Fish Oil


Fish oil contains both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both of these are members of omega-3 family of fatty acids and are different from the omega-3 fatty acids found in oils from vegetable sources. In the late 1970s, scientists learned that the native Inuits in Greenland, who consumed a diet very high in omega-3 fatty acids, had surprisingly low rates of heart attacks. Since that time thousands of scientific studies have evaluated the multiple ways that omega-3 fatty acids promote not only cardiovascular health, but also the healthy functioning of many other biological activities. Many Americans don't get enough of it in their diets. One reason is that omega-3 oils are very susceptible to spoilage and so many food manufacturers remove it to keep products fresh. Another reason is that omega-3 oils mostly come from cold water fish and wild game— something most Americans don't eat in great quantities. The body can manufacture EPA and DHA by conversions from linolenic acid.

For more in-depth information on these fatty acids, please refer to EPA and DHA in the index of supplements in this database.

Dosage Info

Dosage Range

FISH OILS (EPA and DHA): 500-2,000 mg daily.

Most Common Dosage

FISH OILS (EPA and DHA): 1200 mg of EPA and DHA, or 3-4 grams of fish oil.

Dosage Forms

Gelatin capsules.

Interactions and Depletions


Reported Uses

Omega-3 fatty acids are one of the primary structural components in cell walls and membranes throughout the body. They are also instrumental in regulating inflammation, blood pressure and thickness, hormone production, and the activities of the immune and central nervous systems. (1) Omega-3 fatty acids are important for infants (and a developing fetus) for proper development of the brain and retina of the eyes. (2) Fish oil supplementation during pregnancy significantly increased omega-3 PUFA levels in breast milk indicating this could have an effect on immune function in infants. (3)

There are many clinical applications for omega-3. Studies suggest that Attention Deficit Hyperactivity Disorder (ADHD) may be linked to omega-3 deficiency. (4) Deficiencies have also been found in people who have allergies, asthma, and skin disorders like eczema and psoriasis. (5) , (6) , (7)

Omega-3 may also be a preventative measure for many major illnesses. Researchers think omega-3 can help prevent breast, prostrate, and colon cancers. (8) , (9) , In a multicentre, randomised, double-blind trial, 200 patients with pancreatic cancer were given either a high-calorie, high-protein supplement or an energy-dense, protein supplement enriched with omega-3 fatty acids and vitamins E and C. The results were that only the omega-3 fatty acid supplement group had net weight gain, lean tissue, and improved quality of life. (10)

Omega-3 fatty acids may support cardiovascular health by lowering blood pressure, relaxing blood vessels, and lowering cholesterol levels. (11) , (12) , (13) Taking 3 to 5 grams of omega-3 fatty acids per day can decrease elevated serum triglycerides as much as 50%. (14) Results of a recent study in Italy reported that patients taking 850 milligrams per day of omega-3 fatty acids had a lower rate of death related to heart conditions than those who were not taking the fatty acid. (15)

Omega-3 may also reduce pain for sufferers of rheumatoid arthritis. (16) Deficiencies of omega-3 in the United States may also be linked to depression. (17) Omega-3 fish oil supplementation seemed to improve symptomatic disease activity in systemic lupus erythematosus (SLE) patients. (18)

Toxicities & Precautions


[span class=alert]Be sure to tell your pharmacist, doctor, or other health care providers about any dietary supplements you are taking. There may be a potential for interactions or side effects.[/span]


This dietary supplement is considered safe when used in accordance with proper dosing guidelines.

Omega-3 fatty acids are extremely susceptible to damage from free radicals. It is recommended that the antioxidants vitamin E, vitamin C and selenium be taken in concert with omega-3s. (19) , (20)

Care should be taken to minimize exposure of omega-3 fatty acids to heat, light, and oxygen. Refrigerate flaxseed oil to prevent it from becoming rancid.

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Yet little is known about the use of this dietary supplement while pregnant or breast-feeding. Therefore, it is recommended that you inform your healthcare practitioner of any dietary supplements you are using while pregnant or breast-feeding.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Since young children may have undiagnosed allergies or medical conditions, this dietary supplement should not be used in children under 10 years of age unless recommended by a physician.


  1. View Abstract: Delarue J, Matzinger O, Binnert C, Schneiter P, Chiolero R, Tappy L. Fish oil prevents the adrenal activation elicited by mental stress in healthy men. Diabetes Metab. Jun2003;29(3):289-95.
  2. View Abstract: Lauritzen L, Jorgensen MH, Mikkelsen TB, et al. Maternal fish oil supplementation in lactation: effect on visual acuity and n-3 fatty acid content of infant erythrocytes. Lipids. Mar2004;39(3):195-206.
  3. View Abstract: Dunstan JA, Roper J, Mitoulas L, Hartmann PE, Simmer K, Prescott SL. The effect of supplementation with fish oil during pregnancy on breast milk immunoglobulin A, soluble CD14, cytokine levels and fatty acid composition. Clin Exp Allergy. Aug2004;34(8):1237-42.
  4. View Abstract: Stevens L, Zentall SS, Deck JL. Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder. Am J Clin Nutr. 1995;62:761-768.
  5. View Abstract: Galland L. Increased Requirements for Essential Fatty Acids in Atopic Individuals: A Review with Clinical Descriptions. J Am Coll Nutr. 1986;5(2):213-28.
  6. View Abstract: Masuev KA. The Effect of Polyunsaturated Fatty Acids of the Omega-3 Class on the Late Phase of the Allergic Reaction in Bronchial Asthma Patients. Ter Arkh. 1997;69(3):31-33.
  7. View Abstract: Isseroff RR. Fish Again for Dinner! The Role of Fish and other Dietary Oils in the Therapy of Skin Disease. J Am Acad Dermatol. Dec1988;19(6):1073-80.
  8. View Abstract: Bagga D, et al. Dietary Modulation of Omega-3/Omega-6 Polyunsaturated Fatty Acid Ratios in Patients with Breast Cancer. J Natl Cancer Inst. Aug1997;89(15):1123-31.
  9. View Abstract: Pandalai PK, et al. The Effects of Omega-3 and Omega-6 Fatty Acids on in Vitro Prostate Cancer Growth. Anticancer Res. Apr1996;16(2):815-20.
  10. View Abstract: Fearon KC, Von Meyenfeldt MF, Moses AG, et al. Effect of a protein and energy dense n-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia: a randomised double blind trial. Gut. Oct2003;52(10):1479-1486.
  11. View Abstract: Kinsella JE, et al. Dietary n-3 Polyunsaturated Fatty Acids and Amelioration of Cardiovascular Disease: Possible Mechanisms. Am J Clin Nutr. Jul1990;52(1):1-28.
  12. View Abstract: Garg ML, et al. Alpha-linolenic Acid and Metabolism of Cholesterol and Long-chain Fatty Acids. Nutrition. Jun1992;8(3):208-10.
  13. View Abstract: Knapp HR, et al. The Antihypertensive Effects of Fish Oil. A Controlled Study of Polyunsaturated Fatty Acid Supplements in Essential Hypertension. N Engl J Med. Apr1989;320(16):1037-43.
  14. View Abstract: O'Keefe JH, Harris WS. From Inuit to implementation: omega-3 fatty acids come of age. Mayo Clin Proc. Jun2000;75(6):607-14.
  15. View Abstract: O'Keefe JH, Harris WS. From Inuit to implementation: omega-3 fatty acids come of age. Mayo Clin Proc. Jun2000;75(6):607-14.
  16. View Abstract: Geusens P, et al. Long-term Effect of Omega-3 Fatty Acid Supplementation in Active Rheumatoid Arthritis. A 12-month, Double-blind, Controlled Study. Arthritis Rheum. Jun1994;37(6):824-29.
  17. View Abstract: Hibbeln JR, et al. Dietary polyunsaturated fatty acids and depression: when cholesterol does not satisfy. Am j Clin Nutr. Jul1995;62(1):1-9.
  18. View Abstract: Duffy EM, Meenagh GK, McMillan SA, Strain JJ, Hannigan BM, Bell AL. The Clinical Effect of Dietary Supplementation with Omega-3 Fish Oils and/or Copper in Systemic Lupus Erythematosus. J Rheumatol. Aug2004;31(8):1551-6.
  19. View Abstract: Holm T, et al. Omega-3 fatty acids enhance tumor necrosis factor-alpha levels in heart transplant recipients. Transplantation. Aug2001;72(4):706-11.
  20. View Abstract: Yam D, Peled A, Shinitzky M. Suppression of tumor growth and metastasis by dietary fish oil combined with vitamins E and C and cisplatin. Cancer Chemother Pharmacol. 2001;47(1):34-40.