Does cod liver oil help rheumatoid arthritis pain?
Publication Date:26/03/2008
Cod liver oil may help people with rheumatoid arthritis reduce the number of painkillers they have to take. But there are problems with the research that mean it's hard to rely on the results.
What do we know already?
Cod liver oil has been used for many years to treat stiff joints. But there hasn’t been much good-quality research to show whether it can be helpful.
Rheumatoid arthritis is a type of arthritis where the joints are damaged by the body's own immune system. Usually, our immune systems protect us from infections. But when people get rheumatoid arthritis, the immune system causes inflammation around the lining of the joints. This can be painful and make it hard to move the joints.
Most people with rheumatoid arthritis take several medicines. These include drugs that help with pain and inflammation, called nonsteroidal anti-inflammatory drugs (NSAIDs for short). Examples include ibuprofen, diclofenac and naproxen. But NSAIDs can have drawbacks if you take them at high doses for a long time. They may cause upset stomachs or stomach ulcers. And they slightly increase your risk of having a heart attack or stroke.
Because of these drawbacks, doctors advise that people should take the lowest doses that help their pain. A new study tested whether taking cod liver oil helped people with their pain, so that they could reduce their doses of NSAIDs.
What does the new study say?
The study showed that almost 4 in 10 people who were given capsules of cod liver oil were able to cut the number of NSAID tablets they took each day by almost one-third. This compared to only 1 in 10 people who were given dummy (placebo) capsules.
Everyone in the study had the capsules for 12 weeks before they tried reducing the numbers of NSAIDs they were taking. The people taking cod liver oil had slightly less pain, even though they were taking fewer NSAID painkillers. The results were measured after 9 months.
Some people stopped taking the cod liver oil capsules because they had stomach upsets or didn’t like taking them. The people in the study had to take 10 large capsules a day, on top of their normal medicine.
Where does the study come from?
The study was carried out by doctors at Dundee University in Scotland. It was published in Rheumatology, a medical journal owned by the Oxford University Press.
How reliable are the findings?
There are two important problems with the study:
- It's quite a small study (only 97 patients) and a lot of people dropped out. Only 58 people completed the study.
- The dummy capsules were empty, which meant that people who were taking dummy capsules could quite easily tell they weren't the 'real' ones. People who knew they weren't getting cod liver oil capsules may not have expected to feel better. They may not have been willing to reduce the number of NSAIDs they were taking.
- The people taking cod liver oil could taste that their capsules were fishy. If they knew they were getting cod liver oil, they may have expected to feel better and been more willing to stop taking NSAIDs.
So the results are based on quite a small number of people, who were all able to tell whether they had the real capsules or not. This means the findings in favour of the cod liver oil capsules could be exaggerated.
What does this mean for me?
If you have rheumatoid arthritis, you'll probably be interested in anything that can help you deal with the pain and reduce the number of painkillers you need to take. Unfortunately, the problems with this study mean it is not clear whether cod liver oil can really help.
However, lots of people take cod liver oil and it is unlikely to cause serious harm. The people in the study took quite high doses (10 grams of cod liver oil daily) which some people find unpleasant or difficult to swallow. Some people get upset stomachs from cod liver oil.
We don't know yet whether cod liver oil can be helpful for other types of arthritis. The research only looked at rheumatoid arthritis.
What should I do now?
If you are concerned about your treatment for rheumatoid arthritis, start by talking to your doctor. It's a good idea to check with your doctor before you start taking any new supplements, as they might react with the medicines your doctor prescribes.
From:
Galarraga B, Ho M, Youssef HM, et al. Cod liver oil (n-3 fatty acids) as an non-steroidal anti-inflammatory drug sparing agent in rheumatoid arthritis. Rheumatology. Published online 24 March 2008.
To find out more, read our information on rheumatoid arthritis.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
