Cod Liver Oil

What is Cod Liver Oil

Cod liver oil is used as a dietary supplement and is available in both liquid and capsule forms.

It is rich in vitamin A, vitamin D, and omega-3 fatty acids; some commercial formulations may contain additional vitamins and nutrients.

The omega-3 content includes two essential fatty acids (EFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EFAs are not synthesized by the human body and therefore must be consumed in the diet to prevent EFA deficiency.

However, caution is advised as cod liver oil products may also contain toxic organochlorines, including the pesticides DDT and lindane and polychlorinated biphenyls (PCBs), which are concentrated in the fish liver prior to harvest.

Additionally, high vitamin A and vitamin D concentrations in cod liver oil could lead to hypervitaminosis. Patients should consult a health care provider prior to initiating supplementation for appropriate monitoring and therapy.

As the name implies, cod liver oil is derived from the livers of cod fish. The practice of drinking cod liver oil was started several centuries ago by the fisherman of Scandinavia and Greenland for fortification under cold and harsh working conditions.

In the late 1800s, prior to the addition of vitamin D to milk, cod liver oil was used successfully to treat and prevent rickets.

Currently, fish oil supplements are promoted for a variety of health conditions including hypertriglyceridemia, migraine prophylaxis, psychiatric conditions, secondary prevention of cardiovascular disease, type 2 diabetes mellitus, various nephropathies, and also for inflammatory conditions such as asthma, gingivitis, inflammatory bowel disease, and rheumatoid arthritis.

Although data for most conditions are limited and preliminary, fish oil supplements, including cod liver oil, are ‘Generally Recognized As Safe’ (GRAS) by the FDA. The data are most compelling for the ingestion of fish in the diet to maintain a healthy heart.

The American Heart Association (AHA) recommends eating fish two times per week as a source of lean protein. Until compelling data indicate that fish oil supplements benefit overall cardiovascular health, the AHA does not recommend the use of supplements for this purpose.

In November 2004, the FDA approved a prescription only fish oil supplement capsule Omacor™ (see separate monograph: Fish Oils, Omega-3 Fatty Acids) for the treatment of hypertriglyceridemia.


  • nutritional supplementation

Side Effects

  1. abdominal pain
  2. alopecia
  3. anorexia
  4. arthralgia
  5. ataxia
  6. azotemia
  7. constipation
  8. dehydration
  9. diarrhea
  10. dysgeusia
  11. dysmenorrhea
  12. dyspepsia
  13. ecchymosis
  14. elevated hepatic enzymes
  15. epiphyseal closure
  16. epistaxis
  17. eructation
  18. exophthalmos
  19. fatigue
  20. growth inhibition
  21. halitosis
  22. headache
  23. hepatomegaly
  24. hypercalcemia
  25. hypercalciuria
  26. hypercholesterolemia
  27. hyperphosphatemia
  28. hypertension
  29. hyperthermia
  30. hypervitaminosis A
  31. hypervitaminosis D
  32. increased intracranial pressure
  33. irritability
  34. jaundice
  35. lethargy
  36. leukopenia
  37. malaise
  38. metallic taste
  39. musculoskeletal pain
  40. myalgia
  41. nausea
  42. nocturia
  43. osteoporosis
  44. papilledema
  45. photophobia
  46. polydipsia
  47. polyuria
  48. prolonged bleeding time
  49. pruritus
  50. rash
  51. renal failure (unspecified)
  52. skin hyperpigmentation
  53. splenomegaly
  54. teratogenesis
  55. tinnitus
  56. vertigo
  57. vomiting
  58. weakness
  59. weight gain
  60. weight loss
  61. xerostomia

Monitoring Parameters

  • laboratory monitoring not necessary


  • alcoholism
  • anticoagulant therapy
  • asthma
  • biliary tract disease
  • bipolar disorder
  • bleeding
  • breast-feeding
  • cardiac disease
  • children
  • dental work
  • diabetes mellitus
  • fish hypersensitivity
  • gallbladder disease
  • hepatic disease
  • hepatitis
  • hypercalcemia
  • hypercholesterolemia
  • hyperlipidemia
  • hyperphosphatemia
  • hypertension
  • hypervitaminosis A
  • hypervitaminosis D
  • infants
  • inflammatory bowel disease
  • malabsorption syndrome
  • migraine
  • myocardial infarction
  • nephrolithiasis
  • obesity
  • pregnancy
  • pulmonary disease
  • renal disease
  • rheumatoid arthritis
  • sarcoidosis
  • schizophrenia
  • surgery
  • systemic lupus erythematosus (SLE)
  • thrombolytic therapy


There are no drug interactions associated with Cod Liver Oil products.


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