Purpose of review: This review discusses the structural composition of intestinal microbiota, the functional relationship between the latter and the host, and the role of abnormal microflora in chronic diseases.
Recent findings: A more complete view of the gut microbiota is being developed following the Human Microbiome Project. The microflora in children is plastic, susceptible to changes in response to diet modifications, antibiotic treatment and other events, providing the opportunity to study its functional role. Increasing evidence highlights the role of nutrition in the age-related development of microflora. Eubiosis, that is, a normal microflora structure, provides protection against infections, educates the immune system, ensures tolerance to foods, and contributes to nutrient digestion and energy harvest. Changes in microflora, consisting in the overpresence of harmful species or underpresence of commensal species, or dysbiosis produce dysfunctions, such as intestinal inflammation or dysmotility. Moreover abnormal pattern of microflora have been consistently detected in specific diseases.
Summary: A relationship exists between eubiosis and functions and conversely between dysbiosis and dysfunctions or even diseases. Abnormalities in microflora composition may trigger or contribute to specific diseases. This raises the hypothesis to target microflora in order to restore eubiosis through the use of antibiotics, probiotics or nutrients.