The impact of diet on intestinal microbiota and overall health

The Gut Microbiota: An Overview

The gastrointestinal (GI) tract is an ecosystem where different microbial communities coexist. Over the last 15 years, research has begun to characterize the gut microbiota and unravel its contribution to maintaining our overall health. The gut barrier prevents the passage of harmful, non-self-components from the intestinal lumen, such as pathogen-associated molecular patterns and antigens from food and bacteria. The microbiota, along with the host's mucosal immunity, plays a role in the development, maintenance, and regulation of the gut barrier. Antibiotics, stress, diet, and genetic factors (such as liver and diet-associated fatty acid liver model or irritable bowel syndrome) can disturb the balance of the human microbiota, leading to overgrowth of some bacteria and destruction of the other protective bacteria. The balance of the protective bacteria in the microbiota allows the nutrients to get into the bloodstream and/or participate in the inflammatory response. The intestinal microbiota produces significant amounts of bioactive compounds and vitamins, such as vitamin K, folic acid, lactic acid, and short-chain fatty acids (SCFAs). Among SCFAs, the main metabolites are acetate, butyrate, and propionate. Recently, it has been shown that other microbially-derived metabolites, called secondary bile acids, also have a significant impact on health. Most of these nutrients are absorbed by colonocytes, which contribute up to 60% of the total ATP generated in this organ. These bacteria exert significant beneficial effects on human metabolism, including maintenance of the structural integrity of the lining surface of the intestine. Furthermore, some proteins essential to the formation of tight junctions and mucins, which regulate the immune function and bacterial translocation by strengthening the lining of the intestine, are also produced by these bacteria. This protective barrier maintains the immune system so the bacteria and endotoxins do not have access to epithelial gastrointestinal cells, as well as from infecting pathogenic bacteria. These beneficial bacteria also modulate the host mucosal immune response and prevent invasion.

2.1. Composition and Function

Some microbial genera provide important metabolic functions to the host, including the assimilation of indigestible dietary polysaccharides and the production of essential nutrients and other bioactive compounds. These functions appear to be particularly pertinent for those who eat vegetarian diets and are more likely to benefit from these microbial alliances. Fecal analysis of a sample of APDF members was also consistent with this notion, with a more diverse genus and a greater number of potential functions between the large intestine and those members consuming vegetarian diets. Strictly vegetarian or vegan members were found to have different, higher frequencies than those who were consuming normal carbohydrate diets. One of the documents also emphasized that diets rich in whole carbohydrates support the growth of certain non-pathogenic organisms in the large intestine, particularly members of the genus Bifidobacter. It performed several important metabone research studies and further expanded its community of participating members. In a 2016 document, researchers looked at the impact of diet on the composition of the microbiome of the IB of nine foragers. Using data from a large data collection platform and the software analysis software, Quant showed that food was the strongest modulator of species abundance with fermentation or fission.

2.2. Factors Influencing Gut Microbiota

The gut microbiota can be influenced by a number of factors, including mode of delivery (vaginal versus cesarean), antibiotic use, diet, and stress. At birth, the human intestine is sterile; colonization of the gut with maternal and environmental microbiota begins upon birth as the baby moves through the birth canal and is exposed to maternal microflora. Infants born via cesarean delivery are colonized by bacteria from the immediate family and hospital environments, resulting in lower numbers of Bifidobacterium and Bacteroides in the gut. The bacterial community of the baby born via cesarean delivery is slower to develop, and some essential bacterial species can never reach full maturity. The significant difference in the composition of the gut microbiota between babies born through either mode of delivery could have both short- and long-term health consequences. Long-term microbiota composition can be altered by cesarean delivery, due to the decreased number of Bifidobacterium spp. colonies in the gut; research has shown an association between birth mode, gut microbiota structure, and atopy and asthma risk. The metabolism of early microbiota colonization is interpreted to be crucial for later microbial succession in the gut. The mode of delivery is correlated with differences in the e