Plant-Based Diet Intervention Improves Disease Activity, Symptoms in RA, Osteoarthritis

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Participants described the intervention as complete and coherent and would recommend this intervention to other patients.

Plants for Joints (PFJ), a 16-week multidisciplinary intervention focused on a whole-food plant-based diet, sleep and stress management, and physical activity, improved health outcomes and was deemed feasible among a cohort of patients with rheumatoid arthritis (RA) and osteoarthritis, according to data published in BMC Public Health.1

Investigators noted these findings offer important insights into why this type of intervention works and how it can be optimized for future use. Patients were highly satisfied and reported feelings of perceived effectiveness, indicating the potential for plant-based treatments as a supplementary option for patients with chronic diseases.

Previous research has shown plant-based diets can significantly improve health outcomes in patients with other conditions including cardiovascular disease, obesity, and type 2 diabetes. Additionally, the PFJ lifestyle intervention has demonstrated significant improvements in a variety of symptoms in patients with autoimmune conditions in conjunction with usual care. These included significant reductions in fat mass, weight, and cholesterol.2

“Given the effectiveness of the PFJ intervention on improving disease specific outcomes and (risk factors of) comorbidities, the intervention can potentially be used as an additional treatment option for people with RA, osteoarthritis, and other non-communicable diseases,” wrote a group of investigators led by Carlijn A Wagenaar, MD, associated with the Reade Center for Rheumatology and Rehabilitation, in Amsterdam, The Netherlands.

To better understand how this intervention could achieve these results, investigators used a mixed methods approach. The relationship between the degree of implementation and lifestyle changes was explored, and they determined the context, implementation, and mechanism of impact of this intervention.

Qualitative and quantitative data were collected across the reach, recruitment, delivery, and responsiveness among both patients and coaches, such as the sport coaches and dieticians. Process evaluations were conducted according to the UK Medical Research Council’s (MRC) guidelines.

Data were collecting using focus groups, post-intervention questionnaires, and interviews with the coaches. Data were then analyzed for themes and quantitative information was assessed using linear regression analyses and descriptive statistics. A theory-driven implementation index score was used to determine the degree of implementation.

The intervention consisted of 10 weekly group sessions, including a cooking workshop, in patients who were diagnosed with or at risk for RA, osteoarthritis, and controls. The multidisciplinary team specialized in a variety of lifestyle components. Patients received an individual physical therapy consultation at baseline and were able to request additional guidance. They were given a binder with nutritional information, a meal plan, recipes, a fitness tracker, homework exercises, and an optional fasting protocol.

A total of 155 subjects ultimately participated in the PFJ intervention, of which 68% (n = 106) completed the questionnaire and 22% (n = 34) attended the focus group. The average age was 57 years, most (87%) were female, and the mean body mass index (BMI) was 29 kg/m2 at baseline.

The PFJ intervention was shown to improve health outcomes, including disease activity, metabolic health, and symptoms. These participants described the intervention as complete and coherent and would recommend this intervention to other patients (mean score 9.2 (standard deviation [SD] 1.4) out of 10). Patients said they felt heard and empowered to take control of their health outcomes and lifestyle during this time.

Social support, self-monitoring, practical and theoretical information, and individual guidance provided by a multidisciplinary team were among the most useful components for patients receiving the intervention. The cohort determined PFJ was feasible and effectively improved their personal health outcomes.

No significant differences in healthy lifestyle changes across implementation index score groups were reported.

Although investigators noted the mixed methods approach as a strength of the study, they mentioned limitations including a possibility of bias due to patients receiving a singular questionnaire after the implementation of the intervention. Additionally, selection bias could have influenced results as not all recruited patients participated in the process evaluation.

“This process evaluation further supports the use of lifestyle interventions, like PFJ, as an additional treatment option for people RA or osteoarthritis, as well as other non-communicable diseases, due to its high satisfaction, feasibility, and perceived effectiveness, in addition to its clinical effectiveness,” investigators concluded.


  1. Wagenaar CA, Toonstra A, Walrabenstein W, van Schaardenburg D, van Nassau F. How the Plants for Joints multidisciplinary lifestyle intervention achieved its effects: a mixed methods process evaluation. BMC Public Health. 2024;24(1):1034. Published 2024 Apr 13. doi:10.1186/s12889-024-18554-2
  2. Walrabenstein W, Wagenaar CA, van de Put M, van der Leeden M, Gerritsen M, Twisk JWR, et al. A multidisciplinary lifestyle program for metabolic syndrome-associated osteoarthritis: the "Plants for Joints" randomized controlled trial. Osteoarthritis Cartilage. 2023;31(11):1491–500.