What is an evidence‑based functional diet for adults with rheumatoid arthritis?

Evidence-Based Functional Diet for Rheumatoid Arthritis

The Mediterranean-style diet is the only formally recommended dietary pattern for adults with rheumatoid arthritis, with conditional recommendation from the American College of Rheumatology based on demonstrated improvement in pain symptoms and anti-inflammatory properties. 1, 2

Core Dietary Framework

The Mediterranean diet should serve as your primary dietary prescription for RA patients, as it is the sole evidence-based pattern showing RA-specific benefits while also providing cardiovascular protection. 1, 2

Essential Components to Emphasize

Primary fat source:

• Extra virgin olive oil as the predominant dietary fat 1

Protein sources:

• Oily fish rich in omega-3 fatty acids, specifically 3 portions per week 1
• Moderate amounts of low-fat dairy 2

Plant-based foods:

• High intake of vegetables, fruits, and whole grains 2
• Regular consumption of nuts and seeds 1

Mechanism: This dietary pattern works through anti-inflammatory and antioxidant properties that target RA inflammatory pathways, while also restoring healthier gut microbiome composition that is altered in RA patients. 1

Foods to Strictly Limit or Avoid

High-priority restrictions:

• Added sugars and sugar-sweetened beverages (exacerbate RA symptoms) 1
• Highly processed foods, refined carbohydrates, saturated fats, and trans fats (negative impact on RA symptoms and cardiovascular health) 1, 2
• Sodium/salt (reduce cardiovascular risk) 1

Evidence note: High-fat, high-sugar, and high-salt diets contribute to RA progression, making these restrictions critical rather than optional. 3

What NOT to Recommend

The American College of Rheumatology conditionally recommends AGAINST the following diets due to very low to moderate certainty evidence showing no consistent benefit:

• Ketogenic diet 1
• Paleo diet 1
• Gluten-free diet 1
• Vegetarian/vegan diets 1
• Intermittent fasting 1
• Elemental, elimination, or raw food diets 1

Critical pitfall: Do not allow patients to pursue unsupervised elimination diets or vegan diets, as these lack evidence for RA benefit and risk malnutrition. 4

Supplement Approach

Use a "food first" approach, with dietary supplements only when necessary to correct nutritional deficiencies. 1, 4

Conditionally recommended supplements (when indicated):

• Vitamin D and calcium for bone health 4
• Folic acid when taking methotrexate 4
• Fish oil (omega-3) for cardiovascular benefits, though not specifically for RA symptom management 4

Not recommended: Dietary supplements as primary interventions show no consistent, clinically meaningful benefit for physical function, pain, or disease activity specific to RA. 2 Avoid nutrient megadosing or unregulated supplements that have no proven benefit and may cause drug interactions. 4

Weight Management Integration

Maintaining a healthy body weight is unanimously supported for optimizing RA outcomes. Obesity is associated with higher disease activity, impaired physical function, and poorer treatment response in RA. 1, 2, 4

Interprofessional Team Involvement

Refer to a registered dietitian early as part of the interprofessional care team to develop a personalized eating plan that addresses both nutritional needs and RA management. 2, 4 This is particularly important for patients wishing to modify their diet or those with appetite issues. 4

Essential Lifestyle Integration

Beyond diet, these lifestyle factors are critical for RA outcomes:

• Smoking cessation: Critical for RA outcomes and must be addressed 1, 4
• Physical activity: At least 150 minutes/week of moderate or 75 minutes/week of vigorous aerobic activity 1
• Stress management: Cognitive behavioral therapy approaches 1

Key Clinical Caveat

Do not delay or substitute DMARD therapy while focusing on dietary interventions—pharmacologic treatment remains the foundation of RA management. 4 Diet serves as adjuvant therapy to optimize outcomes alongside appropriate medical treatment. 5