According to a new study conducted by researchers at the Physicians Committee for Responsible Medicine, a low-fat vegan diet improves joint pain in patients with rheumatoid arthritis. The study, published in the American Journal of Lifestyle Medicine, found that, in addition to reductions in pain and swelling, body weight decreased by about 14 pounds on average on the vegan diet, compared with a gain of about 2 pounds on a placebo diet. There were also greater reductions in total, LDL, and HDL cholesterol during the vegan phase of the study.

Rheumatoid arthritis is a long-term autoimmune disease that causes pain, swelling and stiffness in the joints. The condition usually affects the hands, feet and wrists. It’s not clear what triggers this problem with the immune system, although there is an increased risk for women, people with a family history of rheumatoid arthritis, and smokers.

During the study, 44 adults previously diagnosed with rheumatoid arthritis were assigned to two groups. The first group followed a vegan diet for four weeks, with the elimination of additional foods for three weeks, then reintroduction of the eliminated foods individually over nine weeks. The second group followed an unrestricted diet but was asked to take a daily placebo capsule, which had no effect on the study. Then the groups switched diets for 16 weeks.

During the vegan phase of the study, DAS28 (Disease Activity Score-28), an indicator of the pain experienced with the disease, decreased 2 points on average, indicating a greater reduction in joint pain, compared to a decrease of 0.3 points in the placebo phase. The average number of swollen joints decreased from 7.0 to 3.3 in the vegan phase, while that number increased from 4.7 to 5 in the placebo phase. 

Dr Neal Barnard, the lead author of the study and founder of the Physicians Committee, said, “A plant-based diet could be the prescription to alleviate joint pain for millions of people suffering from rheumatoid arthritis…All of the side effects, including weight loss and lower cholesterol, are only beneficial.”