Omega-3 is a polyunsaturated fatty acid that is required by our body and must be obtained through diet, as it is not synthesized in our body. There are three main types of Omega-3 fatty acids: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA).
EPA and DHA are found in cold water fish, but ALA, found in plants, must be converted to EPA and DHA in order to be fully utilized by the body.
Omega-3 fatty acids have been extensively studied in relation to the prevention of cardiovascular disease and are known to have immunomodulatory and anti-inflammatory effects.
Nowadays, the daily menu of developed countries is deficient in Omega-3 but excessive in Omega-6.
Omega-6 is also a polyunsaturated fatty acid that is mostly found in plants and is mainly taken in with vegetable (canola, corn, soybean, sunflower) oils.
The ratio of these two fatty acids is essential, because they are metabolized by the same set of enzymes and there is mutual competition between them, and the excess of one fatty acid leads to a decrease in the metabolism of the other. It is recommended not to exceed the ratio of 1:4 (Omega-3:Omega-6).
Functions and Health
Recent research shows that Omega-3 fatty acids play an important physiological role: they fit into cell membranes and suppress inflammatory processes. DHA is a major component of all cell membranes and is found in large amounts in the brain. As a structural substance, DHA plays an important role in membrane lipids, especially in nerve tissue and the retina of the eye. DHA is essential for brain growth and functional development in infants and is required for normal brain function in adults.
EPA is important for fetal development and healthy aging, it also helps reduce symptoms of depression.
Supplemental intake of the omega-3 fatty acids EPA and DHA may reduce the risk of cardiovascular disease, such as myocardial infarction and stroke.
Several epidemiological studies have shown that low intake of Omega-3 fatty acids (especially DHA) may be associated with risk factors for Alzheimer's disease and other forms of dementia.
Taking extra doses of EPA and DHA may be beneficial for people with diabetes, especially those at high risk of myocardial infarction.
Omega-3 fatty acids and eye health
Omega-3 fatty acids also play an important role in eye health due to their anti-inflammatory, anti-angiogenesis (prevents unwanted blood vessel growth). The retina has a high concentration of Omega-3, especially DHA, it is the main component of the photoreceptor membranes, optimizes the permeability of the retinal photoreceptor membranes.
The latest studies conducted in the USA confirmed that high doses of Omega-3 fatty acids (as one of the dosage forms) reduce the progression of age-related macular degeneration (AMD), studies also show that dietary supplementation with Omega-3 fatty acids reduces symptomatic dry eye syndrome.
Nutritional recommendations
For the majority of the population, two to four portions of fish per week are recommended, one of which should be an oily fish corresponding to 200-400 mg of Omega-3 fatty acids per day.
Elderly people at risk of AMD are recommended to take 1000 mg Omega-3: 350 mg DHA and 650 mg EPA to reduce the progression of AMD. It is very difficult to take in such a quantity with the daily diet, therefore it is additionally recommended to use nutritional supplements containing Omega-3.
Deficiency of Omega-3 fatty acids in the body is common, but acute deficiency of Omega-3 fatty acids is very rare and is usually caused by fat metabolism.
Best food sources of Omega-3
The original form of omega-3 fatty acids is ALA, which is found mainly in legumes, margarine, flaxseed oil, walnuts and small amounts in leaf vegetables. EPA and DHA are mostly found in fatty fish such as mackerel, sardines, herring, salmon and tuna.
Omega-3 fatty acids are very susceptible to free radical damage, usually caused by light, oxygen or heat. Oxidation of polyunsaturated fatty acids affects the quality and nutritional value of food, significantly decreases and creates undesirable flavors. Food products containing Omega-3 fatty acids (animal or vegetable) should be stored in a sealed container in the refrigerator. A rapid change in temperature causes rapid oxidation of EPA and DHA. When frying fish, the loss of Omega-3 can be up to 85%. Grilling and steaming oily fish is the best cooking method to preserve the content and value of EPA and DHA.
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Eat fatty fish (salmon, sardines, trout, herring and fresh tuna) 2 to 3 times a week.
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When cooking, adding polyunsaturated fatty acids (sunflower, corn, wheat bran oils, walnuts, sunflower seeds, flaxseed) to food such as salads will help increase your weekly intake of EPA and DHA.
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When cooking frozen fish, allow it to defrost slowly at room temperature or in the refrigerator, rather than defrosting in the microwave or at elevated temperatures. Slow and steady freezing will not only preserve the Omega-3 but also preserve the texture and flavor of the food.
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Steaming or grilling is a better way to cook fish than frying.
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Unprocessed fatty fish is the best source of Omega-3 fatty acids.
Omega-3 fatty acids are among the most important nutrients that must be obtained through food. Their lack can significantly affect the general health and quality of life. To ensure sufficient intake of Omega-3, a good solution is to use food supplements containing fish oil in addition to the diet.