Cod liver oil

Description Cod liver oil is obtained from the liver of the cod. Cod liver oil and other fish liver oils are rich sources of vitamins A & D; they are also rich sources of the omega-3 essential fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Function/ Used for EPA and DHA are found in every cell membrane in the body and have a wide range of functions.  Their health benefits include1:

  • Reducing triglyceride levels in the blood
  • Heart health
  • Supporting brain function
  • Reducing blood pressure
  • Maintaining eye health


EPA and DHA also inhibit the production of inflammatory chemicals in the body and have an anti-inflammatory effect in their own right.  Fish body oils and fish liver oils are widely used in the management of inflammatory joint conditions2.


EPA may also help to discourage the formation of blood clots and help assist the blood to flow freely around the arteries, maintaining the circulation. EPA may also help maintain a healthy heart.


DHA is important in infant development, particularly in prematurely born infants. It is believed to be necessary to early eye and brain development.  DHA is also thought to support brain development throughout childhood.


Omega 3 fatty acids also help maintain suppleness.

Intake The European Food Safety Authority3 makes recommendations for EPA and DHA intake, substances which are found in fish oils:

·         250mg of EPA/DHA per day for adults and children over the age of 2.

·         100mg DHA per day for infants and young children aged 7-24 months.

·         100-200mg DHA per day in addition to general adult requirements for pregnant and lactating women from fish body oils (fish liver oils should be avoided. See ‘use in pregnancy and breastfeeding’).

As a supplement Cod liver oil and other fish oil supplements are available as capsules and liquids. Food supplements generally provide 100–1500 mg combined EPA/DHA per dose. The dose is not established but doses of 1-3g daily may be adequate.
Found in (dietary sources) Cod liver oil is obtained from the liver of the cod.
Deficiency N/A
Precautions and contraindications Patients with blood clotting disorders or those taking anticoagulants such as warfarin should be monitored while taking cod liver oil or other fish oils.4
Use in pregnancy and breastfeeding Cod liver oil or other fish liver oil supplements should not be taken by women who are pregnant or planning a pregnancy because high amounts of vitamin A may be present.

Fish body oils do not contain vitamin A and are safe to consume up to 3 grams a day.4

Interactions e.g. with other medications Taking cod liver oil or other fish oils with anticoagulants (such as warfarin), aspirin, dipyridamole (a vasodilator), ginkgo biloba or ginseng, may increase the risk of bleeding. Medical supervision in these cases is required.4
Adverse effects Fish liver oils contain vitamins A and D , fat soluble vitamins that can be toxic when consumed in excessive amounts.4

Reflux or “burping up” of fish oil may occur in some individuals. Take with food to avoid this occurring.

References 1EU Community Register of Nutrition and Health Claims

2 Natural Medicines Comprehensive Database, via the National Library of Medicines National Institutes of Health

EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal 2010; 8(3):1461. [online] Available at: [Accessed February 2017].

4 Mason, P. Dietary Supplements. Pharmaceutical Press, London, 2001.