Bread Affects Clinical Parameters and Induces Gut Microbiome-Associated Personal Glycemic Responses.

Tal Korem, David Zeevi, Niv Zmora, Omer Weissbrod, Noam Bar, Maya Lotan-Pompan, Tali Avnit-Sagi, Noa Kosower, Gal Malka, Michal Rein, Jotham Suez, Ben Z Goldberg, Adina Weinberger, Avraham A Levy, Eran Elinav, Eran Segal

Journal: Cell metabolism 2018;25(6):1243-1253.e5

PMID: 28591632

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Plain Language Summary

Bread is a key ingredient of the human diet. Wheat is the most commonly used cereal for baking bread. The aim of this study was to compare the effects of traditionally milled and prepared whole-grain sourdough bread and industrial white bread made from refined wheat on multiple clinical and disease markers and on the composition and function of the gut microbiome. The study is a randomized crossover trial with 20 healthy subjects. Participants received either industrial white bread made from mostly refined wheat flour or a sourdough-leavened bread made from whole-grain wheat flour. Results indicate that there were no significant differences on a broad array of clinical parameters between the two 1-week-long dietary interventions. Additionally, gut microbiome analysis showed that the microbiota composition remained generally stable and person specific throughout the trial. Authors conclude that their study underlines the importance of personalisation in dietary recommendations as the interpersonal variation in the effect of bread would allow the personalisation of bread-related nutritional recommendations and optimisation of food choices worldwide.

Abstract

Bread is consumed daily by billions of people, yet evidence regarding its clinical effects is contradicting. Here, we performed a randomized crossover trial of two 1-week-long dietary interventions comprising consumption of either traditionally made sourdough-leavened whole-grain bread or industrially made white bread. We found no significant differential effects of bread type on multiple clinical parameters. The gut microbiota composition remained person specific throughout this trial and was generally resilient to the intervention. We demonstrate statistically significant interpersonal variability in the glycemic response to different bread types, suggesting that the lack of phenotypic difference between the bread types stems from a person-specific effect. We further show that the type of bread that induces the lower glycemic response in each person can be predicted based solely on microbiome data prior to the intervention. Together, we present marked personalization in both bread metabolism and the gut microbiome, suggesting that understanding dietary effects requires integration of person-specific factors.

Address: Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.; Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel; Internal Medicine Department, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel; Research Center for Digestive Tract and Liver Diseases, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6423906, Israel.; Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel.; Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.; Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel. Electronic address: [email protected].; Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel. Electronic address: [email protected].; Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel. Electronic address: [email protected].

DOI: 10.1016/j.cmet.2017.05.002