The presence of cardiovascular and metabolic risk factors, like elevated glycemia and cholesterol, hypertension, … is influenced by the composition of the intestinal microbiota.
Metabolic syndrome, which affects around 10% of the French population1, is a collection of risk factors, such as obesity, high blood sugar, dyslipidemia and/or hypertension2,3, that increase the risk of type 2 diabetes and strokes.
Risk depends on the microbiota composition
The results of preclinical experiments showed that the risk of developing those metabolic disturbances is related to the composition of the gut flora4 . In humans, changes of the intestinal microbiota composition have been associated with hyperglycemia and type 2 diabetes5,6 .
It seems that the displacement of bacterial components from the intestinal microbiota via the bloodstream, such as lipopolysaccharides (components of the wall of Gram-negative bacteria)4,7, or even entire bacteria8, contributes to the development of metabolic syndromes through increased inflammation.
A sufficiently sealed intestinal barrier
This transfer of bacterial components via the blood is facilitated by changes of the intestinal barrier in obese people or those with a high fat diet8.
Some bacteria have positive effects
Some intestinal bacteria, however, can have beneficial effects, particularly through the production of secondary bile acids, which lead to increased intestinal L-cell synthesis of the insulin-sensitive hormone glucagon-like peptide-1 (GLP-1)9.
According to preclinical study findings, Akkermansia muciniphila or Saccharomyces boulardii administration to obese and diabetic animals affected on the host’s metabolism, with notably less weight gain10-13.
1- Azimi-Nezhad M et al. High prevalence of metabolic syndrome in Iran in comparison with France: what are the components that explain this? Metab Syndr Relat Disord. 2012;10(3):181–8. doi: 10.1089/met.2011.0097. https://www.ncbi.nlm.nih.gov/pubmed/?term=High+prevalence+of+metabolic+syndrome+in+Iran+in+comparison+with+France%3A+what+are+the+components+that+explain+this
2- Alberti KG et al. Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: diagnosis and classification of diabetes mellitus provisional report of a WHO consultation. Diabet Med 1998;15:539-53 https://www.ncbi.nlm.nih.gov/pubmed/term=Definition%2C+diagnosis+and+classification+of+diabetes+mellitus+and+its+complications.+Part+1%3A+diagnosis+and+classification+of+diabetes+mellitus+provisional+report+of+a+WHO+consultation
3- Alberti KG et al. The metabolic syndrome—a new worldwide definition. Lancet 2005;366:1059-62. https://www.ncbi.nlm.nih.gov/pubmed/16182882
4- Backhed F et al. The gut microbiota as an environmental factor that regulates fat storage. Proc Natl Acad Sci USA 2004;101:15718-23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC524219/
5- Sepp E et al. Higher blood glucose level associated with body mass index and gut microbiota in elderly people. Microb Ecol Health Dis 2014;25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4048595/pdf/MEHD-25-22857.pdf
6- Qin Jet al. A metagenome-wide association study of gut microbiota in type 2 diabetes. Nature 2012;490 55-60. https://www.ncbi.nlm.nih.gov/pubmed/23023125
7- Cani PD et al. Changes in gut microbiota control metabolic endotoxemia-induced inflammation in high-fat diet-induced obesity and diabetes in mice. Diabetes 2008;57:1470-81. http://diabetes.diabetesjournals.org/content/57/6/1470.full-text.pdf
8- Burcelin R et al. Metagenome and metabolism: the tissue microbiota hypothesis. Diabetes Obes Metab 2013;15 3) 61-70. https://www.ncbi.nlm.nih.gov/pubmed/24003922
9- Prawitt J et al. Bile acid metabolism and the pathogenesis of type 2 diabetes. Curr Diabetes Reps 2011;11:160-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338411/
10- Everard A et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity. Proc Natl Acad Sci USA 2013;110:9066-71. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3670398/pdf/pnas.201219451.pdf
11- Shin NR et al. An increase in the Akkermansia spp. population induced by metformin treatment improves glucose homeostasis in diet-induced obese mice. Gut 2014;63:727-35. https://www.ncbi.nlm.nih.gov/pubmed/?term=An+increase+in+the+Akkermansia+spp.+population+induced+by+metformin+treatment+improves+glucose+homeostasis+in+diet-induced+obese+mice
12- Everard A et al. Saccharomyces boulardii administration changes gut microbiota and reduces hepatic steatosis, low-grade inflammation, and fat mass in obese and type 2 diabetic db/db mice. MBio. 2014 Jun 10;5(3):e01011-14. https://www.ncbi.nlm.nih.gov/pubmed/24917595
13- Girard P1, Pansart Y, Verleye M. Anti-hypercholesterolemic effect of Saccharomyces boulardii in the hamster. Pharmacology. 2014;94(5-6):239-44. https://www.ncbi.nlm.nih.gov/pubmed/25427779