Moving microbiota research toward establishing causal associations that represent viable targets for effective public...

There appears to be great promise in developing targeted interventions that exploit the complex interactions between commensal microbiota colonizing various anatomic sites and the health of the human host. Although data about variations in microbiota composition across various population groups are accumulating, there remains a limited understanding of the driving forces behind the observed intraindividual and interindividual differences in microbiota.

Using information derived from research on gut microbiota, the anatomic site that harbors the highest numbers of bacteria and associated microbial functions, we emphasize the need for establishing causality of observed correlations. Progress to date in establishing microbiota-based targets for novel prevention and treatment approaches is reviewed, suggesting avenues for future research endeavors.

The complexities associated with the diverse interactions among environmental exposures, microbiota composition and activities and health of the human host require multidisciplinary study approaches to move knowledge beyond current descriptions of correlations without considerations of temporality and mechanisms.

Information gleaned from studies of the potential contributions of diet-mediated microbiota effects on colorectal carcinogenesis will be useful in designing future large population-based studies for determining the causal pathways for microbiota contributions to human health and disease.