Review article: dietary fibre in the era of microbiome science.
O'Grady J, O'Connor EM, Shanahan F
Aliment Pharmacol Ther. Mar 2019. doi: 10.1111/apt.15129
COMMENT: The review remarks the importance of knowing the gut microbiome composition for personalized diagnostics and diet advice. The traditional role of fibre in our diet is reviewed from the novel point of view provided by microbiome science. The work provides a redefinition of dietary fibre and its effects on health linked to the quality and composition of the gut microbiota. The authors also describe the main challenges related to reintroduction and adherence to a fibre-rich diet in western countries. Here are some of the main points covered in this publication.
Dietary fibre is a complex family of materials, which can be subtyped and classified depending on their monomeric units and properties like solubility, viscosity and fermentation. These properties correlate with the biologic effects of dietary fibre: viscosity influences on digestion and satiety, with effects associated to decrease in appetite, improvement in glycaemic control and local anti-microbial action due to binding and release of certain ions during digestion.
On the other hand, fermentation by gut microbiota plays a role in providing energy in the first place, but also has an immunoregulatory role, since it generates metabolites and molecules that influence several signalling pathways related to transcription and regulation of cytokine expression.
It is evident that a fibre‐based diet, in both animal and human studies, has favourable effects on gut microbial diversity
Response to a fibre-based diet is not homogeneous among individuals, since this beneficial response depends on the established microbiota and previous dietary habits. Several studies both in human groups with different dietary habits and in animal models have shown the favourable effects of a fibre-based diet in the microbiome population diversity and maintenance. By contrast, low fibre diet has a role in loss of microbial diversity, which has been associated to co-morbidity and inflammation. This reduced microbial diversity may be transmitted to the next generations and is not easily reversed by fibre reintroduction, since there is evidence suggesting that changing dietary habits alone is not enough to reverse this loss and would require artificial reintroduction of specific taxa in the host microbiome.
Although Western countries show low fibre consumption in the dietary habits, findings suggest that reintroduction of fibre in the diet should be made in a progressive way. Regarding this, microbiome composition studies used as diagnostics tools will serve to address personalized dietary recommendations.
Microbiome read‐outs will help predict those with the greatest likelihood of a beneficial response