What is the difference between cod liver oil and fish oil?
Q) I am 51 years old, have mild osteoarthritis and for years have taken 1,500 mg of cod liver oil. Recently the advice about taking cod liver oil seems to have changed. I now read that taking large amounts of cod liver oil may be unwise, and that taking fish oil might be a better bet. Can you explain the differences between these two types of oil? I'm becoming increasingly confused! What's your advice?
Lesley, Bristol (Autumn 2006)
A) The reason that advice has changed relates to the high content of vitamin A in cod liver oil. Vitamin A can be harmful to pregnant mothers and the high concentration in fish liver means that you may approach the recommended daily limit for adults (3,000 micrograms a day). The oil derived from whole fish has less vitamin A. The signs of vitamin A overdose include loss of appetite, irritability, dryness of the skin, a coarseness of the hair and an enlarged liver. These, however, are common symptoms so it's important to be aware of the risk.
This answer was provided by Dr Philip Helliwell for the Autumn 2006 edition of our magazine, Arthritis Today, and was correct at the time of publication.
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