Johan Frostegard of Karolinska University Hospital in Stockholm and colleagues divided 66 rheumatoid arthritis patients randomly into two groups. They randomly assigned 38 of the volunteers to eat a gluten-free vegan diet, and the other 28 a well-balanced but non-vegan diet for one year.

The study, published in Arthritis Research & Therapy, found the diet raised the levels of natural antibodies that fight the damaging compounds -- phosphorylcholine -- that cause the chronic inflammatory symptoms of rheumatoid arthritis.

The diet also protected against heart attacks and stroke by lowering cholesterol levels and lowering body weight, the study said.

In contrast, none of the indicators differed significantly for the control group on the conventional healthy diet, the study said.