Enteral nutrition in Crohn's disease: an underused therapy

Mechanical stress-induced connective tissue growth factor plays a critical role in intestinal fibrosis in Crohn's-like colitis

Crohn's disease (CD) is an inflammatory bowel disease characterized by transmural inflammation and intestinal fibrosis. Mechanisms of fibrosis in CD are not well understood. Transmural inflammation is associated with inflammatory cell infiltration, stenosis, and distention, which present mechanical stress (MS) to the bowel wall. We hypothesize that MS induces gene expression of profibrotic mediators such as connective tissue growth factor (CTGF), which may contribute to fibrosis in CD. A rodent model of CD was induced by intracolonic instillation of TNBS to the distal colon. TNBS instillation induced a localized transmural inflammation (site I), with a distended colon segment (site P) proximal to site I. We detected significant fibrosis and collagen content not only in site I but also in site P in CD rats by day 7. CTGF expression increased significantly in sites P and I, but not in the segment distal to the inflammation site. Increased CTGF expression was detected mainly in the smooth muscle cells (SMCs). When rats were fed exclusively with clear liquid diet to prevent mechanical distention in colitis, expression of CTGF in sites P and I was blocked. Direct stretch led to robust expression of CTGF in colonic SMC. Treatment of CD rats with anti-CTGF antibody FG-3149 reduced fibrosis and collagen content in both sites P and I and exhibited consistent trends toward normalizing expression of collagen mRNAs. In conclusion, our studies suggest that mechanical stress, by upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.NEW & NOTEWORTHY We found that CTGF expression increased significantly not only in the inflammation site but in the distended segment proximal to inflammation in a rodent model of CD-like colitis. Release of mechanical distention prevented CTGF expression in CD rats, whereas direct stretch induced CTGF expression. Treatment with anti-CTGF antibody reduced fibrosis and collagen contents in CD rats. Thus, mechanical stress, via upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.

Dietary Therapy to Improve Nutrition and Gut Health in Paediatric Crohn’s Disease; A Feasibility Study

Bovine colostrum (BC) has anti-inflammatory, anti-infective, growth and intestinal repair factors that may be beneficial in Crohn’s disease (CD). We assessed whether daily BC for up to 3 months was acceptable to children and young people (CYP) with CD in remission or of mild/moderate severity. CYP were randomised to receive either BC or matching placebo milk daily for 6 weeks (blinded phase); all received BC for the following 6 weeks (open phase). In 23 CYP, median (inter-quartile range) age was 15.2 (13.9–16.1) years and 9 (39.1%) were girls. A similar proportion of CYP in the BC and placebo arms completed the blinded phase (8/12, 75.0% and 9/11, 81.8% respectively). Twelve (70.6%) CYP completed the open phase with 7 (58.3%) tolerating BC for 3 months. Diaries in weeks 2, 6 and 12 revealed that most CYP took BC every day (5/7, 71.4%; 5/8, 62,5% and 6/11, 54.5% respectively). In interviews, opinions were divided as to preference of BC over the placebo milk and some preferred BC over other nutritional supplements. Symptoms, clinical and laboratory variables and quality of life were similar in the two arms. BC may be an acceptable nutritional supplement for daily, longer-term use in CYP with CD.

Targeting Mechano-Transcription Process as Therapeutic Intervention in Gastrointestinal Disorders

Mechano-transcription is a process whereby mechanical stress alters gene expression. The gastrointestinal (GI) tract is composed of a series of hollow organs, often encountered by transient or persistent mechanical stress. Recent studies have revealed that persistent mechanical stress is present in obstructive, functional, and inflammatory disorders and alters gene transcription in these conditions. Mechano-transcription of inflammatory molecules, pain mediators, pro-fibrotic and growth factors has been shown to play a key role in the development of motility dysfunction, visceral hypersensitivity, inflammation, and fibrosis in the gut. In particular, mechanical stress-induced cyclooxygenase-2 (COX-2) and certain pro-inflammatory mediators in gut smooth muscle cells are responsible for motility dysfunction and inflammatory process. Mechano-transcription of pain mediators such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) may lead to visceral hypersensitivity. Emerging evidence suggests that mechanical stress in the gut also leads to up-regulation of certain proliferative and pro-fibrotic mediators such as connective tissue growth factor (CTGF) and osteopontin (OPN), which may contribute to fibrostenotic Crohn's disease. In this review, we will discuss the pathophysiological significance of mechanical stress-induced expression of pro-inflammatory molecules, pain mediators, pro-fibrotic and growth factors in obstructive, inflammatory, and functional bowel disorders. We will also evaluate potential therapeutic targets of mechano-transcription process for the management of these disorders.

The pharmacotherapeutic management of pediatric Crohn's disease

Introduction: Crohn's disease (CD) is a chronic inflammatory condition that can occur throughout the gastrointestinal tract. The aims of treatment of children with CD are to induce and maintain clinical remission of disease, optimize nutrition and growth, minimize adverse effects of therapies, and if possible, achieve mucosal healing.Areas covered: This review summarizes evidence for the various therapeutic options in the treatment of children with CD. Exclusive enteral nutrition, corticosteroids, and biologics may be used for induction of remission. Immunomodulators (thiopurines, methotrexate) and biologics (infliximab, adalimumab) may be employed for maintenance of remission to prevent flares of disease and avoid chronic steroid use. In cases of fibrotic disease, intestinal perforations, or medically refractory, surgery may be the best therapeutic option.Expert opinion: Exclusive enteral nutrition, corticosteroids, and biologics (including anti-TNF inhibitors) may be used for induction of remission in patients with active flare of their disease. Immunomodulators and TNF inhibitors may be used for maintenance of remission. Early use of anti-TNF inhibitors in patients with moderate to severe CD may improve efficacy and prevent penetrating complications of disease. While pediatric data is limited, newer biologics, such as vedolizumab and ustekinumab, are used off-label in anti-TNF refractory disease.

Benefits of Exclusive Enteral Nutrition in Adults With Complex Active Crohn’s Disease: A Case Series of 13 Consecutive Patients

Background and Aims

Immunosuppressive therapy is routine for adults with complex active Crohn’s disease (CD), however carries risks, particularly in the setting of sepsis. Exclusive enteral nutrition (EEN) is widely used in paediatric CD, yet efficacy data in adults are sparse. This study evaluated outcomes of EEN in adults with complex active CD.

Methods

Between December 2016 and June 2018, 13 patients with complex active CD (range 20–74 years) managed at a single hospital received 2 or more weeks of EEN. Patients were offered EEN based on either malnutrition, contraindication to immunosuppression, or CD refractory to multiple therapies. Subjective and objective outcomes were recorded at 2 and 6 weeks and compared with baseline data.

Results

Nine of 13 patients experienced subjective improvement in wellbeing. Objective improvements included nine CRP decrements (median = 87.7 mg/L, IQR = 70.6 mg/L), nine serum albumin increments (median = 7 g/L, IQR = 4 g/L), and six gained weight (median = 3.6 kg, IQR = 3.0 kg). All five patients with complex abscess resolved without surgery. One ileocolic fistula and one enterocutaneous fistula achieved resolution without surgery. One of two perianal fistulae cases resolved without surgery. Seven of 10 patients initially thought to need surgery avoided it due to disease resolution. Only one of the three patients who proceeded to surgery sustained a post-operative complication. There were no EEN-associated complications.

Conclusions

In complex active CD, our real-world data show that EEN improves wellbeing, decreases inflammatory markers, leads to healthy weight gain, reduces need for surgical intervention, and reduces postoperative complications.

Enteral Nutrition in Adult Crohn's Disease: Toward a Paradigm Shift

Medical and surgical treatments for Crohn's disease are associated with toxic effects. Medical therapy aims for mucosal healing and is achievable with biologics, immunosuppressive therapy, and specialised enteral nutrition, but not with corticosteroids. Sustained remission remains a therapeutic challenge. Enteral nutrition, containing macro- and micro-nutrients, is nutritionally complete, and is provided in powder or liquid form. Enteral nutrition is a low-risk and minimally invasive therapy. It is well-established and recommended as first line induction therapy in paediatric Crohn's disease with remission rates of up to 80%. Other than in Japan, enteral nutrition is not routinely used in the adult population among Western countries, mainly due to unpalatable formulations which lead to poor compliance. This study aims to offer a comprehensive review of available enteral nutrition formulations and the literature supporting the use and mechanisms of action of enteral nutrition in adult Crohn's disease patients, in order to support clinicians in real world decision-making when offering/accepting treatment. The mechanisms of actions of enteral feed, including their impact on the gut microbiome, were explored. Barriers to the use of enteral nutrition, such as compliance and the route of administration, were considered. All available enteral preparations have been comprehensively described as a practical guide for clinical use. Likewise, guidelines are reported and discussed.

Enteral nutritional therapy for induction of remission in Crohn's disease

BACKGROUND

Corticosteroids are often preferred over enteral nutrition (EN) as induction therapy for Crohn's disease (CD). Prior meta-analyses suggest that corticosteroids are superior to EN for induction of remission in CD. Treatment failures in EN trials are often due to poor compliance, with dropouts frequently due to poor acceptance of a nasogastric tube and unpalatable formulations. This systematic review is an update of a previously published Cochrane review.

OBJECTIVES

To evaluate the effectiveness and safety of exclusive EN as primary therapy to induce remission in CD and to examine the importance of formula composition on effectiveness.

SEARCH METHODS

We searched MEDLINE, Embase and CENTRAL from inception to 5 July 2017. We also searched references of retrieved articles and conference abstracts.

SELECTION CRITERIA

Randomized controlled trials involving patients with active CD were considered for inclusion. Studies comparing one type of EN to another type of EN or conventional corticosteroids were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by at least two authors. The primary outcome was clinical remission. Secondary outcomes included adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (CI). A random-effects model was used to pool data. We performed intention-to-treat and per-protocol analyses for the primary outcome. Heterogeneity was explored using the Chi² and I² statistics. The studies were separated into two comparisons: one EN formulation compared to another EN formulation and EN compared to corticosteroids. Subgroup analyses were based on formula composition and age. Sensitivity analyses included abstract publications and poor quality studies. We used the Cochrane risk of bias tool to assess study quality. We used the GRADE criteria to assess the overall quality of the evidence supporting the primary outcome and selected secondary outcomes.

MAIN RESULTS

Twenty-seven studies (1,011 participants) were included. Three studies were rated as low risk of bias. Seven studies were rated as high risk of bias and 17 were rated as unclear risk of bias due to insufficient information. Seventeen trials compared different formulations of EN, 13 studies compared one or more elemental formulas to a non-elemental formula, three studies compared EN diets of similar protein composition but different fat composition, and one study compared non-elemental diets differing in glutamine enrichment. Meta-analysis of 11 trials (378 participants) demonstrated no difference in remission rates. Sixty-four per cent (134/210) of patients in the elemental group achieved remission compared to 62% (105/168) of patients in the non-elemental group (RR 1.02, 95% CI 0.88 to 1.18; GRADE very low quality). A per-protocol analysis (346 participants) produced similar results (RR 1.04, 95% CI 0.91 to 1.18). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no differences in remission rates. An analysis of 7 trials including 209 patients treated with EN formulas of differing fat content (low fat: < 20 g/1000 kCal versus high fat: > 20 g/1000 kCal) demonstrated no difference in remission rates (RR 1.03; 95% CI 0.85 to 1.26). Very low fat content (< 3 g/1000 kCal) and very low long chain triglycerides demonstrated higher remission rates than higher content EN formulas. There was no difference between elemental and non-elemental diets in adverse event rates (RR 1.00, 95% CI 0.63 to 1.60; GRADE very low quality), or withdrawals due to adverse events (RR 1.29, 95% CI 0.80 to 2.09; GRADE very low quality). Common adverse events included nausea, vomiting, diarrhea and bloating.Ten trials compared EN to steroid therapy. Meta-analysis of eight trials (223 participants) demonstrated no difference in remission rates between EN and steroids. Fifty per cent (111/223) of patients in the EN group achieved remission compared to 72% (133/186) of patients in the steroid group (RR 0.77, 95% CI 0.58 to 1.03; GRADE very low quality). Subgroup analysis by age showed a difference in remission rates for adults but not for children. In adults 45% (87/194) of EN patients achieved remission compared to 73% (116/158) of steroid patients (RR 0.65, 95% CI 0.52 to 0.82; GRADE very low quality). In children, 83% (24/29) of EN patients achieved remission compared to 61% (17/28) of steroid patients (RR 1.35, 95% CI 0.92 to 1.97; GRADE very low quality). A per-protocol analysis produced similar results (RR 0.93, 95% CI 0.75 to 1.14). The per-protocol subgroup analysis showed a difference in remission rates for both adults (RR 0.82, 95% CI 0.70 to 0.95) and children (RR 1.43, 95% CI 1.03 to 1.97). There was no difference in adverse event rates (RR 1.39, 95% CI 0.62 to 3.11; GRADE very low quality). However, patients on EN were more likely to withdraw due to adverse events than those on steroid therapy (RR 2.95, 95% CI 1.02 to 8.48; GRADE very low quality). Common adverse events reported in the EN group included heartburn, flatulence, diarrhea and vomiting, and for steroid therapy acne, moon facies, hyperglycemia, muscle weakness and hypoglycemia. The most common reason for withdrawal was inability to tolerate the EN diet.

AUTHORS' CONCLUSIONS

Very low quality evidence suggests that corticosteroid therapy may be more effective than EN for induction of clinical remission in adults with active CD. Very low quality evidence also suggests that EN may be more effective than steroids for induction of remission in children with active CD. Protein composition does not appear to influence the effectiveness of EN for the treatment of active CD. EN should be considered in pediatric CD patients or in adult patients who can comply with nasogastric tube feeding or perceive the formulations to be palatable, or when steroid side effects are not tolerated or better avoided. Further research is required to confirm the superiority of corticosteroids over EN in adults. Further research is required to confirm the benefit of EN in children. More effort from industry should be taken to develop palatable polymeric formulations that can be delivered without use of a nasogastric tube as this may lead to increased patient adherence with this therapy.

Enteral Nutrition in the Management of Crohn's Disease: Reviewing Mechanisms of Actions and Highlighting Potential Venues for Enhancing the Efficacy

Crohn's disease (CD) is a chronic condition that affects the gut and has adverse effects on growth and development. There is a global increase in the incidence and prevalence rates, and several factors are believed to contribute to this rise, including dietary habits. In contrast, the use of enteral nutrition (EN) as an exclusive source of nutrition is increasingly becoming the preferred induction treatment of pediatric CD patients in part to address the nutrition complications. However, EN therapy is considered less effective in adults with CD. A better understanding of the molecular mechanisms of enteral therapy will help improve the clinical management of CD. It is increasingly becoming evident that the therapeutic utility of EN is in part due to the reversal of the microbial changes and the direct immunomodulatory effects. Moreover, there is a potential tendency for enhancing the efficacy of EN therapy by improving the palatability of the given formulas and, more important, by magnifying the anti-inflammatory properties. Recent observations have shown that the immunomodulatory effects of EN are mediated at least in part by blocking nuclear factor-κB. Furthermore, it is likely that several ingredients of EN contribute to this activity, in particular glutamine and arginine amino acids. In addition, manipulating the composition of EN therapy by altering concentrations of the key ingredients is found to have the potential for more efficient therapy. In this review, the underlying mechanisms of EN actions will be discussed further with a focus on the potential methods for enhancing the efficacy.

Impact of Preoperative Exclusive Enteral Nutrition on Postoperative Complications and Recurrence After Bowel Resection in Patients with Active Crohn's Disease

BACKGROUND

The impact of preoperative enteral nutrition (EN) on postoperative complications and recurrence in Crohn's disease (CD) has not been investigated to date. The purpose of the present study was to determine the effect of preoperative exclusive EN on postoperative complications and recurrence after bowel resection in patients with active CD.

METHODS

Patient data were obtained from a prospectively maintained database. 81 patients who received bowel resection for ileal or ileocolonic CD were studied. Before operation, 42 CD patients received exclusive EN for 4 weeks, and the other patients had no nutritional therapy. All patients were followed up regularly for 2 years after surgery, and ileocolonoscopy was performed every 6 months after bowel resection.

RESULTS

Patients receiving exclusive EN had a dramatic improvement of nutritional (BMI, albumin, pre-albumin, and Hb) and inflammatory (CRP and CDAI) status compared with baseline after the EN therapy for 4 weeks (P < 0.05). Furthermore, significantly lower incidence of both infectious and non-infectious complications was observed in patients receiving exclusive EN compared with those received no nutritional therapy (P < 0.05). Exclusive EN therapy for 4 weeks significantly reduced endoscopic recurrence rates after resection for CD 6 months after operation. However, during the 2-year follow-up, incidence of clinical recurrence was similar in both groups (P > 0.05).

CONCLUSIONS

Preoperative exclusive EN therapy for 4 weeks reduced postoperative complications, which may be associated with improvement of nutritional and inflammatory status in patients with active CD.

The effect of polymeric formula on enterocyte differentiation

Exclusive enteral nutrition is established as an initial therapy to induce remission in active Crohn's disease (CD), especially in children, but the mechanisms of action of this therapy are yet to be fully defined. Intestinal alkaline phosphatase (IAP), a recognised marker of enterocyte differentiation, is implicated in the innate gut immune response to enteric pathogens. Using the Caco-2 human adenocarcinoma cell line, this study showed that the incubation of human cells with a polymeric formula (PF) resulted in a dose-dependent increase in the expression of IAP on the cell surface. While further investigation is required to determine the pathway(s) involved, this finding suggests that cell surface-associated IAP may be an aspect of the gut's innate immune response to pathogenic bacteria that is strengthened by PF in the setting of CD.

Exploring and Enhancing the Anti-Inflammatory Properties of Polymeric Formula

BACKGROUND

Exclusive enteral nutrition (EEN) therapy using a polymeric formula (PF) can substantially attenuate intestinal inflammation in Crohn's disease (CD) patients. However, the mechanism(s) by which EEN suppresses inflammation are not yet fully understood. The aims were to examine cellular mechanism(s) through which EEN may suppress inflammation and investigate potential pathways to enhance anti-inflammatory properties of EEN.

METHODS

Glutamine, arginine, vitamin D3, and α linolenic acid (ALA), present in PF, along with curcumin, were identified as immunoactive nutrient therapies. Tumor necrosis factor (TNF)-α-exposed HT-29 colonic epithelial cells were used to investigate the immunosuppressive activity of the nutrients by assessing their effect on cell viability, cell activity, chemokine response (interleukin-8 [IL-8]), nuclear factor (NF)-κB, P38 mitogen-activated protein kinase, IκB kinase (Iκκ), and nitric oxide (NO).

RESULTS

Cellular viability and activity were maintained with all nutrient treatments. Glutamine, arginine, and vitamin D3, but not ALA, significantly attenuated IL-8 production. Glutamine and arginine led to phosphorylation blockade of the signaling components in NF-κB and P38 pathways, reduction in kinase activity, and enhancement in NO production. Combining glutamine, arginine, and curcumin at optimal concentrations completely abolished the IL-8 response.

CONCLUSIONS

These data indicate that glutamine, arginine, and vitamin D3 can suppress inflammation at concentrations equivalent to those used in PF. The mechanisms of this action were mediated through influencing the NF-κB and P38 cascades. Glutamine and arginine-fortified PF with curcumin might be a promising option to enhance the effectiveness and expand the scope of EEN therapy in CD treatment.

Recent advances in clinical practice: a systematic review of isolated colonic Crohn's disease: the third IBD?

The genetics of isolated colonic Crohn's disease place it approximately midway between Crohn's disease with small intestinal involvement and UC, making a case for considering it as a separate condition. We have therefore systematically reviewed its epidemiology, pathophysiology and treatment. Key findings include a higher incidence in females (65%) and older average age at presentation than Crohn's disease at other sites, a mucosa-associated microbiota between that found in ileal Crohn's disease and UC, no response to mesalazine, but possibly better response to antitumour necrosis factor than Crohn's disease at other sites. Diagnostic distinction from UC is often difficult and also needs to exclude other conditions including ischaemic colitis, segmental colitis associated with diverticular disease and tuberculosis. Future studies, particularly clinical trials, but also historical cohorts, should assess isolated colonic Crohn's disease separately.

Dietary treatment of Crohn's disease: perceptions of families with children treated by exclusive enteral nutrition, a questionnaire survey

Background

Diet is strongly associated with the aetiology of Crohn’s Disease (CD) and exclusive enteral nutrition (EEN) is the primary induction treatment in paediatric CD. This study explored opinions around the use of EEN and alternative novel, solid food-based diets (SFDs) expressed by paediatric patients with CD, previously treated with EEN and their parents.

Methods

This anonymous questionnaire surveyed families of CD patients treated with EEN over 1 year. Two questionnaire forms were completed; one asking the patients’ opinions and another referring to their main carer. This questionnaire explored participants’ demographic characteristics; acceptability of a repeat EEN course to treat a future flare (EEN repeat); their opinion on how difficult EEN would be compared to an example SFD; and their intention to participate in a future clinical trial assessing the therapeutic efficacy of an SFD in CD.

Results

Forty-one families of CD patients were approached with 29 sending replies (71%). Most of our participants were positive on completing another EEN course, however the majority would choose an SFD alternative (Patients:66, Parents:72%). Both patients and their parents rated EEN to be more difficult to adhere to compared to an example SFD (p < 0.05), and their ratings were strongly correlated (EEN:r = 0.83, SFD:r = 0.75, p < 0.001). The majority of our respondents would agree to participate in a clinical trial assessing an SFD’s effectiveness (Patients:79, Parents:72%) for the management of active CD.

Conclusions

While patients with CD and their families would accept an EEN repeat, the majority would prefer an SFD alternative. CD families surveyed are supportive of the development of solid food-based dietary treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-016-0564-7) contains supplementary material, which is available to authorized users.

Modulating Composition and Metabolic Activity of the Gut Microbiota in IBD Patients

The healthy intestine represents a remarkable interface where sterile host tissues come in contact with gut microbiota, in a balanced state of homeostasis. The imbalance of gut homeostasis is associated with the onset of many severe pathological conditions, such as inflammatory bowel disease (IBD), a chronic gastrointestinal disorder increasing in incidence and severely influencing affected individuals. Despite the recent development of next generation sequencing and bioinformatics, the current scientific knowledge of specific triggers and diagnostic markers to improve interventional approaches in IBD is still scarce. In this review we present and discuss currently available and emerging therapeutic options in modulating composition and metabolic activity of gut microbiota in patients affected by IBD. Therapeutic approaches at the microbiota level, such as dietary interventions alone or with probiotics, prebiotics and synbiotics, administration of antibiotics, performing fecal microbiota transplantation (FMT) and the use of nematodes, all represent a promising opportunities towards establishing and maintaining of well-being as well as improving underlying IBD symptoms.

Nutritional Support of Patient with Inflammatory Bowel Disease

Ideally, surgical patients should be nutritionally optimized, as better nutritional status correlates with favorable outcomes during the perioperative period. As inflammatory bowel disease often leads to overall malnutrition, special consideration should be given to this patient population by surgeons. In this article, we review methods for nutritional assessment and provide nutritional recommendations for this special surgical population.

Dietary management of IBD--insights and advice

The current general interest in the use of food choice or diet in maintaining good health and in preventing and treating disease also applies to patients with IBD, who often follow poor or nutritionally challenging dietary plans. Unfortunately, dietary advice plays only a minor part in published guidelines for management of IBD, which sends a message that diet is not of great importance. However, a considerable evidence base supports a focused and serious attention to nutrition and diet in patients with IBD. In this Review, a step-wise approach in the evaluation and management of these patients is proposed. First, dietary intake and eating habits as well as current nutritional state should be documented, and corrective measures instituted. Secondly, dietary strategies as primary or adjunctive therapy for the reduction of inflammation and/or prevention of relapse of IBD should be seriously contemplated. Thirdly, use of diet to improve symptoms or lessen the effects of complications should be considered. Finally, dietary advice regarding disease prevention should be discussed when relevant. An increasing need exists for applying improved methodologies into establishing the value of current and new ways of using food choice as a therapeutic and preventive tool in IBD.

Review article: the diagnosis and management of food allergy and food intolerances

BACKGROUND

Adverse reactions to food include immune mediated food allergies and non-immune mediated food intolerances. Food allergies and intolerances are often confused by health professionals, patients and the public.

AIM

To critically review the data relating to diagnosis and management of food allergy and food intolerance in adults and children.

METHODS

MEDLINE, EMBASE and the Cochrane Database were searched up until May 2014, using search terms related to food allergy and intolerance.

RESULTS

An estimated one-fifth of the population believe that they have adverse reactions to food. Estimates of true IgE-mediated food allergy vary, but in some countries it may be as prevalent as 4-7% of preschool children. The most common food allergens are cow's milk, egg, peanut, tree nuts, soy, shellfish and finned fish. Reactions vary from urticaria to anaphylaxis and death. Tolerance for many foods including milk and egg develops with age, but is far less likely with peanut allergy. Estimates of IgE-mediated food allergy in adults are closer to 1-2%. Non-IgE-mediated food allergies such as Food Protein-Induced Enterocolitis Syndrome are rarer and predominantly recognised in childhood. Eosinophilic gastrointestinal disorders including eosinophilic oesophagitis are mixed IgE- and non-IgE-mediated food allergic conditions, and are improved by dietary exclusions. By contrast food intolerances are nonspecific, and the resultant symptoms resemble other common medically unexplained complaints, often overlapping with symptoms found in functional disorders such as irritable bowel syndrome. Improved dietary treatments for the irritable bowel syndrome have recently been described.

CONCLUSIONS

Food allergies are more common in children, can be life-threatening and are distinct from food intolerances. Food intolerances may pose little risk but since functional disorders are so prevalent, greater efforts to understand adverse effects of foods in functional disorders are warranted.