“Several studies have shown a correlation between modifiable risk factors and improvement of symptoms and outcomes in RA patients,” the study authors wrote. “Excessive body weight and diets that include animal products (e.g., dairy and red meat) tend to impair RA management efforts and exacerbate symptoms, presumably due to their pro-inflammatory effects. In contrast, diets rich in vegetables, fruits, and fiber are associated with lower [body mass index], have anti-inflammatory properties and help reduce pain and inflammation in these patients.”
Therefore, the researchers analyzed how a vegan diet could help patients manage their RA symptoms.
Weight Management and RA
Past studies have established an association between excessive bodyweight and RA, and overweight RA patients tend to have worse outcomes compared to normal-weight patients. This can be attributed to the fact that excess fat in cells causes inflammation. The researchers also pointed out that “extra stress placed on weight-bearing joints by excess body weight further exacerbates inflammation in these patients,” making the case that weight management can help improve RA outcomes.
“A 2018 retrospective analysis (n = 174) evaluated the association between weight loss and RA disease activity, and found that overweight individuals who lost ≥5 kg had a three-fold increased odds of disease activity improvement compared to those who lost <5 kg,” the authors observed.
Previous research has also found that vegetarian and vegan diets are useful weight management tools.
Two meta-analyses of randomized clinical trials showed a benefit of vegetarian, especially vegan, diets on body weight, compared with other diets. The strong evidence is supported by observational studies,” the study authors wrote, adding, “Elkan et al. (n = 66) observed reductions in BMI, LDL, and total cholesterol after both 3 and 12 months of a gluten-free vegan diet (p < 0.01). These results correspond with the improvements in Disease Activity Score of 28 joints, Health Assessment Questionnaires, and CRP levels (p ≤ 0.008) after 12 months. These findings suggest that by improving weight loss and lowering serum cholesterol levels, plant-based diets might improve RA symptoms and decrease the risk of developing the disease.”
Diet Affects Inflammation
Food choices play a role in inflammation in the body. The researchers cited a 2015 study that found patients randomized to a vegan, vegetarian, or pesco-vegetarian diet had greater reductions in inflammatory scores than patients on a semi-vegetarian or omnivorous diet.
“The researchers attributed this observation to the elimination of the leading sources of fat in the western diet (beef, cheese, milk, and poultry),” the authors wrote. “Diets high in fat and processed meat have been positive associated with inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), and homocysteine, while diets high in whole grains and fruit have been inversely associated with these biomarkers.”
Low-fat vegan diets have also been associated with improved RA symptoms including the degree of pain, joint tenderness, and joint swelling. The study cited another randomized clinical trial that found an association between a gluten-free vegan diet and decreased immunoglobulin G in RA patients.
“The naturally low-fat, fiber-rich components of a vegan diet might mediate the pathways that alleviate joint inflammation and pain, as observed through reduced CRP levels and improved inflammatory scores. These findings highlight the need for a randomized study that objectively measures biomarkers of inflammation related to plant-based dietary changes,” the authors wrote.
The researchers wrote in their conclusion that “although some of the trigger foods in RA patients are individualized, a vegan diet comprised of fruits, whole grains, legumes, and vegetables, can improve symptoms by eliminating many common trigger foods. Elimination of additional food triggers may be necessary depending on the individual food sensitivities. Further research is needed to test the effectiveness of plant-based diets on joint pain, inflammation, and quality of life in patients with RA.”