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Fish oil

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Important fish oil facts

Fish oil is full the important omega-3 essential fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).

The human body needs essential fatty acids for normal growth, maintenance of cell membranes, to ensure the immune system is working well and to balance the body's hormone levels to a normal level.

The main functions of omega 3 fatty acids are to decrease LDL cholesterol levels, regulating inflammatory prostaglandin formation, decrease fibrinogen and thrombin levels and reduce platelet aggregation and blood viscosity.

  • Long terms use of fish oil can deplete vitamin E stores and cause a deficiency of vitamin E, so these two supplements should be taken together
  • The body is not capable of producing omega-3 fatty acids so they must be taken in the diet
  • Oily fish such as salmon and mackerel are great sources of omega 3 fatty acids

Fish oil and health

  • Heart health - several studies show that men who eat fish several times a week have less heart disease than men who don't eat fish regularly. Other studies show that fish oil supplements can help prevent sudden death from heart rhythm problems. Fish oil supplements may also prevent blood clots from blocking the arteries leading to the heart
  • Fat levels - taking fish oil supplements can lower triglycerides level if they are too high, but conversely it may increase LDL (bad) cholesterol levels
  • Crohn's disease - several studies have shown that fish oil supplements can be very helpful for keeping Crohn's disease under control
  • Rheumatoid arthritis - several studies have shown that some patients found relief from taking omega-3 fatty acids to relieve pain and inflammation in this condition
  • Depression - people with a deficiency of omega-3 fatty acids or who have an imbalance of omega-3 fatty acids to omega-6 fatty acids have been shown to be at a higher risk for depression. Studies have shown omega-3 fatty acid supplementation helps to improve brain activity and reduce symptoms of depression

People who wish to take an acidophilus supplement should talk to a medical professional BEFORE taking it.

Fish oil recommended intake

Dosage of fish oil depends on the condition that is being treated. A medical doctor and/or alternative health care provider can advise on individual cases - this information is provided as a guide only:

Lifestage Age Amount (per day)
INFANTS 0-12mths Seek medical advice before taking it
CHILDREN 1-8yrs Seek medical advice before taking it
CHILDREN 9-18yrs
Seek medical advice before taking it
ADULTS 19-50yrs
1g fish oil 3 times a day
(equiv to 0.3-0.5g of EPA & DHA)
SENIORS 51+yrs 1g fish oil 3 times a day
(equiv to 0.3-0.5g of EPA & DHA)
PREGNANT   Seek medical advice before taking it
LACTATING   NSeek medical advice before taking it


Fish oil (omega-3) in foods

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FOOD AMOUNT Omega-3 (mg)
Salmon, canned Chinook 1 Can 3000
Sardines 1 Can 2900
Mackerel 1 Fillet2200-2600
Tuna, canned 1 Can 1500-1700
Salmon, sockeye 1 Fillet 1300
Bluefish 1 Fillet 1200
Trout 1 Fillet 1100-2000
Herring 1 Fillet 1100-1700
Mullet 1 Fillet 1100
Salmon, pink 1 Fillet 1000-1900
Bass 1 Fillet 600
Catfish 1 Fillet 600
Crab, Alaska King 1 Fillet 600
Shrimp 1 Fillet 300-400
>Flounder 1 Fillet 300
Swordfish 1 Fillet 200

Types of fish oil supplements

Fish oil supplementation is available in the following ways:

  • Liquid - sometimes fish oil is available in the pure oil form, but is usually flavoured as it is not very pleasant tasting
  • Soft gel capsules - liquid fish oil is added to the capsules

Fish oil supplementation checklist

  • Check expiration date
  • Look for a supplement that has both EPA and DHA in it
  • Light, air, excessive storage times and processing destroy essential fatty acids - store in the refrigerator

Fish oil works best with

Overdosage, toxicity and cautions for fish oil

No toxicity has been reported in healthy individuals but people with health problems should be careful with taking any supplements.


People with any of the medical conditions listed below should discuss supplementation with a medical profession BEFORE taking fish oil:

  • People taking blood thinning medications - such as Coumadin or Warfarin should seek medical advice before taking a fish oil supplement, as there may be bleeding complications - talk to a medical professional
  • People on anti-convulsant medication for epilepsy - are NOT recommended to take essential fatty acid supplements - talk to a medical professional
  • People with Diabetes - should be cautious using fish oil supplements as they can raise blood sugar levels and lower insulin production - talk to a medical professional

Large amounts of fish oil supplements (over 5gm/day) can cause blood to become dangerously thin and make bleeding happen more often and more profusely when it does occur.



  • Ingeborg A B, et al. Effect of Fish Oil on Ventricular Tachyarrhythmia and Death in Patients With Implantable Cardioverter Defibrillators: The Study on Omega-3 Fatty Acids and Ventricular Arrhythmia (SOFA) Randomized Trial. JAMA, June 14, 2006; 295: 2613 - 2619
  • Mozaffarian D, Rimm EB. Fish Intake, Contaminants, and Human Health: Evaluating the Risks and the Benefits. JAMA, October 18, 2006; 296: 1885-1899
  • Sanders TA, Hinds A. The influence of a fish oil high in docosahexaenoic acid on plasma lipoprotein and vitamin E concentrations and haemostatic function in healthy male volunteers. Br J Nutr. 1992;68(1):163-173
  • Yosefy C, Viskoper JR, Laszt A, Priluk R, Guita E, Varon D, et al. The effect of fish oil on hypertension, plasma lipids and hemostasis in hypertensive, obese, dyslipidemic patients with and without diabetes mellitus. Prostaglandins Leukot Essential Fatty Acids. 1999;61(2):83-87

Last reviewed 21 April 2019