Food Intolerance: Etiology, Diagnosis, Mechanisms, Evidence
Food Intolerance: Etiology, Diagnosis, Mechanisms, Evidence
Background Food intolerance is non-immunological and is often associated with gastrointestinal symptoms.
Aim To focus on food intolerance associated with gastrointestinal symptoms and critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence.
Methods A search using the terms and variants of food intolerance, lactose, FODMAP, gluten, food chemicals within Pubmed, Embase and Scopus was carried out and restricted to human studies published in English. Additionally, references from relevant papers were hand searched for other appropriate studies.
Results Food intolerance affects 15–20% of the population and may be due to pharmacological effects of food components, noncoeliac gluten sensitivity or enzyme and transport defects. There have been significant advances in understanding the scientific basis of gastrointestinal food intolerance due to short-chain fermentable carbohydrates (FODMAPs). The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction. A low FODMAP diet is effective, however, it affects the gastrointestinal microbiota and FODMAP reintroduction to tolerance is part of the management strategy.
Conclusions There is increasing evidence for using a low FODMAP diet in the management of functional gastrointestinal symptoms where food intolerance is suspected. Exclusion diets should be used for as short a time as possible to induce symptom improvement, and should be followed by gradual food reintroduction to establish individual tolerance. This will increase dietary variety, ensure nutritional adequacy and minimise impact on the gastrointestinal microbiota.
Food intolerance is non-immunological and may occur in response to pharmacological effects of food or food components, noncoeliac gluten sensitivity or enzyme/transport defects. Food intolerance should not be confused with food hypersensitivity which is an umbrella term used to describe food intolerance and food allergy, the latter being defined as an adverse reaction to food whereby immunoglobulin E (IgE)-mediated or non-IgE-mediated immunological mechanisms have been demonstrated.
Food intolerance is common in the modern world, and depending on data collection methods and definitions, it affects up to 15–20% of the population. Even 20 years ago, 20% of the population reported food intolerance. Most people with food intolerance report gastrointestinal symptoms and in patients with functional gastrointestinal disorders, the most common of which being irritable bowel syndrome (IBS), 50–84% perceive their symptoms are related to food intolerance. The most commonly reported food intolerances leading to gastrointestinal symptoms are provided in Table 1.
This review will focus on food intolerance leading to gastrointestinal symptoms such as increased flatulence, abdominal pain, bloating or diarrhoea and will critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence. Extra-intestinal symptoms such as migraine, asthma, eczema, malaise will not be reviewed.
Abstract and Introduction
Abstract
Background Food intolerance is non-immunological and is often associated with gastrointestinal symptoms.
Aim To focus on food intolerance associated with gastrointestinal symptoms and critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence.
Methods A search using the terms and variants of food intolerance, lactose, FODMAP, gluten, food chemicals within Pubmed, Embase and Scopus was carried out and restricted to human studies published in English. Additionally, references from relevant papers were hand searched for other appropriate studies.
Results Food intolerance affects 15–20% of the population and may be due to pharmacological effects of food components, noncoeliac gluten sensitivity or enzyme and transport defects. There have been significant advances in understanding the scientific basis of gastrointestinal food intolerance due to short-chain fermentable carbohydrates (FODMAPs). The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction. A low FODMAP diet is effective, however, it affects the gastrointestinal microbiota and FODMAP reintroduction to tolerance is part of the management strategy.
Conclusions There is increasing evidence for using a low FODMAP diet in the management of functional gastrointestinal symptoms where food intolerance is suspected. Exclusion diets should be used for as short a time as possible to induce symptom improvement, and should be followed by gradual food reintroduction to establish individual tolerance. This will increase dietary variety, ensure nutritional adequacy and minimise impact on the gastrointestinal microbiota.
Introduction
Food intolerance is non-immunological and may occur in response to pharmacological effects of food or food components, noncoeliac gluten sensitivity or enzyme/transport defects. Food intolerance should not be confused with food hypersensitivity which is an umbrella term used to describe food intolerance and food allergy, the latter being defined as an adverse reaction to food whereby immunoglobulin E (IgE)-mediated or non-IgE-mediated immunological mechanisms have been demonstrated.
Food intolerance is common in the modern world, and depending on data collection methods and definitions, it affects up to 15–20% of the population. Even 20 years ago, 20% of the population reported food intolerance. Most people with food intolerance report gastrointestinal symptoms and in patients with functional gastrointestinal disorders, the most common of which being irritable bowel syndrome (IBS), 50–84% perceive their symptoms are related to food intolerance. The most commonly reported food intolerances leading to gastrointestinal symptoms are provided in Table 1.
This review will focus on food intolerance leading to gastrointestinal symptoms such as increased flatulence, abdominal pain, bloating or diarrhoea and will critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence. Extra-intestinal symptoms such as migraine, asthma, eczema, malaise will not be reviewed.
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