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The impact of nutrition on COVID-19 susceptibility and long-term consequences.
Butler, MJ, Barrientos, RM
Brain, behavior, and immunity. 2020;87:53-54
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The impacts of Covid-19 are being felt across the world, affecting health, healthcare and economies. Statistics from across the world are showing that the elderly, those with underlying medical conditions and under-represented minority groups are particularly vulnerable to severe complications and have a higher risk of dying of Covid-19. This opinion piece presents arguments for the importance of focusing on diet to support health resilience in general and the immune system in particular, to minimise the impact of this and future viruses. Research is presented on excessive intake of saturated fat leading to chronic activation of the innate immune system (first line, rapid defence against infection), resulting in inflammation, and associated heightened susceptibility to complications of viral infection. The standard western diet (high saturated fat, refined carbohydrates and sugars, low levels of fibre, unsaturated fat and antioxidants) has also been shown to affect the adaptive immune system (second line, delayed defence against infection), depressing its action against infection. The piece also discusses possible long-term, future impacts of those recovered from Covid-19 infection, particularly in relation to neurodegenerative diseases such as Alzheimer’s. The authors call for fresh, healthy wholefoods to be readily available and affordable to everyone in society.
Abstract
While all groups are affected by the COVID-19 pandemic, the elderly, underrepresented minorities, and those with underlying medical conditions are at the greatest risk. The high rate of consumption of diets high in saturated fats, sugars, and refined carbohydrates (collectively called Western diet, WD) worldwide, contribute to the prevalence of obesity and type 2 diabetes, and could place these populations at an increased risk for severe COVID-19 pathology and mortality. WD consumption activates the innate immune system and impairs adaptive immunity, leading to chronic inflammation and impaired host defense against viruses. Furthermore, peripheral inflammation caused by COVID-19 may have long-term consequences in those that recover, leading to chronic medical conditions such as dementia and neurodegenerative disease, likely through neuroinflammatory mechanisms that can be compounded by an unhealthy diet. Thus, now more than ever, wider access to healthy foods should be a top priority and individuals should be mindful of healthy eating habits to reduce susceptibility to and long-term complications from COVID-19.
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Can Vitamin D and L-Cysteine Co-Supplementation Reduce 25(OH)-Vitamin D Deficiency and the Mortality Associated with COVID-19 in African Americans?
Jain, SK, Parsanathan, R
Journal of the American College of Nutrition. 2020;39(8):694-699
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African Americans are more susceptible to vitamin D deficiency. In addition they have lower amounts of cellular glutathione (GSH), which is an antioxidant produced in the body from L-cysteine, capable of affecting genes involved in vitamin D production. Clinical trials have indicated a relationship between vitamin D deficiency and poorer outcomes in patients with COVID-19. This review paper looked at data in humans, animal models and at the cellular level and proposed that African Americans are susceptible to vitamin D deficiency due to increased skin pigmentation affecting its production. Reduced GSH was attributed to decreased dietary intake of L-cysteine, and lower levels of biological compounds, which are involved in the production of GSH. Research surrounding vitamin D’s role in immunity and lowering viral infection risk was reviewed and several routes were proposed, such as increasing anti-microbial action, decreasing inflammation, increasing anti-oxidants and blocking viruses entering cells. It was concluded that randomised control trials on vitamin D supplementation have been underwhelming. This disconnect with trials showing a relationship between low vitamin D levels and poor clinical outcomes is due to the fact that vitamin D was tested in isolation. More randomised control trials are needed to investigate co-supplementation with L-cysteine on outcomes of COVID-19 infection in African Americans. Clinicians could use this review to understand the relationship between vitamin D and L-cysteine and, in lieu of any randomised control trials, as a potential justification for co- supplementation of Vitamin D and L-cysteine in patients with vitamin D deficiency and COVID-19.
Abstract
Early reports indicate an association between the severity of the COVID-19 infection and the widespread 25-hydroxy vitamin D deficiency known to exist in populations around the world. Vitamin D deficiency is extremely common among African American (AA) communities, where the COVID-19 infection rate is three-fold higher, and the mortality rate nearly six-fold higher, compared with rates in predominantly white communities. COVID-19 infection primarily affects the lungs and airways. Previous reports have linked 25-hydroxy vitamin D deficiency with subclinical interstitial lung disease. AA are at risk for lower cellular glutathione (GSH) levels, and GSH deficiency epigenetically impairs VD biosynthesis pathway genes. Compared with vitamin D alone, co-supplementation of vitamin D and L-cysteine (a GSH precursor) showed a better efficacy in improving levels of GSH and VD-regulatory genes at the cellular/tissue level, increasing 25(OH) vitamin D levels, and reducing inflammation biomarkers in the blood in mice studies. We propose that randomized clinical trials are needed to examine the potential of co-supplementation with anti-inflammatory antioxidants, vitamin D and L-cysteine in correcting the 25(OH)VD deficiency and preventing the 'cytokine storm,' one of the most severe consequences of infection with COVID-19, thereby preventing the adverse clinical effects of COVID-19 infection in the vulnerable AA population.
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Treatment With a Marine Oil Supplement Alters Lipid Mediators and Leukocyte Phenotype in Healthy Patients and Those With Peripheral Artery Disease.
Schaller, MS, Chen, M, Colas, RA, Sorrentino, TA, Lazar, AA, Grenon, SM, Dalli, J, Conte, MS
Journal of the American Heart Association. 2020;9(15):e016113
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Peripheral artery disease (PAD) is one of the most advanced forms of atherosclerosis. This disease state begins from an inflammatory lesion. The aim of this study was to investigate the impact of a short-course, oral, enriched marine oil supplement on circulating leukocytes and biochemical mediators in patients with symptomatic PAD and healthy controls. This study is a prospective, open-label, nonblinded study. Twenty participants completed the study: ten with PAD and 10 healthy individuals. Results show: - a shift in the leukocyte profiling towards a less inflammatory and more pro-resolving phenotype, most notably within the PAD cohort. - that supplementation led to an increase in phagocytic [a type of immune cell] activity of peripheral blood monocytes and neutrophils. - that circulating monocyte phenotyping demonstrated reduced expression of multiple proinflammatory markers. - that gene expression patterns in mono-derived macrophage from patients with PAD displayed a less inflammatory (type 1 macrophage) and greater reparative (type 2 macrophage) phenotype after supplementation. Authors conclude that their findings provide a foundation for characterising biochemical and cellular biomarkers of inflammation and resolution in PAD.
Abstract
Background Peripheral artery disease (PAD) is an advanced form of atherosclerosis characterized by chronic inflammation. Resolution of inflammation is a highly coordinated process driven by specialized pro-resolving lipid mediators endogenously derived from omega-3 fatty acids. We investigated the impact of a short-course, oral, enriched marine oil supplement on leukocyte phenotype and biochemical mediators in patients with symptomatic PAD and healthy volunteers. Methods and Results This was a prospective, open-label study of 5-day oral administration of an enriched marine oil supplement, assessing 3 escalating doses in 10 healthy volunteers and 10 patients with PAD. Over the course of the study, there was a significant increase in the plasma level of several lipid mediator families, total specialized pro-resolving lipid mediators, and specialized pro-resolving lipid mediator:prostaglandin ratio. Supplementation was associated with an increase in phagocytic activity of peripheral blood monocytes and neutrophils. Circulating monocyte phenotyping demonstrated reduced expression of multiple proinflammatory markers (cluster of differentiation 18, 163, 54, and 36, and chemokine receptor 2). Similarly, transcriptional profiling of monocyte-derived macrophages displayed polarization toward a reparative phenotype postsupplementation. The most notable cellular and biochemical changes over the study occurred in patients with PAD. There were strong correlations between integrated biochemical measures of lipid mediators (specialized pro-resolving lipid mediators:prostaglandin ratio) and phenotypic changes in circulating leukocytes in both healthy individuals and patients with PAD. Conclusions These data suggest that short-term enriched marine oil supplementation dramatically remodels downstream lipid mediator pathways and induces a less inflammatory and more pro-resolution phenotype in circulating leukocytes and monocyte-derived macrophages. Further studies are required to determine the potential clinical relevance of these findings in patients with PAD. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02719665.
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Reductions in anti-inflammatory gut bacteria are associated with depression in a sample of young adults.
Liu, RT, Rowan-Nash, AD, Sheehan, AE, Walsh, RFL, Sanzari, CM, Korry, BJ, Belenky, P
Brain, behavior, and immunity. 2020;88:308-324
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Alterations to the gut microbiota may be associated with depression and anxiety disorders through a pathway known as the gut-brain axis. Inflammation may be the mediator between the two, as individuals with major depressive disorder (MDD) have reported high levels of inflammation, which the gut microbiota may have the capacity to protect against. This observational study of the gut microbiota of 90 young adults with MDD and 47 healthy controls aimed to determine the relationship between inflammatory gut microbiota and symptoms of depression. The results showed changes to several species of gut microbiota in those with MDD and that the level of change was related to MDD symptom severity. These changes were observed even in those taking psychotropic medications. Changes at the taxonomic level indicated that those with higher symptoms of depression had more pronounced differences compared with healthy controls. Although the observed differences were indicative of an inflammatory microbiome, no changes were observed in blood markers of inflammation between those individuals with MDD and healthy controls. It was concluded that the gut microbiome of individuals with MDD was different from healthy individuals in favour of an inflammatory environment. This study could be used by healthcare professionals to understand that the status of the gut microbiota may be an important measure in individuals with MDD and that a treatment plan to ensure gut health is considered may help with symptoms of depression.
Abstract
We assessed the gut microbiota of 90 American young adults, comparing 43 participants with major depressive disorder (MDD) and 47 healthy controls, and found that the MDD subjects had significantly different gut microbiota compared to the healthy controls at multiple taxonomic levels. At the phylum level, participants with MDD had lower levels of Firmicutes and higher levels of Bacteroidetes, with similar trends in the at the class (Clostridia and Bacteroidia) and order (Clostridiales and Bacteroidales) levels. At the genus level, the MDD group had lower levels of Faecalibacterium and other related members of the family Ruminococcaceae, which was also reduced relative to healthy controls. Additionally, the class Gammaproteobacteria and genus Flavonifractor were enriched in participants with MDD. Accordingly, predicted functional differences between the two groups include a reduced abundance of short-chain fatty acid production pathways in the MDD group. We also demonstrated that the magnitude of taxonomic changes was associated with the severity of depressive symptoms in many cases, and that most changes were present regardless of whether depressed participants were taking psychotropic medications. Overall, our results support a link between MDD and lower levels of anti-inflammatory, butyrate-producing bacteria, and may support a connection between the gut microbiota and the chronic, low-grade inflammation often observed in MDD patients.
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Vitamin D for the Immune System in Cystic Fibrosis (DISC): a double-blind, multicenter, randomized, placebo-controlled clinical trial.
Tangpricha, V, Lukemire, J, Chen, Y, Binongo, JNG, Judd, SE, Michalski, ES, Lee, MJ, Walker, S, Ziegler, TR, Tirouvanziam, R, et al
The American journal of clinical nutrition. 2019;109(3):544-553
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Patients with cystic fibrosis (CF) have a mutation in a particular gene which results in derangements in chloride transport across epithelial surfaces, leading to abnormally thickened mucus on the surfaces of the lung, pancreas, intestines, and other organs. The aim of this study was to investigate the impact of high-dose vitamin D3 administered to adults with CF during and after an acute pulmonary exacerbation. The study is a double-blind, randomised, placebo-controlled clinical trial. Subjects were randomly assigned and stratified to one of the two groups: vitamin D (5 capsules of vitamin D3 containing 50,000 IU) or placebo (5 capsules that were identical in size, shape, and colour to the vitamin D3 capsule). Results demonstrated that high-dose vitamin D3 administration to adults with CF initiated at the time of a pulmonary exacerbation did not improve time to next pulmonary exacerbation or 1 year survival. Authors conclude that a high-dose vitamin D3 bolus, combined with maintenance therapy given to adults with CF during acute pulmonary exacerbation of CF did not improve 1 year survival or recovery of lung function.
Abstract
BACKGROUND Patients with cystic fibrosis (CF) have increased risk of vitamin D deficiency owing to fat malabsorption and other factors. Vitamin D deficiency has been associated with increased risk of pulmonary exacerbations of CF. OBJECTIVES The primary objective of this study was to examine the impact of a single high-dose bolus of vitamin D3 followed by maintenance treatment given to adults with CF during an acute pulmonary exacerbation on future recurrence of pulmonary exacerbations. METHODS This was a multicenter, double-blind, placebo-controlled, intent-to-treat clinical trial. Subjects with CF were randomly assigned to oral vitamin D3 given as a single dose of 250,000 International Units (IU) or to placebo within 72 h of hospital admission for an acute pulmonary exacerbation, followed by 50,000 IU of vitamin D3 or an identically matched placebo pill taken orally every other week starting at 3 mo after random assignment. The primary outcome was the composite endpoint of the time to next pulmonary exacerbation or death within 1 y. The secondary outcomes included circulating concentrations of the antimicrobial peptide cathelicidin and recovery of lung function as assessed by the percentage of predicted forced expiratory volume in 1 s (FEV1%). RESULTS A total of 91 subjects were enrolled in the study. There were no differences between the vitamin D3 and placebo groups in time to next pulmonary exacerbation or death at 1 y. In addition, there were no differences in serial recovery of lung function after pulmonary exacerbation by FEV1% or in serial concentrations of plasma cathelicidin. CONCLUSIONS Vitamin D3 initially given at the time of pulmonary exacerbation of CF did not alter the time to the next pulmonary exacerbation, 12-mo mortality, serial lung function, or serial plasma cathelicidin concentrations. This trial was registered at clinicaltrials.gov as NCT01426256.
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The effect of a short-term low-carbohydrate, high-fat diet with or without postmeal walks on glycemic control and inflammation in type 2 diabetes: a randomized trial.
Myette-Côté, É, Durrer, C, Neudorf, H, Bammert, TD, Botezelli, JD, Johnson, JD, DeSouza, CA, Little, JP
American journal of physiology. Regulatory, integrative and comparative physiology. 2018;315(6):R1210-R1219
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Inflammation is associated with the pathogenesis of insulin resistance, type 2 diabetes (T2D), and related complications. Lifestyle therapy is a frontline treatment for improving glucose control in people with T2D. The main aim of this study was to determine whether reducing hyperglycaemia with a low-carbohydrate high-fat (LC) diet could lower markers of innate immune cell activation and systemic inflammation in people with T2D. A secondary aim was to examine if the combination of an LCHF diet with strategically timed postmeal walking was superior to an LCHF diet alone. The study is a randomised cross over study which enrolled Individuals with physician-diagnosed T2D to complete three short-term controlled-intervention periods. Sixteen participants were enrolled (men = 8 and women = 8) who were aged between 48 and 72 years. Results indicate that while LC and LC together with exercise (LC+Ex) led to superior improvements in glucose control and fasting proinsulin (the pro-hormone precursor to insulin) levels as compared with low-fat low glycaemic index diet (GL), all three diets (GL, LC and LC+Ex), appeared to lower a particular marker of cellular inflammation over the short-term. Authors conclude that an LCHF diet with or without daily postmeal walks improved four-day glycaemic control and fasting proinsulin levels compared with a GL diet.
Abstract
Lowering carbohydrate consumption effectively lowers glucose, but impacts on inflammation are unclear. The objectives of this study were to: 1) determine whether reducing hyperglycemia by following a low-carbohydrate, high-fat (LC) diet could lower markers of innate immune cell activation in type 2 diabetes (T2D) and 2) examine if the combination of an LC diet with strategically timed postmeal walking was superior to an LC diet alone. Participants with T2D ( n = 11) completed a randomized crossover study involving three 4-day diet interventions: 1) low-fat low-glycemic index (GL), 2) and 3) LC with 15-min postmeal walks (LC+Ex). Four-day mean glucose was significantly lower in the LC+Ex group as compared with LC (-5%, P < 0.05), whereas both LC+Ex (-16%, P < 0.001) and LC (-12%, P < 0.001) conditions were lower than GL. A significant main effect of time was observed for peripheral blood mononuclear cells phosphorylated c-Jun N-terminal kinase ( P < 0.001), with decreases in all three conditions (GL: -32%, LC: -45%, and LC+Ex: -44%). A significant condition by time interaction was observed for monocyte microparticles ( P = 0.040) with a significant decrease in GL (-76%, P = 0.035) and a tendency for a reduction in LC (-70%, P = 0.064), whereas there was no significant change in LC+Ex (0.5%, P = 0.990). Both LC (-27%, P = 0.001) and LC+Ex (-35%, P = 0.005) also led to significant reductions in circulating proinsulin. An LC diet improved 4-day glycemic control and fasting proinsulin levels when compared with GL, with added glucose-lowering benefits when LC was combined with postmeal walking.
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Maternal diet during pregnancy is related with the infant stool microbiome in a delivery mode-dependent manner.
Lundgren, SN, Madan, JC, Emond, JA, Morrison, HG, Christensen, BC, Karagas, MR, Hoen, AG
Microbiome. 2018;6(1):109
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The mechanism by which the maternal diet may influence the gut microbiota of an infant remains unknown. This study aimed to examine the association of maternal diet during pregnancy and mode of delivery on the gut microbiome 6 weeks post-delivery. 976 subjects were enrolled aged of 18 and 45 years old, between 24 and 28 weeks of gestation and their maternal diet during pregnancy was assessed with a validated food frequency questionnaire. Effects of maternal dairy intake on infant gut microbiota showed decreased colonization of milk-digesting bacteria in infants delivered by caesarean section, when compared to those who were born vaginally. The authors concluded that future studies examining the relationship between maternal diet and components of breast milk including microbial and nutritional profiles, may help to offer insight into the mechanism by which maternal diet influences the gut microbiome of an infant.
Abstract
BACKGROUND The gut microbiome has an important role in infant health and immune development and may be affected by early-life exposures. Maternal diet may influence the infant gut microbiome through vertical transfer of maternal microbes to infants during vaginal delivery and breastfeeding. We aimed to examine the association of maternal diet during pregnancy with the infant gut microbiome 6 weeks post-delivery in mother-infant dyads enrolled in the New Hampshire Birth Cohort Study. Infant stool samples were collected from 145 infants, and maternal prenatal diet was assessed using a food frequency questionnaire. We used targeted sequencing of the 16S rRNA V4-V5 hypervariable region to characterize infant gut microbiota. To account for differences in baseline and trajectories of infant gut microbial profiles, we stratified analyses by delivery mode. RESULTS We identified three infant gut microbiome clusters, characterized by increased abundance of Bifidobacterium, Streptococcus and Clostridium, and Bacteroides, respectively, overall and in the vaginally delivered infant stratum. In the analyses stratified to infants born vaginally and adjusted for other potential confounders, maternal fruit intake was associated with infant gut microbial community structure (PERMANOVA, p < 0.05). In multinomial logistic regression analyses, increased fruit intake was associated with an increased odds of belonging to the high Streptococcus/Clostridium group among infants born vaginally (OR (95% CI) = 2.73 (1.36, 5.46)). In infants delivered by Cesarean section, we identified three clusters that differed slightly from vaginally delivered infants, which were characterized by a high abundance of Bifidobacterium, high Clostridium and low Streptococcus and Ruminococcus genera, and high abundance of the family Enterobacteriaceae. Maternal dairy intake was associated with an increased odds of infants belonging to the high Clostridium cluster in infants born by Cesarean section (OR (95% CI) = 2.36 (1.05, 5.30)). Linear models suggested additional associations between maternal diet and infant intestinal microbes in both delivery mode strata. CONCLUSIONS Our data indicate that maternal diet influences the infant gut microbiome and that these effects differ by delivery mode.
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Human Gut Microbiota and Gastrointestinal Cancer.
Meng, C, Bai, C, Brown, TD, Hood, LE, Tian, Q
Genomics, proteomics & bioinformatics. 2018;16(1):33-49
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In this article the authors review research on the influence of the human gut microbiota on the development and progression of gastrointestinal cancers, and go into significant detail about the molecular mechanisms involved. Helicobacter pylori is a known risk factor for gastric cancer (GC) but other dysbiotic changes in the gut microbiota are also observed in GC. On the other hand, H. pylori is associated with a decreased risk for oesophageal cancer (OC). An increase in gram-negative bacteria is associated with OC, whilst gram-positive bacteria are dominant in a healthy oesophagus. Dietary factors are associated with the risk for colorectal cancer (CRC) and may be due to their effect on the bacterial composition of the bowel. The authors explore possible mechanisms for these links. Although the liver is considered sterile, carcinogenesis can be influenced by the gut microbiota through pathogens and bacterial metabolites which can disturb metabolic pathways and immune responses in the liver. In pancreatic cancer (PC), the gut microbiota may influence carcinogenesis by promoting inflammation. In addition to various lifestyle factors, H. pylori is a risk factor for PC. The authors also review the use of prebiotics, probiotics, synbiotics (a combination of pre- and pro-biotics) and Traditional Chinese Medicine as an adjunct to conventional cancer treatment to reduce side effects, as well as their potential preventive mechanisms.
Abstract
Human gut microbiota play an essential role in both healthy and diseased states of humans. In the past decade, the interactions between microorganisms and tumors have attracted much attention in the efforts to understand various features of the complex microbial communities, as well as the possible mechanisms through which the microbiota are involved in cancer prevention, carcinogenesis, and anti-cancer therapy. A large number of studies have indicated that microbial dysbiosis contributes to cancer susceptibility via multiple pathways. Further studies have suggested that the microbiota and their associated metabolites are not only closely related to carcinogenesis by inducing inflammation and immune dysregulation, which lead to genetic instability, but also interfere with the pharmacodynamics of anticancer agents. In this article, we mainly reviewed the influence of gut microbiota on cancers in the gastrointestinal (GI) tract (including esophageal, gastric, colorectal, liver, and pancreatic cancers) and the regulation of microbiota by diet, prebiotics, probiotics, synbiotics, antibiotics, or the Traditional Chinese Medicine. We also proposed some new strategies in the prevention and treatment of GI cancers that could be explored in the future. We hope that this review could provide a comprehensive overview of the studies on the interactions between the gut microbiota and GI cancers, which are likely to yield translational opportunities to reduce cancer morbidity and mortality by improving prevention, diagnosis, and treatment.
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Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults.
Vanegas, SM, Meydani, M, Barnett, JB, Goldin, B, Kane, A, Rasmussen, H, Brown, C, Vangay, P, Knights, D, Jonnalagadda, S, et al
The American journal of clinical nutrition. 2017;105(3):635-650
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Increased whole grain consumption has been associated with reduced levels of inflammation. This randomised, controlled trial aimed to assess the effects of a whole grain diet in comparison with a refined grain diet on the immune system, levels of inflammation and gut bacteria. 81 men and women aged between 40 and 60 were randomly assigned to either a whole grain or a refined grain diet for a period of 6 weeks. All other dietary components were kept the same and calorie levels were controlled to maintain weight levels. The study findings showed a positive effect on stool frequency and stool weight with the whole grain diet in comparison to the refined grain diet. The whole grain diet also showed modest positive effects on gut bacteria profiles and aspects of immunity. The whole grain diet showed no effects on markers of inflammation.
Abstract
Background: Observational studies suggest an inverse association between whole-grain (WG) consumption and inflammation. However, evidence from interventional studies is limited, and few studies have included measurements of cell-mediated immunity.Objective: We assessed the effects of diets rich in WGs compared with refined grains (RGs) on immune and inflammatory responses, gut microbiota, and microbial products in healthy adults while maintaining subject body weights.Design: After a 2-wk provided-food run-in period of consuming a Western-style diet, 49 men and 32 postmenopausal women [age range: 40-65 y, body mass index (in kg/m2) <35] were assigned to consume 1 of 2 provided-food weight-maintenance diets for 6 wk.Results: Compared with the RG group, the WG group had increased plasma total alkyresorcinols (a measure of WG intake) (P < 0.0001), stool weight (P < 0.0001), stool frequency (P = 0.02), and short-chain fatty acid (SCFA) producer Lachnospira [false-discovery rate (FDR)-corrected P = 0.25] but decreased pro-inflammatory Enterobacteriaceae (FDR-corrected P = 0.25). Changes in stool acetate (P = 0.02) and total SCFAs (P = 0.05) were higher in the WG group than in the RG group. A positive association was shown between Lachnospira and acetate (FDR-corrected P = 0.002) or butyrate (FDR-corrected P = 0.005). We also showed that there was a higher percentage of terminal effector memory T cells (P = 0.03) and LPS-stimulated ex vivo production of tumor necrosis factor-α (P = 0.04) in the WG group than in the RG group, which were positively associated with plasma alkylresorcinol concentrations.Conclusion: The short-term consumption of WGs in a weight-maintenance diet increases stool weight and frequency and has modest positive effects on gut microbiota, SCFAs, effector memory T cells, and the acute innate immune response and no effect on other markers of cell-mediated immunity or systemic and gut inflammation. This trial was registered at clinicaltrials.gov as NCT01902394.
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Influence of diet on the gut microbiome and implications for human health.
Singh, RK, Chang, HW, Yan, D, Lee, KM, Ucmak, D, Wong, K, Abrouk, M, Farahnik, B, Nakamura, M, Zhu, TH, et al
Journal of translational medicine. 2017;15(1):73
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Gut microbiome plays an important role in modulating the risk of many chronic diseases through its impact on host immunity and metabolic health. Diet, in turn, can alter the composition of the microbiota. This paper reviewed current understanding of the effects of common dietary components and three select diets on gut microbiota composition and host health. Dietary components included plant and animal protein, saturated and unsaturated fats, digestible and non-digestible carbohydrates, probiotics and polyphenols. The diets included Western diet, gluten-free diet and Mediterranean diet. Based on the reviewed papers, the authors concluded that diet can modify the intestinal microbiome, which in turn has a profound impact on overall health. The impact can be beneficial or detrimental, depending on the abundance and identity of microbial populations and the nature of their interactions with the host. The authors also state that further research using large, long-term clinical trials to evaluate a greater variety of food components would be helpful in making specific dietary recommendations to patients.
Abstract
Recent studies have suggested that the intestinal microbiome plays an important role in modulating risk of several chronic diseases, including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease, and cancer. At the same time, it is now understood that diet plays a significant role in shaping the microbiome, with experiments showing that dietary alterations can induce large, temporary microbial shifts within 24 h. Given this association, there may be significant therapeutic utility in altering microbial composition through diet. This review systematically evaluates current data regarding the effects of several common dietary components on intestinal microbiota. We show that consumption of particular types of food produces predictable shifts in existing host bacterial genera. Furthermore, the identity of these bacteria affects host immune and metabolic parameters, with broad implications for human health. Familiarity with these associations will be of tremendous use to the practitioner as well as the patient.