Symptoms of rheumatoid arthritis often get worse on diets abundant in meats, especially red meats.
Can vegan and/or raw food diets have positive effects on people with this disease?
According to Arthritis Research UK, there is some evidence of vegan diet improving medical condition of people suffering from arthritis.
This may be part of due to lack of red meat in such diet, which has been found to be linked to increased risk of this illness. Another culprit that lacks in vegan/raw diets which is mentioned with regard to arthritis is dairy.
It might be important for vegan people suffering form arthritis to see whether they have sufficient protein intake as this can lack in vegan diet and is mentioned to be important in tackling the symptoms. Other important parts of the diet that helps with arthritis are eg. Omega 3, vitamin C and vitamin E.
Results seem to be mixed, some studies show a positive effect, others no effect at all. The studies referenced by Arthritis Research suggest that going vegan seems to show better results than being vegetarian. Going vegetarian or vegan may have the additional benefit that you're more likely to lose weight over time which will put less strain on your joints. Most studies don't really run long enough to prove this though.
On the other hand, I suppose it's only fair to point out if you are thinking of becoming vegetarian and vegan solely for the above reasons that there is also evidence that the consumption of oily fish can improve the symptoms of rheumatoid arthritis.
According to arthritisresearchuk.org, "On balance, changing your diet probably won’t have as great an impact on your arthritis as the medicine prescribed by your doctor will."