Gut Reaction #16: Microbiota and the Gut
There are billions of bacteria in the human gut and they are referred to as the gut microbiome. Its role in health and disease is the subject of extensive research. Imbalance of the normal gut microbiota, or dysbiosis, is thought to be related, at least in part, to inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) as well as some non-gut related conditions such as obesity, type 2 diabetes and allergic disorders.
Bacteria are unevenly distributed along the length of the gut with the lowest numbers in the stomach (due to acid) then increasing in the small intestine, and rising to very large amounts in the the large intestine. In addition the type of bacteria (biodiversity) varies: there are relatively more firmicutes in the small intestine and relatively more bacteroides in the large intestine.
Diet may alter the composition of the gut microbiome for example switching from a meat-based to a plant-based diet. The significance of more monotonous diet is unclear but it appears that loss of diversity of the microbiota may be associated with an increase in risk of infections and inflammation.
In IBD there appears to be a decrease in the amount and diversity of firmicutes. This may be important as these bacteria produce short chain fatty acids that are thought to have anti-inflammatory properties.
In IBS there may be a relative increase in firmicutes compared with bacteroides leading to altered colonic fermentation. It is possible than a low FODMAP diet or even probiotics, may alter the gut microbiota under these circumstances and hence improve symptoms.
A lot of research is underway investigating our gut microbiota both in health and disease to see if changing the biodiversity can prevent or treat various conditions or diseases.
For more information, please do not hesitate to contact Dr. Harris.