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You Are What You Eat-The Relationship between Diet, Microbiota, and Metabolic Disorders-A Review.
Moszak, M, Szulińska, M, Bogdański, P
Nutrients. 2020;12(4)
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The gut microbiota (GM) is a collection of microorganisms living in the digestive tract of humans, which if unbalanced, may have a role in the development of certain disorders such as type 2 diabetes and obesity. A number of factors can imbalance the gut microbiota, one of the main being diet. This review paper of 190 papers aimed to summarise the relationship between GM, diet and modifiable diseases such as type 2 diabetes and obesity. Dietary components and the role of carbohydrates, protein and fats in shaping the GM were discussed. It was determined that carbohydrates have the greatest influence, with simple carbohydrates such as the sugars fructose and sucrose having a negative impact and the more complex forms being beneficial. Diet types were also reviewed. Vegetarian and vegan diets appear to increase the diversity of the GM, the Mediterranean diet changes the species balance, and the Western diet imbalances the GM causing diseases such as heart disease. Interestingly the literature points towards a negative impact of the gluten free diet. Diseases such as type 2 diabetes, obesity and increased fats in the blood all display an imbalanced GM causing increased energy harvest from food and disruption of various energy pathways in the body. It was concluded that a balanced diet rich in fruit, vegetables, fibre and healthy fats can promote GM diversity and activity. This study could be used by health care professionals to understand the importance of certain dietary components to promote GM diversity in order to reduce the risk of diseases such as obesity and type 2 diabetes.
Abstract
The gut microbiota (GM) is defined as the community of microorganisms (bacteria, archaea, fungi, viruses) colonizing the gastrointestinal tract. GM regulates various metabolic pathways in the host, including those involved in energy homeostasis, glucose and lipid metabolism, and bile acid metabolism. The relationship between alterations in intestinal microbiota and diseases associated with civilization is well documented. GM dysbiosis is involved in the pathogenesis of diverse diseases, such as metabolic syndrome, cardiovascular diseases, celiac disease, inflammatory bowel disease, and neurological disorders. Multiple factors modulate the composition of the microbiota and how it physically functions, but one of the major factors triggering GM establishment is diet. In this paper, we reviewed the current knowledge about the relationship between nutrition, gut microbiota, and host metabolic status. We described how macronutrients (proteins, carbohydrates, fat) and different dietary patterns (e.g., Western-style diet, vegetarian diet, Mediterranean diet) interact with the composition and activity of GM, and how gut bacterial dysbiosis has an influence on metabolic disorders, such as obesity, type 2 diabetes, and hyperlipidemia.
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Recent Advances in Psoriasis Research; the Clue to Mysterious Relation to Gut Microbiome.
Komine, M
International journal of molecular sciences. 2020;21(7)
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Psoriasis is a chronic inflammatory disease where the skin forms bumpy red patches covered with white scales. There is no cure, but medications have focused on supressing the immune response. There is a link between the gut microbiome and psoriasis but it is poorly understood. This review includes the current understanding of how psoriasis develops and discusses the recent findings to support further research in this area. The composition of the gut microbiome affects inflammation in the whole body. This inflammation is associated with cardiovascular disease, diabetes mellitus and other inflammatory disorders. Recent studies have linked cardiovascular disease, insulin resistance, and metabolic syndrome to an imbalance in the gut microbiome. Psoriasis is often found alongside these conditions with similar abnormalities in gut bacteria. An imbalance in gut microbiome could cause certain people to develop psoriasis. The role of the gut microbiome needs to be further clarified but mounting evidence for this gut/skin link means that other therapeutic options may be available for treatment in the future.
Abstract
Psoriasis is a chronic inflammatory cutaneous disease, characterized by activated plasmacytoid dendritic cells, myeloid dendritic cells, Th17 cells, and hyperproliferating keratinocytes. Recent studies revealed skin-resident cells have pivotal roles in developing psoriatic skin lesions. The balance in effector T cells and regulatory T cells is disturbed, leading Foxp3-positive regulatory T cells to produce proinflammatory IL-17. Not only acquired but also innate immunity is important in psoriasis pathogenesis, especially in triggering the disease. Group 3 innate lymphoid cell are considered one of IL-17-producing cells in psoriasis. Short chain fatty acids produced by gut microbiota stabilize expression of Foxp3 in regulatory T cells, thereby stabilizing their function. The composition of gut microbiota influences the systemic inflammatory status, and associations been shown with diabetes mellitus, cardiovascular diseases, psychomotor diseases, and other systemic inflammatory disorders. Psoriasis has been shown to frequently comorbid with diabetes mellitus, cardiovascular diseases, psychomotor disease and obesity, and recent report suggested the similar abnormality in gut microbiota as the above comorbid diseases. However, the precise mechanism and relation between psoriasis pathogenesis and gut microbiota needs further investigation. This review introduces the recent advances in psoriasis research and tries to provide clues to solve the mysterious relation of psoriasis and gut microbiota.
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Role of Probiotics in Non-alcoholic Fatty Liver Disease: Does Gut Microbiota Matter?
Xie, C, Halegoua-DeMarzio, D
Nutrients. 2019;11(11)
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Non-alcoholic fatty liver disease (NAFLD) is characterised by an excessive accumulation of fat in the liver tissue, without excessive alcohol consumption, and appears to be related to metabolic syndrome. It is thought to have a prevalence of 25% globally and there are no pharmacological treatments available. This review discusses the connection between the gut microbiota (GM) and NAFLD. Various mechanisms by which the GM may be involved in the development of NAFLD are discussed. As probiotics and prebiotics can normalise GM and reverse dysbiosis their use may benefit patients with NAFLD. This has been confirmed in animal models. The authors review 26 randomised controlled trials (RCTs) of probiotics and/or prebiotics in the treatment of NAFLD which evaluate biochemical markers, as well as five meta-analyses, and found that overall there is strong evidence that probiotics and/or prebiotics can lower ALT and AST (markers of NAFLD), although results for other biochemical markers were mixed. They also reviewed RCTs assessing NAFLD by imaging and histological means, and again found benefits from probiotic and/or prebiotic supplementation.
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the hepatic consequence of metabolic syndrome, which often also includes obesity, diabetes, and dyslipidemia. The connection between gut microbiota (GM) and NAFLD has attracted significant attention in recent years. Data has shown that GM affects hepatic lipid metabolism and influences the balance between pro/anti-inflammatory effectors in the liver. Although studies reveal the association between GM dysbiosis and NAFLD, decoding the mechanisms of gut dysbiosis resulting in NAFLD remains challenging. The potential pathophysiology that links GM dysbiosis to NAFLD can be summarized as: (1) disrupting the balance between energy harvest and expenditure, (2) promoting hepatic inflammation (impairing intestinal integrity, facilitating endotoxemia, and initiating inflammatory cascades with cytokines releasing), and (3) altered biochemistry metabolism and GM-related metabolites (i.e., bile acid, short-chain fatty acids, aromatic amino acid derivatives, branched-chain amino acids, choline, ethanol). Due to the hypothesis that probiotics/synbiotics could normalize GM and reverse dysbiosis, there have been efforts to investigate the therapeutic effect of probiotics/synbiotics in patients with NAFLD. Recent randomized clinical trials suggest that probiotics/synbiotics could improve transaminases, hepatic steatosis, and reduce hepatic inflammation. Despite these promising results, future studies are necessary to understand the full role GM plays in NAFLD development and progression. Additionally, further data is needed to unravel probiotics/synbiotics efficacy, safety, and sustainability as a novel pharmacologic approaches to NAFLD.
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Dietary Fructose and the Metabolic Syndrome.
Taskinen, MR, Packard, CJ, Borén, J
Nutrients. 2019;11(9)
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Fructose is a naturally occurring sugar in carbohydrate foods and is often used as an ingredient in foods and sugar sweetened beverages (SSB) such as sport and energy drinks. The consumption of these drinks accounts for up to 15-17% of calorie intake in the modern western diet. Excessive sugar consumption is becoming a major public health issue with high sugar intake linked to Metabolic Syndrome (MetS), cardiovascular disease, type II diabetes and non-alcoholic fatty liver disease. Fructose is largely absorbed in the small intestines however the liver is considered the major organ for fructose metabolism. Too much fructose in the diet appears to stimulate the liver to produce more sugars and triglyceride fats which can raise cholesterol levels and promote insulin resistance. This partially explains the role of fructose in promoting a build-up of fat around the liver leading to non-alcoholic fatty liver disease and central obesity. Too much fructose is also linked to unfavourable changes in gut bacteria which may contribute to obesity and MetS. Overall the study concludes that too much fructose contributes to an unhealthy lifestyle and is a risk factor for metabolic disturbances.
Abstract
Abstract: Consumption of fructose, the sweetest of all naturally occurring carbohydrates, has increased dramatically in the last 40 years and is today commonly used commercially in soft drinks, juice, and baked goods. These products comprise a large proportion of the modern diet, in particular in children, adolescents, and young adults. A large body of evidence associate consumption of fructose and other sugar-sweetened beverages with insulin resistance, intrahepatic lipid accumulation, and hypertriglyceridemia. In the long term, these risk factors may contribute to the development of type 2 diabetes and cardiovascular diseases. Fructose is absorbed in the small intestine and metabolized in the liver where it stimulates fructolysis, glycolysis, lipogenesis, and glucose production. This may result in hypertriglyceridemia and fatty liver. Therefore, understanding the mechanisms underlying intestinal and hepatic fructose metabolism is important. Here we review recent evidence linking excessive fructose consumption to health risk markers and development of components of the Metabolic Syndrome.
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Diet-Gut Microbiota Interactions and Gestational Diabetes Mellitus (GDM).
Ponzo, V, Fedele, D, Goitre, I, Leone, F, Lezo, A, Monzeglio, C, Finocchiaro, C, Ghigo, E, Bo, S
Nutrients. 2019;11(2)
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Gestational diabetes mellitus (GDM) is an increasing public health concern that affects approximately 5-20% of pregnancies with rising prevalence. The potential impact of specific dietary interventions on the gut bacteria composition and function are of considerable interest to prevent and treat GDM. The aim of the study was to analyse the changes in the gut microbiota and the diet-microbiota interactions occurring during healthy pregnancies and pregnancies complicated by GDM. This study is a systemic review. Literature shows that pregnancies complicated with GDM may have an impaired gut microbiota, and this microbiota can be transmitted to the offspring. Diets can shape the gut microbiota, in fact dietary changes can rapidly change the gut microbiota. However, it generally reverts to the original status with short-term dietary modifications. Authors conclude that the optimal nutritional strategy in GDM patients remains unresolved. It is important that the potential benefits of diet are taken into consideration.
Abstract
Medical nutritional therapy is the first-line approach in managing gestational diabetes mellitus (GDM). Diet is also a powerful modulator of the gut microbiota, whose impact on insulin resistance and the inflammatory response in the host are well known. Changes in the gut microbiota composition have been described in pregnancies either before the onset of GDM or after its diagnosis. The possible modulation of the gut microbiota by dietary interventions in pregnancy is a topic of emerging interest, in consideration of the potential effects on maternal and consequently neonatal health. To date, very few data from observational studies are available about the associations between diet and the gut microbiota in pregnancy complicated by GDM. In this review, we analyzed the available data and discussed the current knowledge about diet manipulation in order to shape the gut microbiota in pregnancy.
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The Effect of Probiotic Yogurt on Glycemic Control in Type 2 Diabetes or Obesity: A Meta-Analysis of Nine Randomized Controlled Trials.
Barengolts, E, Smith, ED, Reutrakul, S, Tonucci, L, Anothaisintawee, T
Nutrients. 2019;11(3)
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The metabolic disorders type 2 diabetes and obesity are highly prevalent worldwide. There are multiple merging treatments for type 2 diabetes and obesity, but the management of both conditions remains challenging. The aim of the study was to review the effects of probiotics on glycaemic outcomes in type 2 diabetes or obesity. The study is a meta-analysis of RCTs that utilized probiotic yoghurt as a main intervention in participants with type 2 diabetes or obesity. Nine studies were included in the meta-analysis, seven of which were conducted in subjects with type 2 diabetes and the rest were conducted in subjects with obesity. Results indicate that probiotic yoghurt provides no significant improvement compared with the control in glycaemic markers. Authors conclude that their study did not demonstrate the benefits of consuming probiotic yoghurt compared with conventional yoghurt for improving glucose control in patients with type 2 diabetes or obesity.
Abstract
Probiotic yogurt is suggested as a nutritional approach in type 2 diabetes (T2D) and obesity. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the effects of probiotic yogurt on glycemic outcomes in T2D or obesity. The databases used to search for RCTs included Medline and Scopus. The RCTs were eligible if outcomes included selected glycemic markers. In nine eligible trials, 237 and 235 subjects were in treatment (probiotic yogurt) and control (mostly conventional yogurt) groups, respectively. There was no significant difference for pooled unstandardized mean difference (USMD) hemoglobin A1c (HbA1c) by probiotic yogurt compared with the control in T2D (USMD: -0.366; 95% CI: -0.755, 0.024, p = 0.066) and obesity (USMD: 0.116, 95% CI: -0.007, 0.238, p = 0.065). Similarly, there were no effects of probiotic yogurt on fasting blood glucose, fasting insulin, or insulin resistance (estimated by homeostatic model assessment of insulin resistance (HOMA-IR)) in either T2D or obesity. In conclusion, the present meta-analysis has not demonstrated the benefits of consuming probiotic compared with conventional yogurt for improving glucose control in patients with diabetes or obesity. Larger trials are needed to verify the benefits of probiotic and/or conventional yogurt or other probiotic fermented milk (e.g., kefir) on glycemic markers in patients with diabetes and obesity.
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Metabolic Syndrome Features: Is There a Modulation Role by Mineral Water Consumption? A Review.
Costa-Vieira, D, Monteiro, R, Martins, MJ
Nutrients. 2019;11(5)
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Metabolic syndrome, defined as having high blood pressure, triglycerides, blood glucose and being obese, is becoming an increasing worldwide health problem. It’s considered to be a result of modern-day life styles and there is no effective cure other than diet and life style interventions. This review paper looks at the mineral content and the alkalising effects of mineral water when consumed by participants with metabolic syndrome. The minerals within mineral water are thought to be more readily absorbed in the body than when consumed in foods and since Westernised diets are low in mineral content and high in acidity, consuming mineral water could help counteract mineral deficiencies and help to balance pH in those with metabolic syndrome. 20 studies, both animal and human, were selected for evaluation of the effect of mineral water on blood pressure, lipid profile, blood glucose and waist circumference. The authors conclude that mineral water is indeed beneficial to those with metabolic syndrome and can help counteract mineral deficiencies and balance pH. However, it is unclear whether mineral water in high quantities would be detrimental to a person with adequate mineral status and a pH within optimal range. Further studies are needed.
Abstract
Metabolic syndrome (MetSyn) promotes, among others, the development of atherosclerotic cardiovascular disease and diabetes. Its prevalence increases with age, highlighting the relevance of promoting precocious MetSyn primary prevention and treatment with easy-to-implement lifestyle interventions. MetSyn features modulation through mineral water consumption was reviewed on Pubmed, Scopus and Google Scholar databases, using the following keywords: metabolic syndrome, hypertension, blood pressure (BP), cholesterol, triglycerides, apolipoprotein, chylomicron, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein (HDL), glucose, insulin, body weight, body mass index, waist circumference (WC), obesity and mineral(-rich) water. Twenty studies were selected: 12 evaluated BP, 13 assessed total-triglycerides and/or HDL-cholesterol, 10 analysed glucose and/or 3 measured WC. Mineral waters were tested in diverse protocols regarding type and composition of water, amount consumed, diet and type and duration of the study. Human and animal studies were performed in populations with different sizes and characteristics. Distinct sets of five studies showed beneficial effects upon BP, total-triglycerides, HDL-cholesterol and glucose. WC modulation was not reported. Minerals/elements and active ions/molecules present in mineral waters (and their pH) are crucial to counterbalance their inadequate intake and body status as well as metabolic dysfunction and increased diet-induced acid-load observed in MetSyn. Study characteristics and molecular/physiologic mechanisms that could explain the different effects observed are discussed. Further studies are warranted for determining the mechanisms involved in the putative protective action of mineral water consumption against MetSyn features.
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Impact of vegan diets on gut microbiota: An update on the clinical implications.
Wong, MW, Yi, CH, Liu, TT, Lei, WY, Hung, JS, Lin, CL, Lin, SZ, Chen, CL
Ci ji yi xue za zhi = Tzu-chi medical journal. 2018;30(4):200-203
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Gut microbiota is defined as microbes that collectively inhabit the gut ecosystem. Several factors, including diet, age, birth mode, breast-feeding or formula-feeding, geography, exercise, alcohol consumption, and exposure to antibiotics may influence gut microbiota. Previous conventional culturing together with recent culture-independent molecular studies show that vegan diets appear to affect gut microbiota. Furthermore, recent literature also indicates that vegan diets may have various health benefits, including amelioration of metabolic syndrome, cardiovascular disease and rheumatoid arthritis. Authors conclude that these findings have their limitations. Thus, further research may help to clarify the complex mechanisms and interrelationships between vegan diets and gut microbiota.
Abstract
Numerous studies indicate that microbiota plays an important role in human health. Diet is a factor related to microbiota which also influences human health. The relationships between diet, microbiota, and human health are complex. This review focuses on the current literature on vegan diets and their unique impact on gut microbiota. We also report on the health benefits of a vegan diet for metabolic syndrome, cardiovascular disease, and rheumatoid arthritis concerning relevant impacts from gut microbiota. Despite evidence supporting the clinical relevance of vegan gut microbiota to human health, the whole mechanism awaits further investigation.
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Metabolic and Microbiota Measures as Peripheral Biomarkers in Major Depressive Disorder.
Horne, R, Foster, JA
Frontiers in psychiatry. 2018;9:513
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Though the connection between the gut microbiome, physical health and mental health is becoming more established, there remains a lack of understanding around the underlying cause of major depressive disorder (MDD). There is a need to identify biomarkers in MDD in order to help identify individual differences and improve treatment outcomes. The aim of this review is to investigate the link between metabolic biomarkers and the gut microbiota in individuals experiencing MDD. The current literature points to two potential biomarkers, leptin and ghrelin, which play a role in both metabolic disease and depression. Based on these findings, the authors conclude these biomarkers may help researchers and clinicians establish subgroups in depressed individuals in order to better predict treatment responses and develop more targeted therapies.
Abstract
Advances in understanding the role of the microbiome in physical and mental health are at the forefront of medical research and hold potential to have a direct impact on precision medicine approaches. In the past 7 years, we have studied the role of microbiota-brain communication on behavior in mouse models using germ-free mice, mice exposed to antibiotics, and healthy specific pathogen free mice. Through our work and that of others, we have seen an amazing increase in our knowledge of how bacteria signal to the brain and the implications this has for psychiatry. Gut microbiota composition and function are influenced both by genetics, age, sex, diet, life experiences, and many other factors of psychiatric and bodily disorders and thus may act as potential biomarkers of the gut-brain axis that could be used in psychiatry and co-morbid conditions. There is a particular need in major depressive disorder and other mental illness to identify biomarkers that can stratify patients into more homogeneous groups to provide better treatment and for development of new therapeutic approaches. Peripheral outcome measures of host-microbe bidirectional communication have significant translational value as biomarkers. Enabling stratification of clinical populations, based on individual biological differences, to predict treatment response to pharmacological and non-pharmacological interventions. Here we consider the links between co-morbid metabolic syndrome and depression, focusing on biomarkers including leptin and ghrelin in combination with assessing gut microbiota composition, as a potential tool to help identify individual differences in depressed population.
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Disruption of the Gut Ecosystem by Antibiotics.
Yoon, MY, Yoon, SS
Yonsei medical journal. 2018;59(1):4-12
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The gut microbiome is a complex ecosystem of different micro-organisms, such as bacteria, viruses and fungi, living in the human intestines. It’s involved in numerous functions, such as extracting energy and nutrition from food, protecting against disease-causing microorganisms, and supporting the immune system of the host, and therefore affecting human health and disease. This paper is a review of studies on the effects of antibiotics on the gut microbiota. It outlines how different types of antibiotics can alter the intestinal environment and the composition of the microbes, resulting in various physiological changes that can trigger disease. Relevant mechanisms, such as inflammatory response and the use of intestinal nutrients by infectious bacteria are discussed. Finally, it discusses faecal microbiota transplantation (FMT) and probiotics as treatment approaches, aimed at restoring a disturbed intestinal environment.
Abstract
The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state.