Food is often considered to be a precipitating factor of irritable bowel syndrome (IBS) symptoms. In recent years, there has been a growing interest in FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides, And Polyols), which can be found in many common foods. A low FODMAP diet (LFD) is increasingly suggested for IBS treatment. However, long-term, large, randomized controlled studies are still lacking, and certainties and doubts regarding LFDs have grown, often in a disorderly and confused manner. Some potential LFD limitations and concerns have been raised, including nutritional adequacy, cost, and difficulty in teaching the diet and maintaining it. Most of these limitations can be solved with the involvement of a skilled nutritionist, who can clearly explain the different phases of the LFD and ensure nutritional adequacy and compliance. Further studies should focus on new methods of teaching and learning the LFD and on predictors of response. Moreover, particular interest should be focused on the possible use of LFD in gastrointestinal diseases other than functional disorders and, possibly, also in non-gastrointestinal diseases. The aim of the present review was to clarify the effective and appropriate indications and limitations of an LFD and to discuss its possible future uses.

A low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet (LFD) is a possible therapy for irritable bowel syndrome (IBS). This study investigates the short- and long-term efficacy and nutritional adequacy of an LFD and the patients’ long-term acceptability. Patients’ adherence and ability to perceive the “trigger” foods were also evaluated. Seventy-three IBS patients were given an LFD (T0) and after 2 months (T1), 68 started the reintroduction phase. At the end of this period (T2), 59 were advised to go on an Adapted Low-FODMAP Diet (AdLFD) and 41 were evaluated again after a 6–24 month follow-up (T3). At each time, questionnaires and Biolectrical Impedance Vector Analysis (BIVA) were performed. The LFD was effective in controlling digestive symptoms both in the short- and long-term, and in improving quality of life, anxiety and depression, even if some problems regarding acceptability were reported and adherence decreased in the long term. The LFD improved the food-related quality of life without affecting nutritional adequacy. When data collected at T0 were compared with those collected at T2, the perception of trigger foods was quite different. Even if some problems of acceptability and adherence are reported, an LFD is nutritionally adequate and effective in improving IBS symptoms also in the long term.

Chronic constipation (CC) is one of the most common gastroenterological diagnoses in clinical practice. Treatment includes several steps, depending on the severity of symptoms. Lifestyle modifications and increased intake of fiber and water are suggested by most health professionals. Unfortunately, the recommendations in this regard are the most varied, often conflicting with each other and not always based on solid scientific arguments. This paper aims to clarify this topic by providing practical indications for the management of these patients in every day clinical practice. The literature available on this topic is scarce, and dietary studies have important methodological biases. However, fiber, mainly by binding water and acting as bulking agents and/or as prebiotics for the intestinal microbiota, and mineral water, especially if rich in magnesium and/or bicarbonate, are useful tools. An adequate, well-designed diet should be a cornerstone of any effective treatment for chronic constipation. High-quality studies on larger samples are mandatory to give scientific validity to the role of the food in CC therapy and to enable professionals to choose the best approach for their patients, combining nutritional and pharmacological agents.

Irritable Bowel Syndrome (IBS) is a very common functional gastrointestinal disease. Its pathogenesis is multifactorial and not yet clearly defined, and hence, its therapy mainly relies on symptomatic treatments. Changes in lifestyle and dietary behavior are usually the first step, but unfortunately, there is little high-quality scientific evidence regarding a dietary approach. This is due to the difficulty in setting up randomized double-blind controlled trials which objectively evaluate efficacy without the risk of a placebo effect. However, a Low Fermentable Oligo-, Di- and Mono-saccharides And Polyols (FODMAP) Diet (LFD) and Gluten Free Diet (GFD) are among the most frequently suggested diets. This paper aims to evaluate their possible role in IBS management. A GFD is less restrictive and easier to implement in everyday life and can be suggested for patients who clearly recognize gluten as a trigger of their symptoms. An LFD, being more restrictive and less easy to learn and to follow, needs the close supervision of a skilled nutritionist and should be reserved for patients who recognize that the trigger of their symptoms is not, or not only, gluten. Even if the evidence is of very low-quality for both diets, the LFD is the most effective among the dietary interventions suggested for treating IBS, and it is included in the most updated guidelines.

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