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

Effects of a telehealth-delivered Mediterranean diet intervention in adults with Rheumatoid Arthritis (MEDRA): a randomised controlled trial

OBJECTIVE

To compare the effects a Mediterranean diet (MedDiet) versus the Irish Healthy Eating Guidelines (HEG) on physical function and quality of life in adults with rheumatoid arthritis (RA) in Ireland.

METHODS

Forty-four adults with RA were randomised (1:1) to the MedDiet or HEG for 12 weeks. The intervention included three video teleconsultations and two follow-up telephone calls facilitated by a Registered Dietitian (RD). Changes in physical function by Health Assessment Questionnaire- Disability Index (HAQ-DI) and quality of life by Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL) were the primary outcomes measured. Secondary outcomes included changes in dietary adherence, physical activity by Yale Physical Activity survey (YPAS), patient-perceived pain and general health, and anthropometric measures. All measurements were administered at baseline and repeated at 6 and 12 weeks.

RESULTS

Forty participants completed the study. Participants were primarily females (87.5%), mean age was 47.5 ± 10.9 years. At the end of the intervention, participants in the MedDiet group reported significantly better physical function (p = 0.006) and quality of life (p = 0.037) compared to HEG group. From baseline to 12 weeks, physical function significantly improved in both diet groups, MedDiet (0.9 ± 0.5 to 0.5 ± 0.4 units, p < 0.001) and HEG (1.4 ± 0.7 to 1.0 ± 0.6 units, p < 0.001). Quality of life also significantly improved in the MedDiet (10.1 ± 7.5 to 4.0 ± 4.7 units, p < 0.001) and HEG group (11.25 ± 7.2 to 7.9 ± 6.4 units, p = 0.048). Physical activity improved significantly in the MedDiet (56.7 ± 28.6 to 70.6 ± 33.5 points, p = 0.01) but not within the HEG group despite similar recommendations.

CONCLUSION

Adhering to the MedDiet and Irish Healthy Eating Guidelines resulted in improvements in RA patient-reported outcomes. The changes observed in both diet groups are likely due to the improvement in overall diet quality irrespective of dietary prescription.

TRIAL REGISTRATION NUMBER

NCT04262505.

Effects of omega-3 supplementation on lipid metabolism, inflammation, and disease activity in rheumatoid arthritis: a meta-analysis of randomized controlled trials

INTRODUCTION

Omega-3 possesses anti-inflammatory and lipid metabolism modifying effects in rheumatoid arthritis (RA), but inconsistency exists among previous studies. This meta-analysis intended to explore the effects of omega-3 supplementation on fatty acid distribution, blood lipid profiles, inflammation, and disease activity in RA patients.

METHODS

This meta-analysis followed the Preferred Reporting Item for Systematic Reviews and Meta-Analyses (PRISMA) protocol. PubMed, Web of Science, and Embase databases were searched until August 31, 2023.

RESULTS

Eighteen randomized controlled trials with 1018 RA patients were included. Regarding fatty acid distribution, omega-3 supplementation increased eicosapentaenoic acid (EPA) [standardized mean difference (SMD): 0.74; 95% confidence interval (CI): 0.46, 1.01; P < 0.001] and docosahexanoic acid (DHA) (SMD: 0.62; 95% CI: 0.35, 0.89; P < 0.001), but reduced omega-6:omega-3 ratio (SMD: -1.06; 95% CI: -1.39, -0.73; P < 0.001) in RA patients. Regarding blood lipid, omega-3 supplementation decreased triglyceride (TG) in RA patients (SMD: -0.47; 95% CI: -0.78, -0.16; P = 0.003). Regarding clinical symptoms, omega-3 supplementation reduced tender joint count (TJC) in RA patients (SMD: -0.59; 95% CI: -0.79, -0.39; P < 0.001). Notably, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and disease activity score on 28 joints (DAS28) score were slightly decreased by omega-3 supplementation but without statistical significance (all P > 0.05). Publication bias was low, and stability assessed by sensitivity analysis was good.

CONCLUSION

Omega-3 supplementation increases EPA and DHA, but reduces the omega-6:omega-3 ratio, TG, and TJC in RA patients.

Essential Fatty Acids and Osteoarthritis

OBJECTIVE

Inflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Although n-3 fatty acids reduce inflammation, different n-3 fatty acids have different effects on inflammation and clinical outcomes, with eicosapentaenoic acid (EPA) having the strongest effect. We examined whether specific essential fatty acid levels affected the development of OA.

METHODS

We studied participants from the Multicenter Osteoarthritis Study (MOST) at risk of developing knee OA. As part of MOST, participants were asked repeatedly about knee pain, and knee radiographs and magnetic resonance images (MRIs) were obtained. Using baseline fasting samples, we analyzed serum fatty acids with standard assays. After excluding participants with baseline OA, we defined two sets of cases based on their status through 60 months' follow-up: those developing incident radiographic OA and those developing incident symptomatic OA (knee pain and radiographic OA). Controls did not develop these outcomes. Additionally, we examined worsening of MRI cartilage damage and synovitis and worsening knee pain and evaluated the number of hand joints affected by nodules. In regression models, we tested the association of each OA outcome with levels of specific n-3 and n-6 fatty acids, adjusting for age, sex, body mass index, education, physical activity, race, baseline pain, smoking, statin use, and depressive symptoms.

RESULTS

We studied 363 cases with incident symptomatic knee OA and 295 with incident radiographic knee OA. The mean age was 62 years (59% women). We found no associations of specific n-3 fatty acid levels, including EPA, or of n-6 fatty acid levels with incident OA (eg, for incident symptomatic knee OA, the odds ratio per SD increase in EPA was 1.0 [95% confidence interval 0.87-1.17]). Results for other OA outcomes also failed to suggest a protective effect of specific n-3 fatty acids with OA outcomes.

CONCLUSION

We found no association of serum levels of EPA or of other specific n-3 fatty acids or n-6 fatty acids with risk of incident knee OA or other OA outcomes.

Nutrition and chronic musculoskeletal pain: A narrative review and directions for temporomandibular disorder research and management

BACKGROUND

Recent evidence suggests neuro-immune mechanisms may link dietary patterns to chronic painful conditions (CPC). In the research field of oro-facial pain (OFP), studies focuses primarily on dietary mechanical limitations due to pain and dysfunction.

OBJECTIVE

This narrative review aimed to overview the role of nutrition on CPC, with emphasis on temporomandibular disorder (TMD), enlightening OFP researcher on dietary assessment possibilities and providing directions for studies in the field of OFP and nutrition.

METHODS

A PubMed database search was performed using the MeSH and non-MeSH descriptors: "temporomandibular joint disorder"; "orofacial pain"; "musculoskeletal pain"; "chronic pain disorders"; "nutrition"; "diet"; "dietary therapy"; "dietary intake" and "inflammation". No time restrictions were applied. Literature reviews, systematic reviews, meta-analyses and clinical and pre-clinical trials were included.

RESULTS

Exogenous oxidants from unhealthy dietary patterns may contribute to peripheral and central pro-inflammatory immune signalling leading to peripheral and central sensitization. Furthermore, diets rich in bioactive compounds are suggested to contribute to pain management of CPC. High dietary intake of ultra-processed foods impacts the quality of the diet and shows adverse health outcomes. In this context, the role of nutrition on TMD remains overlooked.

CONCLUSION

Considering diet may influence CPC, allied with the scarcity of studies evaluating the role of nutrition on TMD, well-designed clinical trials based on dietary assessments and measurements capable of evaluating food quality, UPF consumption and nutrient adequacy-added to serum nutrient levels evaluation-are suggested.

Developmentally programmed obesity: Is there a role for anti-inflammatory nutritional strategies?

Pregnancy represents a period of immense maternal physiological adaptation, with progressive increases in lipid storage potential and insulin resistance to support fetal/placental growth. This requires significant change in the adipose tissue. Women living with obesity/overweight are more susceptible to these changes causing complications such as gestational diabetes. This is particularly worrying as up to 60% of European women are living with overweight/obesity at the onset of pregnancy. Furthermore, less than 1% meet all nutrition guidelines. There is now evidence that these deep metabolic changes can result in a predisposition to metabolic disease in both the mother and child in later life. Health and nutrition status during this period therefore represents a window to future health. This period offers a valuable opportunity for intervention to prevent the negative consequences of poor in utero environments and increases the long-term quality of life for mother and offspring. This review will examine a range of in utero factors which determine adipose tissue development, the impact of these factors on later-life obesity and metabolic health and the therapeutic value of dietary anti-inflammatory nutritional interventions during pregnancy and early life. When it comes to early life nutrition, a 'one size fits all' approach is not always appropriate. Understanding the mechanisms of adipose tissue development in response to differing nutritional strategies may be important in the context of complicated or adverse in utero environments and represents a substantial step towards a more personalised nutritional approach for the prevention of obesity, metabolic syndrome and related non-communicable diseases in future generations.

Deficit of Omega-3 Fatty Acids in Acne Patients-A Cross-Sectional Pilot Study in a German Cohort

Omega-3 fatty acids (ω-3 FAs) exert anti-inflammatory effects, including the downregulation of pro-inflammatory cytokines, eicosanoids, and insulin-like growth factor-1. Therefore, they may improve acne severity as an adjunct treatment. However, there is a paucity of data regarding patients' existing deficits. The aim of this study was to determine ω-3 FA levels in acne patients in correlation with self-reported dietary preferences and clinical severity. A single-center, cross-sectional study of 100 acne patients was conducted. Patients' blood parameters, including ω-3 FAs levels, were assessed using the HS-omega-3 Index® in erythrocytes (Omegametrix® GmbH, Martinsried, Germany). Dietary preferences were assessed using a standardized food frequency questionnaire. Clinical dermatologic evaluation was performed using the Investigator Global Assessment (IGA) of acne. The values of the HS-omega-3 Index® were outside the recommended range of 8-11% in 96 patients (mean 5.15%), independent of the clinical severity or affected anatomic sites. A severe deficit (HS-omega-3 Index® < 4%) was seen more commonly in men than in women (p = 0.021). The regular consumption of legumes was significantly associated with higher ω-3 FA levels (p = 0.003), as was oral ω-3 FA supplementation (p = 0.006) and the lack of sunflower oil intake (p = 0.008). This pilot study demonstrated a deficit of ω-3 FAs in a German acne cohort. Higher ω-3 FAs levels were observed in patients with regular legume intake and oral ω-3 FAs supplementation. Further prospective studies are needed to investigate whether the clinical severity of acne improves in patients with normal HS-omega-3 Index®.

Association of circulating vitamin D and omega 3 fatty acid with all-cause mortality in patients with rheumatoid arthritis: A large population-based cohort study

OBJECTIVES

To assess the associations of both the level of circulating vitamin D and the ratio of omega-3 fatty acids to total fatty acids (omega-3 %) with mortality among participants with rheumatoid arthritis.

STUDY DESIGN

This study included 4,293 and 1,157 adults with rheumatoid arthritis identified by self-report from the UK Biobank for the analysis of vitamin D and omega-3 %, respectively.

MAIN OUTCOME MEASURES

Death outcomes were obtained from the National Health Service Information Centre (England and Wales) and the National Health Service Central Register Scotland (Scotland). Cox proportional hazards models were used to estimate hazard ratios and 95 % confidence intervals for mortality.

RESULTS

The medians (25th-75th percentiles) of serum 25(OH)D and omega-3 % were 45.8 (31.4-62.9) nmol/L and 4.1 % (3.3 %-5.1 %), respectively. During 52,612 person-years of follow-up in the 25(OH)D group, 502 all-cause deaths occurred; and during 14,192 person-years of follow-up in the omega-3 % group, 122 all-cause deaths occurred. Rheumatoid arthritis patients with vitamin D levels of at least 20 nmol/L had an approximately 40-50 % lower risk of all-cause mortality than those with severe vitamin D deficiency (hazard ratio ranging from 0.51 to 0.62, all P values < 0.05). Each unit increase in natural log-transformed 25(OH)D was associated with a 22 % reduction in the risk of all-cause mortality, and a U-shaped association between serum 25(OH)D and all-cause mortality was found. However, the association between omega-3 % and mortality was not significant.

CONCLUSIONS

Lower serum 25(OH)D concentration, but not omega-3 %, was significantly associated with higher all-cause mortality in patients with rheumatoid arthritis. Optimizing serum vitamin D levels may be an important factor in reducing mortality risk in this population.

The impact of COVID-19 on clinical research: the PIPPRA and MEDRA experience

Background

Coronavirus disease 2019 (COVID-19) has had a significant impact on clinical research. This paper aims to provide an insight into how the COVID-19 pandemic, associated public health restrictions and international guidance on the conduct of clinical research impacted two clinical rheumatology research trials - the Physiotherapist-led Intervention to Promote Physical Activity in Rheumatoid Arthritis (PIPPRA) and the MEDiterranean diet in Rheumatoid Arthritis (MEDRA) projects.

Methods

The March 2019 public health restrictions imposed to mitigate the risk of COVID-19 occurred at a time when PIPPRA was in the process of delivering assessment and intervention on a face-to-face basis (n=48) and MEDRA had commenced recruitment. Participants in PIPPRA and MEDRA had a diagnosis of rheumatoid arthritis, with some being immunosuppressed and thus at a higher risk for COVID-19. The decision-making processes of both trials is outlined to demonstrate the required amendments to continue in the context of the COVID-19 pandemic.

Results

Amendments to PIPPRA and MEDRA trial protocols were agreed and received ethical and funder approval. Both trials switched from a face-to-face delivery to a telehealth using online platforms. The PIPPRA study was paused for five months (April-August 2020), resulting in n=33 (60%) negative deviations from assessment protocol. MEDRA switched from face-to-face to online recruitment with 20% (n=35/44) negative deviations in recruitment. Of the n=18 participants who consented to participating in a face-to-face trial, just n=2 (11%) opted to engage with telehealth delivery of the intervention. MEDRA assessment and intervention deviations were 100% as no sessions were completed as planned in 2020.

Conclusions

The COVID-19 pandemic has severely impacted the PIPPRA and MEDRA clinical trials. Moving face-to-face clinical research to telehealth delivery may not be the panacea it is purported to be. Our experiences may be of benefit to researchers, clinicians, and funders in seeking to continue clinical research during a global pandemic.

Experience and perceptions among rheumatoid arthritis patients following a telehealth-delivered dietary intervention: a qualitative study

The effects of dietary modifications have been assessed in people living with rheumatoid arthritis (RA) with consistent benefits reported from clinical trials. However, the lived experience of making and sustaining positive dietary changes for people with RA remains unknown. The aim of this qualitative study was to explore the experiences of adults with RA and their perceptions of a 12-week telehealth-delivered dietary intervention and to assess the acceptability of the programme. Qualitative data was collected via four online focus groups with participants who had just completed a 12-week dietary intervention programme delivered through telehealth methods. Thematic analysis was used to code and summarize the identified key themes. Twenty-one adults with RA (47.5 ± 12.3 years, 90.5% females) were included in this qualitative study. Overarching themes included: (a) motivation to join the programme, (b) benefits of the programme, (c) factors influencing adherence to dietary prescription, and (d) advantages and disadvantages of telehealth. The study demonstrated that a dietary intervention delivered through telehealth methods by a Registered Dietitian (RD) appears to be well-accepted and may be used to complement face-to-face care for people with RA. The identified factors influencing the adoption of a healthier eating pattern will aid in the development of future dietary interventions for a RA population.

Decoding the Microbiome's Influence on Rheumatoid Arthritis

The aim is better to understand and critically explore and present the available data from observational studies on the pathogenetic role of the microbiome in the development of rheumatoid arthritis (RA). The electronic databases PubMed, Scopus, and Web of Science were screened for the relevant literature published in the last ten years. The primary outcomes investigated included the influence of the gut microbiome on the pathogenesis and development of rheumatoid arthritis, exploring the changes in microbiota diversity and relative abundance of microbial taxa in individuals with RA and healthy controls (HCs). The risk of bias in the included literature was assessed using the GRADE criteria. Ten observational studies were identified and included in the qualitative assessment. A total of 647 individuals with RA were represented in the literature, in addition to 16 individuals with psoriatic arthritis (PsA) and 247 HCs. The biospecimens comprised fecal samples across all the included literature, with 16S rDNA sequencing representing the primary method of biological analyses. Significant differences were observed in the RA microbiome compared to that of HCs: a decrease in Faecalibacterium, Fusicatenibacter, Enterococcus, and Megamonas and increases in Eggerthellales, Collinsella, Prevotella copri, Klebsiella, Escherichia, Eisenbergiella, and Flavobacterium. There are significant alterations in the microbiome of individuals with RA compared to HCs. This includes an increase in Prevotella copri and Lactobacillus and reductions in Collinsella. Collectively, these alterations are proposed to induce inflammatory responses and degrade the integrity of the intestinal barrier; however, further studies are needed to confirm this relationship.

Does Pizza Consumption Favor an Improved Disease Activity in Rheumatoid Arthritis?

To our knowledge, no studies so far have investigated the role of pizza and its ingredients in modulating disease activity in rheumatoid arthritis (RA). We assessed this question via a recent cross-sectional study including 365 participants from Italy, the birthplace of pizza. Multiple robust linear and logistic regression models were fitted with the tertile consumption categories of each available pizza-related food item/group (i.e., pizza, refined grains, mozzarella cheese, and olive oil) as independent variables, and each available RA activity measure (i.e., the Disease Activity Score on 28 joints with C-reactive protein (DAS28-CRP), and the Simplified Disease Activity Index (SDAI)) as the dependent variable. Stratified analyses were carried out according to the disease severity or duration. Participants eating half a pizza >1 time/week (vs. ≤2 times/month) reported beneficial effects on disease activity, with the significant reductions of ~70% (overall analysis), and 80% (the more severe stratum), and the significant beta coefficients of -0.70 for the DAS28-CRP, and -3.6 for the SDAI (overall analysis) and of -1.10 and -5.30 (in long-standing and more severe RA, respectively). Among the pizza-related food items/groups, mozzarella cheese and olive oil showed beneficial effects, especially in the more severe stratum. Future cohort studies are needed to confirm this beneficial effect of pizza and related food items/groups on RA disease activity.

The Integral Role of Diets Including Natural Products to Manage Rheumatoid Arthritis: A Narrative Review

Genetic and environmental factors including lifestyle are thought to play a key role in the pathophysiology of rheumatoid arthritis (RA). There is evidence that diet can enhance the inflammatory response in genetically predisposed individuals. On the other hand, certain types of diets can alleviate RA symptoms due to their anti-inflammatory and antioxidant activities. Also, natural compounds with potential effectiveness in RA management belong to different chemical classes such as flavonoids, polyphenols, carotenoids, and alkaloids with their antioxidant characteristics as well as probiotics. The nutritional approaches to prevent or extenuate the disease progress were examined in this narrative review which was conducted using the PubMed, ScienceDirect and Google Scholar databases and conforms to the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines. Mediterranean and vegan diets equally have been shown to exhibit positive effects on RA as the consumption of dietary fiber, antioxidants and anti-inflammatory compounds from fruits, vegetables, grains, nuts, and seeds are high. Whereas Mediterranean diet additionally includes beneficial nutrients of animal origin such as omega-3 polyunsaturated fatty acids from fish and seafood, patients on vegan diet need to be monitored closely for intake of all critical nutrients. Certain calorie restrictions and intermittent fasting diets have been shown to benefit RA patients although there is an obvious need for further studies to establish solid evidence-based recommendations and guidelines. The research data available strongly suggest that dietary approaches with anti-inflammatory properties may help delay the onset of RA and/or improve symptoms and thus nutrition should be routinely addressed to facilitate management of the disease.

Nutrition and its role in prevention and management of rheumatoid arthritis

Accumulating research evidence suggests that nutrition might be implicated in the risk of development and in the management of autoimmune disease, including rheumatoid arthritis (RA), characterized by immune-inflammatory response. Nutrition can have direct roles through the provision of pro- or anti-inflammatory foods, and indirect roles through management of co-morbidity management. The review updates on the evidence relating RA risk and management with focus on specific foods such as fish and diets/dietary patterns such as the Mediterranean diet, fasting and elimination diets and oral nutritional supplements including omega-3 polyunsaturated fatty acids (PUFA). Evidence on herbs and spices, beverages, Vitamin D, and probiotics is also reviewed. Diet has been shown to improve disease activity through reducing inflammation and oxidation and through its beneficial effects on the gut microbiota. Based on the existing evidence, it is recommended that as an adjunct to medical treatment, nutrition therapy for RA should be based on an anti-inflammatory Mediterranean diet (MD) supplemented with at least twice a week consumption of oily fish and/or omega-3 PUFA supplements at 2 g/day. The need for rheumatologists to work more closely with registered dietitians in the management of patients particularly in supporting a well-balanced diet according to individual needs, is highlighted.

Inflammation and Nutrition: Friend or Foe?

The importance of the interplay between inflammation and nutrition has generated much interest in recent times. Inflammation has been identified as a key driver for disease-related malnutrition, leading to anorexia, reduced food intake, muscle catabolism, and insulin resistance, which are stimulating a catabolic state. Interesting recent data suggest that inflammation also modulates the response to nutritional treatment. Studies have demonstrated that patients with high inflammation show no response to nutritional interventions, while patients with lower levels of inflammation do. This may explain the contradictory results of nutritional trials to date. Several studies of heterogeneous patient populations, or in the critically ill or advanced cancer patients, have not found significant benefits on clinical outcome. Vice versa, several dietary patterns and nutrients with pro- or anti-inflammatory properties have been identified, demonstrating that nutrition influences inflammation. Within this review, we summarize and discuss recent advances in both the role of inflammation in malnutrition and the effect of nutrition on inflammation.

TNF-α Mediates the Association between Dietary Inflammatory Index and Depressive Symptoms in Breast Cancer

This study examined the association between the energy-adjusted Dietary Inflammatory Index (E-DII)-based dietary inflammatory potential and depressive symptoms (DepS) among patients with breast cancer and explores whether systemic inflammation mediates this association. We assessed dietary intake and DepS in 220 breast cancer patients by three 24 h dietary recalls and the Center for Epidemiological Studies Depression Scale (CES-D), respectively, and determined plasma levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin (IL)-1β, IL-4, and IL-6 in 123 blood samples. We found that each one-point increase of E-DII was related to a 53% elevated risk of DepS. Patients with the most pro-inflammatory diets had a 5.13 times higher risk of DepS than those with the most anti-inflammatory diets. Among the E-DII components, vitamin B₂, zinc, and iron were inversely associated with DepS risk. Furthermore, E-DII scores were positively associated with CRP and TNF-α. Higher levels of TNF-α and IL-6 were associated with higher DepS risk. A significant mediating effect of TNF-α was revealed between E-DII and DepS. Our findings suggest that a pro-inflammatory diet is positively associated with breast cancer-related DepS, which may be mediated by TNF-α.

Lifestyle Factors and Their Influence on Rheumatoid Arthritis: A Narrative Review

In recent years, a possible association of lifestyle factors with rheumatoid arthritis (RA) has attracted increasing public interest. The aim of this review is to provide an overview of the extent and the limitations of current evidence regarding lifestyle factors and RA. The PubMed medical database was screened for epidemiological and prospective studies investigating the contribution of lifestyle factors to the development and the course of the disease. Large epidemiological studies have identified smoking, unhealthy diet and adiposity, as well as a low educational level and low socioeconomic status, as factors that increase the incidence of RA. In addition, several lifestyle habits influence the response of RA to antirheumatic drugs. Among others, smoking, obesity and poor physical activity are associated with a worse treatment outcome. Methodological problems often impair firm conclusions with respect to the causal role of these factors in the risk and the course of RA. However, current evidence is sufficient to recommend a healthy diet, the prevention of obesity, the cessation of smoking and the maintenance of a high level of physical activity to support the effectivity of modern antirheumatic medication.

Mitochondrial Dysfunction and Oxidative Stress in Rheumatoid Arthritis

Control of excessive mitochondrial oxidative stress could provide new targets for both preventive and therapeutic interventions in the treatment of chronic inflammation or any pathology that develops under an inflammatory scenario, such as rheumatoid arthritis (RA). Increasing evidence has demonstrated the role of mitochondrial alterations in autoimmune diseases mainly due to the interplay between metabolism and innate immunity, but also in the modulation of inflammatory response of resident cells, such as synoviocytes. Thus, mitochondrial dysfunction derived from several danger signals could activate tricarboxylic acid (TCA) disruption, thereby favoring a vicious cycle of oxidative/mitochondrial stress. Mitochondrial dysfunction can act through modulating innate immunity via redox-sensitive inflammatory pathways or direct activation of the inflammasome. Besides, mitochondria also have a central role in regulating cell death, which is deeply altered in RA. Additionally, multiple evidence suggests that pathological processes in RA can be shaped by epigenetic mechanisms and that in turn, mitochondria are involved in epigenetic regulation. Finally, we will discuss about the involvement of some dietary components in the onset and progression of RA.

A Meta-Analysis of the Impact of Nutritional Supplementation on Osteoarthritis Symptoms

Conflicting evidence exists concerning the effects of nutrient intake in osteoarthritis (OA). A systematic literature review and meta-analysis were performed using PubMed, EMBASE, and Cochrane Library up to November 2021 to assess the effects of nutrients on pain, stiffness, function, quality of life, and inflammation markers. We obtained 52 references including 50 on knee OA. Twelve studies compared 724 curcumin patients and 714 controls. Using the standardized mean difference, improvement was significant with regard to pain and function in the curcumin group compared to placebo, but not with active treatment (i.e., nonsteroidal anti-inflammatory drugs, chondroitin, or paracetamol). Three studies assessed the effects of ginger on OA symptoms in 166 patients compared to 164 placebo controls. Pain was the only clinical parameter that significantly decreased. Vitamin D supplementation caused a significant decrease in pain and function. Omega-3 and vitamin E caused no changes in OA parameters. Herbal formulations effects were significant only for stiffness compared to placebo, but not with active treatment. A significant decrease in inflammatory markers was found, especially with ginger. Thus, curcumin and ginger supplementation can have a favorable impact on knee OA symptoms. Other studies are needed to better assess the effects of omega-3 and vitamin D.