Introduction

The acronym ‘FODMAP' (Fermentable Oligo-, Diand Monosaccharides and Polyols) was created to describe a group of short-chain carbohydrates and sugar alcohols (polyols)⁽¹⁾. They comprise fructose, lactose, fructoand galactooligosaccharides (fructans, and galactans), and polyols (such as sorbitol, mannitol, xylitol and maltitol). These molecules are poorly absorbed in the small intestine, they are osmotically active and are rapidly fermented by bacteria producing gas⁽²⁾. The additional gas and water inside the gut stretches the bowel wall and triggers symptoms such as abdominal pain, gas and bloating, distension, constipation and diarrhea in some situations and patients⁽³⁾.

It was in 2005, when researchers in the Department of Gastroenterology at Monash University⁽³⁾ identified this group of short-chain carbohydrates in food. The research team measured the FODMAP content of a wide range of foods, including fruit, vegetables, breads, cereals, nuts, legumes, dairy products and processed foods. This food composition information allowed the team to develop the first low FODMAP diet. The team used this low FODMAP diet in the first research studies which showed that a low FODMAP diet reduces symptoms in people with Irritable Bowel Syndrome (IBS)⁽³⁾.

The FODMAP concept in the management of functional gut symptoms relies on a dietary approach that restricts FODMAP intake globally, not individually; and represents an opportunity for reducing symptoms⁽²⁾. Restriction of individual FODMAP has been used with varying success in the management of functional gut symptoms for a long time. However, such approaches have not become widespread in their application, perhaps in part related to their limited success. Restricting one FODMAP in isolation ignores the likelihood that there is potentially a range of FODMAP in the diet, all of which have similar end-effects in the bowel⁽⁴⁾. The innovation in the FODMAP concept is that global restriction should have a far greater and more consistent effect than limited restriction⁽²⁾.

There is considerable evidence that FODMAP induce abdominal symptoms. Acute provocation tests with lactose⁽⁵⁾, fructose^(5,6), fructo-oligosaccharides (FOS)⁽⁷⁾ or sorbitol^(5,8) cause abdominal symptoms such as bloating, pain, nausea and disturbed bowel habit (diarrhoea and/or constipation) in many people, especially those with IBS.

All the research applying the low FODMAP diet indicates that up to 70% of the patients who follow a diet low in FODMAP present a significant improvement in symptoms, especially those related to abdominal pain and bloating^(9-13). The symptom that least improves is constipation, which can be related to the low fiber intake of this dietary model⁽¹⁴⁾. The low FODMAP diet has not only shown to have nutritional and symptomatic benefits in gastrointestinal diseases (e.g. IBS⁽¹⁵⁾, non-celiac gluten sensitivity⁽¹⁶⁾ or celiac disease⁽¹⁷⁾), but also in patients with fibromyalgia⁽¹⁸⁾, sclerosis⁽¹⁹⁾ and endometriosis⁽²⁰⁾.

A global approach to restricting carbohydrates that have similar actions (high osmotic effect and rapid fermentation) should optimize symptom control in patients. Nonetheless, the low FODMAP diet may not alleviate symptoms of every subject, being compliance a main factor ⁽²⁾. Because the diet is fairly complex, advice should be given by a specialized dietitian trained in the area with appropriate resources, along with a multidisciplinary team of other health professionals, and food intake should be monitored for nutritional adequacy⁽²⁾. Since the first low FODMAP diets were described⁽²¹⁾, there have been modifications to the food lists that have been prompted by new scientific data on food composition. Robust data now exist describing the FODMAP content of commonly consumed foods⁽²²⁾. However, not all studies provide the list of foods allowed in the low FODMAP diet or if they do, they differ between studies, as well as the quantities of FODMAP each food may have. Even some studies^(23,24) allow foods (peeled apples, pears and milk) as part of the low FODMAP diet, which are not consistent with a low FODMAP diet as it was originally described. Inconsistency in the data provided has not only been found in relation to the FODMAP diet, but also in histamine content lists for histamine intolerance patients⁽²⁵⁾. Other limitations of the low FODMAP diet include lack of clear cutoff levels for FODMAP content in foods and non-availability of information on FODMAP content on food packages⁽²⁾. All of the above make it difficult to standardize, homogenize and create a tool for clinical practice and research. It is also important to note that low FODMAP diets are very restrictive. Therefore they can produce a reduction in the intake of certain dietary components such as calcium, fiber, iron, zinc, folic acid and vitamin D⁽²⁶⁾. Thus, in order to ensure that the diet is not deficient despite the restrictions, it is necessary that the treatment is controlled by experienced dietitians⁽²⁶⁾. Generally, the strict low FODMAP diet is not recommended to be followed long term, as it may also result in reduced total bacterial abundance⁽²⁷⁾ and reduced concentration of bifidobacterial⁽⁹⁾.

Despite the disadvantages of a low FODMAP diet, the diet has provided symptomatic relief in more patients with IBS compared to a standard dietary advice consisting of healthy eating principles, alteration of insoluble and soluble fibers, and limiting sugar-free foods and foods containing sorbitol (86% and 49%, respectively)⁽²⁸⁾. There are many studies carried out in the field of a low FODMAP diet, finding more than 350 results in some search databases, although many of them are retrospective^(21,24) or prospective and uncontrolled^(29-31) making the studies potentially subject to bias and confounding. However, in recent years well-designed clinical trials have been designed to support the efficacy of low FODMAP diet in patients with IBS; to date, two controlled trials^(24,28) and six randomized controlled trials ^{(9,11,12,29,32,33)}. However, more studies are needed to compare and establish more robust and specific food lists and quantities of FODMAP in foods. Further research is needed to standardize the information regarding the FODMAP diet and create reliable guidelines for clinical practice.

The lack of culturization and adaptation of the diet, through lists and gastronomic customs of countries where this diet is not very widespread, such as Latin American countries, can pose a problem in the treatment follow-up. Therefore, the aim of this research was to propose a FODMAP diet guide culturally adapted to different countries for Dietitians-Nutritionists and nutrition experts, to facilitate the management of patients who benefit from this diet.

Material and methods

A consortium of FODMAP diet experts was created among Spanish-speaking countries between June and August 2020. Dieticians from 11 Latin American countries (Argentina, Colombia, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Panama, Peru, Uruguay and Venezuela) and Spain were enrolled in the project. Universidad de Belgrano (Argentina), Clínica Universitaria Colombia (Colombia), Consulta Adriana Pérez-Chávez (Ecuador), Nexa Resources Cajamarquilla S.A. (Peru), the Nutrition School at Universidad de la República (Uruguay), Centro de Medicina Deportiva y Rehabilitación MEDKAR (Venezuela), Centro de Hemodiálisis y de Salud Renal and Universidad Dr. Andrés Bello (El Salvador), the Nutrition department at Universidad del Valle de Guatemala (Guatemala), Universidad Tecnológica Centroamericana and Consulta María Regina Pacheco Blanco (Honduras), GenoVive (Mexico), Hospital Punta Pacífica and Instituto de Investigaciones Científicas y Servicios de Alta Tecnología INDICASAT-AIP (Panama) and Research Centers in Nutrition and Health CINUSA (Spain) participated in the elaboration of low FODMAP diets adjusted each to the culture of their own country.

At enrolment time, all participating institutions were asked to elaborate a low FODMAP balanced menu, adapted to the gastronomic culture of their own country (including typical recipes and ways of cooking and eating). Two examples of a menu were given to each participant as well as a unique list of foods rich (worst tolerated) and low (best tolerated) in FODMAP, to serve as a guide. In any case, participants were encouraged to use the Monash University FODMAP diet app⁽²²⁾ to access the library of low FODMAP foods, recommendations and recipes. Each diet had to be structured as a 7-day balanced healthy menu. Each intake must consist of carbohydrate + vegetable + protein or vegetable + protein, with an approximate distribution of 40-60% carbohydrates (no ultra-processing products, soft drinks, simple sugars, pastries or fast food), 15-30% protein (both animal and plant origin), and 20-35% fat (including blue fish, nuts, oleaginous fruits, and avoiding trans fats). The menus were revised by an experienced dietician on the FODMAP diet to ensure they all followed the same criteria.

All the collaborators were also asked for a list of foods, which are frequently consumed in their country, to be reintroduced in phase 2 (or reintroduction phase) of the FODMAP diet, along with typical recipes from the country where the reintroduction foods could be included.

Results

Discussion

Numerous studies in other countries have reported the use of the FODMAP diet⁽³⁷⁾. However, the information available in Spanish is scarce⁽³⁸⁾ and there are barely no local studies that have estimated the applicability and effectiveness of this strategy on the symptoms and the health-related quality of life in patients in the Hispanic setting.

The benefits of restricting dietary FODMAPs appears to be durable⁽³⁴⁾. The nature of the diets used, however, is generally poorly defined. While all FODMAP are potentially important in the genesis of symptoms, the relative contribution of different subgroups of FODMAP varies across ethnic and dietary groups due to the dose delivered in the diet⁽²⁾. In Western European and Central and South American diets, fructose and fructans are by far the most widespread in the diet and therefore the ones to which nearly all patients with IBS are exposed in their everyday diet⁽²⁾.

Using a well-defined diet, restriction of fructose and fructans, together with general avoidance of other FODMAP leads to impressive global symptoms response⁽³⁵⁾. There are limitations in developing tables of FODMAP-rich and FODMAP-poor foods. Published lists of foods are generally limited in the description of FODMAP content. This limitation has been assisted by the development of methodologies to measure FODMAP content, together with a systematic examination of fruits, vegetables and cereals⁽³⁶⁾. The cut-off levels of FODMAP content, which dictates whether it is classified as ‘high' or not, are not clearly defined. This is further complicated by the fact that the total of FODMAPs ingested (not the individual FODMAP) at any one meal is a major factor in determining whether symptoms will be induced or not.

More studies are needed on the use of the FODMAP diet. The current criticism towards the FODMAP diet and the lack of evidence and robustness for its clinical and dietary use seems to be justified. There is a great variation between the different lists of FODMAP content in foods. The intervention studies are mostly of short duration, usually less than 3-6 months. Besides, the necessary trained professionals are not always available in hospitals and primary care, therefore, the recommendation of the diet is limited.

In resume, defining qualitatively the typical eating practices and style of the patient and the subsequent adaptation of the diet to local gastronomy is pertinent, as it provides the basis for a better understanding of food choice and may increase the likelihood of durable adherence. An understanding of the dietary principles and allocation of time to work on applying the diet are also important to ensure success.

This publication is merely intended as a guide to help professionals manage the FODMAP diet.