A systematic review and meta-analysis of observational studies on the association between animal protein sources and risk of rheumatoid arthritis

The association between dietary intake of branched-chain amino acids and odds and severity of rheumatoid arthritis

This case-control study investigated the link between dietary branched-chain amino acids (BCAAs) and the risk and severity of rheumatoid arthritis (RA). We assessed dietary BCAA intake in 95 RA patients and 190 matched controls using a food frequency questionnaire. We also assessed the disease severity using the disease activity score 28 (DAS-28), ESR, VAS, morning stiffness, and tender and swollen joints. Higher BCAA intake, expressed as a percentage of total protein, was significantly associated with increased risk of RA for total BCAAs (OR 2.14, 95% CI 1.53-3.00, P < 0.001), leucine (OR 2.40, 95% CI 1.70-3.38, P < 0.001), isoleucine (OR 2.04, 95% CI 1.46-2.85, P < 0.001), and valine (OR 1.87, 95% CI 1.35-2.59, P < 0.001). These associations remained significant even after adjusting for potential confounders (P < 0.001). However, BCAA intake did not show any significant association with RA severity in either crude or multivariate models (P > 0.05). Our findings suggest that higher dietary BCAA intake may contribute to the development of RA, but further research is needed to confirm these observations and explore the underlying mechanisms.

The association of milk products with rheumatoid arthritis: A cross-sectional study from NHANES

OBJECTIVE

Milk products are a major part of the western diet, but the role of their effect in rheumatoid arthritis (RA) is controversial. The objective of this study was to explore the relationship between milk products and RA in the United States (US) population.

METHODS

In the cross-sectional study, a total of 12,813 participants aged 20years or older were selected from the National Health and Nutrition Examination Survey (NHANES). Consumption of milk products was collected by personal interview, and RA status was obtained by self-reported questionnaires. The association between milk products and RA was estimated by using the weighted logistic regression model.

RESULTS

We found a negative association of once a day or more milk products intake with self-reported RA prevalence (odds ratio [OR]: 0.68; 95% confidence interval [CI]: 0.53 to 0.86; P<0.001). A linear trend between consumption of milk products and the prevalence of RA (P<0.01) was also observed. In subgroup analysis, protective effects of milk products on RA were more pronounced in several groups (i.e., Mexican Americans, highly educated and drinking individuals, etc.). However, no interaction effect of stratification variables and the frequency of milk products intake with RA was detected. After imputing missing data, the sensitivity analysis showed the same association.

CONCLUSION

This study suggested a negative association between consumption of milk products and RA among US population. Further investigations are warranted to validate the causal association and the underlying mechanism.

The Role of Marine n-3 Polyunsaturated Fatty Acids in Inflammatory-Based Disease: The Case of Rheumatoid Arthritis

Inflammation is a conserved process that involves the activation of immune and non-immune cells aimed at protecting the host from bacteria, viruses, toxins and injury. However, unresolved inflammation and the permanent release of pro-inflammatory mediators are responsible for the promotion of a condition called "low-grade systemic chronic inflammation", which is characterized by tissue and organ damage, metabolic changes and an increased susceptibility to non-communicable diseases. Several studies have demonstrated that different dietary components may influence modifiable risk factors for diverse chronic human pathologies. Marine n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), are well-recognized anti-inflammatory and immunomodulatory agents that are able to influence many aspects of the inflammatory process. The aim of this article is to review the recent literature that relates to the modulation of human disease, such as rheumatoid arthritis, by n-3 PUFAs.

Combined Effects of Diet and Physical Activity on Inflammatory Joint Disease: A Systematic Review and Meta-Analysis

Research evidence suggests that, individually, diet and physical activity are effective interventions for reducing levels of inflammation in inflammatory joint diseases (IJD), however little is known about their combined use. This systematic review and meta-analysis aimed to examine the effects and/or associations of combined diet and physical activity interventions in IJD, specifically rheumatoid arthritis (RA) and the spondyloarthropathies (SpA) (PROSPERO registration number: CRD42022370993). Ten out of 11 eligible studies examined RA patients. We found that a combination of diet/nutrition and physical activity/exercise improved Health Assessment Questionnaire score (standardized mean difference = -1.36, confidence interval (CI) = (-2.43)-(-0.30), I² = 90%, Z = 2.5, p = 0.01), while surprisingly they increased erythrocyte sedimentation rate (mean difference = 0.20, CI = 0.09-0.31, I² = 0%, Z = 3.45, p < 0.01). No effects were found on C-reactive protein or weight (p > 0.05) of RA patients. We did not find studies in other IJDs that provided sufficient data for a meta-analysis. The narrative data synthesis provided limited evidence to address our research question. No firm conclusions can be made as to whether the combination of diet/nutrition and physical activity/exercise affects inflammatory load in IJDs. The results of this study can only be used as a means of highlighting the low-quality evidence in this field of investigation and the need for further and better-quality research.

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.

Diet and the risk of rheumatoid arthritis - A systematic literature review

OBJECTIVES

Diet has received attention as a factor possibly contributing to the development of Rheumatoid arthritis (RA). Several dietary exposures have been examined in various populations using different diet assessment methods. The aim of this study was to systematically assess the literature on the relation between dietary patterns, different food and food groups, macronutrients, non-alcoholic beverages and the risk of developing RA.

METHODS

A systematic literature search was performed to identify relevant articles on diet and the risk of developing RA. The selection of articles and overall quality assessment of all included studies were performed independently by two examiners. Overall study quality was evaluated using the Newcastle-Ottawa Scales. We excluded all articles where the temporal relation between dietary data collection and time of RA diagnosis was not presented. Main findings were summarized for cohort-based studies and case-control studies separately.

RESULTS

A total of 984 articles were screened. Nineteen relevant cohort-based studies, and eight case-control studies, were included in our review. Two articles were excluded due to lacking data on the relation between RA diagnosis and time of dietary data collection and one due to incorrect outcome. Identified studies suggested protective effects of fish, vegetables and Mediterranean-style diets, although study results and methods were heterogenous. An issue in some case-control studies was that unvalidated diet assessment methods were used. A vast majority of the cohort-based studies used validated diet assessment methods, although the definitions of exposures studied varied.

CONCLUSION

There is lack of consistent evidence on the role of diet in the development of RA, partly due to differences in study quality and methodology Limited evidence suggests that some healthy eating habits may reduce the risk of RA. More high-quality studies in the area are needed for a deeper understanding of the effect of diet, and to enable strategies to prevent RA.

Nutrients and rheumatoid arthritis: From the perspective of neutrophils

Neutrophils are considered as core immune cells involve in the early stage of rheumatoid arthritis (RA) and participate in the disease progression. The underlining mechanisms include the elevated chemotaxis and infiltration of neutrophils, the increase in the reactive oxygen species and the promotion of neutrophil extracellular traps formation. Accumulating studies demonstrated the important role of nutrients intake played in the initiation and progression of RA. This study summarized the effects of several macronutrients and micronutrients on regulating RA through the modulation of activated neutrophils and appealed for a healthy diet in RA-risk individuals as well as RA patients.

Lifestyle, Hormonal, and Metabolic Environmental Risks for Rheumatoid Arthritis

Although there is a substantial body of literature focused on understanding noninhalational risk-factors for rheumatoid arthritis, the data are mixed and often conflicting. Given the other health benefits for certain lifestyle modifications, it seems reasonable for clinicians to promote healthy lifestyle habits related to diet, exercise, maintenance of health weight, and maintenance of good dental hygiene. Overall, however, these lifestyle modifications may be expected to have modest benefit, and other strategies to prevent rheumatoid arthritis in high-risk patients are needed.

Cardiovascular Risk Prediction Parameters for Better Management in Rheumatic Diseases

The early detection of cardiovascular disease (CVD) serves as a key element in preventive cardiology. The risk of developing CVD in patients with rheumatic disease is higher than that of the general population. Thus, the objective of this narrative review was to assess and describe updated risk-prediction parameters for CVD in patients suffering from rheumatic diseases, and, additionally, to evaluate therapeutic and risk management possibilities. The processes of recognizing CVD risk factors in rheumatic diseases, establishing diagnoses, and discovering CV risk assessments are currently displeasing in clinical practice; they have a limited clinical impact. A large number of references were found while screening PUBMED, Scopus, and Google scholar databases; the 47 most relevant references were utilized to build up this study. The selection was limited to English language full text articles, RCTs, and reviews published between 2011 and 2021. Multiple imaging techniques, such as ECG, ultrasound, and cIMT, as well as biomarkers like osteoprotegerin cytokine receptor and angiopoietin-2, can be beneficial in both CV risk prediction and in early subclinical diagnosis. Physical exercise is an essential non-pharmacological intervention that can maintain the health of the cardiovascular system and, additionally, influence the underlying disease. Lipid-lowering drugs (methotrexate from the non-biologic DMARDs family as well as biologic DMARDs such as anti-TNF) were all associated with a lower CV risk; however, anti-TNF medication can decrease cardiac compliance and promote heart failure in patients with previously diagnosed chronic HF. Although they achieved success rates in reducing inflammation, glucocorticoids, NSAIDs, and COX-2 inhibitors were correlated with an increased risk of CVD. When taking all of the aforementioned points into consideration, there appears to be a dire need to establish and implement CVD risk stratification models in rheumatic patients.

Can I Prevent Developing a Rheumatic and Musculoskeletal Disease Through Lifestyle Changes? A Focus on Nutrition

Accumulating evidence suggests that nutrition can reduce the risk of rheumatic and musculoskeletal disease and especially rheumatoid arthritis (RA) development. This effect may be achieved either directly or indirectly through the consumption of anti-inflammatory nutrients or the reduction of comorbidities, respectively. A pro-inflammatory diet increases RA risk while the Mediterranean diet and oily fish consumption providing anti-inflammatory omega-3 fatty acids both reduce risk. High sugar and salt consumption is also associated with increased RA risk. Therefore, the Mediterranean diet supplemented with dietary omega-3 fatty acids is recommended for individuals genetically susceptible to RA.

Fish and the Thyroid: A Janus Bifrons Relationship Caused by Pollutants and the Omega-3 Polyunsaturated Fatty Acids

Benefits of the omega-3 polyunsaturated fatty acids (PUFA) on a number of clinical disorders, including autoimmune diseases, are widely reported in the literature. One major dietary source of PUFA are fish, particularly the small oily fish, like anchovy, sardine, mackerel and others. Unfortunately, fish (particularly the large, top-predator fish like swordfish) are also a source of pollutants, including the heavy metals. One relevant heavy metal is mercury, a known environmental trigger of autoimmunity that is measurable inside the thyroid. There are a number of interactions between the omega-3 PUFA and thyroid hormones, even at the level of the thyroid hormone transport proteins. Concerning the mechanisms behind the protection from/amelioration of autoimmune diseases, including thyroiditis, that are caused by the omega-3 PUFA, one can be the decreased production of chemokines, a decrease that was reported in the literature for other nutraceuticals. Recent studies point also to the involvement of resolvins. The intracellular increase in resolvins is associated with the tissue protection from inflammation that was observed in experimental animals after coadministration of omega-3 PUFA and thyroid hormone. After having presented data on fish consumption at the beginning, we conclude our review by presenting data on the market of the dietary supplements/nutraceuticals. The global omega-3 products market was valued at USD 2.10 billion in 2020, and was projected to go up at a compound annual growth rate of 7.8% from 2020 to 2028. Among supplements, fish oils, which are derived mainly from anchovies, are considered the best and generally safest source of omega-3. Taking into account (i) the anti-autoimmunity and anti-cancer properties of the omega-3 PUFA, (ii) the increasing incidence of both autoimmune thyroiditis and thyroid cancer worldwide, (iii) the predisposing role for thyroid cancer exerted by autoimmune thyroiditis, and (iv) the risk for developing metabolic and cardiovascular disorders conferred by both elevated/trendwise elevated serum TSH levels and thyroid autoimmunity, then there is enough rationale for the omega-3 PUFA as measures to contrast the appearance and/or duration of Hashimoto's thyroiditis as well as to correct the slightly elevated serum TSH levels of subclinical hypothyroidism.