Cod Liver Oil Benefits and Side Effects

Recently we have been hearing more and more about the benefits of cod liver oil as if it were some form of new alternative supplement that has only recently been discovered. While the benefits of cod liver oil may have recently resurfaced, people have in fact known about this amazing substance for literally hundreds of years. While it was used as a source of fuel for lamps and as a softening agent for leather goods, cod liver oil has also been used medicinally to prevent children from contracting rickets from a vitamin D deficiency. In the mid part of the last century, there probably wasn’t a schoolchild in the Western Hemisphere who wasn’t dosed with cod liver oil before being sent out the door, lunch in hand, to attend classes.

Somewhere along the line it was noted that children who took their daily dose of cod liver oil didn’t seem to come down with as many colds and inner ear infections, but it wasn’t until recent decades that the benefits of this amazing oil extracted from the liver of cod (a fresh water fish) have begun to be more fully understood. Based on verifiable research conducted by some of the world’s most prestigious medical universities including Harvard University in the United States and the College of Medicine at Dundee University in Scotland, it has been ascertained that cod liver oil does promote a number of healthful benefits. However, there are also some side effects which should be mentioned at the same time.

Benefits of Cod Liver Oil

As noted previously, cod liver oil does indeed have the capacity to allay a deficiency in vitamin D, most especially in children. At one point in time, rickets was a common disorder of the bones that was commonly caused by a severe deficiency of this vitamin. By introducing cod liver oil into the dietary intake of children around the world, rickets which had been prevalent at epidemic proportions was finally laid to rest. In fact, cod liver oil is still administered to children in third world countries to compensate for an adequate dietary source of this essential vitamin. Other benefits of cod liver oil that have been proven through research and clinical studies include:

  • Reduction of inflammation in osteoarthritic conditions
  • Prevention of inner ear infections
  • Reduction in levels of triglycerides in the bloodstream
  • Potential reduction of cholesterol in the bloodstream
  • Prevention of blood clots that lead to stroke and heart attacks
  • Effective in preventing/treating psoriasis
  • Prevention of birth defects from vitamin A & D deficiency
  • Alternative treatment for Crohn’s disease
  • Reduction of high blood pressure

And the list goes on from there. There is also a good deal of research that indicates that cod liver oil may be effective to some degree in treating certain mental disorders, cystic fibrosis, asthma, allergies, lupus, macular degeneration, and believe it or not, sickle cell anemia. Anyone who has been diagnosed with a deficiency in either vitamin D or vitamin A can also benefit from cod liver oil as can anyone who has had to rely on NSAIDs for inflammation and the resulting pain. Some studies even indicate that cod liver oil may aid in the prevention of Type I Diabetes.

Potential Side Effects of Cod Liver Oil

Before discussing any of the potential side effects, it should always be understood that if you are pregnant or lactating, you should talk to your doctor prior to taking any supplements no matter how safe they are deemed to be. Also, anyone under a doctor’s care for heart disease or taking any prescription medications such as anticoagulants should also talk to their doctor first. Remember, cod liver oil does prevent blood clots and it does have the capacity to lower blood pressure so it would be contraindicated when these medications are being routinely taken.

While cod liver oil is generally considered to be safe when taken in recommended doses, there is a potential for toxicity if it is taken in high doses over a period of time. The toxic side effects could result in liver damage, hair loss, mental confusion and even bone loss. When taken in recommended amounts cod liver oil promotes strong and healthy bones, but when it is taken at toxic levels it promotes loss of bone mass. Other side effects could include loose stools, bad breath, nosebleeds, heartburn and perhaps even nausea. Simply because it is generally recognized as safe (GRAS), doesn’t mean that it is safe for all people all of the time. As with any other supplement, it is always encouraged that you speak with your personal physician prior to embarking on any new dietary or alternative treatments or remedies.

Cod liver oil has been used as a homeopathic remedy safely and effectively for so long that it is amazing how so many people are just now becoming aware of the many benefits this natural product has to offer. You may hear it referred to as Omega-3 supplements, or a compound of Omega-3 and Omega-6, but those are just trendy names for an age old remedy. From preventing middle ear infections to treating arthritis, cod liver oil is nature’s answer to several chemical pharmaceuticals. Take the time to do a little more research, talk to your doctor, but by all means, don’t dismiss this amazing fish oil as just another marketing ploy. (And if all else fails, talk to your grandmother! She will tell you just how many children were fed cod liver oil in the 1940’s and 50’s and were kept free from colds and influenzas in the process.)


  1. Richard Blackburn

    In this article it states that the Cod is a fresh water fish. Surely this is incorrect as Cod are found in the seas and oceans.

  2. Was surprised to find out that it could interfere with my stroke meds. I'm one of the granny's who took it as a child and would not have thought of this. Thanks will now check with my doc.

  3. Loved to hear why my Mother was given my Sister and I a tsp. full every winter before our leaving for school. Of course, I did give to my sons in winter time, because my Mother had done it, not knowing lack of sun in the winter could be replaced by Cod Liver Oil! Until our pharmacist told me I should give it to them all year round. Now, I have teenager grandchildren, unfortunately their Mothers did not do it!

  4. At 2 n 3 I bean giving codliver to my children now 26 n 27 after a spanish person shared the reason her children didn't get sick n healthy hair.

  5. Great article… One comment, cod liver oil is from fish caught in the ocean not fresh waters… There are varieties of fresh water cod but not in commercial use… Thank you!

  6. I used it for 50 years.

  7. I was given cod liver oil pills in school, every morning by the teacher…

  8. Yes, I suppose too much cod liver oil does cause nose bleeding. Thank you for the article. Very helpful!

  9. When my children were younger they suffered from inner ear infections frequently, getting a new set of antibiotics every other week. My grandmother told me to give the kids a teaspoon of "scotsemoltion" an English product which was made from cod liver oil. My children were cured from infections, whether runny nose or inner ear infection. I am currently using Omega 3 to control my inflammation from RA/OA.

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