Scientists from the Karolinska Institute derived their study from an experiment that involved 58 patients divided into two groups: the vegan diet group and the non-vegan diet group.
The 30 vegan diet subjects and the 28 non-vegan diet subjects were then observed for at least three months.
According to the Guardian, those on the vegan diet showed a significant improvement in the number of swollen joints, from 5.3 to 4.3. They also showed a decrease in, "bad cholesterol", and a blood chemical that determines the body's inflammatory activity.
Those on the non-vegan diet showed no changes.
The scientists noted the "large body of evidence" that was present to suggest the changes' effects on artery blockage and cardiovascular conditions.
Other results showed a drop in the lower body mass index, and higher immune system factors.
"I think it's a quite unexpected and interesting finding," said Prof. Johan Frostegĺrd, study leader. "The effects on the immune system are quite new."
Experts from the Arthritis Research Campaign said the study was in fact interesting, but the actual role of the diet could be debatable.
"However we do know that, for example, eating oily fish can reduce inflammation, and risk factors for developing the condition include high consumption of red meat and low consumption of fruit and vegetables," the BBC quoted an ARC spokeswoman. "So diet does play a role, however limited."
The study findings are published in an issue of the journal Arthritis Research and Therapy.
