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Nutrition Interventions in Rheumatoid Arthritis: The Potential Use of Plant-Based Diets. A Review.
Alwarith, J, Kahleova, H, Rembert, E, Yonas, W, Dort, S, Calcagno, M, Burgess, N, Crosby, L, Barnard, ND
Frontiers in nutrition. 2019;6:141
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Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by joint pain and inflammation with both genetic and modifiable risk factors. Research suggests a plant-based diet may play a role in management and remission. The aim of this review was to summarize the associations between plant-based diet patterns and RA symptoms. Current studies indicate an association between improvements in RA symptoms with weight loss and with plant-based diets. Based on these findings, the authors conclude excess weight and diets that include animal products may exacerbate symptoms associated with RA, whereas plant-based diets may help reduce pain and inflammation in these patients. The authors suggest further research is needed to test the effectiveness of plant-based diets on patients with RA.
Abstract
Rheumatoid arthritis (RA), a chronic inflammatory autoimmune disease, affects roughly 1% of the world's population. RA pathogenesis remains unclear, but genetic factors account for 50-60% of the risk while the remainder might be linked to modifiable factors, such as infectious diseases, tobacco smoking, gut bacteria, and nutrition. Dietary triggers may play an inciting role in the autoimmune process, and a compromised intestinal barrier may allow food components or microorganisms to enter the blood stream, triggering inflammation. In addition, excessive body weight may affect pharmacotherapy response and the likelihood of disease remission, as well as the risk of disease mortality. Evidence suggests that changes in diet might play an important role in RA management and remission. Several studies have shown improvements in RA symptoms with diets excluding animal products. Studies have also shown that dietary fiber found in these plant-based foods can improve gut bacteria composition and increase bacterial diversity in RA patients, thus reducing their inflammation and joint pain. Although some of the trigger foods in RA patients are individualized, a vegan diet helps improve symptoms by eliminating many of these foods. This review examines the potential role of a plant-based diet in mediating RA symptoms. Further research is needed to test the effectiveness of plant-based diets on joint pain, inflammation, and quality of life in patients with RA.
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Inflammatory Bowel Diseases and Food Additives: To Add Fuel on the Flames!
Marion-Letellier, R, Amamou, A, Savoye, G, Ghosh, S
Nutrients. 2019;11(5)
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Inflammatory Bowel Diseases (IBDs), such as Crohn’s disease (CD) and Ulcerative Colitis (UC) are becoming increasingly common. Diet is thought to play a role in the development of IBDs. The consumption of Ultra Processed Food (UPF) is increasing and has been associated with a higher risk of some chronic diseases. Food additives may be an aspect of UPF responsible for its harmful effects. This literature review examined the role of food additives in the development and severity of IBDs. The authors discuss how common food additives such as salt, emulsifiers, stabilisers, bulking agents, sweeteners, and food colouring may promote inflammation and disrupt gut bacteria. Metals and compounds found in food packaging such as aluminium and bisphenol A (BPA) may trigger intestinal permeability and increase inflammatory markers. Much of the evidence available is based on clinical trials on animals, whilst epidemiological studies on food additives and IBD risk are still limited. The authors concluded that the majority of food consumed by IBD patients should be home-cooked in order to reduce exposure to additives in the diet.
Abstract
Inflammatory bowel diseases (IBDs) develop in genetically predisposed individuals in response to environmental factors. IBDs are concomitant conditions of industrialized societies, and diet is a potential culprit. Consumption of ultra-processed food has increased over the last decade in industrialized countries, and epidemiological studies have found associations between ultra-processed food consumption and chronic diseases. Further studies are now required to identify the potential culprit in ultra-processed food, such as a poor nutritional composition or the presence of food additives. In our review, we will focus on food additives, i.e., substances from packaging in contact with food, and compounds formed during production, processing, and storage. A literature search using PubMed from inception to January 2019 was performed to identify relevant studies on diet and/or food additive and their role in IBDs. Manuscripts published in English from basic science, epidemiological studies, or clinical trials were selected and reviewed. We found numerous experimental studies highlighting the key role of food additives in IBD exacerbation but epidemiological studies on food additives on IBD risk are still limited. As diet is a modifiable environmental risk factor, this may offer a scientific rationale for providing dietary advice for IBD patients.
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Gut microbial metabolites in depression: understanding the biochemical mechanisms.
Caspani, G, Kennedy, S, Foster, JA, Swann, J
Microbial cell (Graz, Austria). 2019;6(10):454-481
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Major depressive disorder is a leading cause of disability and is linked to shortened life expectancy and suicide. Despite its prevalence, for near to a third of patients, long-term treatment options are ineffective. In addition to the primary presentation of persistent low mood, other emotional and physiological symptoms, researchers have also identified alterations in metabolism, hormones and the immune system. Furthermore, increasing evidence suggests that depression and depressive behaviour is also influenced by divergences in gut health and gut bacteria composition. With insights from animal and human research, this review highlights how the gut and gut bacteria-derived metabolites can directly or indirectly influence mood. Described are the pathways of how the gut and its microorganism communicate with the brain, the essential role the immune system has as part of the gut-brain communication, and the impact of low-grade, chronic inflammation on neurofunction. Comprehensive summaries are dedicated to how several metabolites or by-products from gut bacteria can influence the nervous system and gene expression in relation to depression. These include substances like neurotransmitters, short-chain fatty acids, tryptophan metabolites, lactate, bile acids, choline metabolites and folate. This article yields a detailed overview of how gut health and microbiota can influence neurofunction and mental health. The authors promote the idea of the gut as a suitable target for the management of depressive disorders, whilst also eluding to the current limitations and need for further research.
Abstract
Gastrointestinal and central function are intrinsically connected by the gut microbiota, an ecosystem that has co-evolved with the host to expand its biotransformational capabilities and interact with host physiological processes by means of its metabolic products. Abnormalities in this microbiota-gut-brain axis have emerged as a key component in the pathophysiology of depression, leading to more research attempting to understand the neuroactive potential of the products of gut microbial metabolism. This review explores the potential for the gut microbiota to contribute to depression and focuses on the role that microbially-derived molecules - neurotransmitters, short-chain fatty acids, indoles, bile acids, choline metabolites, lactate and vitamins - play in the context of emotional behavior. The future of gut-brain axis research lies is moving away from association, towards the mechanisms underlying the relationship between the gut bacteria and depressive behavior. We propose that direct and indirect mechanisms exist through which gut microbial metabolites affect depressive behavior: these include (i) direct stimulation of central receptors, (ii) peripheral stimulation of neural, endocrine, and immune mediators, and (iii) epigenetic regulation of histone acetylation and DNA methylation. Elucidating these mechanisms is essential to expand our understanding of the etiology of depression, and to develop new strategies to harness the beneficial psychotropic effects of these molecules. Overall, the review highlights the potential for dietary interventions to represent such novel therapeutic strategies for major depressive disorder.
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Small talk: microbial metabolites involved in the signaling from microbiota to brain.
Caspani, G, Swann, J
Current opinion in pharmacology. 2019;48:99-106
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The gut-brain axis (GBA) is the communication network between the gastrointestinal tract and the central nervous system. An array of gut bacteria-derived metabolites mediates this interaction between the gastrointestinal system and the brain, influencing physiological and pathological processes in direct and indirect ways. Thus a variation in the gut microbiome can alter the functional capacity and output of the gut-brain-communication. In this review, the authors summarise key bacterial metabolites from the gut and their effect on the brain. Addressed are short-chain fatty acids, their impact on gut and brain barrier integrity, their role in appetite regulation, and their association with anxiety and depressive disorders amongst other aspects. Secondly, bile acids, which are processed by the microbiome, can activate several receptors. And thus divergence gut bacteria can alter the composition of bile acids and change their signalling capacity. Bile acids can also directly modify gut and blood-brain barrier function and may carry a signalling role in the brain. A few neurotransmitters are covered in this article, as several types of gut bacteria synthesize neurotransmitters, such as serotonin and dopamine. Though, it is uncertain whether all gut-derived neurotransmitters can reach the brain. However, certain GABA-producing bacteria have been shown to elicit higher GABA levels in the brain. The microbiota can also be involved with the conversion of neurotransmitters such as dopamine. The final section briefly capture the evidence of other brain health-relevant molecules derived from the intestinal microbiota, including Lipopolysaccharides, choline, lactate and B-Vitamins. This review yields a short and comprehensive summary highlighting the many ways the gut can influence brain function and health and could be of interest to those providing mental health support in light of gut function.
Abstract
The wealth of biotransformational capabilities encoded in the microbiome expose the host to an array of bioactive xenobiotic products. Several of these metabolites participate in the communication between the gastrointestinal tract and the central nervous system and have potential to modulate central physiological and pathological processes. This biochemical interplay can occur through various direct and indirect mechanisms. These include binding to host receptors in the brain, stimulation of the vagus nerve in the gut, alteration of central neurotransmission, and modulation of neuroinflammation. Here, the potential for short chain fatty acids, bile acids, neurotransmitters and other bioactive products of the microbiome to participate in the gut-brain axis will be reviewed.
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Inflammaging and Oxidative Stress in Human Diseases: From Molecular Mechanisms to Novel Treatments.
Zuo, L, Prather, ER, Stetskiv, M, Garrison, DE, Meade, JR, Peace, TI, Zhou, T
International journal of molecular sciences. 2019;20(18)
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Reactive oxygen species (ROS) are produced during normal metabolic processes or can be induced by environmental factors. High levels of ROS in the cell can lead to oxidation causing cellular damage and a subsequent increase in inflammation, which is a significant contributor to disease. Age-associated increases in such chronic, low-grade inflammation is also referred to as inflammaging. This review summarizes how inflammaging plays a role in various age-related health conditions. Described are the mechanisms of how ROS and the age-related decline in cellular turn-over and immune activation contribute to the pathology of cardiovascular disease, cancer, neurodegeneration concerning Alzheimer’s and Parkinson’s disease, diabetes and rheumatoid arthritis. Furthermore, the authors discuss potential treatments that could assist in the management of such inflammaging-related diseases. These include vaccines to stimulate immune activity, stem cell intervention, drugs like metformin, nutritional and nutraceutical supplements like zinc, vitamin E, vitamins C, D, carotenoids, polyphenols and flavonoids like resveratrol, red algae extract and melatonin. Addressed are also general dietary concepts like calorie restriction, the benefits of the Mediterranean diet or a whole foods diet, and the potential of specific plant derived compounds like baicalin and sulforaphanes. The authors also briefly highlight the importance of the gut microbiome, as a poor gut microbiota has been associated with unfavourable age-related immune alterations and overall inflammaging. This review provides a comprehensive resource, detailing the effects and mechanisms of oxidative damage and its contribution to age-related diseases, including a list of interventions to consider when navigating the impact and risks associated with inflammaging.
Abstract
It has been proposed that a chronic state of inflammation correlated with aging known as inflammaging, is implicated in multiple disease states commonly observed in the elderly population. Inflammaging is associated with over-abundance of reactive oxygen species in the cell, which can lead to oxidation and damage of cellular components, increased inflammation, and activation of cell death pathways. This review focuses on inflammaging and its contribution to various age-related diseases such as cardiovascular disease, cancer, neurodegenerative diseases, chronic obstructive pulmonary disease, diabetes, and rheumatoid arthritis. Recently published mechanistic details of the roles of reactive oxygen species in inflammaging and various diseases will also be discussed. Advancements in potential treatments to ameliorate inflammaging, oxidative stress, and consequently, reduce the morbidity of multiple disease states will be explored.
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Tryptophan Metabolism in Inflammaging: From Biomarker to Therapeutic Target.
Sorgdrager, FJH, Naudé, PJW, Kema, IP, Nollen, EA, Deyn, PP
Frontiers in immunology. 2019;10:2565
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Inflammation is a normal physiological process activated by the immune system in response to injury or infection. As we age, the immune system changes and the balance between pro- and anti-inflammatory agents can shift. This causes a chronic inflammatory state referred to as inflammaging. The rate of inflammaging is strongly associated with age-related disability, disease and mortality. The way in which the essential amino acid tryptophan (Trp) is broken down affects inflammation. If it is converted to kynurenine (Kyn) and its metabolites, inflammation is modulated. Studies have shown that the Kyn/Trp ratio, measured in blood, is strongly associated with ageing in humans. It could therefore be a useful marker to predict the onset of age-related diseases. This review discusses the metabolism of Trp and the links to inflammation. The authors hypothesize how intervening in these pathways could impact health- and lifespan. Future studies are needed to confirm the value of Trp metabolism as a biomarker for (un)healthy ageing and as drug target for inflammaging-related disease.
Abstract
Inflammation aims to restore tissue homeostasis after injury or infection. Age-related decline of tissue homeostasis causes a physiological low-grade chronic inflammatory phenotype known as inflammaging that is involved in many age-related diseases. Activation of tryptophan (Trp) metabolism along the kynurenine (Kyn) pathway prevents hyperinflammation and induces long-term immune tolerance. Systemic Trp and Kyn levels change upon aging and in age-related diseases. Moreover, modulation of Trp metabolism can either aggravate or prevent inflammaging-related diseases. In this review, we discuss how age-related Kyn/Trp activation is necessary to control inflammaging and alters the functioning of other metabolic faiths of Trp including Kyn metabolites, microbiota-derived indoles and nicotinamide adenine dinucleotide (NAD+). We explore the potential of the Kyn/Trp ratio as a biomarker of inflammaging and discuss how intervening in Trp metabolism might extend health- and lifespan.
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Meta-inflammaging at the crossroad of geroscience.
Chen, G, Yung, R
Aging medicine (Milton (N.S.W)). 2019;2(3):157-161
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The concept of “geroscience” represents a perspective in the understanding of the molecular underpinning of aging. Currently, seven biological processes are regarded as the underpinning of the aging process. This study is a review which focused on the link between chronic low‐grade sterile inflammation prevalent in old age and obesity‐associated metabolic inflammation. Old age, particularly in elderly adults with poor physical function or frailty, is linked to a state of chronic low‐grade sterile inflammation (inflammaging) with elevated pro‐inflammatory cytokines [a general term for the immunoregulatory cytokines that favour inflammation]. Another potential source of pro‐inflammatory cytokines in aging is adipose, or fat tissue, which can be the largest organ in obese individuals. Obesity has been linked to a low‐grade sterile chronic inflammatory state, with similarities to inflammaging, and is termed “metainflammation”. Adiposity has emerged as a major source of inflammation in both diet‐ and aging‐associated obesity, which in turn is linked to most common diseases in old age.
Abstract
Geroscience posits that selected fundamental biological processes are the foundation of age-related chronic diseases and are responsible for the decline in physical and mental function in old age. Late-life chronic low-grade inflammation ("inflammaging") and altered signal transduction pathways in metabolism have been identified as two of the key themes in the aging process. Age-related changes in the immune and metabolic responses are also recognized as playing a critical pathogenic role in most common chronic medical conditions that plague the elderly. Emerging investigations emphasize the interconnectedness of the immune and metabolic responses in aging, an area of gerontological research that can be termed "meta-inflammaging."
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Danger signals and inflammaging in osteoarthritis.
Millerand, M, Berenbaum, F, Jacques, C
Clinical and experimental rheumatology. 2019;37 Suppl 120(5):48-56
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Osteoarthritis (OA) is the most common and disabling joint disease worldwide and aging is the most important risk factor for its development. It was considered a ‘wear and tear’ disease for a long time, however it is now clear that low-grade inflammation is at the root of OA. This process is called ‘inflammaging’ – the presence of low-grade inflammation and decreased efficiency of the immune system with aging. This highly technical review paper describes the reaction of the immune system to small molecules that begin to circulate after cell stress or damage in the joints (known as damage-associated molecular patterns or DAMPs), causing inflammation. The paper includes a discussion on potential medication targets, including anti-inflammatory compounds such as ginger. Nutrition Practitioners working with OA and wanting to understand the inflammatory process involved will find this paper useful.
Abstract
Osteoarthritis (OA) is the most common age-related chronic and disabling joint disease. Long considered to be a "wear and tear" disease, OA is now seen as a low-grade inflammation disease that affects all tissues of the joint, involving cartilage degradation, bone remodelling, osteophytes, and synovitis. The process, called inflammaging, is characterised by the association of low-grade inflammation, profound changes in intra-cellular mechanisms, and the decreased efficiency of the immune system with ageing. The activation of innate immunity plays a critical role in the development and progression of OA. Innate immunity, including inflammasome activation, is triggered by small endogenous molecules called alarmins or damage-associated molecular patterns (DAMPs). These molecules are released in the extracellular media after cell stress or damage, bind to pathogen-recognition receptors (PRRs), such as Toll-like receptors (TLRs) and the receptor for advanced glycation end products (RAGE), and activate the secretion of pro-inflammatory factors, leading to joint inflammation. Moreover, such sterile inflammation triggers cell senescence, characterised by a senescence-associated secretory phenotype (SASP). Understanding the substantial age-related changes of joint tissues that influence the pathogenesis of OA is critical to improving the quality of life of elderly people in the context of increased life expectancy. This review will focus on age-related sterile inflammation in OA and highlight the various innovative and promising therapies targeting the mechanisms of aging.
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Nutritional Challenges in Metabolic Syndrome.
Hoyas, I, Leon-Sanz, M
Journal of clinical medicine. 2019;8(9)
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Metabolic syndrome is a cluster of symptoms and risk factors for cardiovascular disease where the main therapeutic treatment is focused on weight loss and improvements in insulin sensitivity. However, there is no one dietary therapy that works for everyone, so weight reduction is often approached differently. Common dietary plans involve calorie reduction, low-carbohydrate, low-fat or a lifestyle-based approach such as the Mediterranean diet. What is scientifically accepted is that the different macronutrients each play a role in promoting weight loss. An elevated intake of high GI carbohydrates can cause insulin resistance over time. High fibre foods can help mitigate this as well as supporting satiety. There is a lot more focus on low carb, low GI and ketogenic diets. Fat intake has also been studied intensely and different lipids can influence cholesterol and other cardiovascular markers. Omega-3 fatty acids have been shown to be especially healthful. Limiting saturated and trans fats, added sugars, and sodium is also considered a healthy pattern. Proteins are associated with increased satiety and maintaining muscle mass. Each dietary pattern has a different metabolic effect although calorie restriction is typically the more effective intervention for metabolic intervention.
Abstract
Metabolic Syndrome (MetS) is a combination of risk factors for the development of cardiovascular disease (CVD) and type 2 diabetes. Different diagnostic criteria were proposed, but a consensus was reached in 2009 based on values of waist circumference, blood pressure, fasting glycemia, triglycerides, and high-density lipoprotein (HDL)-cholesterol levels. The main underlying etiologic factor is insulin resistance. The quality and quantity of individual macronutrients have an influence on the development and resolution of this syndrome. However, the main treatment goal is weight loss and a decrease in insulin resistance. A controlled energy dietary recommendation, together with moderate levels of physical activity, may positively change the parameters of MetS. However, there is no single dietary or exercise prescription that works for all patients. Dietary patterns such as Mediterranean-style, dietary approaches to stop hypertension (DASH), low-carbohydrate, and low-fat diets can ameliorate insulin resistance and MetS. Long-term adherence to a healthy lifestyle is key in assuring that individuals significantly reduce the risk of CVD and diabetes mellitus.
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A Scientific Perspective of Personalised Gene-Based Dietary Recommendations for Weight Management.
Drabsch, T, Holzapfel, C
Nutrients. 2019;11(3)
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Basic recommendations of eat less, move more can have varying levels of success in weight loss depending on the individual. As a result, the focus has begun to shift to personalised nutrition based on genetics, however evidence is lacking. This review paper aimed to evaluate what evidence was available. The authors stated that the literature has no set definition for personalised nutrition but did state that it should consider social, lifestyle, genetic and metabolic factors and the microbiome. 500 genes have been recognised as associated with body morphology and although the function of most of them is still unclear, the fat mass and obesity associated (FTO) gene has the strongest effect on body weight. Individuals can carry different versions of the FTO gene, and the research has been conflicting on whether weight loss is greater depending on which version an individual carries. The regulation of food intake and the amount of fat and protein consumed may also be affected by the FTO version. The use of dietary recommendations based on genetic tests that can be bought by the general public was also reviewed and it was concluded that this science is still in its infancy. The authors concluded that personalised nutrition based on genetics is complex and further studies are warranted.
Abstract
Various studies showed that a "one size fits all" dietary recommendation for weight management is questionable. For this reason, the focus increasingly falls on personalised nutrition. Although there is no precise and uniform definition of personalised nutrition, the inclusion of genetic variants for personalised dietary recommendations is more and more favoured, whereas scientific evidence for gene-based dietary recommendations is rather limited. The purpose of this article is to provide a science-based viewpoint on gene-based personalised nutrition and weight management. Most of the studies showed no clinical evidence for gene-based personalised nutrition. The Food4Me study, e.g., investigated four different groups of personalised dietary recommendations based on dietary guidelines, and physiological, clinical, or genetic parameters, and resulted in no difference in weight loss between the levels of personalisation. Furthermore, genetic direct-to-consumer (DTC) tests are widely spread by companies. Scientific organisations clearly point out that, to date, genetic DTC tests are without scientific evidence. To date, gene-based personalised nutrition is not yet applicable for the treatment of obesity. Nevertheless, personalised dietary recommendations on the genetic landscape of a person are an innovative and promising approach for the prevention and treatment of obesity. In the future, human intervention studies are necessary to prove the clinical evidence of gene-based dietary recommendations.