Human Gut Microbiota in Health and Selected Cancers

Abstract

The majority of the epithelial surfaces of our body, and the digestive tract, respiratory and urogenital systems, are colonized by a vast number of bacteria, archaea, fungi, protozoans, and viruses. These microbiota, particularly those of the intestines, play an important, beneficial role in digestion, metabolism, and the synthesis of vitamins. Their metabolites stimulate cytokine production by the human host, which are used against potential pathogens. The composition of the microbiota is influenced by several internal and external factors, including diet, age, disease, and lifestyle. Such changes, called dysbiosis, may be involved in the development of various conditions, such as metabolic diseases, including metabolic syndrome, type 2 diabetes mellitus, Hashimoto’s thyroidis and Graves’ disease; they can also play a role in nervous system disturbances, such as multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, and depression. An association has also been found between gut microbiota dysbiosis and cancer. Our health is closely associated with the state of our microbiota, and their homeostasis. The aim of this review is to describe the associations between human gut microbiota and cancer, and examine the potential role of gut microbiota in anticancer therapy.

The Emerging Roles of Human Gut Microbiota in Gastrointestinal Cancer

“…The gut microbiota mainly includes bacteria, fungi, protozoa, archaea, and viruses, among which bacteria are dominant ( 2 ). The composition of the human gut microbiota is not homogeneous ( 3 ). According to the differences in intestinal pH and oxygen content, bacterial groups were distributed at different locations, and bacterial concentrations increased from stomach to rectum.…”

“…The gut microbiota has a strong metabolic capacity and is deemed an important “metabolic organ,” which plays an important role in host digestion, nutrient absorption, metabolism, immunity, and other processes ( 3 ). Recently, with the rapid progression of sequencing technology, gut microbiota has been confirmed to be involved in the occurrence and development of various tumors.…”

Physicochemical characteristics of Ganoderma lucidum oligosaccharide and its regulatory effect on intestinal flora in vitro fermentation

“…Intestinal flora, numerous and diverse, is considered as an invisible organ to human beings ( Sedzikowska & Szablewski, 2021 ). The balance of intestinal flora is very important for human health.…”

Positive effects of dietary fiber from sweet potato [Ipomoea batatas (L.) Lam.] peels by different extraction methods on human fecal microbiota in vitro fermentation

“…As the core part of intestinal microecology, the gut microbiota (GM) is closely related to human health ( 1 ). Maintaining the balance of GM has a variety of positive effects, such as enhancing immunity, reducing blood lipids, anti-aging and anti-oxidation ( 2 ). The potential contribution of GM to human health has attracted widespread attention over the last decade.…”