What is fish oil and where does the omega 3 stuff fit in? Fish oil contains two types of omega 3 fatty acids - eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These essential fatty acids help our bodies fight inflammation by regulating the production of inflammatory chemicals (cytokines) and encouraging the release of anti-inflammatory chemicals.
For inflammatory arthritis, like rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis, there are a good number of studies that suggest doses of fish oil can help relieve both pain and inflammation. A range of studies all show that subjects needed fewer painkillers when taking about 1.5g of fish oil a day and some studies also show a reduction in inflammatory cytokines in those who take fish oil. Sadly, there doesn't seem to be much evidence to support the idea that fish oils prevent joint damage.
There isn't any conclusive research on osteoarthritis at the moment. Given, that fish oils are also good for your heart, brain and skin, you could give them a go anyway.
You can get plenty of omega 3s through what you eat. Eat oily fish 3 times a week (2 if you are planning on getting pregnant) - salmon, mackerel, trout, tuna and sardines all count. You can also try a supplement of 1-3 capsules of 1000mg fish oil a day. When you are choosing one look for good levels of EPA and DHA (at least 180mg and 120mg respectively). Cod liver oil is not the same thing at all - don't bother with it!
For further info, try this by Arthritis Research UK for a good, straightforward summary. If you want to get more into the science, then you I recommend the US National Institute of Health research summary. You might also want to read about how to make sure the fish you eat is being caught sustainably by checking out the Marine Stewardship Council.
Finally, if all this talk about fish is too much for you, there are some vegetarian sources of omega 3 fatty acids. These can be converted by your body into some of these beneficial fatty acids, but I will post more on this soon.