The most important polyunsaturated fatty acids class ω -3 are alpha-linolenic acid(C 18:3, ω-3), from which long-chain PUFA ω-3 can be synthesized in cells: eicosapentaenoic acid(From 20:5, ω-3) and docosahexaenoic acid(C 22:6, ω-3) with an effectiveness of about 5% in men and slightly higher effectiveness in women. The ability to synthesize docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in the body is very limited, so they must come from exogenous sources. With aging of the body and some diseases, the ability to synthesize DHA and EPA is completely lost. In addition, it must be taken into account that the chain elongation and desaturation reactions of ω-3 and ω-6 fatty acids are catalyzed by the same enzymes, and fatty acids compete for enzymes in these reactions. Therefore, an excess of fatty acids of one family, for example, arachidonic acid (C 20: 4, ω-6), will suppress the synthesis of the corresponding acid of another family, for example, eicosapentaenoic acid (C 20: 5, ω-3). This effect highlights the importance of a balanced composition of omega-3 and omega-6 PUFAs in the diet. Thus, tissue accumulation of long-chain EPA and DHA is most effective when it comes directly from food, or when competing amounts of omega-6 analogues are low.

Natural sources of PUFAs are vegetable oils from wheat ovaries, flax seeds, camelina oil, mustard oil, sunflower oil, soybeans, peanuts, as well as walnuts, almonds, sunflower seeds, fish oil and fatty and semi-fat fish (salmon, mackerel, herring, sardines, mackerel, trout, tuna and others), cod liver and shellfish.

Figure 1. Food sources of essential polyunsaturated fatty acids

Main food source Omega-6 PUFAs are vegetable oils. Omega-6 fatty acids are synthesized by most plants that grow on land. The main dietary sources of omega-3 PUFAs are fatty cold-water fish and fish oil, as well as vegetable oils such as flaxseed, perilla, soybean and canola.

Researchers' attention to the fatty acid composition of dietary fat was first drawn in the mid-70s of the last century, when epidemiological studies showed a low prevalence of diseases associated with atherosclerosis in the Eskimos of Greenland and 10 times lower mortality from myocardial infarction than in Denmark and North America, despite the fact that fat and cholesterol intakes were similarly high in all these populations. The difference was in the composition of fatty acids. Among Danes, consumption of saturated fatty acids and omega-6 PUFAs was 2 times higher than among Eskimos. Eskimos consumed 5-10 times more long-chain omega-3 PUFAs: EPA and DHA. Further experimental and clinical studies confirmed antiatherogenic effect of omega-3 PUFAs. It has been established that omega-3 PUFAs reduce the content of atherogenic lipoproteins (low and very low density lipoproteins) in the blood. Confirmed cardioprotective and antiarrhythmic effects(free EPA and DHA in cardiac cell membranes inhibit ion channels) Omega-3 PUFAs. Recently, studies have been conducted showing immunoprotective effect omega-3 fatty acids. Recent scientific discoveries have found that omega-3 fatty acids can block tumor growth.

Omega-3 PUFAs have been known to be essential factors for normal height since the 1930s. DHA along with EPA are nutritional components normal development of children and longevity. A growing organism needs plastic material for its growth and development and is most sensitive to a deficiency of polyunsaturated fatty acids. PUFAs are part of structural lipids, including the phospholipids of cell membranes. They are regulators of the phase state of cell membranes. An increase in omega-3 PUFAs in biomembranes leads to an increase in their fluidity, reduces membrane viscosity and improves the functions of integral proteins. With age, the content of omega-3 PUFAs in cell membranes decreases. E Icosapentaenoic acid is a component of the lipids of most tissues. Docosahexaenoic acid is an important component membranes of CNS cells, accumulates in synapses, photoreceptors, spermatozoa and is vital for their functions. Scientific research has confirmed that omega-3 PUFAs are required for normal brain function.

Except structural function, such PUFAs as arachidonic acid and eicosapentaenoic acid are precursors to a group of highly active substances called eicosanoids (Figure 2). These include prostaglandins, prostacyclins, thromboxanes and leukotrienes, which are widely distributed in body tissues. The ratio of omega-3 to omega-6 PUFAs directly affects the type of eicosanoids synthesized by the body.

Polyunsaturated fatty acids

General formula: CH 3 -(CH 2) m -(CH=CH-(CH 2) x (CH 2)n-COOH

Eicosanoids, synthesized from omega-6 PUFAs, mainly arachidonic acid, are the so-called second series of prostanoids: prostaglandins (PGI 2, PGD 2, PGE 2, PGF 2), thromboxane A 2 (TXA 2), as well as leukotrienes of the fourth series. They have pro-inflammatory, vasoconstrictive and proaggregant properties, providing protective reactions of the body - inflammation and stopping bleeding. Eicosanoids, synthesized from omega-3 PUFAs, mainly eicosapentaenoic acid (the third series of prostaglandins and the fifth series of leukotrienes), are characterized by anti-inflammatory and antithrombotic effects, as opposed to the biological effects of arachidonic acid metabolites. Thus, under pathological conditions, EPA metabolites are preferred for humans. The easiest way to reduce the synthesis of omega-6 eicosanoids has been found to be the consumption of more omega-3 PUFAs. Dietary administration of EPA and DHA blocks the synthesis of eicosanoids from both arachidonic acid and endogenous eicosatrienoic acid (ω9). At the same time, if AA is completely excluded from the diet of a healthy person, this will only bring a negative result, since EPA metabolites do not fully perform the functions that AA metabolites perform. This is confirmed by the results of epidemiological studies: residents of coastal areas who eat exclusively seafood do not suffer from atherosclerosis, but they have increased bleeding and low blood pressure.

For a healthy person, it is enough to follow proper nutrition. Industrial processing of fats and oils has significantly reduced the content of essential fatty acids in our diet. In the diet, essential fatty acids should account for (by calorie content) at least 1-2% of the body's total calorie needs. The optimal ratio of ω-3:ω-6 fatty acids in food is 1:4. The Russian Ministry of Health recommends 1 g ALA/EPA/DHA per day for adequate intake. The minimum daily human need for linoleic acid is 2-6 g, but this need increases in proportion to the proportion of saturated fats entering the body. One way to get adequate amounts of EPA and DHA is to eat fatty marine fish. For example, a typical serving of fish (85 g) may contain between 0.2 and 1.8 g of EPA/DHA. American experts recommend eating two servings of fish per week.

For certain pathologies it is important increased intakeω-3 fatty acids, which can be in the form of dietary supplements or medications.

Rice. 3. Omega-3 polyunsaturated fatty acids in capsules

To receive maximum benefit from PUFAs, you should follow the storage rules (protection from atmospheric oxygen and other oxidizing agents, from direct sunlight) and consume them in the required quantities. Consumption of excess amounts of PUFAs can lead to disruption of the body's prooxidant-antioxidant homeostasis. All PUFAs are subject to the process of peroxidation, and with a lack of natural antioxidants, this leads to the formation of free radicals with shifts towards increased atherogenicity and carcinogenesis. A necessary condition is the presence of natural antioxidants in physiological doses in preparations containing PUFAs. For example, vitamin E, which is found in fish and seafood, is such an antioxidant.

I am glad to welcome dear readers of my blog! Today my news is not very good. The skin became very dry, even irritation and peeling appeared. As it turns out, I need polyunsaturated fatty acids, do you know where they are found? Let's figure it out together: what their role is in the body, as well as the benefits and harms.

Vitamins, fats, proteins, carbohydrates and microelements are necessary for our body. Many of the substances we need are found in food. Polyunsaturated fatty acids (PUFAs) are no exception. The name is based on the structure of the molecule. If an acid molecule has double bonds between carbon atoms, it is polyunsaturated. Please do not confuse PUFAs with polyunsaturated fats. The second are fatty acids paired with glycerol, they are also called triglycerides. They are the source of cholesterol and excess weight.

Alpha-linolenic acid is often found in dietary supplements and vitamins. In such compositions you can see docosahexaenoic and ecosapentaenoic fatty acids. These are omega-3 PUFAs.

In the composition of the preparations you can also see linoleic, arachidonic or gamma-linolenic acids. They are classified as omega-6. These elements cannot be synthesized in our body. That's why they are so valuable. They can come to us either through food or medications.

The foods you eat must contain PUFAs. If they are not there, symptoms of a lack of necessary substances will appear over time. I think you've heard about vitamin F. It is found in many vitamin complexes. So, vitamin F contains omega-3 and omega-6 acids. If you take vitamins, be sure to pay attention to its presence.

What is the value of these substances:

• normalize blood pressure;
• lower cholesterol;
• effective in the treatment of acne and various skin diseases;
• promote weight loss by burning saturated fats;
• participate in the structure of cell membranes;
• prevent thrombosis;
• neutralize any inflammation in the body;
• have a positive effect on the reproductive system.

Omega-6 and omega-3 are best taken not separately, but together. For example, Eskimos consume these fats in equal proportions. Proof of this is the low mortality rate from heart and vascular diseases.

Most scientists agree that the optimal proportion of these fats is 5:1 (less is always omega-3)

If a person is sick, then 2:1. But since everything is quite individual, your doctor can recommend a different ratio just for you.

Foods rich in omega-3 and omega-6 fats

Acids of the omega-3 family, their biological role is very large, are involved in the construction of biological cell membranes. Membranes serve to transmit signals between neurons. They affect the condition of the retina, blood vessels and heart, and brain function.

Flaxseed oil contains about 58% omega-3, soybean oil – 7%. This element is also found in tuna -1.5g/100g, mackerel -2.6g/100g. The yolk also contains it, although it is not much – 0.05g/100g.

There is a lot of omega-6 in vegetable oils. The highest content is in sunflower oil – 65%, corn oil – 59%. And also soybean oil – 50%. In flaxseed there is only 14%, and in olive – 8%. Tuna and mackerel contain 1g/100g of product. In the yolk – 0.1g/100g. These fats prevent multiple sclerosis and are important in treating the disease. Relieves arthritis, regulates blood sugar. Indicated for people with skin diseases, liver diseases, etc.

These PUFAs are also found in tofu, soybeans, wheat germ, and green beans. In fruits such as apple, banana, strawberry. They contain walnuts, sesame seeds, and pumpkin seeds.

Omega-6 - benefits and harms

How do you know if you don’t have enough PUFAs or if you have too much of them? Inflammatory diseases may indicate an excess of polyunsaturated fats. Repeated depression and thick blood also indicate this. If you find an excess of these fatty acids, try to exclude from your diet: walnuts, vegetable oils, pumpkin seeds, sesame seeds.

It wouldn't hurt to consult a doctor. After all, it may be that the above symptoms are not related to omega-6. With a lack of this substance, as well as with its excess, thick blood is observed. Also, high cholesterol. With excess and deficiency of acids of this type, similar symptoms can occur. A lack of these polyunsaturated fats may be indicated by:

• loose skin;
• obesity;
• weak immunity;
• infertility in women;
• hormonal disorders;
• joint diseases and problems with intervertebral discs.

It is difficult to overestimate the benefits of this type of fat. Thanks to them, our body accelerates the removal of toxins. The functioning of the heart and the condition of blood vessels improves. The risk of mental illness is reduced. Brain activity increases. Improves the growth of nails and hair, their appearance. An adult should consume at least 4.5-8 g of this PUFA per day.

What are the dangers of a lack or excess of omega-3?

A lack of healthy omega-3 fats manifests itself in brittle nails, various types of rashes and peeling skin (for example, dandruff). Blood pressure increases and joint problems appear.

If there is too much of this PUFA in the body, then frequent diarrhea and digestive problems appear. Also, hypotension and bleeding may be associated with its excess.

You should consume at least 1 - 2.5 g of this type of fat per day

Omega-3 have great value for our body, because:

• Strengthens blood vessels and improves heart function;
• Normalize blood sugar levels;
• Restore the nervous system;
• Improve the functioning of the thyroid gland;
• Take part in the construction of cell membranes;
• Block inflammatory processes.

If you are deficient in these fats, try to consume the following foods daily

Preface

So, what are these mysterious omega fats and why is it so important for every thinking person who cares about their health and the health of their children to know about them.

Nowadays, products that do not contain fat or contain it in minimal quantities have become very popular.
Did you know that fats can be not only not harmful, but also vital for health?
We are talking about polyunsaturated essential fatty acids (PUFAs) or vitamin F. Vitamin F was discovered in the late 1920s by George and Mildred Burr. In those years, their discovery did not make much of an impression in science. However, in recent decades there has been a resurgence of interest in vitamin F. During this time, a large amount of information has accumulated about the importance of polyunsaturated fats for human health. PUFAs cannot be synthesized human body and therefore should always be part of our food. They are essential for the proper growth and functioning of the human body.

Of greatest interest to us now are the omega-3 and omega-6 PUFA families.

Historically, the content of omega-3 and omega-6 fats in human diets has been balanced. This was achieved by eating plenty of green leafy vegetables in the diet, containing small amounts of omega-3. In the meat of animals that our ancestors ate, there was also a balance of PUFAs, since the main food of animals was the same leafy plants.
Nowadays, meat from farmed animals contains large amounts of omega-6 and small amounts of omega-3. Cultivated vegetables and fruits also contain lower amounts of omega-3s than wild plants. In the last 100 - 150 years, the amount of omega-6 in the diet has increased significantly also due to the large consumption of vegetable oils, such as corn, sunflower, safflower, cottonseed and soybean. The reason for this is the recommendation to replace saturated fats vegetable oils to lower blood cholesterol levels. Fish consumption and seafood products, rich in omega-3 fats, decreased significantly. In modern western diet The ratio of omega-6 to omega-3 is in the range of 10–30:1 instead of the traditional 1-4:1.

Table 1. Types of fats.

Note: Canola oil is high in both monounsaturated and polyunsaturated fatty acids, which is why it is included in both categories.

Description of omega-3 and omega-6 PUFAs

The parent acid of the omega-3 PUFA family is alpha-linolenic acid ALC, the parent acid of the omega-6 family is linoleic acid OK.

In a healthy body, in the presence of the required amount of enzymes, linoleic acid is converted into gamma-linolenic acid GLK.
Gamma-linolenic acid is a precursor to dihomo-gamma-linolenic acid DGLK, the parent of the first series of prostaglandins, as well as the precursor of arachidonic acid AK, the parent of the second series of prostaglandins.

Alpha-linolenic acid is converted to eicosapentaenoic acid EPK, the parent of the third series of prostaglandins, and docosahexaenoic acid DHA.

Arachidonic AK and docosahexaenoic DHA acids belong to long-chain PUFAs (LCPUFAs). They are important structural components phospholipid membranes of tissues throughout the body and are especially abundant in the tissues of the brain and nervous system. The amount of DHA in most human tissues is small in percentage terms, but in the retina, brain and sperm, DHA accounts for up to 36.4% of all fatty acids. With a long-term lack of LA and ALA in the diet, or insufficient conversion of them, the amount of long-chain PUFAs in the brain and nervous system may decrease.

Table 2. Omega-6 and omega-3 PUFA families.

Sometimes the body cannot break down LA and ALA due to some defects or due to a lack of desaturase and elongase enzymes necessary for the breakdown. In such cases, it is necessary to introduce foods rich in GLA, DGLA (omega-6), for example, borage oil, evening primrose oil (borage oil, evening primrose oil) and EPA, DHA (omega-3) - fish oil, fatty fish.

Effects of omega fat derivatives on the body

PUFAs play another, equally important role in the body. Eicosanoids (prostaglandins, prostacyclins, thromboxanes and leukotrienes) are synthesized from them. Eicosanoids are local tissue hormones. They do not travel in the blood like normal hormones, but are created in cells and regulate numerous cellular and tissue functions, including platelet concentration, inflammatory reactions and the functioning of leukocytes, vasoconstriction and dilation, blood pressure, bronchial contractions and uterine contractions.
To make it clearer to you the effect of different families of PUFAs on the body, below I provide a table of examples physiological action prostaglandins of different series. Prostaglandins are divided into three series: 1, 2 and 3.
Prostaglandins 1 and 2 series are synthesized from omega-6 acids, prostaglandins 3 series - from omega-3 acids.

Table 3. Examples of the physiological action of prostaglandins 1, 2 and 3 series

Often series 2 prostaglandins are conventionally called “bad”, and series 1 and 3 are called “good”. However, it is incorrect to conclude from this that omega-3 fats are healthy and omega-6 fats are harmful. A balance of omega-3 and omega-6 fats in the body is necessary to maintain optimal health.
Due to the significant predominance of omega-3 fats in the diet (more than 7-10 g/day), for example, Greenlandic Eskimos have an increased tendency to bleeding.
It would be fair to note that a large excess of omega-6 still has worse health consequences.
In general, omega-6 deficiency often results in skin symptoms such as dry, thickened, flaky skin and impaired growth. Also possible: skin rashes similar to eczema, hair loss, degeneration of the liver, kidneys, frequent infections, poor wound healing, infertility.
Omega-3 deficiency has less noticeable clinical symptoms and includes neurodevelopmental abnormalities, abnormal visual functioning, and peripheral neuropathy.

As stated above, the diet of most modern people contains too many omega-6 and too little omega-3 PUFAs. An excess of AA arachidonic acid (from the omega-6 PUFA family) in tissues plays a negative role in the development of inflammatory processes and an increased susceptibility to certain diseases.
The following is a partial list of diseases that can be prevented or improved by adding omega-3 PUFAs to the diet. The diseases are listed in descending order of strength of evidence:

1. coronary heart disease and stroke;
2. PUFA deficiency in infancy (retinal and brain development);
3. autoimmune diseases (eg, lupus and nephropathy);
4. Crohn's disease (inflammatory bowel disease);
5. breast, colon and prostate cancer;
6. slightly elevated blood pressure;
7. rheumatoid arthritis (4).

Other sources also mention bronchial asthma, type 2 diabetes, kidney disease, ulcerative colitis, chronic obstructive pulmonary disease (15); critically ill patients with lung damage, eczema, attention deficit hyperactivity in children, dyslexia, allergic rhinitis, depression, including postpartum depression, and even schizophrenia and some other mental illnesses. Not for all of these diseases the results of using omega acids have been established accurately; the study continues. For some of these diseases, the addition of DGLA and GLA from the omega-6 PUFA family to the diet is also used.

Omega fats in infant formulas

Of great interest now is the addition of long-chain PUFAs to infant formulas. The presence of large amounts of DHA and AA in the tissues of the retina and brain, as well as the presence of these LCPUFAs in breast milk suggestive of their role in infant development. Various studies have shown that breastfeeding in early childhood is associated with greater cognitive development in later childhood; that the functioning of the retina and brain matures faster in breastfed children; IQ is higher in children fed breast milk. It is very likely that the difference in the amount of long-chain PUFAs received during infancy is responsible for these differences, although it cannot be ruled out that there are also other factors still unknown to science.

Modern formulas have been supplemented with soybean oil (LA to ALA ratio of 7:1), which has significantly improved their omega-3 status. Previously, blends were made only with corn and coconut oils, which are rich in omega-6 and contain trace amounts of omega-3. But – there is still debate whether the baby’s body can convert LA and ALA into long-chain PUFAs? And is it necessary to add arachidonic and docosahexaenoic acids to the mixture?

It is known that during pregnancy, AA and DHA are transferred into the blood of the fetus through the placenta. There are two critical moments in a child's development when they need omega LCPUFAs - during fetal development and after birth, until the biochemical development of the retina and brain is completed. If a pregnant woman does not consume enough omega-3 fats through food, her body will withdraw them from its own reserves. The requirements for the presence of DHA and AA in the body of a pregnant woman are especially high in the third trimester of pregnancy, when rapid growth of the fetal brain occurs. During pregnancy, the concentration of omega-3 LCPUFAs in the mother's blood plasma changes little, but in the postpartum period there is a gradual decline, independent of breastfeeding, and sometimes long-term. This decline can be stopped or prevented by timely dietary adjustments (DHA 200-400 mg/day). Maternal plasma DHA levels may continue to decline with each subsequent pregnancy.

Full-term infants are born with approximately 1,050 mg of DHA stored in body fat. During the first 6 months of life, breastfed infants continue to increase the amount of DHA in their body at a rate of 10 mg/day, with about 48% of DHA deposited in brain tissue. During this time, artificial babies accumulate in the brain only about half of the DHA accumulated by breastfed infants and at the same time lose DHA reserves in the body. To date, there is no evidence that formula-fed infants can convert ALA to DHA in sufficient quantities during infancy (14). Many studies have concluded that during infancy (up to approximately 6 months), DHA should be considered an essential element along with LA and ALA. Infants fed formulas not fortified with long-chain PUFAs have lower proportions of DHA (as well as AA) in plasma, red blood cells, and brain than those fed breast milk. Infants fed fortified formulas do not achieve the same amounts of DHA in their bodies as those fed with breast milk, but their DHA status is much improved relative to formula-fed infants. It is possible that these artificially accumulated amounts of DHA are sufficient for their optimal development. It is known that already deposited LCPUFAs are retained in the retina and brain with enviable strength, even if the diet is subsequently poor in omega-3 fats.

Human breast milk always contains small amounts of DHA and AA (0.3% and 0.44% of total fat, respectively) along with LA, ALA and small amounts of other omega acids. The amount of DHA in milk depends on the mother's diet.
When sources of omega-3 fats are introduced into the mother's diet, the concentration of DHA in the mother's breast milk and the baby's blood increases.

A significant positive effect of adding DHA and AA to formula on infant development has been established for premature infants (especially in visual functioning). Since the greatest accumulation of DHA in the fetus occurs in the third trimester of pregnancy, premature babies are born with a greater lack of DHA in the brain and body. Naturally, they respond most gratefully to the addition of the DHA they lack to their diet. However, there are no answers regarding the safety and necessity of adding AA and DHA to formulas for full-term infants.
Different studies come to different results, which are difficult to compare. Different designs of studies, selection of different mixtures, addition of different amounts of different omega-3 PUFAs, sometimes accompanied by the addition of AA (omega-6), sometimes not, different tests used by researchers do not allow an unambiguous interpretation of the results of these studies.
To date, no reliable standardized tests have been developed to assess the effects of long-chain PUFA supplementation on child development.
Minimum requirements for PUFAs are difficult to establish because:
1) long-chain PUFAs can be synthesized from ALA, LA;
2) the concentrations of omega-6 and omega-3 LCPUFAs have not been clearly determined, indicating their deficiency or sufficiency;
3) there are still no recognized clinical tests to determine the deficiency and sufficiency of omega-3 LCPUFA.

Also complicating the issue, some studies suggest that adding too much omega-3 DHA and ALA to formulas may result in underconversion of omega-6s (due to a concomitant increase in EPA (omega-3) content that competes with AA ( omega-6)), which may result in slower growth, delayed speech development, and changes in the development of the nervous system in a positive or negative direction.
The simultaneous addition of AA arachidonic acid to the mixture should neutralize this negative effect.

Conclusion: Until there is a specific measurement of the effects of PUFA supplementation in infants (eg, visual acuity, cognitive development scores, insulin sensitivity index, height) in relation to blood concentrations of different PUFAs, the composition of breast milk from healthy mothers should be used as a guide. including fish in their diet as an example of dietary recommendations for infants.

In Europe, infant formulas fortified with AA and DHA in quantities similar to those found in human breast milk have already appeared on sale. Unfortunately, the addition of LCPUFA increases the cost of formulas. Fortified formulas are not yet available in the United States.

Omega fats in foods

The main sources of omega-3 fats are fish and vegetable oils. Fish is rich in EPA and DHA, vegetable oils are rich in ALA.
Other sources include nuts, seeds, vegetables, some fruits, egg yolks, poultry, meat: these sources contribute negligible amounts of omega-3 to the diet.

Of the publicly available oils, the richest in ALA are canola (canola or rapeseed oil) and soybean oils, 9.2% and 7.8% ALA, respectively. Flaxseed oil contains especially large amounts of ALA, but it is not a commonly consumed oil.

Oily fish containing large amounts of EPA and DHA include mackerel, herring, and salmon. For example, raw salmon contains 1.0–1.4 g omega-3 fats/100 g serving, mackerel contains ~2.5 g omega-3 fats/100 g serving. Fat content can vary depending on the type of fish; different types of salmon, for example, contain different amounts of fat. Other, leaner types of fish contain much lower amounts of omega-3 fats.

Of the animal products enriched with omega-3 PUFAs, only omega-3 eggs are currently available on the market.

Table 4. Content of omega-3 PUFAs in some seafood products.

Note: Don't forget that some types of fish contain high levels of mercury.
The United States and Canada recommend that pregnant women, nursing mothers and young children avoid the following types of fish: shark, swordfish, king mackerel (shark, swordfish, king mackerel, tilefish), questionable tuna steaks, or at least not eat them more than once a month. Other people should not eat these types of fish more than once a week.
You can eat other types of fish, starting with canned tuna and ending with mollusks, crustaceans and smaller ocean fish. However, try to eat different types fish, not the same one. Some US states recommend that pregnant women eat no more than 198 g (7 ounces) of canned tuna per week.

Table5. Plant sources of ALA.

Note: The table shows only the most significant plant sources of omega-3 PUFAs. Other plants contain smaller amounts of omega-3 PUFAs.

Omega-3 PUFA dietary supplements

Various dietary supplements containing omega-3 PUFAs are now available to consumers. Many are made from marine oils and contain 180 mg of EPA and 120 mg of DHA in each capsule.
Another source of omega-3 PUFAs is cod liver oil, typically 173 mg EPA and 120 mg DHA in each capsule. These supplements should be taken with caution, noting that they contain large amounts of vitamins A and D. A vegetarian source of DHA (100 mg per capsule) extracted from seaweed (algae) is also now available.

Canada recommends an intake of 1.2–1.6 g/day of omega-3 fats, which is similar to the US recommendations, but does not differentiate between different omega-3 fats.
The UK recommends that 1% energy be ALA and 0.5% EPA + DHA.
Commission on medical aspects The UK nutrition policy recommends the co-administration of EPA and DHA 0.2 g/day.
Australia recommends a moderate increase in omega-3 fat sources from plant foods (ALA) and fish (EPA and DHA).
Finally, the NATO Preliminary Symposium on Omega-3 and Omega-6 Fatty Acids recommended co-administration of EPA and DHA at 0.27% energy or 0.8 g/day.

Some recommendations have been made based on the ratio of omega-6 fats to omega-3 fats.
The WHO recommends an omega-6 to omega-3 ratio of 5–10:1.
Sweden recommended 5:1, and Japan changed the recommendation from 4:1 to 2:1 (5).

To achieve the suggested recommendations for both grams and proportions, while increasing omega-3 fats in the diet, you need to reduce the amount of omega-6 fats. Due to competition between omega-6 and omega-3 fats for elongase and desaturase enzymes, the amount of LA in the diet influences the amount of EPA and DHA converted from ALA.
Additionally, simply adding omega-3 fats to the other types of fat you already consume can lead to weight gain over time.

Omega-3 fats, just like others polyunsaturated fats, are susceptible to oxidative damage from free radicals, radiation, and toxic exposure. They are the most easily damaged fats in the body. Although not yet fully understood, fat oxidation is considered an important mechanism involved in the pathogenesis of inflammation, cancer, and atherosclerosis. Therefore, it is often recommended, simultaneously with taking omega-3 PUFAs, to increase the amount of foods rich in vitamin E in the diet or to take additional vitamin E. Under no circumstances should you eat already oxidized, rancid fats (any fats).
They are easily identified by their unpleasant smell and taste.

Foods containing large amounts of vitamin E:

Vitamin E is often found in the same plant foods that are rich in LA and ALA.
The best sources are unrefined vegetable oils, seed and nut oils, and grains. When chemically processing (refining) oils and grinding, refining and bleaching flour, vitamin E is lost. Animal sources such as butter, egg yolk, milk fat and liver contain smaller amounts of vitamin E.

Some sources of vitamin E.

Unrefined oils: safflower, sunflower, cotton, soybean, corn, peanut, sea buckthorn; wheat germ and oil from them; legumes; grain and legume sprouts; soybeans, nuts, seeds, nut butters, brown rice, oatmeal, dark green leafy vegetables, green peas, spinach, asparagus.

Table 6.Approximate amounts of vegetable and fish products rich in omega-3 PUFAs,in accordance with current dietary recommendations (5)

List of products containing significant amounts of omega-3 and omega-6 PUFAs

OMEGA-3.
ALC. Flax seeds or flaxseed oil; walnuts, pumpkin seeds or their oils; wheat germ oil, canola, soybean oil (preferably unrefined), dark green leafy vegetables, especially purslane.
Olive oil, although it does not contain large amounts of omega-3, helps increase the content of omega-3 in body cells (according to some sources). Flaxseed oil and ground flax seeds should be stored in the dark in the refrigerator. Flaxseed oil is not used in cooking, as high temperature deprives it of its beneficial properties. Ground flax seeds can be used in baking, especially breads.
EPA, DHA. The general rule is that the fattier the fish, the more omega-3 fats it contains. In addition to salmon, mackerel and herring, sardines, tuna, and trout are also sometimes mentioned. Here we will also include fish oil and eggs with a high content of omega-3 fats.

OMEGA-6.
OK. Sunflower, safflower, corn, cottonseed, soybean oils (preferably unrefined). Raw pistachios, pine nuts, raw sunflower seeds, sesame seeds, pumpkin seeds.
GLK. Borage, evening primrose and black currant seed oils.
AK. Butter, animal fat, especially pork fat, red meat, organ meats and eggs.

Table 7. Oils with a relatively high content of omega-3 and omega-6 PUFAs.

Note: Soybean oil has the highest omega-6 PUFA content of most omega-3 oils, so it belongs in both categories.

PUFA - polyunsaturated essential fatty acids - polyunsaturated fatty acids (PUFAs).

LCPUFA – long-chain polyunsaturated fatty acids - long-chain polyunsaturated fatty acids (LCPUFAs).

ALC - alpha-linolenic acid from the omega-3 PUFA family - linolenic acid (ALA; 18:3 n -3).

EPK – eicosapentaenoic acid from the omega-3 PUFA family - Eicosapentaenoic acid (EPA; 20:5 n -3).

DHA - docosahexaenoic acid from the omega-3 PUFA family, refers to LCPUFA - Docosahexaenoic acid (DHA; 22:6 n -3).

OK - linoleic acid from the omega-6 family - Linoleic acid (LA; 18:2 n -6).

GLK – gamma-linolenic acid from the omega-6 family - Gamma linolenic acid (GLA; 18:3 n -6).

DGLK – Dihomo-gamma-linolenic acid from the omega-6 family - Dihommo - gamma - linolenic acid (DGLA; 20:3 n -6).

AK– arachidonic acid from the omega-6 family, belongs to LCPUFA - Arachidonic acid (AA; 20:4 n -6).

Omega is often referred to as n, that is, omega-3 = n -3, omega-6 = n-6, or w - w-3, w -6 respectively.

1. B present moment There is no consensus on the optimal ratio of omega-3 to omega-6, as well as on the acceptable maximum amounts of omega-3 in the diet, so figures may vary slightly from one source to another.

2. Medicinal borage ( Borago officinalis) – borage; evening primrose, evening primrose, evening primrose, aspenberry ( Oenothera biennis, family Onagraceae) - evening primrose.

3. The cause of the above symptoms in our time is often not a lack of linoleic acid in the diet, but its insufficient breakdown into subsequent fatty acids.

4. Brain development ends by 6-7 years, but the most active period of development occurs in the first and second years of a child’s life.

5. There is a point of view, not yet proven, that it is this decline in DHA in the blood that explains the development postpartum depression and emotional swings in the mood of the woman who gave birth. (Immediately after giving birth, the chances of developing serious mental health problems such as depression and obsessive neurosis, increase 6 times and remain elevated for 2 years. Gitlin MJ, Pasnau RO. Psychiatric syndromes linked to reproductive function in women: a review of current knowledge. Am J Psychiatry 1989; 146(11):1413-1422).

6. In countries with high fish consumption, such as Japan, DHA in breast milk typically accounts for 0.6% of total fat.

7. Fish oil, especially from fish liver, may be contaminated with polychlorinated biphenyls and dioxins. Seaweed fats like new food, are not yet approved for use in all countries.

8. Desaturase enzymes are also easily bound by trans fats (margarines, hydrogenated vegetable oils).

9. The US has not made official recommendations for omega-3 fat intake; The above recommendations were given by a group of American scientists. Existing official recommendations refer to total PUFA intake: 1–2% of energy from FA to prevent fatty acid deficiency and total PUFA intake should be 7% of energy and not exceed 10% of energy.

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