In recent years, constant and increasing attention has been paid to omega-3s, essential substances for the well-being and good functioning of the organism. To better understand what they are, what their properties are and what roles they play, we we are addressed to Dr. 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).
»Explains Professor Scapagnini. They are defined polyunsaturated because "they have many unsaturated groups; this means that their chemical structure is characterized by the presence of many double bonds between carbon atoms." This fact, which may seem a pure question of chemistry, is quite different. how banal: 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 feature, especially when it comes to cell membranes, inside 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 ensure fluidity, which means having structure motility, better signal quality and interaction with the "environment".
The presence of many double bonds also gives polyunsaturated fatty acids an "other important property, that is" it 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.
for the organism. There is, in fact, another type of polyunsaturated fatty acids defined as follows: they are omega-6, which also have structural roles in cell membranes but have almost opposite functions. , viruses or other dangerous situations for our body. On the other hand, if we lose control of inflammation, the inflammation itself becomes a harmful element. In fact, it is no coincidence that all chronic or degenerative diseases related to aging - as well as many other diseases - 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 on and the other turns off the "inflammation".
We remember, in fact, that the progenitor of all omega-6 is alpha linoleic acid (or AL); it produces arachidonic acid (or AA, the main type of omega-6 accumulated in cell membranes). 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, they are linked to the activation of the inflammatory process, to vasoconstriction and to platelet aggregation, therefore to the formation of thrombus. From omega-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 the "inflammation." omega-3 is so well established and proven that, in the scientific literature, they are not called with the names of prostaglandins, leukotrienes and thromboxanes but with the names of "resolvine, protectine and maresine".
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 fundamental in controlling the physiology of" switching on and off of "inflammation".
or ALA "; the latter" is the precursor of all fatty acids of the omega-3 series. Once introduced with 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," are long-chain omega-3 fatty acids which are our body's favorite form to accumulate and use 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, the intake of these omega-3s through nutrition or integration represents the "only way to increase the amount in our body.
From a chemical point of view, EPA and DHA are structurally different: EPA is made up of a chain of 20 carbon atoms with 5 double bonds; DHA is made up of a chain of 22 carbon atoms with 6 double bonds. point of view of the distribution in the organism, explains Professor Scapagnini, EPA and DHA differ: for example, the brain is richer in DHA, while in other parts of the body it is more likely to have higher concentrations of EPA.
Furthermore, EPA and DHA "are substrates from which molecules are produced that control inflammation in a sense of resolution," but even then, there is a difference between the molecules obtained from EPA and those derived from DHA.
, 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 - works only on fat ». Omega-3s, therefore, are beneficial for the heart "because - in addition to being a potentially usable source of energy - they have the ability to stimulate the" use of fat by the heart muscle ".
To all this, we must also add the well-documented triglyceride lowering action exerted by omega-3s. In this regard, Professor Scapagnini informs us that "their effectiveness is so strong that they have been recognized by the EFSA (European Food Safety Authority) and, this year for the first time, the use of omegas -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 dosages of omega-3 equal to 4 grams per day of EPA, from take in two divided doses. Clearly, such dosages are not achievable with diet alone.
, Professor Scapagnini informs us, they are "rich in polyunsaturated fatty acids, in particular, in DHA"; in the light of what has been said so far, therefore, it appears clear that the correct lipid composition of the brain depends on the adequate intake of this molecule with the diet. In addition to the important structural role, many studies have highlighted 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 the nerve impulse - and in the correct functioning of the retina ( where, even here, there are high levels of this type of omega-3).Furthermore, the right amount of omega-3 is essential for the brain development of the fetus and baby, therefore it is essential during pregnancy and breastfeeding. Professor Scapagnini also explains that "on the one hand, omega 3s allow for correct development of the nervous system of the fetus, on the other hand they have shown to exert a "positive action also on the quality of birth".
by 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 the levels of omega-3. In practice, the more you run and the more kilometers you do, the more you become depleted of omega-3" .
In the progress 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 muscle accidents. We have developed a "hypothesis that" 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 amount of omega 3 is not reintroduced adequately - with diet or supplementation - one exposes more to their impoverishment ", with all the consequences of the case.
, algae; the latter are an extraordinary source of omega-3 fatty acids. However, these are products that are not part of our food tradition; the percentage introduced of these foods is, in fact, minimal compared to other types of vegetables ».As for the animal world, however, "fish and in particular blue fish such as anchovies, sardines," herring and mackerel are excellent sources of omega-3 and contain both EPA and DHA ". salmon, about 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-3 present depends on the "feed that the animal has received, even if significant quantities are reached".
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-3 of which 898 of EPA and 1401 of DHA;
- Farmed salmon: 1966 mg of omega-3 of which 862 mg of EPA and 1104 of DHA;
- Herring: 1571 mg of omega-3 of which 709 of EPA and 862 of DHA;
- Sea bass: 595 mg of omega-3 of which 161 of EPA and 434 of DHA.
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