Impact of tailored dietary interventions on suspected carbohydrate intolerance patients based on genetic testing

Background: carbohydrate intolerance presents a complex scenario where symptoms arise following the consumption of specific substrate and alleviate upon their elimination from the diet. Lactose Intolerance is one of the most prevalent types of food intolerance. Primary lactose intolerance is linked to genetic factors, Lactase Non-Persistence phenotype, while secondary lactose intolerance might be a temporary condition resulting from intestinal damage and loss of disaccharidase activity. Fructose absorption is an energy-independent process, leading to limited and variable absorption. Fructose undergoes quick absorption into the bloodstream through active transporters, specifically GLUT-5 and GLUT-2, found in the initial segment of the small intestine. The management of carbohydrate intolerance requires precise testing methods, accurate diagnostics, and customized dietary interventions. Genetic testing plays a crucial role in determining an individual's genetic profile, helping decide whether permanent restrictions on specific nutrients, such as lactose, are necessary. Objective: this research aims to understand the origin of suspected carbohydrate intolerance, combining genetic testing with breath tests to enhance the efficacy of treatment plans, as customized dietary interventions will be based on the patient's genetic profile and carbohydrate absorption capacity. Material and methods: a combination of genetic testing (lactase non-persistence and celiac disease risk) and breath test for lactose and fructose were performed. Recommendations such as low lactose, low fructose or gluten-free diets; or a combination of them were provided based on each patient's testing profile results. Results: after the nutritional intervention, a significant improvement was noted in all gastrointestinal symptoms, except for reflux and nausea, and in all of the extraintestinal symptoms. Conclusions: designing dietary interventions based on primary and secondary causes for carbohydrate intolerance can avoid unnecessary food restrictions; improving patients' quality of life and treatment effectiveness through tailored dietary interventions.