Normal Gut Flora
The gut is home to millions of microorganisms that live there normally. They are collectively known as gut flora. Gut flora commonly live in the digestive system of humans and animals. Gut flora help create energy by fermenting carbohydrates in the intestines while absorbing short-chain fatty acids such as butyrate, which passes through the colon to the liver and to the target muscles. These microorganisms also help synthesize vitamins such as vitamins K and B and helps metabolize sterols, xenobiotics and bile acids. Most of these microbes are anaerobic bacteria, however, aerobic bacteria can also be found on the cecum.
It is even said that there are more gut microbial flora than the number of cells in the human body. This is why some experts consider them as an organ also. The gut flora also contains more genes than the human genome. They are mostly found in the colon and are passed out of the body as feces. These microbes are not harmful to us but are even helpful to us. For example, after digestion of food, there may be remnants of substrates in the gut. These microbes clear up the gut by fermenting the leftover substrates so that there is smooth functioning of the colon. They also help shield against the growth of disease-causing bacteria that may invade our gut in times of sickness, and can also boost the immune system. They can also create vitamins for the use of the other body systems such as Vitamin K and biotin; they also create hormones that encourage the redistribution of fats.
Gut flora synthesize undigested carbohydrates in the gut. This is because these microorganisms have the necessary enzymes that can digest polysaccharides that the human body lacks. These polysaccharides include fiber, sugars and starches. Lactose cannot be digested by people who lack the enzyme responsible for digesting it; the condition is termed as lactose intolerance. This is when microorganisms enter the picture; they are able to ferment lactose because they have the necessary enzymes in doing so. They can also ferment carbohydrates into short chain fatty acids that can be used by many cells in the body for energy and nutrients.
Aside from these effects, gut flora encourages water absorption by the gut, gets rid of harmful bacteria, facilitates growth and repair of gut cells and facilitate growth of other favourable microorganisms. Gut microflora also stimulates lymphoid tissue located within the gut mucosa to create antibodies that can fight off disease-causing microorganisms.
Gut microorganisms belong to the Bifidobacterium, Bacteroides, Fusobacterium, Clostridium, Peptostreptococcus, Escherichia, Peptococcus, Ruminococcus, Lactobacillus, and Eubacterium species. Other fungi may be present in the gut such as Saccharomyces, Penicillium, Aspergillus and Candida. As soon as a baby is born, these microorganisms start to proliferate in the gut to boost immune function even in newborn infants. Initially, facultative anaerobes predominate during infancy until obligate anaerobic microorganisms take over during adulthood. These microorganisms facilitate the expression of toll-like receptors in the intestines that can repair damage to the intestinal mucosa. They can also prevent allergies especially towards food and can prevent inflammatory bowel disease.
Gut Flora and Fiber
Recently, some experts from the University of British Columbia have identified the genes that enables gut flora to metabolize fiber in the gut. Through these findings, they are able to identify how specialized the roles of microbial flora are in the gut in the maintenance of good intestinal health especially after illness or antibiotic use. Researchers discovered the sequence of genes that has enabled Bacteroides ovatus to digest xyloglucan, a major fiber found in vegetables. These genes may be responsible for the digestion of fiber in the gut and for playing other roles which are beneficial for our health.
The researchers commented that more studies are needed, especially those studies which focus on other bacteria and their ability to digest fiber. For more medical news, feel free to browse other articles on this site.