Emerging evidence suggests that low-grade systemic inflammation plays a key role in altering brain activity, behaviour and affect. Modulation of the gut microbiota using prebiotic fibre offers a potential therapeutic tool to regulate inflammation, mediated via the production of short-chain fatty acids (SCFA). However, the impact of prebiotic consumption on affective symptoms and the possible contribution from inflammation, gut symptoms and the gut microbiome are currently underexamined. In this 12-week study, the effects of a diverse prebiotic blend on inflammation, gut microbiota profiles and affective symptoms in a population with metabolic syndrome (MetS) were examined. Sixty males and females with MetS meeting the criteria for MetS were randomised into a treatment group (n 40), receiving 10 g per day of a diverse prebiotic blend and healthy eating advice, and a control group (n 20), receiving healthy eating advice only. Our results showed a significant reduction in high sensitivity C-reactive protein (hs-CRP) in the treatment (–0·58 [–9·96 to–2·63]) compared with control (0·37 [–3·64 to–3·32]), alongside significant improvements in self-reported affective scores in the treatment compared with the control group. While there were no differences in relative abundance between groups at week 12, there was a significant increase from baseline to week 12 in fecal Bifidobacterium and Parabacteroides in the treatment group, both of which are recognised as SCFA producers. Multivariate regression analyses further revealed an association between gastrointestinal symptoms and hs-CRP with affective scores. Together, this study provides preliminary support for a diverse prebiotic blend for mood, stress and anxiety.

This review will provide an overview of the immune system and then describe the effects of frailty, obesity, specific micronutrients and the gut microbiota on immunity and susceptibility to infection including data from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic where relevant. A key role for the immune system is providing host defence against pathogens. Impaired immunity predisposes to infections and to more severe infections and weakens the response to vaccination. A range of nutrients, including many micronutrients, play important roles in supporting the immune system to function. The immune system can decline in later life and this is exaggerated by frailty. The immune system is also weakened with obesity, generalised undernutrition and micronutrient deficiencies, which all result in increased susceptibility to infection. Findings obtained during the SARS-CoV-2 pandemic support what was already known about the effects of ageing, frailty and obesity on immunity and susceptibility to infection. Observational studies conducted during the pandemic also support previous findings that multiple micronutrients including vitamins C, D and E, zinc and selenium and long-chain n-3 fatty acids are important for immune health, but whether these nutrients can be used to treat those already with coronavirus disease discovered in 2019 (COVID-19), particularly if already hospitalised, is uncertain from current inconsistent or scant evidence. There is gut dysbiosis in patients with COVID-19 and studies with probiotics report clinical improvements in such patients. There is an inverse association between adherence to a healthy diet and risk of SARS-CoV-2 infection and hospitalisation with COVID-19 which is consistent with the effects of individual nutrients and other dietary components. Addressing frailty, obesity and micronutrient insufficiency will be important to reduce the burden of future pandemics and nutritional considerations need to be a central part of the approach to preventing infections, optimising vaccine responses and promoting recovery from infection.

Individuals with coeliac disease (CeD) often experience gastrointestinal symptoms despite adherence to a gluten-free diet (GFD). While we recently showed that a diet low in fermentable oligo-, di-, monosaccharides and polyols (FODMAP) successfully provided symptom relief in GFD-treated CeD patients, there have been concerns that the low FODMAP diet (LFD) could adversely affect the gut microbiota. Our main objective was therefore to investigate whether the LFD affects the faecal microbiota and related variables of gut health. In a randomised controlled trial GFD-treated CeD adults, having persistent gastrointestinal symptoms, were randomised to either consume a combined LFD and GFD (n 39) for 4 weeks or continue with GFD (controls, n 36). Compared with the control group, the LFD group displayed greater changes in the overall faecal microbiota profile (16S rRNA gene sequencing) from baseline to follow-up (within-subject β-diversity, P < 0·001), characterised by lower and higher follow-up abundances (%) of genus Anaerostipes (Pgroup < 0·001) and class Erysipelotrichia (Pgroup = 0·02), respectively. Compared with the control group, the LFD led to lower follow-up concentrations of faecal propionic and valeric acid (GC-FID) in participants with high concentrations at baseline (Pinteraction ≤ 0·009). No differences were found in faecal bacterial α-diversity (Pgroup ≥ 0·20) or in faecal neutrophil gelatinase-associated lipocalin (ELISA), a biomarker of gut integrity and inflammation (Pgroup = 0·74), between the groups at follow-up. The modest effects of the LFD on the gut microbiota and related variables in the CeD patients of the present study are encouraging given the beneficial effects of the LFD strategy to treat functional GI symptoms (Registered at clinicaltrials.gov as NCT03678935).

The present paper reviews progress in research on dietary fibre and human health over the past five decades. There is now convincing evidence from prospective cohort studies that diets low in dietary fibre are associated with increased risk of common non-communicable diseases including CVD, type 2 diabetes and colorectal cancer. These findings provide strong support for hypotheses proposed by Denis Burkitt 50 years ago, based on very limited evidence but with considerable imagination and insight. For the first two to three decades of this period, research on dietary fibre was hampered by the lack of consensus about the definition, and measurement, of this complex and diverse dietary component and by the lack of appropriate tools for investigating the gut microbiome that is central to understanding mechanisms of action. Recent technical and scientific advances in microbiome research (based on fast, low-cost, DNA sequencing) are facilitating investigation of the associations between dietary fibre, the gut microbiome and human health. Current challenges include the need for agreement about the characteristics of a healthy gut microbiome. Although the health benefits attributed to higher dietary fibre intake are likely to be shared with most types of dietary fibre, one should anticipate that different sources of dietary fibre and the other components (resistant starch and non-digestible oligosaccharides) that make up dietary fibre will have characteristically different effects on human physiology and disease risk. In conclusion, population-level intakes of dietary fibre are low and there is a public health priority to develop and implement more effective interventions to increase intake.

Dietary fibre modulates gastrointestinal (GI) health and function, providing laxation, shifting microbiota, and altering bile acid (BA) metabolism. Fruit juice production removes the polyphenol- and fibre-rich pomace fraction. The effects of orange and apple pomaces on GI outcomes were investigated in healthy, free-living adults. Healthy adults were enrolled in two double-blinded, crossover trials, being randomised by baseline bowel movement (BM) frequency. In the first trial, subjects (n 91) received orange juice (OJ, 0 g fibre/d) or OJ + orange pomace (OJ + P, 10 g fibre/d) for 4 weeks, separated by a 3-week washout. Similarly, in the second trial, subjects (n 90) received apple juice (AJ, 0 g fibre/d) or AJ + apple pomace (AJ + P, 10 g fibre/d). Bowel habit diaries, GI tolerance surveys and 3-d diet records were collected throughout. Fresh faecal samples were collected from a participant subset for microbiota and BA analyses in each study. Neither pomace interventions influenced BM frequency. At Week 4, OJ + P tended to increase (P = 0·066) GI symptom occurrence compared with OJ, while AJ + P tended (P = 0·089) to increase flatulence compared with AJ. Faecalibacterium (P = 0·038) and Negativibacillus (P = 0·043) were differentially abundant between pre- and post-interventions in the apple trial but were no longer significant after false discovery rate (FDR) correction. Baseline fibre intake was independently associated with several microbial genera in both trials. Orange or apple pomace supplementation was insufficient to elicit changes in bowel habits, microbiota diversity or BA of free-living adults with healthy baseline BM. Future studies should consider baseline BM frequency and habitual fibre intake.

In this study, we aimed to examine the association between gastrointestinal (GI) symptom presence during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the prevalence of GI symptoms and the development of post-infectious irritable bowel syndrome (PI-IBS). We used data from a prospective cohort and logistic regression to examine the association between GI symptom status during confirmed SARS-CoV-2 infection and prevalence of persistent GI symptoms at ≥45 days. We also report the incidence of PI-IBS following SARS-CoV-2 infection. Of the 1475 participants in this study, 33.8% (n = 499) had GI symptoms during acute infection. Cases with acute GI symptoms had an odds of persisting GI symptoms 4 times higher than cases without acute GI symptoms (odds ratio (OR) 4.29, 95% confidence interval (CI) 2.45–7.53); symptoms lasted on average 8 months following infection. Of those with persisting GI symptoms, 67% sought care for their symptoms and incident PI-IBS occurred in 3.0% (n = 15) of participants. Those with acute GI symptoms after SARS-CoV-2 infection are likely to have similar persistent symptoms 45 days and greater. These data indicate that attention to a potential increase in related healthcare needs is warranted.

We assessed the effectiveness of lyophilised banked human milk (HM) as a fortifier to feed very-low-birth-weight infants (VLBWI). This study aimed to evaluate the safety and tolerability of HM with HM lyophilisate as an additive compared with the standard additive (cows’ milk protein). In this phase I double-blind randomised controlled clinical trial, set in the intensive and intermediate care units of a tertiary hospital, forty VLBWI were enrolled and allocated into two groups: HM plus HM lyophilisate (LioNeo) or HM plus commercial additive (HMCA). The inclusion criteria were preterm infants, birth weight 750–1500 g, small or adequate for gestational age, exclusively receiving donor HM, volume ≥ 100 ml/kg per d and haemodynamically stable. Participants were followed up for 21 consecutive days. The primary outcome measures were necrotising enterocolitis (NEC), late-onset sepsis (LOS), death, gastrointestinal (GI) bleeding or perforation, diarrhoea, regurgitation, vomiting and abdominal distension. The LioNeo and HMCA groups had similar weights at baseline. The regression models showed no differences between the groups in terms of the primary outcomes. Diarrhoea, GI perforation, NEC and LOS were absent in the LioNeo group (one LOS and one NEC in the HMCA group). Multiple regression analysis with the total volume of milk as a covariate did not show significant differences. The lyophilisation of donor HM was considered safe and tolerable for use in stable haemodynamically VLBWI.

An outbreak surveillance system for Salmonella integrating whole genome sequencing (WGS) and epidemiological data was developed in South East and London in 2016–17 to assess local WGS clusters for triage and investigation. Cases genetically linked within a 5 single-nucleotide polymorphism (SNP) single linkage cluster were assessed using a set of locally agreed thresholds based on time, person and place, for reporting to local health protection teams (HPTs). Between September 2016 and September 2017, 230 unique 5-SNP clusters (442 weekly reports) of non-typhoidal Salmonella 5-SNP WGS clusters were identified, of which 208 unique 5-SNP clusters (316 weekly reports) were not reported to the HPTs. In the remaining 22 unique clusters (126 weekly clusters) reported to HPTs, nine were known active outbreak investigations, seven were below locally agreed thresholds and six exceeded local thresholds. A common source or vehicle was identified in four of six clusters that exceeded locally agreed thresholds. This work demonstrates that a threshold-based surveillance system, taking into account time, place and genetic relatedness, is feasible and effective in directing the use of local public health resources for risk assessment and investigation of non-typhoidal Salmonella clusters.

COVID-19 pandemic continues to be a global health crisis. The gut microbiome critically affects the immune system, and some respiratory infections are associated with changes in the gut microbiome; here, we evaluated the role of nutritional and lifestyle habits that modulate gut microbiota on COVID-19 outcomes in a longitudinal cohort study that included 200 patients infected with COVID-19. Of these, 122 cases were mild and seventy-eight were moderate, according to WHO classification. After detailed explanation by a consultant in clinical nutrition, participants responded to a written questionnaire on daily sugar, prebiotic intake in food, sleeping hours, exercise duration and antibiotic prescription, during the past 1 year before infection. Daily consumption of prebiotic-containing foods, less sugar, regular exercise, adequate sleep and fewer antibiotic prescriptions led to a milder disease and rapid virus clearance. Additionally, data on these factors were compiled into a single score, the ESSAP score (Exercise, Sugar consumption, Sleeping hours, Antibiotics taken, and Prebiotics consumption; 0–11 points), median ESSAP score was 5 for both mild and moderate cases; however, the range was 4–8 in mild cases, but 1–6 in moderate (P = 0·001, OR: 4·2, 95 % CI 1·9, 9·1); our results showed a negative correlation between regular consumption of yogurt containing probiotics and disease severity (P = 0·007, OR: 1·6, 95 % CI 1·1, 2·1). Mild COVID-19 disease was associated with 10–20 min of daily exercise (P = 0·016), sleeping at least 8 h daily, prescribed antibiotics less than 5 times per year (P = 0·077) and ate plenty of prebiotic-containing food.

Current cancer prevention recommendations advise limiting red meat intake to <500 g/week and avoiding consumption of processed meat, but do not differentiate the source of processed meat. We examined the associations of processed meat derived from red v. non-red meats with cancer risk in a prospective cohort of 26 218 adults who reported dietary intake using the Canadian Diet History Questionnaire. Incidence of cancer was obtained through data linkage with Alberta Cancer Registry with median follow-up of 13·3 (interquartile range (IQR) 5·1) years. Multivariable Cox proportional hazards regression models were adjusted for covariates and stratified by age and sex. The median consumption (g/week) of red meat, processed meat from red meat and processed meat from non-red meat was 267·9 (IQR 269·9), 53·6 (IQR 83·3) and 11·9 (IQR 31·8), respectively. High intakes (4th Quartile) of processed meat from red meat were associated with increased risk of gastrointestinal cancer adjusted hazard ratio (AHR): 1·68 (95 % CI 1·09, 2·57) and colorectal cancers AHR: 1·90 (95 % CI 1·12, 3·22), respectively, in women. No statistically significant associations were observed for intakes of red meat or processed meat from non-red meat. Results suggest that the carcinogenic effect associated with processed meat intake may be limited to processed meat derived from red meats. The findings provide preliminary evidence towards refining cancer prevention recommendations for red and processed meat intake.

This review intends to act as an overview of fructose malabsorption (FM) and its role in the aetiology of diseases including, but not limited to, irritable bowel syndrome (IBS) and infantile colic and the relationship between fructose absorption and the propagation of some cancers. IBS results in a variety of symptoms including stomach pains, cramps and bloating. Patients can be categorised into two groups, depending on whether the patients’ experiences either constipation (IBS-C) or diarrhoea (IBS-D). FM has been proposed as a potential cause of IBS-D and other diseases, such as infantile colic. However, our knowledge of FM is limited by our understanding of the biochemistry related to the absorption of fructose in the small intestine and FM’s relationship with small intestinal bacterial overgrowth. It is important to consider the dietary effects on FM and most importantly, the quantity of excess free fructose consumed. The diagnosis of FM is difficult and often requires indirect means that may result in false positives. Current treatments of FM include dietary intervention, such as low fermentable oligo-, di-, monosaccharides and polyols diets and enzymatic treatments, such as the use of xylose isomerase. More research is needed to accurately diagnose and effectively treat FM. This review is designed with the goal of providing a detailed outline of the issues regarding the causes, diagnosis and treatment of FM.

The major complication of end jejunostomy is excessive fluid and electrolyte loss through the stoma, leading to hypovolaemia and dyselectrolytaemia within days and malnutrition within weeks. The aim was to compare the results of two nutritional approaches: unrestricted and restricted oral intake in patients with end jejunostomy commencing home parenteral nutrition (HPN) in terms of liver and renal biochemical markers and time to reconstructive bowel surgery with correlation to stoma output. Twenty patients with stabilised high output end-jejunostomy were divided into two groups. Group A consisted of ten patients with oral intake restricted to keep stomal output under 1000 ml. Group B consisted of ten patients with unrestricted oral intake. The following parameters were evaluated over 6 months: stomal output, self-estimation of general condition, body weight gain, plasma bilirubin and creatinine, number of hospitalisations prior to reconstructive surgery, the frequency of ostomy bag emptying, feelings of hunger and thirst in the daytime, and the time to reconstructive surgery. Stoma losses were compensated by parenteral supply. In group B, lower quality of life was observed, reflected by weakness, permanent feelings of hunger and thirst and the need for night-time emptying of the stoma bag. Patients in group B developed more complications and required more time to prepare for surgery. One death occurred in group B due to renal insufficiency followed by septic complications. Restricted oral intake seems to be more effective for prevention of HPN-related complications and shortening of time to surgery. Unrestricted oral intake appears to provoke uncontrolled losses of energy and protein, inhibiting weight gain.

Sensing of nutrients by chemosensory cells in the gastrointestinal tract plays a key role in transmitting food-related signals, linking information about the composition of ingested foods to digestive processes. In recent years, a number of G protein-coupled receptors (GPCR) responsive to a range of nutrients have been identified. Many are localised to intestinal enteroendocrine (chemosensory) cells, promoting hormonal and neuronal signalling locally, centrally and to the periphery. The field of gut sensory systems is relatively new and still evolving. Despite huge interest in these nutrient-sensing GPCR, both as sensors for nutritional status and targets for preventing the development of metabolic diseases, major challenges remain to be resolved. However, the gut expressed sweet taste receptor, resident in L-enteroendocrine cells and responsive to dietary sweetener additives, has already been successfully explored and utilised as a therapeutic target, treating weaning-related disorders in young animals. In addition to sensing nutrients, many GPCR are targets for drugs used in clinical practice. As such these receptors, in particular those expressed in L-cells, are currently being assessed as potential new pathways for treating diabetes and obesity. Furthermore, growing recognition of gut chemosensing of microbial-produced SCFA acids has led further attention to the association between nutrition and development of chronic disorders focusing on the relationship between nutrients, gut microbiota and health. The central importance of gut nutrient sensing in the control of gastrointestinal physiology, health promotion and gut–brain communication offers promise that further therapeutic successes and nutritional recommendations will arise from research in this area.

Resistant maltodextrin (RMD) from various sources of starch has been extensively studied. However, studies which reported the effects of tapioca RMD (TRM) on glucose and insulin response are lacking. This study investigated the effect of TRM on postprandial plasma glucose and serum insulin in healthy subjects. Additionally, satiety and gastrointestinal tolerability were also evaluated. Sixteen healthy participants received five different treatments on five separate days. Participants received 50 g of either: glucose (GL), tapioca maltodextrin (TM), TRM, MIX15% (7⋅5 g TRM + 42⋅5 g TM) or MIX50% (25 g TRM + 25 g TM). Plasma glucose, serum insulin and subjective appetite responses were measured postprandially over 180 min. Gastrointestinal symptoms were evaluated by questionnaire before and after each test day. Results showed that at 30 min after treatment drinks, plasma glucose after TRM was significantly lowest (104⋅60 (sem 2⋅63 mg/dl) than after GL (135⋅87 (sem 4⋅88) mg/dl; P <0⋅001), TM (127⋅93 (sem 4⋅05) mg/dl; P = 0⋅001), MIX15% (124⋅67 (sem 5⋅73) mg/dl; P = 0⋅039) and MIX50% (129⋅33 (sem 5⋅23) mg/dl; P = 0⋅003) (1 mg/dl = 0⋅0555 mmol/l). In addition, TRM also significantly reduced serum insulin (13⋅01 (sem 2⋅12) μIU/ml) compared with GL (47⋅90 (sem 11⋅93) μIU/ml; P = 0⋅013), TM (52⋅96 (sem 17⋅68) μIU/ml; P = 0⋅002) and MIX50% (33⋅16 (sem 4⋅99) μIU/ml; P = 0⋅008). However, there were no significant differences in subjective appetite between treatments (P > 0⋅05). A single high dose of TRM (50 g) caused flatulence (P < 0⋅05). Tapioca resistant maltodextrin has low digestibility in the small intestine and, therefore, reduced incremental plasma glucose and serum insulin, without affecting satiety in healthy subjects over 180 min. Gastrointestinal tolerability of TRM should be considered when consumed in high doses.

While medical nutrition therapy is an essential part of the care for critically ill patients, uncertainty exists about the right form, dosage, timing and route in relation to the phases of critical illness. As enteral nutrition (EN) is often withheld or interrupted during the intensive care unit (ICU) stay, combined EN and parenteral nutrition (PN) may represent an effective and safe option to achieve energy and protein goals as recommended by international guidelines. We hypothesise that critically ill patients at high nutritional risk may benefit from such a combined approach during their stay on the ICU. Therefore, we aim to test if an early combination of EN and high-protein PN (EN+PN) is effective in reaching energy and protein goals in patients at high nutritional risk, while avoiding overfeeding. This approach will be tested in the here-presented EFFORTcombo trial. Nutritionally high-risk ICU patients will be randomised to either high (≥2·2 g/kg per d) or low protein (≤1·2 g/kg per d). In the high protein group, the patients will receive EN+PN; in the low protein group, patients will be given EN alone. EN will be started in accordance with international guidelines in both groups. Efforts will be made to reach nutrition goals within 48–96 h. The efficacy of the proposed nutritional strategy will be tested as an innovative approach by functional outcomes at ICU and hospital discharge, as well as at a 6-month follow-up.

Stimulation of gastrointestinal taste receptors affects eating behaviour. Intraduodenal infusion of tastants leads to increased satiation and reduced food intake, whereas intraileal infusion of tastants does not affect eating behaviour. Currently, it is unknown whether oral- or intragastric administration of tastants induces a larger effect on eating behaviour. This study investigated the effects of oral- and/or intragastric administration of quinine on food intake, appetite sensations and heart rate variability (HRV). In a blinded randomised crossover trial, thirty-two healthy volunteers participated in four interventions with a 1-week washout: oral placebo and intragastric placebo (OPGP), oral quinine and intragastric placebo (OQGP), oral placebo and intragastric quinine (OPGQ) and oral quinine and intragastric quinine (OQGQ). On test days, 150 min after a standardised breakfast, subjects ingested a capsule containing quinine or placebo and were sham-fed a mixture of quinine or placebo orally. At 50 min after intervention, subjects received an ad libitum meal to measure food intake. Visual analogue scales for appetite sensations were collected, and HRV measurements were performed at regular intervals. Oral and/or intragastric delivery of the bitter tastant quinine did not affect food intake (OPGP: 3273·6 (sem 131·8) kJ, OQGP: 3072·7 (sem 132·2) kJ, OPGQ: 3289·0 (sem 132·6) kJ and OQGQ: 3204·1 (sem 133·1) kJ, P = 0·069). Desire to eat and hunger decreased after OQGP and OPGQ compared with OPGP (P < 0·001 and P < 0·05, respectively), whereas satiation, fullness and HRV did not differ between interventions. In conclusion, sole oral sham feeding with and sole intragastric delivery of quinine decreased desire to eat and hunger, without affecting food intake, satiation, fullness or HRV.

A 63-year-old female patient presents with abdominal pain, vomiting, and abdominal distention. She has previously had a cholecystectomy and hysterectomy. She has had no prior similar episodes, and denies fever, hematemesis, or diarrhea. She takes no medications. Vital signs include blood pressure 123/61 mm Hg, heart rate 97, oral temperature 37.2°C, respiratory rate 18, oxygen saturation 97% on room air. Her abdomen is diffusely tender and distended.

Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.