Omega-3s are compounds belonging to the group of fatty acids. Fatty acids, in turn, belong to the nutritional group of fats, also called lipids. Fatty acids are fundamental components of the so-called glycerides, compounds formed by a molecule of glycerol (an alcohol) which joins with one, two or three chains of fatty acids forming, respectively, mono, di and tri-glycerides. The latter are abundantly present in the human body, since they represent the storage form accumulated in the adipose tissue and constitute about 96-97% of dietary fats.
Omega-3 fatty acids are defined essential since the organism is not able to produce them and for this reason they must necessarily be taken through the diet. The mixture of linoleic acid (The e alpha-linolenic acid (ALA), to which arachidonic acid is also added, is also identified as "Vitamin F", in analogy with vitamins that cannot be produced by the body and must be taken with the diet. In fact, the only truly essential omega-3 is their precursor, the "alpha-linolenic acid (ALA) from which the "organism derives the"eicosapentaneic acid, known as the EPA, and the "docosahexaenoic acid, known as DHA. However, the body's ability to use the precursor to produce the other omega-3s is rather poor and it is therefore preferable to consume a good amount in the diet.
Omega-3s are commonly defined good fats, for their supposed beneficial properties, many of which have been confirmed by scientific studies that highlight their anti-inflammatory activity. It is important to remember that the European Food Safety Authority (EFSA) has rejected many of the claims for omega-3 health claims for which further studies are needed, and only approved those that:
- WING contributes to the maintenance of normal blood cholesterol levels
- EPA and DHA contribute to the normal functioning of the heart
- DHA contributes to the maintenance of normal brain function
- DHA taken by the mother it contributes to the normal development of the eye and brain of the fetus and babies, if they are breastfed
Fatty acids based on their chemical structure can be classified into:
- saturated fatty acids, mainly contained in foods of animal origin
- unsaturated fatty acids, (monounsaturated if there is only one double bond, polyunsaturated if there are more than one double bonds) present in a higher percentage in foods of plant origin
Omega-3 are polyunsaturated fatty acids, and this characteristic makes them liquid even at low temperatures but highly unstable to light, heat and oxygen. The name omega-3 derives from the fact that the last double bond is placed on the third carbon (counting it from the end of the chain). They are also defined as "long chain"Because the carbon atoms that make up the molecule are never less than 13 units.
The main omega-3 fatty acids are three: l "alpha-linolenic acid (ALA), l "eicosapentaneic acid, (EPA), and the "docosahexaenoic acid (DHA).
ALA is referred to as 18: 3, which means it has a molecule made up of 18 carbon atoms in which there are 3 double bonds. EPA is a 20: 5 fatty acid, while DHA a 20: 6.
Fatty acids provide 9 kilocalories per gram when burned. When they are used, however, to produce triglycerides inside the cells that make up the adipose tissue (adipocytes), they constitute a source of reserve for the organism. They also have an "important structural function, since they constitute phospholipids, a type of fat that is contained in the" lipid bilayer "of cell membranes, giving them the characteristic fluidity. Like all fatty acids, omega-3s can also enter in cells and oxidized to produce energy, stored in adipose tissue and used to produce cell membranes by intervening in their maintenance and in stimulating cell regeneration.
Furthermore, omega-3s are the precursors of anti-inflammatory molecules and are also responsible for less platelet aggregation. An "other class of polyunsaturated fatty acids, called omega-6, on the other hand, produces pro-inflammatory molecules. Both anti-inflammatory and pro-inflammatory compounds are necessary for maintaining health but it is important that they are in balance. An excess. omega-6 or an omega-3 deficiency would shift the balance in favor of a "general" inflammation throughout the body (systemic) with the risk of promoting a series of complications.
Omega-3s also have a very important metabolic impact. In fact, they act on the concentration of fats in the blood (lipemia) by significantly decreasing the levels of triglycerides and total cholesterol and increasing the 'good' HDL cholesterol. Finally, omega-3s have a positive effect on blood pressure by reducing arterial pressure.Omega-3s are sensitive to light and heat, should be protected from the sun and eaten raw or after a short cooking.
Food sources of omega-3s
Dietary sources of omega-3s can be both animal and plant-based.
L"alpha-linolenic acid (ALA) is the most abundant omega-3 in plant products, in particular it is found in:
- oil seeds, such as soy, flax seeds, hemp seeds, walnuts, almonds, hazelnuts etc.
- oilseed oils
- green leafy vegetables
On the contrary, the "eicosapentaneic acid, (EPA), and the "docosahexaenoic acid (DHA) are mainly present in foods of animal origin, in particular in fishery products such as:
- blue fish (tuna belly, anchovies, mackerel, sardines, amberjack, etc.)
- tuna fish
Obviously, the foods richest in EPA and DHA are made from animal oils obtained from the liver of fish.
According to the Council for Agricultural Research (CREA), omega-3 intake should account for between 0.5 and 2.0% of total calories (at least 250 milligrams in EPA and DHA). "intake of fatty acids increases proportionally to the overall nutritional needs of the organism. In infants and children up to 2 years of age, an additional 100 milligrams of DHA is recommended and in the elderly up to 100-200 milligrams more.
It is recommended to increase the consumption of polyunsaturated fatty acids (in a correct ratio between the quantities of omega-3 and omega-6, approximately 1: 5) to replace saturated fatty acids (such as those contained in butter, cheese, meat, palm oil, etc.) This objective can be achieved by consuming the quantities of fish, meat and vegetable oils (richer in omega-6) recommended by the guidelines for a healthy diet.
Deficiency or excess of omega-3s
Omega-3s are essential fatty acids and, therefore, must necessarily be obtained through the diet.
Their deficiency is difficult to assess, since it does not manifest itself with disorders (symptoms) or exclusive clinical signs, although it could contribute to the appearance of some metabolic diseases.
On the other hand, an excessive consumption of omega-3 (as indeed of all polyunsaturated fatty acids) could lead both to the formation of potentially toxic compounds (lipoperoxides), and to an increased bleeding speed.
The most effective way to monitor the correct intake of essential fatty acids (omega-3 and omega-6) in the diet is to calculate the "Index of MEAD, that is the relationship between the "eicosatrienoic acid and the "arachidonic acid, inside the phospholipids contained in the blood serum. Abnormal values higher than 0.4 are considered.
The body's ability to produce omega-3 derivatives, as indeed happens for many other biological functions, tends to decrease with increasing age. Also cortisone drug therapy, alcoholism and protein malnutrition can affect negatively on the synthesis of omega-3. Furthermore, the fact that omega-3s are low in Western diet foods has led to many people starting to take omega-3 supplements.
It is essential that omega-3 supplements are taken exclusively under medical supervision in the presence of a state of ascertained deficiency, or in the event of increased demands on the part of the body.
The recommended dose depends on the nutritional status, the physiological condition of the person and the age. In general, in case of need, it is considered safe to take 1-5 grams (g) of omega-3s per day through supplements. The European Food Safety Authority (EFSA) has ruled that in order to achieve a reduction in blood pressure and triglyceride levels, it is necessary to take eicosapentaneic acid, (EPA) and docosahexaenoic acid (DHA) in a dose of between 2 and 4 g per day in total, while an "intake of 250 milligrams (mg) is sufficient to maintain normal heart function. The" EFSA also noted that an additional "intake of EPA + DHA up to 5 g per day, consumed for a maximum period of 12-16 weeks, does not pose any risk to the safety of the population.
It should be noted that omega-3-containing products approved as drugs to be prescribed along with an appropriate diet for people with high blood triglyceride levels differ from regular omega-3 supplements in both composition and controls and regulation. to which they are subjected, and also for the effects they can obtain.
Warnings and possible contraindications
When you choose to take omega-3 supplements, it should be borne in mind that you may incur possible unwanted effects (side effects), mainly caused by taking an excessive dosage or by individual hypersensitivity to omega-3s.
The disorders that can arise as a consequence of the intake of omega-3 are:
- foul-smelling sweat
- gastrointestinal symptoms such as heartburn, nausea, diarrhea
- problems with blood clotting
Omega-3s can increase the risk of bleeding: for this reason it is advisable to avoid them during drug therapies that reduce blood clotting (anticoagulant drugs).
Before taking omega-3 supplements, it is essential to consult with your doctor to rule out any contraindications caused by any diseases or health problems you suffer from or medications you are taking.
Italian Society of Human Nutrition (SINU). Lipids
BioActive Fodds AS. EFSA Regulation - Health claims for EPA and DHA (English)
European Food Safety Authority (EFSA).EFSA evaluates the safety of long-chain omega-3 fatty acids
Regulation (EU) n. 432/2012 of the Commission of 16 May 2012 concerning the compilation of a list of permitted health claims on food products, other than those referring to the reduction of disease risks and the development and health of children