardines , herring and mackerel are excellent sources of omega-3s and contain both EPA and DHA”. Not to forget the salmon ; regarding which Professor Scapagnini specifies that «there is a variability in the content of polyunsaturated fatty acids: wild salmon is very rich in them; while in farmed salmon, the quantity of omega-3s present depends on the feed that the animal has received, even if significant quantities are reached in any case».

To give some practical examples, we report the omega-3 values ​​expressed in milligrams within 100 grams of some types of fish (source: FAO – Food and Agriculture Organization of the United Nations):

  • Mackerel: 2299 mg of omega-3s of which 898 of EPA and 1401 of DHA;
  • Farmed salmon: 1966 mg of omega-3s of which 862 mg of EPA and 1104 of DHA;
  • Herring: 1571 mg of omega-3s of which 709 of EPA and 862 of DHA;
  • Seabass: 595 mg of omega-3s of which 161 of EPA and 434 of DHA.



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