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The Specific Carbohydrate Diet and Diet Modification as Induction Therapy for Pediatric Crohn's Disease: A Randomized Diet Controlled Trial.
Suskind, DL, Lee, D, Kim, YM, Wahbeh, G, Singh, N, Braly, K, Nuding, M, Nicora, CD, Purvine, SO, Lipton, MS, et al
Nutrients. 2020;12(12)
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Crohn’s disease is a painful chronic lifelong condition where the digestive tract gets inflamed. Environmental insults and gut microbial changes may contribute to immune dysregulation by activating and upregulating the immune system in Crohn’s disease. During this single-centre, randomised, double-blind, diet-controlled study, ten male active Crohn's disease patients aged seven to eighteen were randomly assigned to either a specific carbohydrate diet, a modified specific carbohydrate diet, or a whole food diet. All diet groups showed a reduction in symptoms, inflammation, and a positive change in the gut microbial composition after 12 weeks, depending on the degree of variability in the dietary regimen. Based on the results of this study, an exclusionary diet eliminating grains, sugar, dairy, and processed foods may have a positive impact on reducing Crohn's disease symptoms, inflammation, and improving gut microbial composition and biochemical markers. In the future, robust studies with a larger sample size will be needed to figure out better dietary strategies for Crohn's disease. Healthcare professionals can, however, use these results to identify dietary choices that can reduce Crohn's disease symptoms.
Abstract
BACKGROUND Crohn's disease (CD) is a chronic inflammatory intestinal disorder associated with intestinal dysbiosis. Diet modulates the intestinal microbiome and therefore has a therapeutic potential. The aim of this study is to determine the potential efficacy of three versions of the specific carbohydrate diet (SCD) in active Crohn's Disease. METHODS 18 patients with mild/moderate CD (PCDAI 15-45) aged 7 to 18 years were enrolled. Patients were randomized to either SCD, modified SCD(MSCD) or whole foods (WF) diet. Patients were evaluated at baseline, 2, 4, 8 and 12 weeks. PCDAI, inflammatory labs and multi-omics evaluations were assessed. RESULTS Mean age was 14.3 ± 2.9 years. At week 12, all participants (n = 10) who completed the study achieved clinical remission. The C-reactive protein decreased from 1.3 ± 0.7 at enrollment to 0.9 ± 0.5 at 12 weeks in the SCD group. In the MSCD group, the CRP decreased from 1.6 ± 1.1 at enrollment to 0.7 ± 0.1 at 12 weeks. In the WF group, the CRP decreased from 3.9 ± 4.3 at enrollment to 1.6 ± 1.3 at 12 weeks. In addition, the microbiome composition shifted in all patients across the study period. While the nature of the changes was largely patient specific, the predicted metabolic mode of the organisms increasing and decreasing in activity was consistent across patients. CONCLUSIONS This study emphasizes the impact of diet in CD. Each diet had a positive effect on symptoms and inflammatory burden; the more exclusionary diets were associated with a better resolution of inflammation.
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Effects of Lactobacillus plantarum and Lactobacillus paracasei on the Peripheral Immune Response in Children with Celiac Disease Autoimmunity: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.
Håkansson, Å, Andrén Aronsson, C, Brundin, C, Oscarsson, E, Molin, G, Agardh, D
Nutrients. 2019;11(8)
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An abnormal immune response to gluten may lead to lifelong digestive symptoms in patients with celiac disease. Several species of beneficial bacteria in the gut may reduce inflammation by reducing the amount of proinflammatory cytokines released in response to antigens. The purpose of this randomized, double-blind, controlled trial was to investigate the effects of Lactobacillus plantarum HEAL9 and L. paracasei 8700:2 on the development of celiac disease in children who are at high risk of developing the celiac disease while eating a gluten-containing diet. A total of seventy-eight children with celiac autoimmunity were given either 10¹ºCFU/day of L. plantarum HEAL9 and L. paracasei 8700:2 or maltodextrin for six months. It has been observed that six months of intervention with probiotics modulated the immune response in celiac disease autoimmunity. In the intervention group, there were no signs of celiac disease progression. There is a need for further robust and long-term studies to examine more specifically the benefits of Lactobacillus in the prevention of celiac disease as well as modulating effects on the intestinal mucosa. It is important to point out that healthcare professionals can use the results of this study to better understand the immunomodulatory effects of specific Lactobacillus strains in celiac disease.
Abstract
Two Lactobacillus strains have proven anti-inflammatory properties by reducing pro-inflammatory responses to antigens. This randomized double-blind placebo-controlled trial tested the hypothesis that L. plantarum HEAL9 and L. paracasei 8700:2 suppress ongoing celiac disease autoimmunity in genetically at risk children on a gluten-containing diet in a longitudinally screening study for celiac disease. Seventy-eight children with celiac disease autoimmunity participated of whom 40 received 1010 CFU/day of L. plantarum HEAL9 and L. paracasei 8700:2 (probiotic group) and 38 children maltodextrin (placebo group) for six months. Blood samples were drawn at zero, three and six months and phenotyping of peripheral blood lymphocytes and IgA and IgG autoantibodies against tissue transglutaminase (tTG) were measured. In the placebo group, naïve CD45RA+ Th cells decreased (p = 0.002) whereas effector and memory CD45RO+ Th cells increased (p = 0.003). In contrast, populations of cells expressing CD4+CD25highCD45RO+CCR4+ increased in the placebo group (p = 0.001). Changes between the groups were observed for NK cells (p = 0.038) and NKT cells (p = 0.008). Median levels of IgA-tTG decreased more significantly over time in the probiotic (p = 0.013) than in the placebo (p = 0.043) group whereas the opposite was true for IgG-tTG (p = 0.062 respective p = 0.008). In conclusion, daily oral administration of L. plantarum HEAL9 and L. paracasei 8700:2 modulate the peripheral immune response in children with celiac disease autoimmunity.
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Effects of Diet Based on IgG Elimination Combined with Probiotics on Migraine Plus Irritable Bowel Syndrome.
Xie, Y, Zhou, G, Xu, Y, He, B, Wang, Y, Ma, R, Chang, Y, He, D, Xu, C, Xiao, Z
Pain research & management. 2019;2019:7890461
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The causes of irritable bowel syndrome (IBS) are complex and not fully understood, yet the occurrence of migraine has been linked with this disease. As they have an association, therapies used for either disorder may have a direct impact on both. Food sensitivities have been shown to affect both migraines and IBS and the elimination of foods may be of benefit to both disorders. This randomised cross-over trial of 60 individuals with migraine and IBS assessed immune reactions to certain foods and aimed to determine the effect of eliminating these foods and the addition of probiotics on individuals with IBS and migraine. The results showed that after 14 weeks of treatment, only elimination diet combined with probiotics improved migraine and IBS symptoms, resulting in a decrease in the use of medications. Individuals treated with elimination diet or probiotics only did show an improvement in comparison to the start of the trial, however not when compared to the combination treatment It was concluded that elimination diet in combination with probiotics may be of benefit to relieve symptoms of migraine and IBS. This study could be used by healthcare professionals to understand possible causes of IBS and migraines, and that treatments may involve targeting both illnesses.
Abstract
Several research studies have revealed that migraine has a solid link with gastrointestinal diseases especially irritable bowel syndrome (IBS). This study was carried out to investigate therapeutic potential of diet based on IgG elimination combined with probiotics on migraine plus irritable bowel syndrome. A total of 60 patients diagnosed with migraine plus IBS were recruited for the study. IgG antibodies against 266 food varieties were detected by ELISA. Then, the subjects were randomized into three groups for treatment of IgG elimination diet or probiotics or diet combined with probiotics. Migraine symptom, gut function score, medication use, and serum serotonin level were measured at baseline, 7 weeks, and 14 weeks. Improvement of migraine and gut symptom was achieved at a certain time point. Reduced use of over-the-counter- (OTC-) analgesics was seen in all groups. However, use of triptans did not show significant difference. An increased serum serotonin level was seen in subjects treated with elimination diet and elimination diet combined with probiotics. IgG elimination diet combined with probiotics may be beneficial to migraine plus IBS. It may provide new insight by understanding the intricate relationship between migraine and gastrointestinal diseases.
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Efficacy and Safety of Oral Administration of a Mixture of Probiotic Strains in Patients with Psoriasis: A Randomized Controlled Clinical Trial.
Navarro-López, V, Martínez-Andrés, A, Ramírez-Boscá, A, Ruzafa-Costas, B, Núñez-Delegido, E, Carrión-Gutiérrez, MA, Prieto-Merino, D, Codoñer-Cortés, F, Ramón-Vidal, D, Genovés-Martínez, S, et al
Acta dermato-venereologica. 2019;99(12):1078-1084
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Psoriasis is as an immune-mediated, inflammatory dermatological disease characterized by a chronic-relapsing course and associated with multifactorial inheritance. The elevation of inflammatory markers is characteristic in peripheral blood of patients with psoriasis. The aim of this study was to determine the efficacy and safety of a probiotic mixture in the reduction of psoriasis severity. This study is a double-blind, randomised (1:1) placebo-controlled trial. Ninety patients were recruited, evaluated by 3 dermatologists and randomly assigned to one of the two trial arms (probiotics or control). Results show: - a beneficial effect of the probiotic blend, in reducing the severity of psoriasis when administered as coadjutant therapy together with topical corticosteroid. - the efficacy of the probiotic in modulation of the composition of the microbiota. - that patients previously treated with the probiotic mixture have a lower risk of relapse than those who previously received placebo. Authors conclude that more studies are required with the inclusion of patients younger than 18 years, the use of different doses of probiotics, different durations of probiotic administration and different strains, for comparison with the current results.
Abstract
The aim of this 12-week randomized, double-blind, placebo-controlled trial was to determine the efficacy and safety of a probiotic mixture in the reduction of psoriasis severity. Ninety 18-70-year-old adults with plaque psoriasis were randomized into probiotic and placebo groups. At 12-week follow-up, 66.7% of patients in the probiotic group and 41.9% in the placebo group showed a reduction in Psoriasis Area and Severity Index of up to 75% (p < 0.05). A clinically relevant difference was observed in Physician Global Assessment index: 48.9% in the probiotic group achieved a score of 0 or 1, compared with 30.2% in the placebo group. The results of follow-up 6 months after the end of the study showed a lower risk of relapse after the intake of the probiotic mixture. Analysis of gut microbiota confirmed the efficacy of the probiotic in modulation of the microbiota composition.
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The study evaluating the effect of probiotic supplementation on the mental status, inflammation, and intestinal barrier in major depressive disorder patients using gluten-free or gluten-containing diet (SANGUT study): a 12-week, randomized, double-blind, and placebo-controlled clinical study protocol.
Karakula-Juchnowicz, H, Rog, J, Juchnowicz, D, Łoniewski, I, Skonieczna-Żydecka, K, Krukow, P, Futyma-Jedrzejewska, M, Kaczmarczyk, M
Nutrition journal. 2019;18(1):50
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Major depressive disorder (MDD) has historically been recognised as a brain disease, however more recently it is being recognised as a whole-body disorder. The immune system and the gut microbiota have been implicated in MDD with particular focus on the gut wall integrity and the resultant immune reaction and its influence on the brain. Gluten may incite an immune reaction in certain individuals and a gluten free diet may be of benefit to symptoms of depression in those who have gluten-related disorders. This randomised prospective control trial of 120 patients with MDD aims to determine the effect of a gluten free diet and probiotic supplementation in symptom management over 12 weeks. As this was a prospective study, no results were achieved. However, the study does indicate that randomised control trials on the effect of diet in MDD are advancing and there may be scientifically proven avenues to support standard therapies.
Abstract
BACKGROUND Current treatment of major depressive disorder (MDD) often does not achieve full remission of symptoms. Therefore, new forms of treatment and/or adjunct therapy are needed. Evidence has confirmed the modulation of the gut-brain-microbiota axis as a promising approach in MDD patients. The overall purpose of the SANGUT study-a 12-week, randomized, double-blind, and placebo-controlled Study Evaluating the Effect of Probiotic Supplementation on the Mental Status, Inflammation, and Intestinal Barrier in Major Depressive Disorder Patients Using Gluten-free or Gluten-containing Diet - is to determine the effect of interventions focused on the gut-brain-microbiota axis in a group of MDD patients. METHODS A total of 120 outpatients will be equally allocated into one of four groups: (1) probiotic supplementation+gluten-free diet group (PRO-GFD), (2) placebo supplementation+ gluten-free diet group (PLA-GFD), (3) probiotic supplementation+ gluten containing diet group (PRO-GD), and (4) placebo supplementation+gluten containing diet group (PLA-GD). PRO groups will receive a mixture of psychobiotics (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175), and GFD groups will follow a gluten-free diet. The intervention will last 12 weeks. The primary outcome measure is change in wellbeing, whereas the secondary outcome measures include physiological parameters. DISCUSSION Microbiota and its metabolites have the potential to influence CNS function. Probiotics may restore the eubiosis within the gut while a gluten-free diet, via changes in the microbiota profile and modulation of intestinal permeability, may alter the activity of microbiota-gut-brain axis previously found to be associated with the pathophysiology of depression. It is also noteworthy that microbiota being able to digest gluten may play a role in formation of peptides with different immunogenic capacities. Thus, the combination of a gluten-free diet and probiotic supplementation may inhibit the immune-inflammatory cascade in MDD course and improve both psychiatric and gut barrier-associated traits. TRIAL REGISTRATION NCT03877393 .
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Dietary supplementation with inulin-propionate ester or inulin improves insulin sensitivity in adults with overweight and obesity with distinct effects on the gut microbiota, plasma metabolome and systemic inflammatory responses: a randomised cross-over trial.
Chambers, ES, Byrne, CS, Morrison, DJ, Murphy, KG, Preston, T, Tedford, C, Garcia-Perez, I, Fountana, S, Serrano-Contreras, JI, Holmes, E, et al
Gut. 2019;68(8):1430-1438
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Literature shows that higher intakes of dietary fibre are associated with a reduced risk of type 2 diabetes. The main aim of this study was to elucidate the underlying mechanisms behind improvements in glucose homeostasis following long-term delivery of propionate (a short-chain fatty acid produced by human gut microbiota in response to dietary fibre) to the human colon. The study is a randomised, double-blind, placebo-controlled cross over trial. Fourteen participants randomly received 20 g/day of a low-fermentable fibre control, a high-fermentable fibre control and inulin-propionate ester (IPE) for 42 days each. Results indicate that stool concentrations of short-chain fatty acids were not different following the three supplementation periods. Furthermore, dietary supplementation with 20 g/day IPE promoted no superior impacts on measures of glucose homeostasis compared with inulin (high-fermentable fibre), yet both IPE and inulin improved insulin resistance relative to cellulose (low-fermentable fibre). Authors conclude that manipulating the colonic fermentation profile of a dietary fibre in favour of propionate promotes selective effects on the mechanisms that contribute to metabolic dysregulation.
Abstract
OBJECTIVE To investigate the underlying mechanisms behind changes in glucose homeostasis with delivery of propionate to the human colon by comprehensive and coordinated analysis of gut bacterial composition, plasma metabolome and immune responses. DESIGN Twelve non-diabetic adults with overweight and obesity received 20 g/day of inulin-propionate ester (IPE), designed to selectively deliver propionate to the colon, a high-fermentable fibre control (inulin) and a low-fermentable fibre control (cellulose) in a randomised, double-blind, placebo-controlled, cross-over design. Outcome measurements of metabolic responses, inflammatory markers and gut bacterial composition were analysed at the end of each 42-day supplementation period. RESULTS Both IPE and inulin supplementation improved insulin resistance compared with cellulose supplementation, measured by homeostatic model assessment 2 (mean±SEM 1.23±0.17 IPE vs 1.59±0.17 cellulose, p=0.001; 1.17±0.15 inulin vs 1.59±0.17 cellulose, p=0.009), with no differences between IPE and inulin (p=0.272). Fasting insulin was only associated positively with plasma tyrosine and negatively with plasma glycine following inulin supplementation. IPE supplementation decreased proinflammatory interleukin-8 levels compared with cellulose, while inulin had no impact on the systemic inflammatory markers studied. Inulin promoted changes in gut bacterial populations at the class level (increased Actinobacteria and decreased Clostridia) and order level (decreased Clostridiales) compared with cellulose, with small differences at the species level observed between IPE and cellulose. CONCLUSION These data demonstrate a distinctive physiological impact of raising colonic propionate delivery in humans, as improvements in insulin sensitivity promoted by IPE and inulin were accompanied with different effects on the plasma metabolome, gut bacterial populations and markers of systemic inflammation.
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Anti-Fatigue Effects of Yogurt Fermented with Lactobacillus delbureckii subsp. bulgaricus OLL1073R-1 in Healthy People Suffering from Summer Heat Fatigue: A Randomized, Double-Blind, Placebo-Controlled Trial.
Makino, S, Hemmi, J, Kano, H, Kashiwagi, M, Hojo, K, Asami, Y
Nutrients. 2018;10(7)
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Summer heat fatigue is an indefinite complaint along with anorexia, loss of sleep, stress, lack of motivation and, in some cases, catching a cold during high summer temperatures. This randomized, double-blind, placebo-controlled study evaluated the effects of yogurt fermented with L. bulgaricus OLL1073R-1, which contains immunostimulatory compounds (exopolysaccharide, EPS), on summer heat fatigue. The study was conducted in Tokyo, Japan, where temperatures regularly reached above 30 deg C during the study period, and assessed 50 men who had a history of feeling summer heat fatigue every summer. All participants were randomized to receive either yogurt fermented with L. bulgaricus OLL1073R-1 and Streptococcus thermophilus OLS3059 (yogurt) or a placebo and ingested a bottle of 100 mL per day for 12 weeks. Questionnaires were used to establish the typical symptoms of summer heat fatigue and natural killer (NK) cell activities were measured. Between-group differences in the autonomic nervous system and incidence of catching colds were assessed as secondary outcomes. The authors report that L. bulgaricus OLL1073R-1 statistically significantly improved the typical symptoms of summer heat fatigue, compared to placebo. There was no significant difference between changes in NK cells or other parameters between the yoghurt and the placebo group. The authors discuss that mechanisms for the beneficial effects of yogurt fermented with L. bulgaricus OLL1073R-1 on summer heat fatigue remain unclear, but that EPS produced by the bacteria may influence symptoms via immune modulation. They point out that one of the limitations of their study was that only one immune parameter, NK cells, was measured.
Abstract
Fatigue caused by summer heat is a typical indefinite complaint along with anorexia, loss of sleep, stress, lack of motivation and, in some cases, catching a cold. Yogurt fermented with Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1 has been shown to stimulate the immune system and reduce the risk of catching colds. Here, we conducted a randomized, double-blinded, placebo-controlled trial to investigate whether ingesting this yogurt could ameliorate summer heat fatigue in 49 healthy males (median age 40.0 ± 6.0 years; 30⁻49 years) who felt fatigued every summer. Fatigue was evaluated by visual analogue scales (VAS) and the balance of sympathetic/parasympathetic nervous systems. After 12 weeks of ingestion in early autumn, the VAS fatigue scores in the yogurt group were lower than those of the placebo group. These results indicate that yogurt fermented with L. bulgaricus OLL1073R-1 can ameliorate summer heat fatigue lasting up to early autumn.
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Navy Beans Impact the Stool Metabolome and Metabolic Pathways for Colon Health in Cancer Survivors.
Baxter, BA, Oppel, RC, Ryan, EP
Nutrients. 2018;11(1)
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Colorectal cancer (CRC) is one of the leading cause of cancer-related death around the world. Emerging evidence supports that increased consumption of pulses / legumes, such as navy beans, can reduce risk. Consuming navy beans as part of one's diet has been previously shown to positively affect the relationship between a person's gut bacteria and their health status. This study looked at stool samples to assess the impact of navy bean consumption on health based on the by-products of metabolism generated by gut bacteria (metabolites). The study was a 4-week, randomised-controlled trial with overweight and obese CRC survivors and involved consumption of 1 meal and 1 snack daily. People in the intervention group ate 35g of cooked navy bean daily whereas those in the control group had 0g of navy beans. From amongst the hundreds of metabolites identified in both groups, there was a 5-fold increase in ophthalmate for navy bean consumers, which can indicate an increase in glutathione. Glutathione is an antioxidant and detoxifying substance produced in the human liver. It is involved in cancer control mechanisms such as detoxification of xenobiotics (toxins), antioxidant defense, proliferation, and apoptosis. Other interesting results include the metabolism of the amino acid lysine, which supports health immune function, and an increase in plant-based nutrients or phytochemicals in those who consumed navy bean vs the control group. These results are indicative of an acute response to increased navy bean intake, which merit further investigation for improving colonic health after long-term consumption.
Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related death in the United States and emerging evidence supports that increased consumption of legumes, such as navy beans, can reduce risk. Navy bean consumption was previously shown to modulate host and microbiome metabolism, and this investigation was performed to assess the impact on the human stool metabolome, which includes the presence of navy bean metabolites. This 4-week, randomized-controlled trial with overweight and obese CRC survivors involved consumption of 1 meal and 1 snack daily. The intervention contained 35 g of cooked navy bean or macronutrient matched meals and snacks with 0 g of navy beans for the control group (n = 18). There were 30 statistically significant metabolite differences in the stool of participants that consumed navy bean at day 28 compared to the participants' baseline (p ≤ 0.05) and 26 significantly different metabolites when compared to the control group. Of the 560 total metabolites identified from the cooked navy beans, there were 237 possible navy bean-derived metabolites that were identified in the stool of participants consuming navy beans, such as N-methylpipecolate, 2-aminoadipate, piperidine, and vanillate. The microbial metabolism of amino acids and fatty acids were also identified in stool after 4 weeks of navy bean intake including cadaverine, hydantoin-5 propionic acid, 4-hydroxyphenylacetate, and caprylate. The stool relative abundance of ophthalmate increased 5.25-fold for navy bean consumers that can indicate glutathione regulation, and involving cancer control mechanisms such as detoxification of xenobiotics, antioxidant defense, proliferation, and apoptosis. Metabolic pathways involving lysine, and phytochemicals were also modulated by navy bean intake in CRC survivors. These metabolites and metabolic pathways represent an acute response to increased navy bean intake, which merit further investigation for improving colonic health after long-term consumption.
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Intermittent Fasting Confers Protection in CNS Autoimmunity by Altering the Gut Microbiota.
Cignarella, F, Cantoni, C, Ghezzi, L, Salter, A, Dorsett, Y, Chen, L, Phillips, D, Weinstock, GM, Fontana, L, Cross, AH, et al
Cell metabolism. 2018;27(6):1222-1235.e6
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Calorie restriction (CR) has potent anti-inflammatory effects and has shown beneficial effects in an animal model for Multiple Sclerosis (MS). Intermittent Fasting (IF) has similar effects as CR and may be more acceptable long term than CR. This paper reports results from both an animal study and a pilot randomised controlled human clinical trial on IF and MS. The animal study showed that IF had beneficial effects on the MS animal model and that these effects were at least in part mediated by changes in the gut microbiome. 16 patients with relapsing remitting MS were enrolled during a relapse and randomised to either IF (6-7 fasting days during the two-week study) or normal eating. Changes in immune inflammatory parameters and gut flora were seen in the IF group which were similar to the beneficial changes in the animal model. The authors conclude that larger clinical studies to test IF and microbiome manipulation as a potential treatment in MS are warranted.
Abstract
Multiple sclerosis (MS) is more common in western countries with diet being a potential contributing factor. Here we show that intermittent fasting (IF) ameliorated clinical course and pathology of the MS model, experimental autoimmune encephalomyelitis (EAE). IF led to increased gut bacteria richness, enrichment of the Lactobacillaceae, Bacteroidaceae, and Prevotellaceae families and enhanced antioxidative microbial metabolic pathways. IF altered T cells in the gut with a reduction of IL-17 producing T cells and an increase in regulatory T cells. Fecal microbiome transplantation from mice on IF ameliorated EAE in immunized recipient mice on a normal diet, suggesting that IF effects are at least partially mediated by the gut flora. In a pilot clinical trial in MS patients, intermittent energy restriction altered blood adipokines and the gut flora resembling protective changes observed in mice. In conclusion, IF has potent immunomodulatory effects that are at least partially mediated by the gut microbiome.
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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.