Q. What are the major functions of the bacterial flora within the human gut?

Bacteria that live inside the gut have great importance in digestion. Several polysaccharides like cellulose, pectin and hemicellulose are not digested by the digestive enzymes secreted by the body as a substitute they are broken by enzymes released by bacteria of the gastrointestinal tract. The intestinal bacterial flora also makes very important substances for the functioning of the bowels facilitating or blocking the absorption of nutrients and stimulating or reducing peristalsis. A few gut bacteria are the major source of vitamin K for the body and so they are essential for the blood clotting process.

In the intestinal flora there are utile but also potentially harmful bacteria it is estimated that more than 100 trillion bacteria live in a human gut a few bacteria are useful too because they compete with other species preventing excessive proliferation of these bacteria.