Irritable Bowel Syndrome (IBS) and Ulcerative Colitis (UC) affect principally the gut,
causing symptoms that alter intestinal motility, with a multifactorial etiology. The
pharmacological and nutritional treatment varies according to the symptoms and activity of
each patient. The most commonly used are the standard diet (SD), which excludes foods known
as irritants or inflammatory. On the other hand, are the low fodmap diet (LFD) (fermentable
oligosaccharides. disaccharides, monosaccharides and polyols), these highly fermentable
carbohydrates can pass unabsorbed to the colon and induce the gas production due to the
fermentation of gut microbiota and cause symptoms such as: bloating, flatulence, abdominal
pain and altered bowel habit. It consists in two stages: first the restriction of all foods
that contain fodmaps and second the re exposure in which indicate the introduction of each
food restricted before to evaluate the tolerance, for 6 to 8 weeks. Some studies show that
the low fodmap diet improve the symptoms in both groups, however because of the restriction
and the limited content of foods, they have had risk to present nutritional deficiencies. The
aim of the present is to evaluate the effect of a low fodmap diet for 10 weeks on
gastrointestinal symptoms, nutritional status and microbiota in patients with IBS and UC.
Methods: a controlled, blinded clinical trial will be conducted in patients who assist to
medical monitoring in gastroenterology service with diagnosis of IBS or UC. The sample size
was determined with a 0.5 effect size, an alpha error 0.05 and power of 80%, which determined
64 patients for each group (total: 128). After singing the informed consent, will be
determined their total energy expenditure (TEE) and consecutively will be assigned an ID
previously randomized to SD (<16 g of fodmaps) or LFD (<10 g of fodmaps), with a distribution
of 55% carbohydrates, 20% proteins and 25% lipids. During the 10 weeks will be three
follow-ups, first the basal, intermediate (week 5) and final (10 weeks after), will be
performed body composition (RJL Quantum III), anthropometry (waist, hip, arm and chest
circumference), gastrointestinal symptoms (ROMA III and Mayo Scale), quality of life
(WHOQL-BREF), food frequency and 24-hour reminder and blood chemistry (anemia,
hypoalbuminemia, vitamin D, calcium, potassium, c reactive protein, VSG, etc), all of them
basal and final.
