Why do people need polyunsaturated fatty acids? Polyunsaturated fatty acids are essential

Fats have fallen out of favor recently. On the one hand, this is certainly true - fatty food very high in calories, and in the pursuit of slimness, every calorie eaten is strictly accounted for. But don't forget that complete failure This class of nutrients can cause serious health problems. After all, they contain many components necessary for normal operation our body: for example, polyunsaturated fatty acids.

If you remember the school course organic chemistry, then it turns out that fats are compounds of glycerol and fatty acids.

Fatty acids are organic substances in the molecules of which the –COOH fragment, responsible for acidic properties, is connected to carbon atoms that are sequentially linked to each other. Each carbon atom has several more hydrogens attached to it, so the resulting structure looks something like this:

CH3-(CH2-CH2)n-COOH

It happens that in some acids “carbons” are connected to each other not by 1, but by 2 bonds:

CH3-(CH=CH)n-COOH

Such acids are called unsaturated.

If there are many carbon atoms in a compound, connected to each other by 2 bonds, then such acids are called polyunsaturated, from the ancient Greek “polis”, which means many.

The latter, in turn, are divided into several groups, namely:

• omega-9;
• omega-6;
• omega-3 polyunsaturated acids.

Which one does it belong to? unsaturated acid, determined by which carbon atom, if you start from the non-acidic end of the molecule (CH3-), will have the first 2-bond.

By the way, our body produces omega-9 acids itself, but we only get representatives of the other 2 groups from food.

Why are polyunsaturated fatty acids needed?

These compounds are a necessary component for the membrane of all animal cells - the so-called cell membrane. Moreover, the more complex the cell’s activity, the higher the amount of polyunsaturated fatty acids in its membrane. For example, in the membrane of the retinal cells of our eye, there are almost 20% of such acids, and in the membrane of subcutaneous fat cells their content is less than 1%.

In addition to the construction function, these substances are needed for the biosynthesis of endohormones - substances that affect the activity of the very cell in which, so to speak, “local hormones” were formed. I would like to talk about them in more detail, since these compounds are responsible for many processes occurring in our body.

So, endohormones control such things as the occurrence or disappearance of pain and inflammation, and also influence the ability of blood to clot. They are formed, as mentioned above, from acids already familiar to us, which are contained in the cell membrane. Moreover, from different groups, hormones are created that are designed to solve various problems. Thus, omega-6 acids produce substances that are responsible for the adequate response of the human body to damaging environmental factors. Such endohormones increase blood clotting, which prevents large blood loss during wounds, and also cause inflammation and pain - unpleasant reactions, but necessary for survival. However, if there is an excess of these substances, then the process gets out of control: the blood becomes too viscous, the pressure rises, blood clots form in the vessels, the risk of heart attack and stroke increases, and allergic reactions intensify.

Endohormones derived from omega-3 polyunsaturated acids have the opposite effect: they reduce inflammatory reactions, thin the blood, and relieve pain. Moreover, the higher the concentration of omega-3 acids in the body, the fewer hormones are synthesized from omega-6 acids. However, it is still not worthwhile to completely abandon the latter - after all, in this case, hypotension, poor blood clotting and a drop in local blood pressure are ensured. Ideally, your diet should be 4 parts omega-6 to 1 part omega-3 fatty acids.

Foods rich in polyunsaturated fatty acids

The human body is created from living tissues, which during the life process not only perform their functions, but also recover from damage, maintaining their performance and strength. Of course, for this they require nutrients.

Human nutritional balance

Food supplies the body with the energy it needs to support all body processes, especially muscle function, tissue growth and renewal. It should be remembered that the main thing proper nutrition- balance. Balance is the optimal combination of foods from five groups necessary for human nutrition:

• dairy products;
• foods enriched with fats;
• cereals and potatoes;
• vegetables and fruits;
• protein food.

Types of fatty acids

Unsaturated ones are also divided. The latter are polyunsaturated and monounsaturated. Saturated fatty acids are present in butter and hard margarines, polyunsaturated fatty acids are present in vegetable oil, fish products and some soft margarines. Monounsaturated acids found in rapeseed, flaxseed and olive oil. The most necessary and healthy among them are the latter.

Health effects of unsaturated fatty acids

They have antioxidant properties and protect cholesterol contained in the blood from oxidation. The recommended consumption of polyunsaturated acids is about 7% of the daily portion and monounsaturated acids - 10-15%.

Unsaturated fatty acids are essential for the normal functioning of the entire body. Omega-3 and Omega-6 complexes are considered the most valuable of them. They are not synthesized independently in the human body, but are vital for it. Therefore, you should definitely include them in your diet, choosing the most optimal foods rich in these substances.

Properties of Omega acids

Nutritionists have long been interested in the functions of Omega-3 acids and their derivatives - prostaglandins. They tend to turn into messenger molecules that stimulate or suppress inflammation, and are very useful for swollen joints, muscle pain, bone pain, which is often observed in older people. Unsaturated fatty acids strengthen the immune system and mitigate the symptoms of rheumatoid arthritis and osteoarthritis.

They improve bone mineralization, while increasing their density and strength. In addition, Omega-3 unsaturated fatty acids are extremely beneficial for the heart and blood vessels. Complexes of Omega-unsaturated acids are also successfully used in for cosmetic purposes in the form of a dietary supplement, they have a positive effect on skin health. Saturated and unsaturated fatty acids differ in their dietary properties: in unsaturated fats less calories than similar amounts of saturated fat. Omega-3 chemical molecules consist of a paired connection of 3 carbon atoms with a methyl carbon, and Omega-6s are linked by a paired connection of six carbon atoms with a methyl carbon. Omega-6 fatty acids are found most abundantly in vegetable oils and in all varieties of nuts.

Foods with high concentrations of unsaturated fatty acids

Sea fish such as tuna, salmon and mackerel are rich in Omega-unsaturated fatty acids. Their plant analogues include flaxseed and rapeseed oil, pumpkin seeds, and various types of nuts. Fish oil contains omega-3 fatty acids. It can be completely replaced by linseed oil.

The best source of these substances is fatty fish such as mackerel, but you can introduce unsaturated fatty acids into your diet in a variety of ways.

1. Buy omega-3 fortified foods. Nowadays they are often added to bread, milk and cereal bars.
2. Use flaxseed oil instead of sunflower and butter. Add ground flaxseed to baking flour, salads, soups, cereals, yogurts and mousses.
3. Include nuts in your diet, in particular walnuts, Brazil nuts, pine nuts and others.
4. Add unrefined olive oil in any food. It not only saturates the body with essential acids, but also helps digest food.

Patients suffering from diabetes or taking anticoagulants should consume unsaturated fatty acids with caution. May affect blood clotting and sugar regulation. Pregnant women should not take fish oil, because it contains a lot of vitamin A, which is dangerous for the intrauterine development of the fetus.

Unsaturated fatty acids in foods

Monounsaturated acids are generous:

• fish fat;
• olives;
• avocado;
• vegetable oils.

Polyunsaturated fats:

• nuts;
• pumpkin, sunflower, flax, sesame seeds;
• fatty fish;
• corn, cottonseed, sunflower, soybean and linseed oils.

Saturated fats are not as bad as people think they are, and you shouldn't give them up completely. Monounsaturated and polyunsaturated fats should be the main part of the daily portion of fat, and are necessary for the body from time to time, as they promote the absorption of proteins, fiber, and improve the functioning of sex hormones. If fats are completely removed from the diet, memory functions are weakened.

Trans isomers in food consumed

In the process of preparing margarine, modification of unsaturated vegetable fats under the influence of high temperatures, causing trans-isomerization of molecules. All organic substances have a specific geometric structure. When margarine hardens, cis isomers turn into trans isomers, which affect the metabolism of linolenic acid and provoke an increase in the level of bad cholesterol, causing heart and vascular diseases. Oncologists claim that trans isomers of unsaturated fatty acids provoke cancer.

Which foods contain the most trans isomers?

Of course, there are a lot of them in fast food, cooked in a lot of fat. For example, chips contain about 30%, and French fries contain more than 40%.

In confectionery products, trans isomers of unsaturated fatty acids range from 30 to 50%. In margarines their amount reaches 25-30%. In mixed fats, 33% of mutation molecules are formed during the frying process, since overheating causes transformation of molecules, which accelerates the formation of trans isomers. If margarine contains about 24% trans isomers, then during frying their level increases significantly. In crude oils plant origin There are up to 1% trans isomers; in butter there are about 4-8%. In animal fats, trans isomers range from 2% to 10%. It should be remembered that trans fats are garbage and should be avoided entirely.

The effect of polyunsaturated fatty acids on the human body has not yet been fully studied, but it is now obvious that for healthy active life, a person must introduce foods that contain unsaturated fatty acids into his diet.

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 meaning of poly unsaturated 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 is not significant quantities 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 with vegetable oils to lower blood cholesterol levels. Consumption of fish and seafood rich in omega-3 fats has decreased significantly. In the 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 of 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 responses and white blood cell function, vasoconstriction and dilation, blood pressure, bronchial contractions, and uterine contractions.
To make it clearer to you about the effect of different families of PUFAs on the body, below I provide a table of examples of the physiological effects of 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 manifestations: Skin is dry, thickened, flaky, and growth impaired. 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 These include neurodevelopmental abnormalities, abnormal visual functioning, and peripheral neuropathy.

As mentioned 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 high 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, and even schizophrenia and some others mental illness. Not for all of these diseases the results of using omega acids have been established accurately; the study continues. For some of listed 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 with breastfeeding V early childhood associated with greater cognitive development in late 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 fast growth fetal brain. 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, 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.

Significant positive influence The addition of DHA and AA to formula on infant development has been established for premature infants (especially in vision 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 slowed 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 yolk, poultry, meat: these sources contribute small 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. The fat content may vary depending on the type of fish; different types of salmon, for example, contain different quantities 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, from canned tuna to shellfish, 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.
The Medical Aspects of Nutrition Policy Commission, which includes the UK, recommends joint reception 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, like other 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 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.
Best sources– unrefined vegetable oils, seed and nut oils, 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, cottonseed, soybean, corn, peanut, sea buckthorn; wheat germ and oil from them; legumes; grain and legume sprouts; soybeans, nuts, seeds, nut oils, 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). Linseed oil, ground seeds flax should be stored in the dark in the refrigerator. Flaxseed oil is not used in cooking, as high temperature deprives it useful properties. Ground flax seeds can be used in baking, especially breads.
EPA, DHA. General rule- how fatter 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 increased content omega-3 fats.

OMEGA-6.
OK. Sunflower, safflower, corn, cottonseed, soybean oils (preferably unrefined). Raw pistachios, pine nuts, raw seeds sunflower, sesame seeds, pumpkin.
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. At the moment, there is no agreement on the optimal ratio of omega-3 to omega-6, as well as on the permissible maximum amounts of omega-3 in the diet, so the figures may vary slightly in different sources.

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 of postpartum depression and emotional swings in the mood of the woman who gave birth. (Immediately after birth, the chances of developing serious mental disorders 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, as a 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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3. Reto Muggli. Preface. Am J Clin Nutr 2000 71: 169–170.

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6. Jan Eritsland. Safety considerations of polyunsaturated fatty acids. Am J Clin Nutr 2000 71:197–201.

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Polyunsaturated fatty acids include unsaturated fatty acids with two, three or more double bonds. This is linoleic (C 17 H 31 COOH), having two double bonds between the 9-10th and 12--13th carbon atoms; linolenic (C 17 H 29 COOH), having three double bonds between the 9-10th, 12-13th and 15-16th carbon atoms; arachidonic (C 19 H 39 COOH) acids. These highly unsaturated polyunsaturated fatty acids, due to their biological properties, can be classified as vital substances, and therefore by some researchers they are considered vitamins (vitamin F).

PUFAs are essential vital substances that are not synthesized in the animal body. Physiological significance and biological role PUFAs are very important and diverse.

The most important biological property of PUFAs is their participation as structural elements in biologically highly active complexes such as phosphatides, lipoproteins, etc.

PUFA - necessary element in education cell membranes, myelin sheaths, connective tissue and etc.

A connection has been established between PUFAs and cholesterol metabolism, expressed in the ability to increase the excretion of cholesterol from the body by converting it into labile, easily soluble compounds (Dale, Reiser, 1955).

In the absence of PUFAs, cholesterol esterifies with saturated fatty acids, which are deposited on the walls of blood vessels (Sinclair, 1958). In the case of atherification of cholesterol with unsaturated fatty acids, a high level of cholesterol absorption in the intestine is observed (Lang, 1959). According to Lewis and Folke (1958), PUFAs contribute to the rapid conversion of cholesterol into cholic acids and their removal from the body.

PUFAs have a normalizing effect on the walls of blood vessels, increase their elasticity and reduce permeability (Holman, 1957).

There is evidence (Sinclair, Robinson, Poole, 1956) that PUFA deficiency contributes to coronary thrombosis.

PUFAs partially protect against metabolic disorders caused by the intake of large quantities of thyroidine.

A connection has been established between PUFAs and the metabolism of B vitamins (pyridoxine and thiamine), as well as with the metabolism of choline, which, under conditions of PUFA deficiency, reduces or completely loses its lipotropic properties.

Insufficiency of PUFAs negatively affects the ability to activate enzymes, the activity of which is inhibited by foods high in protein (Levy, 1957). Data have been obtained on the stimulating role of PUFAs on the body's defense mechanisms and, in particular, on increasing the body's resistance to infectious diseases and the effects of radiation (Sinclair, 1956).

With PUFA deficiency, the activity of cytochrome oxidase in the liver increases sharply.

PUFA deficiency is manifested by skin lesions.

In animals with PUFA deficiency, duodenal ulcers are more often detected.

PUFAs, as well as some protein amino acids, are essential components not synthesized in the body, the need for which can only be satisfied through food. However, the conversion of some fatty acids to others is possible. In particular, the undoubted transformation of linoleic acid into arachidonic acid in the body has been established.

The participation of pyridoxine in the conversion of linoleic acid to arachidonic acid has been established.

The biologically optimal formula for balancing fatty acids can be the ratio of 10% PUFAs, 30% saturated fatty acids and 60% monounsaturated (oleic) acid in fat.

For natural fats this structure of fatty acids approaches lard, peanut and olive oil. The types of margarine currently produced mostly correspond to the given formula for balancing fatty acids.

According to the US National Nutrition Research Council (1948), the minimum daily requirement in PUFAs is determined at 1% of the daily calorie intake. According to B.I. Kadykov (1956), the daily norm of PUFAs for adults is 1% of the daily calorie intake and for children - 2%. Seimar, Shapiro, Friedman (1955) based on studies conducted on animals (rats), recommend daily norm PUFAs for humans - 7 g. Summarizing and generalizing the available materials on the rationing of PUFAs, we can come to the conclusion that the norm for PUFAs for adults is 5-8 g per day. As already noted, arachidonic acid is the most biologically active, and 5 g of arachidonic acid is sufficient to satisfy the need for PUFAs due to its intake from food.

Polyunsaturated fatty acids: what foods they contain, benefits

What are polyunsaturated fatty acids?

Polyunsaturated fatty acids are a type of dietary fat. PUFAs are one of the types of healthy fats, along with monounsaturated fats. Polyunsaturated fats are found in plant and animal foods such as salmon, vegetable oils, and some nuts and seeds.

Eating moderate amounts of polyunsaturated (and monounsaturated) fat instead of saturated fat and trans fat can benefit your health. Polyunsaturated fats are different from saturated fats and trans fats, which can increase your risk of heart disease and other health problems.

Biological role of polyunsaturated fatty acids

Polyunsaturated fatty acids are essential for the proper development of young organisms and the maintenance of good human health. These acids belong to the Ω-6 and Ω-3 families.

Linoleic acid (C18:2 Ω-6) is also among them, as well as longer chain fatty acids derived from linoleic acids in animal and human tissues, which also belong to the Ω-6 family:

• Dihomo-γ-linolenic acid (DHLA) (C20:3, Ω-6);
• arachidonic acid (AA) (C20:4, Ω-6);
• α-linolenic acid (C18:3 Ω-3).

And which belong to the Ω-3 family:

• eicosapentaenoic acid (EPA) (C20:5, Ω-3);
• docosahexaenoic acid (DHA) (C22:6, Ω-3).

20-carbon acids are substrates for the synthesis of eicosanoids, which contain prostaglandins, prostacyclins, thromboxanes, leukotrienes, hydroxy and epoxy fatty acids and lipoxins, which are necessary for metabolism.

Eicosanoids - tissue hormones and their role in the body

Eicosanoids can be considered as the outermost transmitters of the first class, which enhance or weaken the regulatory activity of hormones and neurotransmitters at the cellular level. Substrates for the synthesis of eicosanoids are located in phospholipids in the cell membrane.

In recent years, many facts have been established that prove that eicosanoids have a very wide spectrum of activity.

They have a significant impact on the regulation of activities of cardio-vascular system and tissue oxygenation, and also have an antiarrhythmic effect (reducing the risk of arrhythmias). They control the regulation of blood pressure, the balance in blood clotting and decoagulation, and the stability of blood vessels. They regulate the content of lipoproteins, in particular HDL, and specific lipoprotein proteins.

They influence the adaptation of the body's immunity to inflammatory processes, proliferation (regeneration and reproduction) of cells, the activity of hormones and neurotransmitters, gene expression and the activity of many organs (such as the brain, kidneys, lungs and digestive tract), the sensation of pain and many other physiological and biochemical processes.

Important Ω-3 family

It has been found that people who eat plenty of seafood containing Ω-3 fatty acids are less likely to suffer from diseases common in industrialized countries.

It was found that these people had a markedly reduced incidence of atherosclerosis, myocardial ischemia, breast carcinoma, colorectal cancer, intravascular thrombi and asthma. It has been experimentally proven that fish oil has healing effect for cerebral hemorrhage, myocardial infarction and psoriasis.

Much scientific evidence has been collected that shows that fatty acids from the Ω-3 family have very positive effects on the circulatory system. Fish oil has been found to have a strong hypotensive effect (lowering blood pressure); therefore it should be recommended for arterial hypertension. They also reduce serum levels of very low-density lipoprotein (VLDL), triglycerides, and cholesterol (particularly total cholesterol) while increasing HDL cholesterol. ()

How polyunsaturated fats affect your health

Polyunsaturated fatty acids may help. Cholesterol is a soft, waxy substance that can cause arteries to become smaller or clogged. Low level LDL cholesterol reduces the risk of developing cardiovascular diseases.

Polyunsaturated fats include omega-3 and . These are essential fatty acids that the body needs for brain function and cell growth. Our bodies DO NOT produce essential fatty acids, so you can only get them from food.

Omega-3 fatty acids are good for your heart in several ways. They are helping:

• Reduce triglyceride levels (a type of fat in the blood).
• Reduce the risk of irregular heartbeat (arrhythmia).
• Prevent the slow formation of plaque on artery walls (cholesterol plaques).
• Reduce blood pressure slightly.

Omega-6 fatty acids may help:

• Control blood sugar levels.
• Reduce the risk of developing diabetes.
• Reduce blood pressure.

Consumption rate of polyunsaturated fatty acids

Your body needs fats for energy and other functions. Polyunsaturated fats are a healthy choice. Dietary Guidelines In 2010, they gave the following recommendations for how much fat you should consume each day:

• Get 25 to 30% of your daily calories from fat. Make sure that most of these fats are monounsaturated or polyunsaturated.
• Limit your intake of saturated fat (found in red meat and whole dairy products)—less than 6% of your daily calories should come from this type of fat. For a 2,000-calorie restricted diet, you should consume no more than 120 calories or 13 grams of saturated fat per day.

Eating healthy fats can lead to certain health benefits. But consuming too much fat can lead to weight gain. All fats contain 9 calories per gram. This is more than twice the calories found in carbohydrates and proteins.

It is not enough to add foods high in unsaturated fats to a diet filled with unhealthy foods and fats. Substitute saturated or trans fats instead. In general, eliminating saturated fat is twice as effective at lowering blood cholesterol levels as increasing your intake of polyunsaturated fat. ()

Reading food labels

All packaged foods have ingredient labels indicating their fat content. Reading these labels can help you keep track of how much fat you eat per day.

• Check the total amount of fat in one serving. Remember to count the number of servings you eat in one sitting.
• Look at the amount of saturated fat and trans fat per serving. The rest is healthy unsaturated fat. Some labels will list monounsaturated and polyunsaturated fats, but most will not.
• Aim to ensure that the majority of your daily fat intake comes from sources containing monounsaturated and polyunsaturated fatty acids.
• Many restaurants fast food They also provide information about the composition of the dishes on their menu. If you don't see it, ask the service staff about it. You can also find the ingredients on the restaurant's website.

Where are polyunsaturated fatty acids found?

Majority food products have a combination of all types of fats. Some have higher amounts of healthy fats than others. Here are the main sources of polyunsaturated fatty acids:

• fish such as , and
• avocado oil
• sunflower oil
• corn oil
• soybean oil
• safflower oil
• peanut butter
• Sesame oil
• walnut oil

To get the health benefits, you need to replace unhealthy fats useful.

• Eat walnuts instead of cookies as a snack. But be sure to stick to small portions, as nuts are high in calories.
• Replace some animal meat with fish. Try to eat according to at least 2 servings per week.
• Add ground flax seeds to your dishes.
• Add walnuts or sunflower seeds to salads.
• Use corn or safflower oil instead butter and solid fats (such as margarine).

The benefits of polyunsaturated fatty acids

Marine fish and fish oil are the most popular and well-known sources of polyunsaturated fatty acids (PUFAs), namely eicosapentaenoic acid (EPA) and. These PUFAs are known to have many beneficial properties, including pronounced hypotriglyceridemic and anti-inflammatory effects, which help prevent the development of cardiovascular diseases.

In addition, various studies show promising antihypertensive, antitumor, antioxidant, antidepressant, antiadhesive and antiarthritic effects.

Moreover, recent studies also indicate anti-inflammatory and insulin-sensitizing effects of these fatty acids in metabolic disorders. Thus, n-3 PUFAs have several health benefits mediated, at least in part, by their anti-inflammatory actions; therefore, their consumption should be encouraged, especially from dietary sources. ()

Reduce triglyceride levels in the blood

The benefit of polyunsaturated fatty acids is that they lower triglyceride levels. American Heart Association recommends to people with high level triglycerides replace saturated fat in the diet with polyunsaturated fats.

Polyunsaturated fats bind and eliminate harmful fats such as saturated fat, cholesterol and triglycerides. In a study led by researcher E. Balk and published in the journal Atherosclerosis" in 2006, fish oil was found to improve levels of "good" cholesterol, known as lipoproteins high density(HDL), and reduces triglyceride levels.

Another study led by William S. Harris, published in May 1997 in " American Journal of Clinical Nutrition" shows that consuming about 4 grams of fish oil daily reduces triglyceride levels by 25-35%.

Reduce blood pressure

Polyunsaturated fatty acids may help lower blood pressure. Several studies have discovered this property, including a study led by researcher Hirotsugu Ueshima published in the journal Hypertension"in 2007. The study analyzed the diets of different people. It was found that people who consumed fish oil and polyunsaturated fats had lower blood pressure.

Improves depression and ADHD

The benefits of polyunsaturated fatty acids include the potential to improve symptoms of depression. Some studies have shown benefits and others have not, although the supplement does not appear to be harmful. In a study published in the journal Nutrition Reviews", which was conducted in 2009 and led by researcher J. Sarris, found that omega-3 fatty acids used on their own probably do not provide benefit unless they are used in combination with an antidepressant.

Polyunsaturated fatty acids may also benefit attention deficit hyperactivity disorder (ADHD). A study conducted in January 2000, led by researcher J. Burgess, and published in the journal American Journal of Clinical Nutrition" reports that 100 boys with ADHD were found to have low levels of polyunsaturated fat, which may be associated with ADHD symptoms and the potential for symptom reduction.