Fish Oil


Fish Oil Introduction

Fish sources contain a classification of fatty acids not produced, or not naturally occurring, within the human body. These oils are considered necessary for the overall functioning of our bodies, thus are termed Essential Fatty Acids (EFAs). These Essential fatty acids play a variety of roles in maintaining human health; including being incorporated as structural components into cellular membranes, and in the building blocks for vital chemicals, important for health (i.e. prostaglandins). Fish oil is not directly used by the body, but must go though a series of enzymatic transformations before it synthesizes into forms usable by the human body. The forms of fish oil that are usable by the body include the compounds, Eicosapentanoic acid (EPA), and Docosahexanoic acid (DHA). It is important to note that many of the enzymes that act on fish oil are zinc dependent. Fish oils are less effective when a deficiency in zince is present. [1]

The nomenclature that is associated with fatty acids can be confusing. The Omega-3, Omega-6, and Omega-9 fatty acids are all different families of fatty acids, and are derived from different sources. The Omega, or “N,” designation indicates a structural feature of the long chain of carbon atoms that make up fatty acids.

Fish Oil Uses


Recent research has shown that the majority of symptoms associated with numerous health conditions are directly caused by the adverse reactions to inflammatory processes. Inflammation is a normal part of the nonspecific immune response and is necessary for our bodies to properly protect themselves in times of injury and illness. When the inflammatory response gets out of control and is either too intense or too prolonged, serious consequences to one’s overall health can result.

As fatty acids are incorporated into the phospholipid layer that makes up cellular membranes, their structure not only effects the consistency of the membrane, but also the nature of the chemicals that are made. The body produces specific compounds from fatty acids called prostaglandins and thromboxanes. Certain fatty acids, primarily those found in red meats and dairy products, can be chemically arranged in such a way as to promote more pro-inflammatory prostaglandins. Conversely, those oils derived from fish sources (the Omega-3 family) assist in the production of prostaglandins that are less inflammatory in nature. [2]


The beneficial effects of fish oil have been studied in children with severe asthma. It has been noted in several studies that symptom scores, as well as reactivity to acetylcholine, decreased in control groups being administered fish oil supplements; as opposed to those that where receiving olive oil alone. [3]

Rheumatoid Arthritis, Systemic Lupus Erythmatosis and Autoimmune Disease:

Autoimmune diseases are characterized by significant malfunctions in immune system functioning. Symptomatically, this class of diseases is progressive and results in the body’s natural defense mechanisms (i.e. immunological functioning) to attack itself. Periods of remission and aggravation, clusters of other autoimmune disease, and inflammation are characteristic of autoimmune disease. Symptoms of these disease can be variable and diffuse, making a correct diagnosis difficult.

Fish oil supplementation is associated with alterations in immune system chemicals called cytokines, which control much of the immune response. In fact, fish oil supplementation has been associated with long term remissions in individuals with Systemic Lupus, a particular autoimmune disease. Patients typically treat the painful symptoms of rheumatoid arthritis using non steroidal anti-inflammatory drugs (NSAIDS). These medications are, however, associated with adverse side effects and reactions as well. Fish oil has been demonstrated to lessen the need for NSAIDS, while efficiently providing reductions in the number and pain associated with ‘flare-ups’ in these type of disorders. [4-6]


While there have been no studies comparing antidepressant medications to fish oil for the treatment of depression, it has been noted that individuals who suffer from depression tend to be lower in levels of specific compounds found in essential fatty acids such as fish oil; as measured by DHA and EPA levels in red blood cells. Although it remains unclear as to whether the low EPA and DHA levels are caused by depression or whether the low DHA/EPA levels contribute to depression. Given the safe nature of fish oil supplements, as well as the other health benefits of fish oil, supplementation is certainly worth consideration for depressed individuals. [7-8]

Cardiovascular Health:

The composition of fats typically consumed in the diet can have significant impacts on the development of numerous diseases and disorders of the cardiovascular system. Supplementation with fish oil has been shown to reduce the levels of triglycerides in the blood after eating, which is an associated risk factor in developing ischemic heart disease. Animal study has demonstrated that the supplementation with fish oils can reduce the amount of damage that is caused by infarction-reperfusion events (heart attacks). Interestingly, animal populations with a high degree of fish and fish oil in their diets have a lower incidence of developing cardiovascular disease.

Diets rich in fish oils, either obtained by food or dietary supplements, have also been shown to decrease the tendency of the blood to coagulate. This platelet aggregation often leads to blockages of blood flow to various organs of the body. It appears that a diet rich in fish oils may act as a down regulator in the rates of platelet activation and aggregation. [9-14]

Chronic Diseases:

It is suspected that the increased consumption of fatty acids found in vegetable oils, combined with a reduced intake of fish oil fatty acids, contributes to specific physiological conditions that may promote the onset of chronic disease. Among the physiological changes that take place with a high intake of n-6 fatty acids (those from most vegetable oils) are; prothrombotic (encouraging clotting of blood), increased blood viscosity, as well as vasospasm that can have adverse effects on blood flow dynamics. Numerous studies have demonstrated the various beneficial effects of fish oils on a number of chronic diseases; ranging from the dyslipidemia of diabetes, to Crohn's Disease. [15, 16]

Cancer Treatment:

Consistent intakes of fish oil have been shown to create a beneficial effect in the overall treatment protocols of cancer patients. It is common for patients with cancer to become malnourished as a result of their disease, treatment, and other individual-specific factors. However, malnourishment may be the greatest health risk of all, as it is associated with decreased weight and increased mortality. The inclusion of supplementary fish oils can help stave off some of the deleterious effects of malnourishment in cancer patients. [17, 18]

Fish Oil Dosages

Dosages for the personal administration of fish oils vary, as documented in various clinical trials. However, 1 - 3000 milligrams / 3 grams per day is considered an effective dose. Fish oil is available in a variety of delivery forms, including liquids, gels, and capsules.

Fish Oil Toxicities and Contraindications

The primary concern with fish oil supplementation is the possibility of the fish source being contaminated with mercury and other heavy metals.  Therefore, it is important to choose fish oil supplements that are labeled as being molecularly distilled.  This will ensure that the process by which the heavy metal contaminants are removed has been completed by the given product manufacturer..

Individuals with blood sugar problems (e.g. diabetes) should consult their physician before beginning a supplementation program with fish oil-containing products.


[1] Mantzioris E, Cleland LG, Gibson RA, Neumann MA, Demasi M, James MJ Biochemical Effects of a Diet Containing Foods Enriched with N-3 Fatty Acids Am J Clin Nutr. 2000;72:42-48.

[2] James MJ, Gibson RA, Cleland LG Dietary Polyunsaturated Fatty Acids and Inflammatory Mediator Production Am J Clin Nutr. 2000;71(suppl):343S-348S.

[3] Nagakura T, Matsuda S, Shichijyo K, Sugimoto H, Hata K Dietary Supplementation with Fish Oil Rich in Omega-3 Polyunsaturated Fatty Acids in Children with Bronchial Asthma Eur Respir J. 2000;16(5):861-865.

[4] Darlington LG, Stone TW Antioxidants and Fatty Acids in the Amelioration of Rheumatoid Arthritis and Related Disorders Br J Nutr. 2001;85(3):251-269.

[5] Das UN Beneficial Effect of Eicosapentaenoic and Docosahexaenoic Acids in the Management of Systemic Lupus Erythematosus and its Relationship to the Cytokine Network.Prostaglandins Leukot Essent Fatty Acids. 1994;51(3):207-213.

[6] Walton AJE, Snaith ML, Locniskar M, Cumberland AG, Morrow WJW, Isenberg DA Dietary Fish Oil and the Severity of Symptoms in Patients With Systemic Lupus Erythematosus Annals of the Rheumatic Diseases. 1991;50:463-466.

[7] Adams PB, Lawson S, Sanigorski A, Sinclair AJ Arachidonic Acid to Eicosapentaenoic Acid Ratio in Blood Correlates Positively with Clinical Symptoms of Depression Lipids. 1996; 31:S157-S161.

[8] Mischoullon D, Fava M Docosahexanoic Acid and Omega-3 Fatty Acids in Depression Psychiatr Clin North Am. 2000;23(4):785-794.

[9] Marckmann P, Bladbjerg EM, Jespersen J Dietary Fish Oil (4 G Daily) and Cardiovascular Risk Markers in Healthy MenArterioscler Thromb Vasc Biol. 1997; 17(12):3384-3391.

[10] Yang B, Saldeen TGP, Nichols WW, Mehta JL Dietary Fish Oil Supplementation Attenuates Myocardial Dysfunction and Injury Caused by Global Ischemia and Reperfusion in Isolated Rat Hearts J Nutr. 1993;123:2067-2074.

[11] Saldeen T, Mehta J. Dietary modulations in the prevention of coronary artery disease:a special emphasis on vitamins and fish oil. Current Opinion in Cardiology 17:559 -567,2002.

[12] Saldeen T, Wallin R, Alving B, Marklinder I Effect of Fish Oil in Bread on Fatty Acids in Plasma Phospholipids and on Serum Triglycerides Lipids from the Sea. Lipidforum, Bergen, Norway 77,1994.

[13] Haglund O, Wallin R, Wretling S, Hultberg B, Saldeen T Effects of Fish Oil Alone and Combined With Long Chain (N-6) Fatty Acids on Some Coronary Risk Factors in Man. Acta U niversitatis Upsaliensis. 1993;428:1-22

[14] Vanschoonbeek K, De Maat MP, Heemskerk JW Fish Oil Consumption and Reduction of Arterial Disease. J Nutr. 2003;133(3):657-660.

[15] Simopoulos AP Essential Fatty Acids in Health and Chronic Disease Am J Clin Nutr. 1999; 70:560S-569S

[16] Appleton J, Ackerson A Health Benefits of a Natural, Stable Fish Oil Adv Stand. 1998;1:1-2.

[17] Gogos CA, Ginopoulos P, Salsa B, Apostolidou E, Zoumbos NC, Kalfarentzos F Dietary Omega-3 Polyunsaturated Fatty Acids Plus Vitamin E Restore Immunodeficiency and Prolong Survival for Severely Ill Patients with Generalized Malignancy: A Randomized Control Trial. Cancer 1998; 82(2):395-402.

[18] Barber MD, McMillan DC, Preston T, Ross JA, Fearon KC Metabolic Response to Feeding in Weight-Losing Pancreatic Cancer Patients and its Modulation by a Fish-Oil-Enriched Nutritional Supplement. Clin Sci (Colch). 2000;98(4):389-399.


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