Dietary fiber consumption is associated with the selection of key microbial species but does not affect overall microbial diversity in a Colombian cohort

The gut microbiome is known to be affected by factors in the host diet. In particular, dietary fiber intake is associated with changes to gut microbial diversity, as one of the key functions of the microbiota is to degrade non-digestible fibers into nutrients and beneficial compounds such as short chain fatty acids (SCFAs). These changes have been characterized in populations at fiber intake extremes, such as populations following Westernized or hunter-gatherer (non-Westernized) lifestyles. However, this relationship has not been well-studied in populations undergoing a shift from a hunter-gatherer to a Westernized lifestyle, a phenomenon currently underway in Colombia. To understand the impact of dietary fiber intake on the host gut microbiota, we analyzed an existing dataset from a Colombian cross-sectional study using a bioinformatics approach. We found that overall microbial diversity does not seem to be impacted by fiber intake. However, there was evidence of over-representation of certain anti-inflammatory SCFA-producing microbial species in individuals with adequate fiber intake. Indicator species analysis also revealed that the enrichment of several SCFA-producing microbes were indicative of adequate fiber consumption. Overall, our findings indicate that dietary fiber does not influence microbial diversity but does enrich specific beneficial microbial taxa in the Colombian population. These results appear to support a beneficial role of fiber consumption and could ultimately aid in our understanding of the gut microbiome in semi-Westernized populations such as the Colombian people.