Rheumatoid arthritis (RA) is a chronic autoimmune disease affecting millions worldwide. Characterized by joint inflammation and progressive cartilage and bone destruction, RA significantly impacts the quality of life. While genetic and environmental factors play a role in RA susceptibility, emerging research highlights the central role of diet in disease risk and progression. This article explores the relationship between diet and RA, drawing upon expert opinions and research findings to provide a comprehensive guide for managing RA through nutrition.
Understanding Rheumatoid Arthritis
Rheumatoid arthritis (RA) is a systemic autoimmune and inflammatory disease primarily characterized by joint involvement, accompanied by systemic features. It is estimated that the global prevalence of the disease is around 1-2%, with a large variation among different populations. RA pathogenesis involves the interaction of genetic and environmental factors in a multistep process that begins years before the onset of the disease.
Diet's Role in Rheumatoid Arthritis
Diet and nutrients have received considerable attention as potential environmental factors influencing the development and the course of RA. Specific dietary choices can have pro-inflammatory effects (for example red meat, salt, excessive caloric intake) or reduce inflammation (oil, fatty fish, fruit and others). The prevalence distribution of RA shows a higher number of RA patients in Western countries, in opposition with Eastern world and developing countries [18].
The Western Diet and RA Risk
The Western diet, characterized by a high intake of red meat, saturated and trans fats, a low ratio of omega-3:omega-6 fatty acids and high consumption of refined carbohydrates, has been associated with an increased RA risk principally through an increase of inflammation and an induction of insulin-resistance and obesity [19,20]. Even if the relationship between RA and diet is not as strong as other risk factors (smoke primarily), dietary influence has been widely studied, also considering the complex nature of nutrient provision.
Inflammation and Chronic Diseases
RA, along with other chronic diseases, including cardiovascular disease (CVD), type 2 diabetes mellitus, different types of cancer, and Alzheimer’s disease, share inflammation as a driving pathophysiological process. Indeed, C-reactive protein (CRP), a marker of inflammation, predicts future development of hypertension and diabetes mellitus better than body mass index [21].
Read also: RA and Body Weight
The Mediterranean Diet: A Potential Ally
It can be assumed that the Mediterranean Diet (MD), together with genetic and other lifestyle factors, could explain the lower RA incidence in Southern Europe (0.3-0.7%) compared with Northern Europe and North America (0.5-1.1%) [2].
The Mediterranean Diet (MD) features mainly vegetables, unrefined cereals, fruit, legumes, fish and extra-virgin olive oil, associated with a moderate intake of eggs, poultry, dairy products and low consumption of refined sugar and red meat. Red wine is also included, and herbs and spices are largely used [25,26,27]. This dietary pattern, present mainly in Southern Europe and in olive-growing regions, is opposed to the Western diet. Featuring an omega3:omega 6 ratio of 1:7 [28], related to a high intake of alfa-linolenic acid (ALA), a specific “anti-inflammatory” PUFA, MD is associated with a reduction in total and cardiovascular mortality, and cancer, Alzheimer’s and Parkinson’s disease incidence.
Several foods included in MD show direct anti-inflammatory effects: extra-virgin olive oil use is associated with a reduction of thromboxane 2 (TXB2) and leukotriene B4 (LTB4), not observed with corn oil and non-virgin olive oil. The consumption of tomato drink for 26 days induces a reduction in TNF-α production. Black tea consumption, exerting an anti-inflammatory effect mainly for its flavonoid content, can decrease CRP levels, leukocyte and platelets aggregation and activation, reducing inflammatory response in healthy men. Moderate red wine intake contributes to a reduction in low-/high-density lipoprotein (LDL/HDL), oxidized LDL, CRP and fibrinogen and to an increase in HDL and total antioxidant capacity [21].
Epidemiological studies also suggested anti-inflammatory properties of flavonoids and carotenoids, groups of natural substances found in fruits and vegetables widely included in MD. In particular, flavonoids are able to inhibit both isoforms of inducible nitric oxide synthase (iNOS) and of cyclooxygenase (COX-2), which are involved in the production of inflammatory mediators; they also downregulate adhesion molecules and increase antioxidant defenses, contributing to enhance their anti-inflammatory capacity [29]. Tomato, largely included in MD, is an important source of lycopene (a carotenoid compound), one of the most potent antioxidants [30]. Lycopene provision from tomato and tomato products, exerts beneficial effects on cardiovascular (CV) risk, reducing LDL-cholesterol and improving endothelial function, as well as on inflammation, reducing inflammatory factors (CRP, IL-6) and adhesion molecules (ICAM-1) expression [31]. Potatoes, included as starchy food in MD, provide key nutrients to diet, including vitamin C, potassium and dietary fiber. Moreover, several potato components contribute to lower blood pressure, to improve lipid profile and to decrease markers of inflammation (CRP, IL6) [32].
Key Components of the Mediterranean Diet
- Olive Oil: Extra virgin olive oil goes through less refining and processing, so it retains more nutrients than standard varieties. Olive oil is loaded with heart-healthy fats, as well as oleocanthal, which has properties similar to nonsteroidal anti-inflammatory drugs (NSAIDs). “Oleocanthal inhibits activity of COX enzymes, with a pharmacological action similar to ibuprofen,” says Ordovás.
- Fruits and Vegetables: Colorful fruits and veggies - the darker or more brilliant the color, the more antioxidants it has. Citrus fruits - like oranges, grapefruits and limes - are rich in vitamin C. Research shows getting the right amount of that vitamin aids in preventing inflammatory arthritis and maintaining healthy joints.
- Fish: Health authorities like the American Heart Association and the Academy of Nutrition and Dietetics recommend three to four ounces of fish, twice a week. Some types of fish are good sources of inflammation-fighting omega-3 fatty acids. One study found those who had the highest consumption of omega-3s had lower levels of two inflammatory proteins: C-reactive protein (CRP) and interleukin-6. Best sources: Salmon, tuna, sardines, herring, anchovies, scallops and other cold-water fish. Hate fish? Take a supplement.
- Nuts: Nuts are jam-packed with inflammation-fighting monounsaturated fat. And though they’re relatively high in fat and calories, studies show noshing on nuts promotes weight loss because their protein, fiber and monounsaturated fats are satiating.
- Beans: Beans are loaded with fiber and phytonutrients, which help lower CRP, an indicator of inflammation found in the blood. At high levels, CRP could indicate anything from an infection to RA. In a study scientists analyzed the nutrient content of 10 common bean varieties and identified a host of antioxidant and anti-inflammatory compounds.
- Whole Grains: Eat foods made with the entire grain kernel, like whole-wheat flour, oatmeal, bulgur, brown rice and quinoa. Whole grains contain plenty of filling fiber - which can help you maintain a healthy weight.
Foods to Limit or Avoid
- Red Meat: Excessive consumption of red meat and a high total protein supply have been associated with an increased risk of inflammatory polyarthritis [10]. The possible explanations of this association lie in the increased inflammation derived by meat fats and nitrites, as well as an increased synovial involvement secondary to the excessive oral iron load [14,33].
- Salt: A high dietary sodium (salt) intake, common in Western countries, has been associated with an increased risk of RA [35]. High levels of salt could potentiate the detrimental effect of other environmental factors, smoking in particular, inducing serum glucocorticoid kinase-1 (SGK-1) expression, with an increased Th17 lymphocyte differentiation and enhanced autoimmunity [36].
- Nightshade Vegetables: They also contain solanine, a chemical that has been branded the culprit in arthritis pain. Test it: Some experts believe these vegetables contain a potent nutrient mix that helps inhibit arthritis pain. However, many people do report symptom relief when they avoid nightshade vegetables. So, if you notice that your arthritis pain flares after eating them, consider eliminating all nightshade vegetables from your diet for a few weeks to see if it makes a difference.
- High Sugary Drinks: High sugary drinks consumption has been associated with RA development.
The Role of Omega-3 Fatty Acids
Omega-3 fatty acids appear to be protective for RA [46]. Different studies analyzed fatty acids as possible protective nutrients for RA. Di Giuseppe et al. observed a reduction (35%) of RA risk in women with a dietary intake of long-chain n-3 polyunsaturated fatty acids higher than 0.21 g/day [47]. The risk reduction of RA associated to a higher intake of omega-3 fatty acids is related to their anti-inflammatory properties, inhibiting leucocyte chemotaxis, adhesion molecule expression and production of pro-inflammatory leukotrienes and prostaglandins from omega-6 fatty acids [49].
Read also: Diet for RA Relief
Other Dietary Considerations
- Coffee: Mikuls et al. found an increased risk of seropositive RA in consumers of 4 or more cups of coffee/day, while consumers of more than 3 cups of tea per day presented a reduced risk [55]. Heliovaara et al. documented a positive association between coffee consumption and rheumatoid factor (RF) positivity [56].
Lifestyle and Coping Strategies
In the fourth edition of Living with Rheumatoid Arthritis, Tammi L. Shlotzhauer, MD, shares new findings about causes and treatments, including:
- Research on risk factors and triggers, from pathologic bacteria in the digestive tract and smoking to pollutant and chemical exposure
- Lifestyle and diet modifications that can help sufferers avoid flare-ups
- How stress contributes to inflammation and other symptoms
- Information about new targeted disease-modifying drugs
- Promising research on biomarkers that may generate a personalized approach to treatment
- Remarkable gains in reducing disability, hospitalizations, and surgeries
Practical Matters
In addition to explaining the causes, symptoms, and treatment options for people who have rheumatoid arthritis, Dr. Shlotzhauer offers practical approaches for managing the pain, fatigue, and emotional toll of a chronic illness. She provides new information on associated diseases such as osteoporosis, tips for finding safe and reliable information online, and information on how to get an accurate diagnosis.
Read also: Keto Diet Arthritis Research
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