Starch rich diets can influence the gut-microbiome and subsequently behavior

The microbiome’s role in modulating the gut-brain axis has been well-supported by a large body of evidence.  Many experiments in the past have demonstrated this in preclinical models by administering probiotics with specific bacterial strains or by fecal microbiome transplant in rodent models, which were then associated with changes in behavior.  Diet has also been implicated in these modulations, as food intake can influence species diversity and composition.  Low-digestible carbohydrates, or resistant starch, have received attention as being beneficial toward health, as these components are not digested but rather fermented by resident microbiota to produce an array of beneficial metabolites.  In a recent study, researchers from Texas Tech University investigated whether a diet rich in resistant starches were also associated with changes in behavior.

48 mice were randomly assigned to 3 different treatment groups, with each group either fed normal corn starch diet, a resistance starch rich diet, or an octenyl-succinate diet for 6 weeks.  The animals were monitored for weight, were subject to robust behavioral tests, and fecal samples were examined for microbiota composition.  The animals on the resistant starch diet exhibited similar weight gains as compared to the normal corn starch diet, and the octenyl-succinate group demonstrated lower weight gain.  Fecal microbiota analysis revealed diet correspondence to specific diet, and that resistant starch diet groups displayed increases in Verrucomicrobia and Actinobacteria as compared to octenyl-succinate and normal corn starch group, respectively.  In all groups, mice displayed significant anxiety-like-behavior in an elevated plus maze, and in open-field tests the mice fed resistance starch rich and octenyl-succinate diet mice exhibited high-anxiety-like behaviors. 

This data again supports that diet manipulation can have marked influence on behavior, and that starch rich diets could perhaps induce undesirable behavioral effect via modulation of the gut-brain axis.  This could be an important drawback to the beneficial components provided for microbial fermentation.  

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