Rheumatoid Arthritis (RA) is one of the most common Autoimmune diseases. It has a global incidence of approx. 0.3-1% and is more prevalent in developed countries. RA can occur at any age but is more common in the 40-70 age group. It has a female to male ratio of 3:1.
RA is a chronic, systemic, inflammatory autoimmune disease. It can cause persistent pain, joint inflammation and damage and can lead to disability. RA can significantly reduce a patient's quality of life and cause emotional distress.
RA affects the synovial joints but can also affect the lungs and vascular system. It is associated with multiple comorbidities including; cardiovascular risk, infections, depression, osteoporosis and cancer. An established RA patient may have two or more comorbid conditions, this is why a holistic management approach is important.
The Autoimmune process in RA drives dysregulated immune cell activity (both innate and adaptive immune cells), proinflammatory cytokine secretion (eg TNFa, IL6, IL-1B) and abnormal tissue repair (fibroblasts), all contributing to destruction of cartilage and bone. The autoantibodies typically identified are; rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA).
Current medical treatments include non-steroidal anti-inflammatory drugs (NSAIDs), steroids, glucocorticoids and immunosuppressants. These may have significant side effects, such as the risk of developing infections and certain malignancies.
What can cause Rheumatoid Arthritis?
The consensus is that there is a complex interaction between genetic and environmental/lifestyle factors. Over many years and due to cumulating factors, immune tolerance maybe lost in genetically susceptible people and they begin to produce RF and ACPA autoantibodies, which then drive damage.
Genetics - genetic polymorphisms are confirmed to have an association with RA. HLA genes show the strongest risk, others include; PTPN22, STAT4, CTLA4 and TRAF1.
Smoking - substantial evidence exists supporting cigarette smoking as a risk factor for development of RA. This was identified over 30 years ago and is still being reported in subsequent studies. In one study of RA patients, those with a smoking history were 3.1 times more likely to be positive for RF autoantibodies, and 2.4 times more likely to have eroded joints than patients who did not smoke.
Infections - microorganisms associated with RA include the bacteria; Porphyromonas gingivalis, Proteus mirabilis, Streptococcus pyogenes and Mycobacterium. Viruses include; Epstein-Barr virus, parvovirus B19, rubella and cytomegalovirus.
Free radicals - such as Reactive Oxygen Species (ROS) are highly reactive, unstable atoms. They can influence the pathogenesis of RA and impair antioxidant defence systems, making RA patients vulnerable to increased oxidative stress. Â
Pollution - Living or working near air pollution is associated with higher risks of developing RA. Airborne inhalants including silica are also a risk.
Mucosal inflammation - chronic inflammation at mucosal sites such as the gut, mouth and lungs is often seen in RA patients. A high presence of periodontitis is common.
Microbiome - Dysbiosis in the gastrointestinal, oral and lung microbiota may influence the pathogenesis and progression of RA. A frequent finding in early RA patients is a significant increase of Prevotella copri  bacteria species. Another common finding in RA is the proliferation of Bacillus and Lactobacillus bacteria .Â
Nutrition & Diet - The following have been associated with RA in various studies; high salt intake, high sugar intake, high red meat intake, dairy and/or gluten intolerance, low fibre intake, low zinc levels, low vitamin C concentration, altered concentrations of serum trace elements and high Copper concentration.
Natural Interventions for Rheumatoid Arthritis
Natural interventions may improve the symptoms of RA by; reducing inflammation, regulating free radical production, regulating pro-inflammatory and anti-inflammatory cytokines and modulating inflammatory signalling pathways, such as NF-kB.
Diet can make a difference by removing pro-inflammatory foods and increasing anti-inflammatory foods and thereby altering the gut microbiota. Furthermore, nutrient density and antioxidant status play a key role. There are many studies and trials that have looked at natural interventions for RA, the following have had the most impact:
Fish oil (high dose) containing omega-3 polyunsaturated fatty acids has demonstrated improvements in inflammatory biomarkers, improved T Regulatory cells and reduction in RA disease activity. In addition, a reduced risk of comorbidities such as cardiovascular disease have been identified.
Antioxidants have shown to regulate free radicals and oxidative stress in RA patients. Plants are a rich source of natural antioxidants such as phenols, phenolic acid and flavonoids. Fruits and vegetables contain abundant source of biological antioxidants. In particular the following polyphenols have shown to have an impact in some RA patients; resveratrol (red grapes), thymoquinone (nigella sativa), curcumin (turmeric), genistein (soybean), hesperidin (citrus fruits), Epigallocatechin 3-gallate (green tea) and 3′3-diindolylmethane (cruciferous veg).
Vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms are possibly linked to RA. A study confirmed that vitamin D deficiency is prevalent among RA patients and the 25(OH)D level is significantly lower compared with healthy controls. Routine assessment and supplementation of vitamin D3 may be necessary.
Fasting or calorie restriction some studies suggest overall improvements, including morning stiffness and the number of painful joints. Different types of fasting elicited different responses.
Vegetarian and vegan diet trials, responses were very individualised. Benefits may have related to improvements in the microbiome, reduced immune responses to food allergens/intolerances or reduced meat-induced gut inflammation.
Elimination diet studies, where the most commonly eliminated foods were dairy, egg, meat, fish, refined sugars, wheat, corn, nuts, citrus fruits, and coffee, among others, there appeared to be improvements in the number of tender joints but also in inflammatory biomarkers. Diets eliminating food groups that trigger an allergic or inflammatory response may result in reduced inflammation.
Mediterranean diet studies and trials demonstrate improvements in pain, early morning stiffness, physical function and vitality and inflammation measures. The Mediterranean diet is characterised by plant foods such as fruit, vegetables, unrefined cereals, legumes, and extra-virgin olive oil; moderate consumption of poultry, dairy products, and eggs; and low consumption of sweets and red meat.
Sodium restriction shows benefits to RA inflammation. Sodium chloride activates pro-inflammatory macrophages and TH17 cells and decreases regulatory T cells. A reduction in salt intake to <5 g/d is recommended by the World Health Organization’s Healthy Eating Guidelines.
Probiotics - supplementation of Lactobacillus casei and Lactobacillus acidophilus probiotic strains in RA patients has shown to decrease inflammatory markers.
It is important to understand an individual's underlying mechanisms that may be driving their Autoimmunity in RA, and to personalise interventions based on their individual needs. It is recommended that any diet changes such as food elimination, is done under the supervision of a nutrition professional to reduce risks of any deficiencies. Furthermore, any supplementation should involve the correct researched doses and checked for interactions with any ongoing medications.
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