Functional gastrointestinal disorders

Irritable bowel syndrome (IBS), the most common FGD

FGDs encompass a set of symptoms such as IBS, constipation, diarrhea, functional bloating, and non-specific FGDs.

IBS alone affects 10% of the population and is distinguished from other FGDs by abdominal pain associated with constipation, diarrhea, or alternations between them. It often presents with abdominal bloating and a higher level of stress than the general population.

FGDs don’t spare children

In very small children, FGDs represent the most common gastrointestinal reason for a doctor’s visit. This includes baby colic with regurgitation and constipation problems, IBS, and other less well characterized functional problems. Stomach pain, bloating, diarrhea, and constipation are commonly associated with FGDs and can have major consequences on a child’s daily life. Stress and anxiety can also favor or prolong certain symptoms, particularly pain.

Disrupted communication between the intestines and the brain

The causes of IBS are still poorly understood. The risk of developing IBS increases five-fold after a bacterial infection causing acute diarrhea. It has been suggested that it could be related to dysfunction in the communication between the brain and the intestine, in conjunction with an imbalance in the intestinal flora. In the majority of cases, there is a loss of diversity (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232.   ) among the bacterial species that make up the microbiota, with fewer positive bacteria and more harmful bacteria. This dysfunction causes intestinal motor problems: transit is slowed, the intestinal barrier is modified, and slight inflammation develops. It also causes hypersensitivity in the mucosa that makes normal phenomena, like the movement of intestinal gas, painful.

Promising data for probiotics

For adults, in addition to a controlled diet, treatment options include antispasmodics, laxatives, and antidiarrheals. In children, relaxation and hypnosis techniques, which can relieve pain, are preferred. Sometimes antispasmodics are also prescribed. To modify the microbiota, there are promising data currently available about probiotics, particularly bifidobacteria (sidenote: Bifidobacterium A genus of Y-shaped bacteria, most species of which are beneficial to humans. They are found in the gut of humans, and in some yogurts.

They:
- Protect the gut barrier 
- Participate in the development of the immune system and help fight inflammation 
- Promote digestion and improve symptoms of gastrointestinal disorders Sung V, D'Amico F, Cabana MD, et al. Lactobacillus reuteri to Treat Infant Colic: A Meta-analysis. Pediatrics. 2018 Jan;141(1):e20171811.  O'Callaghan A, van Sinderen D. Bifidobacteria and Their Role as Members of the Human Gut Microbiota. Front Microbiol. 2016 Jun 15;7:925. Ruiz L, Delgado S, Ruas-Madiedo P, et al. Bifidobacteria and Their Molecular Communication with the Immune System. Front Microbiol. 2017 Dec 4;8:2345. ) and lactobacilli (sidenote: Lactobacilli Rod-shaped bacteria whose main characteristic is the production of lactic acid, from where they get the name “lactic acid bacteria”.  Lactobacilli are present in the oral, vaginal and gut microbiota of humans, but also in plants and animals. They are found in fermented foods, such as dairy products (e.g. certain cheeses and yoghurts), pickles, sauerkraut, etc. Lactobacilli are also found in probiotics, with certain species recognized for their beneficial properties.   W. H. Holzapfel et B. J. Wood, The Genera of Lactic Acid Bacteria, 2, Springer-Verlag, 1st ed. 1995 (2012), 411 p. « The genus Lactobacillus par W. P. Hammes, R. F. Vogel Tannock GW. A special fondness for lactobacilli. Appl Environ Microbiol. 2004 Jun;70(6):3189-94. Smith TJ, Rigassio-Radler D, Denmark R, et al. Effect of Lactobacillus rhamnosus LGG® and Bifidobacterium animalis ssp. lactis BB-12® on health-related quality of life in college students affected by upper respiratory infections. Br J Nutr. 2013 Jun;109(11):1999-2007. ) , and about fecal transplants. However, large-scale clinical trials still have to be conducted to confirm each of these options.