The WHO defines probiotics as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”.
Essential criteria to be considered when selecting a probiotic
Not all probiotics1 are equal when it comes to their beneficial effects, whether they are yeasts or bacteria, and there are many essential criteria to consider2-6:
- Strain-dependent properties
- Manufacturing process and storage method
- Level of proof and effective dose
- Route of administration, oral or topical
Favorable effects on the microbiota
A probiotic has a beneficial effect on the microbiota by keeping it balanced, promoting its reconstruction during and after an episode of dysbiosis, and by preventing certain clinical situations of microbial ecosystem disruption (prevention of other diseases).7
A mode of action for each strain
A probiotic’s mode of action depends on the strain, and cannot be extrapolated to the species or the genus to which it belongs.4 Nevertheless, each probiotic acts in its own way on the host, according to its own physiological and pharmacological properties. They can act on2:
- The host: by modulating the immune system, with its anti-inflammatory properties, trophic effects on tissues, by stimulating the enzymatic capital, and by reinforcing the barrier effect against pathogens
- Pathogens: by releasing antimicrobial effectors against fungi, bacteria, or viruses
- Toxins: by neutralizing pathogenic toxins.
Learned societies like WGO,8 ESPGHAN,9 and ISAPP10 have given their opinions and recommendations on the use of probiotics.
The benefits are numerous; however, the effectiveness of probiotics has been demonstrated in specific indications with specific strains:
- Indications in the digestive system: AAD,11 C. difficile-associated diarrhea,12 gastroenteritis,13 functional gastrointestinal disorders,14 digestion of lactose and other enzymatic effects, IBDs,15 necrotizing enterocolitis in premature infants,16 H. pylori infections,17 tube feeding-associated diarrhea, and traveler’s diarrhea.18
- Indications in the prevention of non-digestive infections: winter respiratory infections,19 recurrent urinary tract infections,20 gynecological infections, and prevention of atopic eczema and allergies.21
Other beneficial effects are being studied, particularly regarding the influence of probiotics on colorectal cancer22 and certain neuropsychiatric disorders.23
- Food and Agricultural Organization of the United Nations and World Health Organization. Health and nutritional properties of probiotics in food including powder milk with live lactic acid bacteria. World Health Organization [online], (2001).
- Hill C et al. Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol. 2014 Aug;11(8):506-14. doi: 10.1038/nrgastro.2014.66. Epub 2014 Jun 10.
- Floch MH et al. Recommendations for probiotic use-2011 update. J Clin Gastroenterol. 2011 Nov; 45 Suppl:S168-71.
- Williams NT. Probiotics. Am J Health Syst Pharm. 2010 Mar 15; 67(6):449-58.
- Huys G et al. Microbial characterization of probiotics--advisory report of the Working Group "8651 Probiotics" of the Belgian Superior Health Council (SHC). Mol Nutr Food Res. 2013 Aug; 57(8):1479-504.
- Sanders ME et al. Effects of genetic, processing, or product formulation changes on efficacy and safety of probiotics. Ann N Y Acad Sci. 2014 Feb; 1309(1):1-18.
- McFarland LV. Use of probiotics to correct dysbiosis of normal microbiota following disease or disruptive events: a systematic review. BMJ Open 2014 ; 4 : e005047
- Szajewska H et al. Probiotics for the prevention of antibiotic-associated diarrhea in children. J Pediatr Gastroenterol Nutr 2016 ; 62 : 495-506.
- McFarland LV et al. A randomized placebo-controlled trial of Saccharomyces boulardii in combination with standard antibiotics for Clostridium difficile disease. JAMA 1994 ; 271 : 1913-8.
- Guarino A et al. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/ European Society for Pediatric Infectious Diseases evidencebased guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr 2014 ; 59 : 132-52.
- Brenner DM, Chey WD. Bifidobacterium infantis 35624: a novel probiotic for the treatment of irritable bowel syndrome. Rev Gastroenterol Disord 2009 ; 9 : 7-15.
- Bejaoui M, Sokol H, Marteau P. Targeting the microbiome in inflammatory bowel disease: critical evaluation of current concepts and moving to new horizons. Dig Dis 2015 ; 33 : 105-12.
- Alfaleh K, Anabrees J. Probiotics for prevention of necrotizing enterocolitis in preterm infants. Cochrane Database Syst Rev 2014 ; 4 : CD005496.
- Malfertheiner P et al. ; European Helicobacter and Microbiota Study Group and Consensus panel. Management of Helicobacter pylori infection-the Maastricht V/ Florence Consensus Report. Gut 2017 ; 66 : 6-30. diarrhées de la nutrition entérale
- McFarland LV. Meta-analysis of probiotics for the prevention of traveler's diarrhea. Travel Med Infect Dis. 2007;5:97-105.
- Smith TJ. 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;109:1999-2007.
- Beerepoot MA et al. Nonantibiotic prophylaxis for recurrent urinary tract infections: a systematic review and meta-analysis of randomized controlled trials. J Urol 2013 ; 190 : 1981-9.
- Drago L et al. Effects of Lactobacillus salivarius LS01 (DSM 22775) treatment on adult atopic dermatitis: a randomized placebo-controlled study. Int J Immunopathol Pharmacol. 2011;24:1037-48.
- Compare D. et al. Contribution of gut microbiota to colonic and extracolonic cancer development. Dig Dis. 2011 ; 29(6) : 554-61.
- Lye Huey Shi et al. Beneficial properties of probiotics. Tropical Life Sciences Research 2016; 27(2): 73–90. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5031164/pdf/tlsr-27-2-73.pdf
Rapport conjoint FAO/OMS sur les probiotiques : ftp://ftp.fao.org/es/esn/food/probio_report_en.pdf