List several beneficial roles of the gastrointestinal microbiome

Question

What will be an ideal response?

Answer 1

A healthy GI tract is home to a vibrant community of some 100 trillion microbes—bacteria, viruses, fungi, protozoa, and other microorganisms, collectively known as the human microbiome. Weighing less than a pound in total, these microbial cells outnumber the body's cells tenfold. The bacteria alone represent more than 400 different species and subspecies. The prevalence of different microbes in various parts of the GI tract depends on such factors as pH, peristalsis, diet, and other microbes. Relatively few microbes can live in the low pH of the stomach with its somewhat rapid peristalsis, whereas the neutral pH and slow peristalsis of the lower small intestine and the large intestine permit the growth of a diverse and abundant population.

Recent research has revealed that a person's health reflects the relative stability, disturbance, and resilience of the microbiome. Its composition and activity may contribute to dozens of common diseases, including inflammatory bowel disease and obesity.

The microbiome population and environment change dramatically in response to diet—both in the short term (daily meals) and in the long term (habitual diet patterns). Consider, for example, that fibers that cannot be digested by the human body provide a major source of energy for bacteria, fostering their growth. As GI bacteria digest and metabolize fibers and other nutrients, they produce compounds such as short fragments of fat, which can influence energy metabolism and immunity. Fibers and some other food components are called prebiotics because they encourage the growth and activity of bacteria. Research suggests that prebiotics may reduce the risk of GI infections, inflammation, and disorders; increase the bioavailability of nutrients; and regulate appetite and satiety.

Some foods contain probiotics, live microbes that change the conditions in the GI tract in ways that seem to benefit health. For example, yogurt contains Lactobacillus and other living bacteria. The potential GI health benefits of probiotics or products of their metabolism include helping to alleviate diarrhea, constipation, inflammatory bowel disease, ulcers, allergies, lactose intolerance, and infant colic; enhance immune function; and protect against colon cancer. Research studies continue to explore how diet influences GI bacteria and which foods—with their prebiotics and probiotics—affect GI health. In addition, research studies are beginning to reveal several health benefits beyond the GI tract—such as improving blood pressure and immune responses.

Bacteria in the GI tract also produce several vitamins, including biotin, folate, pantothenic acid, riboflavin, thiamin, vitamin B6, vitamin B12, and vitamin K. Because the amount produced is insufficient to meet the body's needs, these vitamins are considered essential nutrients that must be provided by the diet.