Research Review of Plant-Based Diet for Patients with Osteoarthritis or Rheumatoid Arthritis

The results of the MSOA trial, published last year in Osteoarthritis and Cartilage,² show that the 32 patients receiving a 16-week intervention, including the outlined plant-based diet, physical activity and stress management plans in addition to regular care, manifested the following statistically significant changes (when compared with a 32-participant control group that did not receive this intervention):

• Mean improvements on the overarching Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) that was 11 points larger (11.7; 95% CI 6–16; P=0.0001), the WOMAC pain scale (1.89; 95% CI 0.77–3.01; P<0.01), WOMAC stiffness (1.3; 95% CI 0.75–1.85; P=0.0001), and WOMAC physical function (8.6; 95% CI 5.2–11.9; P<0.0001);
• Greater mean declines in weight, fat mass and waist circumference—5.3 kg, 3.9 kg and 6 cm, respectively; and
• Patient-Reported Outcomes Measurement Information System (PROMIS) measures of fatigue, pain interference, C-reactive protein, hemoglobin A1c, fasting glucose and low-density lipoproteins also improved.

Three participants in the intervention group decreased their pain medication use vs. none in the control group; five intervention group participants stopped using other drugs, vs. two in the control group.

“The ‘Plants for Joints’ lifestyle program reduced stiffness, relieved pain and improved physical function in people with hip or knee MSOA compared to usual care,” the researchers concluded.

“We hoped for these kinds of results,” Prof. van Schaardenburg says. “It turned out that this went very well.”

Dr. Sammut

This was the first study to test a plant-based diet combined with physical activity and stress management programs in MSOA patients, according to the researchers. “This study is important,” Dr. Sammut says, commenting specifically on the idea of discussing metabolic syndrome-associated osteoarthritis. “It’s wonderful that they’re talking about how osteoarthritis is not just one disease.” She was also pleased to see patients manifested improvements without having to take more medication.

Prof. van Schaardenburg’s team published the results of the other trial, in which 83 participants with rheumatoid arthritis were studied over 16 weeks, in Rheumatology last year.³ Applying the same intervention to a different patient population, the researchers found that the intervention group showed a mean 0.9-point greater improvement in the DAS28 scale measuring disease activity than the control group (95% CI 0.4–1.3; P<0.0001), and greater decreases in weight (3.9 kg), fat mass (2.8 kg), waist circumference (3 cm), HbA1c (1.3 mmol/mol) and low-density lipoprotein (0.32 mmol/l). Depression, fatigue and physical function scores did not significantly improve.