The involvement of the gut microbiota in metabolic disorders, and the ability of whole grains to affect both host metabolism and gut microbial ecology, suggest that some benefits of whole grains are mediated through their effects on the gut microbiome. Nutritional studies that assess the effect of whole grains on both the gut microbiome and human physiology are needed. We conducted a randomized cross-over trial with four-week treatments in which 28 healthy humans consumed a daily dose of 60 g of whole-grain barley (WGB), brown rice (BR), or an equal mixture of the two (BR þ WGB), and characterized their impact on fecal microbial ecology and blood markers of inflammation, glucose and lipid metabolism. All treatments increased microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of the genus Blautia in fecal samples. The inclusion of WGB enriched the genera Roseburia, Bifidobacterium and Dialister, and the species Eubacterium rectale, Roseburia faecis and Roseburia intestinalis. Whole grains, and especially the BR þ WGB treatment, reduced plasma interleukin-6 (IL-6) and peak postprandial glucose. Shifts in the abundance of Eubacterium rectale were associated with changes in the glucose and insulin postprandial response. Interestingly, subjects with greater improvements in IL-6 levels harbored significantly higher proportions of Dialister and lower abundance of Coriobacteriaceae. In conclusion, this study revealed that a short-term intake of whole grains induced compositional alterations of the gut microbiota that coincided with improvements in host physiological measures related to metabolic dysfunctions in humans.

This paper combines national‐level retail food availability information with data on actual purchases to determine the effect that availability of different types of food stores and income have on fruit and vegetable purchases. The results of our mixed effects analysis suggest that the densities of supermarkets and other retail outlets in metropolitan statistical areas do not have significant effects on household fruit and vegetable purchases. Income, however, has a positive significant effect on fruit and vegetable purchases. Results also indicate that while neither food access nor income account for the variability in fruit and vegetable purchases, the interaction of these terms has a small but significant impact indicating that policy actions designed to address access and affordability issues in isolation are not likely to succeed.

Limited access to healthy food is commonly regarded as a contributing factor to poor dietary choices. The objective of this article is to test this hypothesis in a French context given France's increasing obesity rates and incidence of poor dietary habits. We use data on fruit and vegetable consumption frequency and different food retail availability measures, for example the number of food stores, food surface area, and a dispersion measure based on store numbers, store types, and food area surface, from several data sources in France. We also employ different types of geographic units when measuring the food retail environment and instrumental variable model specifications to test the robustness of our results, which indicate that fewer but larger retail outlets increase the odds of consuming the recommended level of fruit and vegetables. We also find that an increase in food supply dispersion will improve fruit and vegetable consumption in Paris, but not in its suburbs.

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