Dietary Interventions with or without Omega-3 Supplementation for the Management of Rheumatoid Arthritis: A Systematic Review.

Rheumatoid Arthritis (RA) is a chronic autoimmune condition characterized by symptoms of inflammation and pain in the joints. RA is estimated to have a worldwide prevalence of 0.5-1%, with a predominance in females. Diet may play an important role in the symptoms of RA; however, little is known about the effects of various diets. The aim of this systematic review is to explore the effect of dietary interventions, with or without omega-3 supplementation for the management of RA. The electronic databases MEDLINE, EMBASE, CINAHL, and the Cochrane Library were systematically searched for clinical trials investigating dietary interventions, with or without omega-3 supplementation to retrieve papers from inception to April 2021. Randomized and non-randomized controlled trials of dietary interventions in adults with RA were eligible for inclusion. Twenty studies with a total of 1063 participants were included. The most frequently reported outcomes were pain, duration of morning stiffness, joint tenderness, grip strength and inflammatory markers. Dietary interventions with an anti-inflammatory basis may be an effective way for adults with RA seeking complementary treatments, potentially leading to improvements in certain parameters. However, there is a need for longer duration studies that are well-designed and sufficiently powered to investigate the influence of diet on RA.

Treatment with coenzyme Q10, omega-3-polyunsaturated fatty acids and their combination improved bioenergetics and levels of coenzyme Q9 and Q10 in skeletal muscle mitochondria in experimental model of arthritis.

Rheumatoid arthritis (RA) and its animal model adjuvant arthritis (AA) are inflammatory diseases characterized by chronic inflammation, systemic oxidative stress and disturbed mitochondrial bioenergetics of skeletal muscle. The present study aimed to evaluate the effects of coenzyme Q10 - CoQ10 (100 mg/kg b.w.), omega-3-polyunsaturated fatty acids - omega-3-PUFA (400 mg/kg b.w.) and their combined treatment in AA on impaired skeletal muscle mitochondrial bioenergetics, inflammation and changes in levels CoQ9 and CoQ10 in plasma. Markers of inflammation (C-reactive protein, monocyte-chemotactic protein-1), antioxidant capacity of plasma, respiratory chain parameters of skeletal muscle mitochondria and concentrations of CoQ9 and CoQ10 in plasma and in muscle tissue were estimated. Treatment of the arthritic rats with CoQ10, omega-3-PUFA alone and in combination partially reduced markers of inflammation and increased antioxidant capacity of plasma, significantly increased concentrations of coenzyme Q in mitochondria and improved mitochondrial function in the skeletal muscle. Combined treatment has similar effect on the mitochondrial function as monotherapies; however, it has affected inflammation and antioxidant status more intensively than monotherapies. Long-term supplementary administration of coenzyme Q10 and omega-3-PUFA and especially their combination is able to restore the impaired mitochondrial bioenergetics and antioxidant status in AA.

Vitamin D deficiency: concern for rheumatoid arthritis and COVID-19?

Vitamin D is an immunomodulatory hormone with an established role in calcium and phosphate metabolism and skeletal mineralization. Evidence showing its immunological benefits by regulating essential components of the innate and adaptive immune system is prevalent. Vitamin D deficiency is reported worldwide and is thereby found to be associated with various immune-related diseases. Rheumatoid Arthritis and COVID-19 are two such diseases, sharing a similar hyperinflammatory response. Various studies have found an association of lower Vitamin D levels to be associated with both these diseases. However, contrasting data is also reported. We review here the available scientific data on risk factor association and supplementation benefits of Vitamin D in Rheumatoid Arthritis and COVID-19, intending to critically evaluate the literature.

Ideal food pyramid for patients with rheumatoid arthritis: A narrative review.

Emerging literature suggests that diet plays an important modulatory role in rheumatoid arthritis (RA) because diet is an environmental factor that affects inflammation, antigen presentation, antioxidant defense mechanisms and gut microbiota. Patients with RA frequently ask their doctors about which diets to follow, and even in the absence of advice from their physicians, many patients are undertaking various dietary interventions. Given this background, the aim of this review is to evaluate the evidence to date regarding the ideal dietary approach for management of RA in order to reduce the counteracting inflammation, and to construct a food pyramid for patients with RA. The pyramid shows that carbohydrates should be consumed every day (3 portions of whole grains, preferably gluten free), together with fruits and vegetables (5 portions; among which fruit, berries and citrus fruit are to be preferred, and among the vegetables, green leafy ones.), light yogurt (125 ml), skim milk (200 ml), 1 glass (125 ml) of wine and extra virgin olive oil; weekly, fish (3 portions), white meat (3 portions), legumes (2 portions) eggs (2 portions), seasoned cheeses (2 portions), and red or processed meats (once a week). At the top of the pyramid, there are two pennants: one green means that subjects with RA need some personalized supplementation (vitamin D and omega 3) and one red means that there are some foods that are banned (salt and sugar). The food pyramid allows patients to easily figure out what to eat.

Rheumatoid arthritis and dietary interventions: systematic review of clinical trials.

CONTEXT: The impact of various dietary interventions on rheumatoid arthritis (RA), characterized by immune-inflammatory response, has been subject to increased attention. OBJECTIVE: A systematic review was conducted to update the current knowledge on the effects of nutritional, dietary supplement, and fasting interventions on RA outcomes. DATA SOURCES: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with prespecification of all methods, Medline and Embase were systematically searched for relevant articles. DATA EXTRACTION: Data were extracted by 2 independent reviewers. RESULTS: A total of 70 human studies were identified. Administration of omega-3 polyunsaturated fatty acids at high doses resulted in a reduction in RA disease activity and a lower failure rate of pharmacotherapy. Vitamin D supplementation and dietary sodium restriction were beneficial on some RA outcomes. Fasting resulted in significant but transient subjective improvements. While the Mediterranean diet demonstrated improvements in some RA disease activity measures, outcomes from vegetarian, elimination, peptide, or elemental diets suggested that responses are very individualized. CONCLUSION: Some dietary approaches may improve RA symptoms and thus it is recommended that nutrition should be routinely addressed.

Autophagy Activation by Resveratrol Reduces Severity of Experimental Rheumatoid Arthritis.

SCOPE: Previous work reported that dietary supplementation with resveratrol lowers synovial hyperplasia, inflammatory and oxidative damage in an antigen-induced arthritis (AIA) model. Here, it is investigated whether resveratrol can regulate the abnormal synovial proliferation by inducing autophagy and controlling the associated inflammatory response. METHODS AND RESULTS: Animals treated with resveratrol 8 weeks before AIA induction show the highest significant signal for microtubule-associated protein 1 light chain 3 by confocal microscopy. Besides, resveratrol significantly reduces p62 expression, but it does not increase the signal of beclin-1. Also, active caspase-3 expression, as well as poly(ADP-ribose) polymerase, is upregulated in the AIA group, and is significantly reduced in resveratrol-treated AIA group. Resveratrol also mitigates angiopoietin-1 and vascular endothelial growth factor signals. Finally, resveratrol significantly reduces the serum levels of IL-1ß, C reactive protein, and prostaglandin E2, as well as nuclear factor κB synovial tissue expression, which shows a significant correlation with p62 expression. CONCLUSION: Dietary supplementation with resveratrol induces the noncanonical autophagy pathway and limits the cross-talk with inflammation, which in consequence modulates the synovial hyperplasia. Preventive strategies that incorporate dietary intervention with resveratrol may offer a potential therapeutic alternative to drugs to influence the risk of rheumatoid arthritis and influence its course.

Diet as a Modulator of Intestinal Microbiota in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic immune-driven inflammatory disease characterised by synovial inflammation, leading to progressive cartilage and bone destruction, impacting patients' functional capacity and quality of life. Patients with RA have significant differences in gut microbiota composition when compared to controls. Intestinal dysbiosis influences the intestinal barrier strength, integrity and function, and diet is considered the main environmental factor impacting gut microbiota. Over the last few years, researchers have focused on the influence of single components of the diet in the modulation of intestinal microbiota in RA rather than whole dietary patterns. In this review, we focus on how the Mediterranean diet (MD), a whole dietary pattern, could possibly act as an adjuvant therapeutic approach, modulating intestinal microbiota and intestinal barrier function in order to improve RA-related outcomes. We also review the potential effects of particular components of the MD, such as n-3 polyunsaturated fatty acids (PUFAs), polyphenols and fibre.

Do Interventions with Diet or Dietary Supplements Reduce the Disease Activity Score in Rheumatoid Arthritis? A Systematic Review of Randomized Controlled Trials.

The aim was to compile the evidence from Randomized Controlled Trials (RCTs) of diet or dietary supplements used to reduce disease activity in adults with Rheumatoid Arthritis (RA). Searches were performed in the databases PubMed, Scopus and Cochrane. Only RCT studies of diets, foods or dietary supplements, looking at effects on the Disease Activity Score in 28 joints (DAS28) among adults with RA, published in peer-reviewed journals, were included. A total of 27 articles were included-three of whole diets (Mediterranean diet, raw food and anti-inflammatory diet), five of food items, five of n-3 fatty acids, five of single micronutrient supplements, four of single antioxidant supplements and five of pre-, pro- or synbiotics. Studies that showed moderate strength evidence for positive effects on disease activity in RA included interventions with a Mediterranean diet, spices (ginger powder, cinnamon powder, saffron), antioxidants (quercetin and ubiquinone), and probiotics containing Lactobacillus Casei. Other diets or supplements had either no effects or low to very low strength of evidence. In conclusion, RCT studies on diet or dietary supplements are limited in patients with RA, but based on the results in this review there is evidence that some interventions might have positive effects on DAS28.

Adherence to Mediterranean diet and patient perception of rheumatoid arthritis.

OBJECTIVE: To evaluate the association between the adherence to Mediterranean diet (MD) and disease impact, activity, and comorbidities in patients with rheumatoid arthritis (RA). DESIGN: Consecutive patients with RA were enrolled in this cross-sectional study. For each patient, Disease Activity Score on 28 joints (DAS28), Simple Disease Activity Index (SDAI), RA Impact of Disease (RAID), Health Assessment Questionnaire (HAQ), patient global assessment (PGA) and general health (GH) and a self-reported questionnaire called MD score were recorded. RESULTS: 205 RA patients (median age 53 years, female 80.49 %) were enrolled. An association between MD score and HAQ (p-value = 0.033), PGA and GH (p-value 0.023 both) was observed. RAID total score had a statistically significant negative relationship with MD score (p-value = 0.016). A statistically significant negative association was found for pain (p-value = 0.025), functional disability (p-value<0.001), sleep (p-value = 0.041), physical well-being (p-value = 0.027) and coping (p-value = 0.008). Multiple regression analysis to evaluate the relationship between significant RAID items and MD score did not show any statistical significance as all items are strongly related to each other. A negative trend, although not statistically significant was found for DAS28 and SDAI. The only comorbidity associated with MD score was arterial hypertension (OR = 0.94). CONCLUSIONS: In this Italian RA cohort, the adherence to MD was significantly associated with a better RAID, PGA and GH, but higher MD score was not significantly associated with lower disease activity. Our study suggests an overall potential beneficial effect of MD in RA patients.

Efficacy of Dietary Supplements in Inflammatory Bowel Disease and Related Autoimmune Diseases.

The microbiome is an important contributor to a variety of fundamental aspects of human health, including host metabolism, infection, and the immune response. Gut dysbiosis has been identified as a contributor to the errant immune response in a variety of immune-mediated inflammatory diseases (IMIDs), such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and psoriatic disease (psoriasis and psoriatic arthritis). Given this, probiotics and prebiotics have been investigated as therapeutic options in these disease states. In our review, we highlight the current evidence on prebiotics and probiotics as well as other supplements (such as fish oils, vitamin D, and curcumin) as therapies for IBD. Recommendations, however, regarding the specific use of such supplements in IBD have been lacking, particularly from professional societies, often due to study limitations related to small sample sizes and design heterogeneity. Hence, we additionally examine the literature on the use of prebiotics, probiotics, and other supplements in related IMIDs, namely RA and psoriasis/psoriatic arthritis, as these diseases share many approved therapeutic options with IBD. Based on these combined findings, we offer additional evidence that may help guide clinicians in their treatment of patients with IBD (and other IMIDs) and provide recommendations on potential next steps in therapeutic research in this area.

Dietary Habits and Nutrition in Rheumatoid Arthritis: Can Diet Influence Disease Development and Clinical Manifestations?

Rheumatoid arthritis (RA) is a systemic, autoimmune disease characterized by joint involvement, with progressive cartilage and bone destruction. Genetic and environmental factors determine RA susceptibility. In recent years, an increasing number of studies suggested that diet has a central role in disease risk and progression. Several nutrients, such as polyunsaturated fatty acids, present anti-inflammatory and antioxidant properties, featuring a protective role for RA development, while others such as red meat and salt have a harmful effect. Gut microbiota alteration and body composition modifications are indirect mechanisms of how diet influences RA onset and progression. Possible protective effects of some dietary patterns and supplements, such as the Mediterranean Diet (MD), vitamin D and probiotics, could be a possible future adjunctive therapy to standard RA treatment. Therefore, a healthy lifestyle and nutrition have to be encouraged in patients with RA.

Anti-inflammatory Diet In Rheumatoid Arthritis (ADIRA)-a randomized, controlled crossover trial indicating effects on disease activity.

BACKGROUND: Many patients with rheumatoid arthritis (RA) report symptom relief from certain foods. Earlier research indicates positive effects of food and food components on clinical outcomes in RA, but insufficient evidence exists to provide specific dietary advice. Food components may interact but studies evaluating combined effects are lacking. OBJECTIVES: We aimed to investigate if an anti-inflammatory diet reduces disease activity in patients with RA. METHODS: In this single-blinded crossover trial, 50 patients with RA were randomly assigned to an intervention diet containing a portfolio of suggested anti-inflammatory foods, or a control diet similar to the general dietary intake in Sweden, for 10 wk. After a 4-mo washout period the participants switched diet. Food equivalent to ∼50% of energy requirements was delivered weekly to their homes. For the remaining meals, they were encouraged to consume the same type of foods as the ones provided during each diet. Primary outcome was change in Disease Activity Score in 28 joints-Erythrocyte Sedimentation Rate (DAS28-ESR). Secondary outcomes were changes in the components of DAS28-ESR (tender and swollen joints, ESR, and visual analog scale for general health) and DAS28-C-reactive protein. RESULTS: In the main analysis, a linear mixed ANCOVA model including the 47 participants completing ≥1 diet period, there was no significant difference in DAS28-ESR between the intervention and control periods (P = 0.116). However, in unadjusted analyses, DAS28-ESR significantly decreased during the intervention period and was significantly lower after the intervention than after the control period in the participants who completed both periods (n = 44; median: 3.05; IQR: 2.41, 3.79 compared with median: 3.27; IQR: 2.69, 4.28; P = 0.04, Wilcoxon's Signed Rank test). No significant differences in the components were observed. CONCLUSIONS: This trial indicates positive effects of a proposed anti-inflammatory diet on disease activity in patients with RA. Additional studies are required to determine if this diet can cause clinically relevant improvements.This trial was registered at clinicaltrials.gov as NCT02941055.

The Role of Dietary Fiber in Rheumatoid Arthritis Patients: A Feasibility Study.

Short-chain fatty acids are microbial metabolites that have been shown to be key regulators of the gut-joint axis in animal models. In humans, microbial dysbiosis was observed in rheumatoid arthritis (RA) patients as well as in those at-risk to develop RA, and is thought to be an environmental trigger for the development of clinical disease. At the same time, diet has a proven impact on maintaining intestinal microbial homeostasis. Given this association, we performed a feasibility study in RA patients using high-fiber dietary supplementation with the objective to restore microbial homeostasis and promote the secretion of beneficial immunomodulatory microbial metabolites. RA patients (n = 36) under routine care received daily high-fiber bars or cereals for 28 days. Clinical assessments and laboratory analysis of immune parameters in blood and stool samples from RA patients were done before and after the high-fiber dietary supplementation. We observed an increase in circulating regulatory T cell numbers, favorable Th1/Th17 ratios, as well as decreased markers of bone erosion in RA patients after 28 days of dietary intervention. Furthermore, patient-related outcomes of RA improved. Based on these results, we conclude that controlled clinical studies of high-fiber dietary interventions could be a viable approach to supplement or complement current pharmacological treatment strategies.

Influence of blue mussel (Mytilus edulis) intake on fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in women with rheumatoid arthritis.

Intake of blue mussels decreased disease activity in women with rheumatoid arthritis (RA) in the randomized cross-over MIRA (Mussels, inflammation and RA) trial. This study investigates potential causes of the decreased disease activity by analysing fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in samples from the participants of the MIRA trial. Twenty-three women completed the randomized 2 × 11-week cross-over dietary intervention, exchanging one cooked meal per day, 5 days a week, with a meal including 75 g blue mussels or 75 g meat. Fatty acid composition in erythrocytes and plasma and 1H Nuclear Magnetic Resonance (1H NMR) metabolomics data were analysed with multivariate data analysis. Orthogonal Projections to Latent Structures with Discriminant Analysis (OPLS-DA) and OPLS with effect projections (OPLS-EP) were performed to compare the two diets. The fatty acid profile in erythrocytes was different after intake of blue mussels compared to the control diet, and all samples were correctly classified to either the blue mussel diet or control diet. Changes following blue mussel intake included significant increases in omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at the group level but not for all individuals. The fatty acid profile in plasma phospholipids and 1H NMR serum metabolites did not differ significantly between the diets. To conclude, modelling fatty acids in erythrocytes may be a better biomarker for seafood intake than only EPA and DHA content. The change in fatty acid pattern in erythrocytes could be related to reduction in disease activity, although it cannot be excluded that other factors than omega-3 fatty acids potentiate the effect.

Dried plum alleviates symptoms of inflammatory arthritis in TNF transgenic mice.

Dried plum (DP), a rich source of polyphenols has been shown to have bone-preserving properties in both animal models of osteoporosis and postmenopausal women. We evaluated if DP alleviated the destruction of joints in transgenic mice (TG) that overexpress human tumor necrosis factor (TNF), a genetic model of rheumatoid arthritis (RA). A four-week treatment of 20% DP diet in TG slowed the onset of arthritis and reduced bone erosions in the joints compared to TG on a regular diet. This was associated with fewer tartrate-resistant acid phosphatase (TRAP) positive cells, suggesting decreased osteoclastogenesis. A DP diet also produced significant protection of articular cartilage and reduction of synovitis. Cultures of human synovial fibroblast in the presence of TNF showed a significant increase in inflammatory interleukin (IL)-1ß, chemokines (monocyte chemoattractant protein-1: MCP1 & macrophage inflammatory protein-1 alpha: MIP1α), cartilage matrix metalloproteinases (MMP1&3), and an osteoclastogenic cytokine (receptor activator of nuclear factor-κB ligand: RANKL) compared to controls. Addition of neochlorogenic acid (NC), a major polyphenol in DP to these cultures resulted in down-regulation of these genes. In the cultures of mouse bone marrow macrophage, NC also repressed TNF-induced formation of osteoclasts and mRNA levels of cathepsin K and MMP9 through inhibition of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) expression and nuclear factor kappa B (NF-κB) activation. Our data suggested that dietary supplementation with DP inhibited TNF singling; leading to decreased erosions of bone and articular cartilage as well as synovitis.

Polyunsaturated fatty acids: any role in rheumatoid arthritis?

BACKGROUND: Polyunsaturated fatty acids (PUFAs) are members of the family of fatty acids and are included in the diet. Particularly, western diet is usually low in n-3 PUFAs and high in n-6 PUFAs. PUFAs play a central role in the homeostasis of immune system: n-6 PUFAs have predominantly pro-inflammatory features, while n-3 PUFAs seem to exert anti-inflammatory and pro-resolving properties. Rheumatoid arthritis (RA) is a chronic inflammatory arthritis in which many inflammatory pathways contribute to joint and systemic inflammation, disease activity, and structural damage. Research on PUFAs could represent an important opportunity to better understand the pathogenesis and to improve the management of RA patients. METHODS: We searched PubMed, Embase, EBSCO-Medline, Cochrane Central Register of Controlled Trials (CENTRAL), CNKI and Wanfang to identify primary research reporting the role of n-3 PUFAs in rheumatoid arthritis both in humans and in animal models up to the end of March 2017. RESULTS: Data from animal models allows to hypothesize that n-3 PUFAs supplementation may represent an interesting perspective in future research as much in prevention as in treating RA. In humans, several case-control and prospective cohort studies suggest that a high content of n-3 PUFAs in the diet could have a protective role for incident RA in subjects at risk. Moreover, n-3 PUFAs supplementation has been assessed as a valuable therapeutic option also for patients with RA, particularly in order to improve the pain symptoms, the tender joint count, the duration of morning stiffness and the frequency of NSAIDs assumption. CONCLUSIONS: n-3 PUFAs supplementation could represent a promising therapeutic option to better control many features of RA. The impact of n-3 PUFAs on radiographic progression and synovial histopathology has not been yet evaluated, as well as their role in early arthritis and the combination with biologics.

Nutrition and fasting mimicking diets in the prevention and treatment of autoimmune diseases and immunosenescence.

Complex and coordinated signals are necessary to initiate and sustain the activation, proliferation, and differentiation of lymphocytes. These signals, which are known to determine T-cell fate and function, also depend on the metabolic state of the organism. Recent studies indicate that both the type and levels of nutrients can influence the generation, survival and function of lymphocytes and therefore can affect several autoimmune diseases. Here, we review the dysregulation of lymphocytes during autoimmunity and aging, the mechanisms associated with loss of immune function, and how fasting mimicking diets and other dietary interventions affect autoimmunity and immunosenescence.

Nutrición y trastornos del sistema inmune / Nutrition and immune system disorders

Introducción: la energía y los nutrientes que obtenemos a través de la alimentación ejercen un papel importante en el desarrollo y preservación del sistema inmune, por lo que cualquier desequilibrio nutricional en el individuo afecta a su competencia e integridad. Objetivos: conocer el abordaje nutricional sobre diferentes trastornos del sistema inmune. Métodos: se ha realizado una revisión sobre los trastornos inmunológicos de mayor prevalencia en países desarrollados, las características nutricionales a los que se encuentran asociados y su abordaje nutricional. Resultados: el abordaje nutricional de los trastornos inmunológicos se ha centrado en los últimos años en los AGP-ω3 y la vitamina D. Mantener el peso corporal, evitar estados de desnutrición y catabolismo proteico, son estrategias clave del tratamiento nutricional. Este debe adecuarse a cada fase de la enfermedad, por lo que se trata de un proceso dinámico. Conclusiones: el abordaje nutricional de los trastornos inmunológicos, sobre todo en las enfermedades autoinmunes, no siempre es del todo claro, debido a los estados agudos y de remisión que presentan. La anorexia es uno de los síntomas más característicos, derivada del tratamiento farmacológico y el proceso inflamatorio. La dieta debe contener una elevada densidad en nutrientes que eviten el deterioro. El abordaje nutricional de los trastornos inmunológicos debe tener como objetivo mantener un estado óptimo de nutrición durante los periodos sintomáticos, prevenir su deterioro durante los episodios agudos y mejorarlo durante los periodos estables libres de sintomatología (AU)

Introduction: Energy and nutrients obtained through food play an important role in the development and preservation of the immune system therefore any nutritional imbalance affects its competence and integrity. Objectives: knowing the nutritional approach on different disorders of the immune system. Methods: A review has been carried out on the most prevalent immunological disorders in developed countries, the nutritional characteristics to which they are associated and their nutritional approach. Results: Nutritional treatment for immune disorders has focused in recent years on the role of PUFA-ω3 and vitamin D. Maintaining body weight, preventing malnutrition and protein catabolism are key strategies for nutritional treatment. This should be adapted to each disease stage because it is a dynamic process. Conclusions: Nutritional treatment for immunological disorders, especially in autoimmune diseases, is not always clear because they present acute and remission states. Anorexia is one of the most characteristic symptoms derived mainly from pharmacological treatment and inflammatory processes. Diet should be dense in nutrients that prevent deterioration. Nutritional treatment of immunological disorders should aim to maintain an optimal state of nutrition during symptomatic periods, prevent their deterioration during acute episodes and improve during stable periods free of symptoms (AU)

Probiotic bacteria: a viable adjuvant therapy for relieving symptoms of rheumatoid arthritis.

The burgeoning use of probiotics has proliferated during the past two decades. However, the effect of probiotic administration for either the prevention or treatment of rheumatoid arthritis (RA) has been investigated in a limited number of studies. Randomized controlled clinical trials have provided evidences that specific probiotics supplementation exhibit anti-inflammatory effects, help to increase daily activities and alleviate symptoms in patients with RA. Therefore, using probiotic bacteria as an adjuvant therapy may be considered as a promising treatment option for RA. This review summarizes the available data about the therapeutic and preventive effect of probiotics in RA, together with probiotic supplement as a possible therapy in clinical treatment.

Equol suppresses inflammatory response and bone erosion due to rheumatoid arthritis in mice.

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune inflammatory disease. Typical pathological findings of RA include persistent synovitis and bone degradation in the peripheral joints. Equol, a metabolite of the major soybean isoflavone daidzein, shows superior bioactivity than other isoflavones. We investigated the effects of equol administration on inflammatory response and bone erosion in mice with collagen-induced arthritis (CIA). The severity of arthritis symptoms was significantly low in the equol-administered CIA mice. In addition, equol administration improved the CIA-induced bone mineral density decline. In the inflamed area of CIA mice, equol administration suppressed the expression of interleukin-6 and its receptor. Furthermore, equol reduced the expression of genes associated with bone formation inhibition, osteoclast and immature osteoblast specificity and cartilage destruction. These results suggest that equol suppresses RA development and RA-induced bone erosion by regulating inflammation and bone metabolism.