CURRENT APPROACHES TO FISH OIL

June 28, 2021 · Dr. Tuba Günebak

Fat in our daily diet is present in the composition of foods and as fat itself. Fats consumed in food composition are called 'invisible fats,' and those consumed as fat are called 'visible fats.' Fatty acids, the components of fats, are classified according to differences in their molecular structures (based on the number of carbons in the molecule and the presence or absence of double bonds betwe

CURRENT APPROACHES TO FISH OIL

Polyunsaturated fatty acids are divided into two groups with different metabolic effects: n-6 (omega-6) and n-3 (omega-3). Fish oil is an important source of omega-3 fatty acids. Alpha-linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are omega-3 fatty acids. Alpha-linolenic acid in this group is one of the essential fatty acids (the other being linoleic acid, which is an n-6 fatty acid). This is because humans and other mammals lack the enzymes to synthesize these fatty acids. Therefore, they must be included in our daily diet. Long-chain fatty acids derived from these essential fatty acids are precursors to many metabolic pathways. For example, prostaglandins, leukotrienes, and thromboxanes have important roles in inflammatory processes, immune response, and blood clotting. These long-chain derivatives can be synthesized by the body as long as dietary essential fatty acid precursors are consumed. Omega-3 fatty acids found in fish oil have significant physiological effects;

The use of fish oil during pregnancy has been reported to be associated with a reduction in the incidence of pregnancy-related hypertension and consequently a reduced risk of preterm birth.
They play a crucial role in fetal and early life neural development and deficiencies during these periods can lead to disorders in brain, optic, and cortical functions. EPA and DHA also have important structural roles in the brain, retina, and nervous system. Providing foods rich in n-3 polyunsaturated fatty acids in the pregnancy diet is effective for the development of the baby's nervous system and essential for complete neural development.
Perinatal n-3 essential fatty acid metabolism plays an important role in protecting against preterm birth. Consumption of seafood rich in n-3 fatty acids has been associated with longer gestational periods and higher birth weights.
In the first half of the first year after birth, in premature infants relative to their gestational age, the use of DHA-enriched formula was found to increase visual acuity (a valid measure of visual function development).
It has an anti-thrombogenic (protective against thrombosis) effect. An increase in the consumption of fish, especially fatty fish, has been reported to be protective against atherosclerosis and myocardial infarction. Atherosclerosis is a disorder of the arteries in the heart, brain, and other organs, as well as the aorta, and is responsible for coronary heart disease, stroke, and other vascular diseases. In childhood, it begins with the accumulation of lipids, particularly cholesterol and its esters, in the arteries. Although this fatty deposit causes slight thickening of the vessel walls in childhood, it does not impede blood flow. However, the deposit rapidly increases with adolescence. In early adulthood, the lipid deposit is covered with smooth muscle and connective tissues. This is called a 'fibrous plaque.' In middle-aged individuals, changes are observed in the fibrous plaque. These changes are related to alterations in the lipids, smooth muscle cells, connective tissue, calcium, and capillaries forming the fibrous plaque. The most significant are the ulceration and bleeding of the connective tissue and smooth muscles. These changes lead to swelling of the plaque, ulceration, and blood clotting. When these lesions occur in the coronary arteries, they cause coronary heart disease (CHD); when they occur in the cerebral arteries, they cause stroke; and in other arteries, they cause pain and inflammation. CHD can lead to myocardial infarction due to blockage of a coronary artery. Blockage of coronary arteries often develops following narrowing of the arteries due to atherosclerotic deposits. However, atherosclerosis does not necessarily cause thrombosis. A statistically significant reduction of 15-20% in non-fatal myocardial infarction, cardiovascular deaths, and total mortality with n-3 fatty acid supplementation has been found.
The use of fish oil has also been reported to have a triglyceride-lowering effect. This effect is stated to be achieved by reducing very-low-density lipoprotein (VLDL) synthesis. An intake of approximately 1.0 g/day of n-3 polyunsaturated fatty acids is sufficient to lower plasma triglyceride levels.
Both EPA and DHA can alter prostaglandin production in a way that reduces the inflammatory response. Therefore, it is stated that fish oil supplementation may have an improving effect on the symptoms of inflammatory disorders such as rheumatoid arthritis or Crohn's disease.
In rheumatoid arthritis, very long-chain n-3 polyunsaturated fatty acids partially reduce pain and morning stiffness and may reduce the need for medical treatment. Very long-chain n-3 polyunsaturated fatty acids have analgesic effects and are therefore effective in other diseases involving chronic pain.
Beneficial effects have been reported in renal immunological disorders, IgA nephropathy, and kidney transplantation. Therapeutic use of very long-chain n-3 polyunsaturated fatty acids can slow the loss of renal function.
In inflammatory bowel disease, clinical and histological improvements have been reported, the need for medical treatment has been reduced, and it is used as an adjunct to drug therapy in ulcerative colitis.
In studies, n-3 fatty acids have been found to have a systolic and diastolic blood pressure-lowering effect in severely hypertensive individuals.
The use of n-3 fatty acid supplementation along with calcium-rich foods has been reported to have positive effects on bone health.
Tumors, defined as physiological disorders, occur as a result of uncontrolled proliferation of certain cells in the organism. During this process, some cells are lost or their normal biochemical functions change. Changes occurring in cells are divided into benign and malignant. Benign tumors grow in their origin site, do not spread to surrounding tissues, and do not cause serious illness or death. Malignant tumors, called cancer, spread from their site of origin to surrounding tissues, metastasize, and are generally fatal. The development of cancer is due to many reasons. According to different sources, its link to diet ranges from 10-70%, with 35% being accepted. The quality and quantity of consumed foods are important for newly forming cells. Any disorder occurring in cells, the basic building blocks of the organism, can spread to tissues, organs, and the entire organism over time by increasing its activity.

Nutrition affects the risk of certain types of cancer, particularly esophageal, stomach, colon, breast, lung, and prostate cancers. Longer-chain n-3 polyunsaturated fatty acids such as EPA and DHA have been reported to have cancer-inhibiting effects in preclinical models of breast, colon, and prostate cancers, and protective effects in breast and colorectal cancers.

The best source of n-3 fatty acids is fatty fish (living in deep cold waters) such as salmon and sea bass. Individuals who cannot regularly consume fatty fish can take fish oil supplements.
While the n-6 group of polyunsaturated fatty acids accelerates thrombosis, the n-3 group has an antithrombotic effect. Therefore, the ratio of n-6 to n-3 in the diet should be 7:1 and below. An intake of 1-2 g of fish oil per day can provide this balance.
To benefit from its positive effects, the daily intake of EPA+DHA should not exceed 3 g.
Due to the high risk of vascular disease in diabetic patients, fish oil use may be recommended. The safe amount for diabetic individuals is also 3g/day.

Asst. Prof. Dr. Ç. Tuba Günebak

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Nutrition and Diet Specialist Asst. Prof. Dr. Tuba Günebak

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