The protective effects of omega-3 fatty acids relate specifically to the following risk factors [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30]:
- Hypertriglyceridemia
- Hypercholesterolemia
- Serum fibrinogen level
- Arterial hypertension
- Increased blood clotting tendency
- Myocardial infarction (heart attack)
- Apoplexy (stroke)
- Circulatory or cardiac arrhythmias
- Coronary artery disease (CAD)
From a multi-arm mega-study of patients after myocardial infarction (heart attack) published in 1999, it was concluded that the use of omega-3 fatty acids is still useful even if a heart attack has already occurred. Administration of omega-3 concentrate capsules for 3.5 years reduced cardiovascular risk by up to 30% in patients after myocardial infarction.Lowering blood lipids (blood fat levels) – prevention of cardiovascular disease [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30]
- Lowering triglyceride levels – elevated triglyceride levels are an independent risk factor for myocardial infarction.
- Lowering total cholesterol
- Lowering of LDL cholesterol
- Increase in HDL cholesterol
- Inhibition of VLDL synthesis in the liver.
- Accelerated elimination of VLDL from the blood.
- Inhibition of lipogenic enzymes in the liver.
- Increased excretion of steroids and bile acids.
These preventive effects are most impressive in the so-called high-risk groups. There, the blood lipid reductions are particularly pronounced. The omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), inhibit the synthesis and secretion of VLDL (engl. very low density lipoproteins). By increasing lipoprotein lipase activity, more triglycerides (TG) are removed from VLDL, thus promoting VLDL degradation. Daily intake of 1.5 g to 3 g of omega-3 fatty acids (EPA and DHA) can reduce TG levels by 25% to 30% in a dose-dependent manner. An intake of 5 g to 6 g can reduce TG by up to 60%. This amount of omega-3 fatty acids is hardly manageable in the framework of a fish-rich diet in everyday life, which is why the use of fish oil capsules is recommended. In contrast to animal omega-3 fatty acids, vegetable omega-3 fatty acids such as alpha-linolenic acid have no effect on TG levels. Increase blood flow and decrease blood pressure [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30].
- Improvement of deformability and increased flexibility of erythrocytes (red blood cells) due to incorporation of omega-3 fatty acids into the cell wall.
- Improvement of blood flow and inhibition of blood clotting.
- Stimulation of the formation of nitric oxide (NO = Endothelium Derived Relaxing Factor) – vasodilation.
- Reduction of systolic and diastolic blood pressure – the reduction is more pronounced, the higher the baseline values were.
Prevention of proatherogenic and prothrombotic factors [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30].
- Formation of growth factors-platelet-derived growth factor.
- Expression of growth correlated genes
- Growth of smooth muscle cells and fibroblasts.
- Synthesis of platelet-activating factor.
- Reduction of plasma fibrinogen by induction of plasminogen activator formation and inhibition of plasminogen activator inhibitor synthesis.
- Release of cytokines – interleukin-1 and tumor necrosis factor (TNF).
- Sensitivity to adrenergic stimulation.
- Calcium and sodium channel activity.
- Activity of calcium magnesium ATP-ase
Influencing rheumatoid diseases [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30].
Therapeutic studies found that daily administration of 2.7 g eicosapentaenoic acid and 1.8 g docosahexaenoic acid resulted in improvement of a number of clinical parameters within 15 days in patients with rheumatoid diseases. Affected individuals reported improved mobility of affected joints, a decrease in morning stiffness, and a decrease in inflammatory parameters.In addition, administration of EPA and DHA significantly reduced the need for nonsteroidal anti-inflammatory drugs. Other effects [3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26, 30]
- Radical scavenging
- Stabilization and fluidity of the cell membrane and positive influence on cell functions – omega-3 fatty acids are mainly incorporated into the phospholipids of cell membranes.
- Relief from menstrual cramps
Important note!The effects of omega-3 fatty acids are based on the fact that eicosapentaenoic acid reduces the conversion of omega-6 fatty acid linoleic acid into arachidonic acid – product inhibition – and competes with arachidonic acid for the enzymes necessary for eicosanoid synthesis – desaturases, elongases, cyclooxygenases, lipoxygenases – competitive inhibition. The omega-3 fatty acid alpha-linolenic acid, in contrast to oleic and linoleic acids, has the highest affinity for both delta-6 desaturase – conversion to EPA – and cyclooxygenase and lipoxygenase – synthesis of anti-inflammatory eicosanoids.Finally, a diet containing alpha-linolenic acid can decrease the turnover of arachidonic acid and increase the synthesis of EPA. Thus, the formation of the strongly proinflammatory mediators – prostaglandins of series 2 and the leukotrienes LTB4, LTC4, LTD4, LTE4 – is reduced and the formation of such eicosanoids that inhibit inflammatory processes is promoted. We are talking about series 3 prostaglandins.Since the conversion of alpha-linolenic acid to eicosapentaenoic acid and docosahexaenoic acid, respectively, is very slow, the intake of fatty marine fish and direct administration of EPA and DHA, respectively, is essential to shift the balance to more positively acting prostaglandins.
Omega-3 fatty acids during pregnancy and lactation
Adequate intake of EPA and DHA plays a critical role during pregnancy and lactation. Both the unborn child and the infant are unable to synthesize the essential fatty acids EPA and DHA on their own.Omega-3 fatty acids promote the development of cognitive function and vision in the fetus while still pregnant, but also during lactation and further fetal development. Relatively new is the finding that omega-3 fatty acids minimize pregnancy symptoms, such as preeclampsia and risks within pregnancy, and protect against both preterm birth and low birth weight.
Components of cell membranes-structural function
A large proportion of omega-3 essential fatty acids are incorporated into the phospholipids of cell membranes as well as the membranes of cell organelles, such as mitochondria and lysosomes. There, EPA and DHA have a beneficial effect on fluidity (flowability) and cellular functions that depend on it.Phospholipids are found in all body cells, especially those of the nervous system. The brain contains the largest amount of structural lipids, relatively speaking.Finally, omega-3 fatty acids are essential for the brain, especially for nerve conduction.For fetal brain development, DHA in particular plays a critical role.Marginal intakes of omega-3 fatty acids result in increased formation of proinflammatory eicosanoids from the omega-6 fatty acid arachidonic acid. These include series 2 prostaglandins – TXA2, PGE2, PGI2 – and the leukotrienes LTB4, LTC4, LTD4, LTE4.Thromboxane A2 promotes platelet aggregation and has a vasoconstrictor (vasoconstricting) effect. Thus, thromboxane promotes blood clotting. Leukotriene B4 exhibits proinflammatory and potent chemotactic effects.A diet rich in arachidonic acid also leads to increased synthesis of proinflammatory mediators and therefore represents a risk factor for the development of rheumatoid diseases, among others.
Eicosapentaenoic acid (EPA)
Eicosapentaenoic acid is the starting substance for the formation of eicosanoids and is thus involved in numerous metabolic processes.Eicosanoids are hormone-like substances that can only be formed from polyunsaturated fatty acids with a chain length of 20 C atoms. They include the prostaglandins, prostacyclins, thromboxanes and leukotrienes. Accordingly, eicosanoids are oxygenated derivatives of the following fatty acids:
- Dihomo-gamma-linolenic acid – C20:4 omega-6.
- Arachidonic acid – C20:4 Omega-6
- Eicosapentaenoic acid – C20:5 omega-3
Eicosanoids have multiple hormone-like functions and are involved in the following physiological processes.
- Regulation of vascular tone – blood pressure [13, 16, 25 ]
- Blood clotting [13, 16, 25 ]
- Regulation of platelets – platelet aggregation, process of atherogenesis.
- Regulation of lipoprotein metabolism.
- Allergic and inflammatory processes
- Influence on heart rate and pain sensation.
- Influence on uterine smooth muscle and musculature.
Depending on the initial substance, eicosanoids have different or opposite mechanisms of action. The eicosanoids, which arise from EPA under the influence of cyclooxygenase and lipoxygenase, exhibit anti-inflammatory effects. These are the prostaglandins of series 3, which include PGE3, TXA3, PGI3, LTB5, LTC5, LTD5 and LTD4.Prostaglandins influence the function of smooth muscles and muscles of the uterus (womb). For example, under the influence of prostaglandin E, relaxation occurs in the intestine. Furthermore, prostaglandins have a regulating effect on secretion processes, especially in the stomach and intestines. Finally, eicosapentaenoic acid exhibits the following physiological effects via series 3 prostaglandins [3, 10, 11, 12, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 30].
Effects on the cardiovascular system
- Prevention of platelet aggregation and adhesion.
- Restricted expression of endothelial adhesion molecules.
- Prevention of adhesion of monocytes and granulocytes to the endothelium.
- Reducing the risk of platelet adhesion to damaged vessel wall areas.
- Antivasoconstrictor – EPA inhibits vasoconstriction and acts vasodilator.
- Increase chemotaxis
Thus, eicosapentaenoic acid leads to lower blood viscosity, improving the flow properties of blood.By changing the membrane structure of platelets, EPA prevents the formation of blood clots (thrombi) in the veins – prevention of arteriosclerotic processes.Already formed thrombi can be dissolved again, which can improve overall blood flow. Inhibition of inflammation – endothelial protection.
- EPA has an anti-inflammatory (anti-inflammatory) effect via the eicosanoids produced from it – synthesis of series 3 prostaglandins.
- Positive effects against hyperuricemia (gout), rheumatoid arthritis, psoriasis (psoriasis), atopic eczema (neurodermatitis) and chronic inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis.
In diets low in high seafood – which is common in our country -, the proportion of arachidonic acid in cell membranes is higher than the proportion of EPA. As a result, eicosanoids are synthesized mainly from arachidonic acid, which is associated, among other things, with various inflammatory tissue reactions, vascular constriction, platelet aggregation and promotion of blood clotting. In contrast, a diet rich in omega-3 fatty acids or EPA leads to increased formation of eicosanoids, which have a positive effect on the cardiovascular system. In addition, due to the low synthesis of arachidonic acid and its reduced concentration in cell membranes, fewer eicosanoids with the above-mentioned negative properties are formed.
