There’s no such thing as one-size-fits-all nutrition. In 2015, researchers from the Weizmann Institute of Science in Israel laid the foundation for this statement with an article that proved that each of us metabolises food differently due, in part, to gut microbiota. Researcher Niv Zmora explained to Gut Microbiota for Health the main results of that study during the GMFH World Summit held in Paris in March 2017.

Now, this same team has focused on bread, one of the most frequently consumed foods worldwide. And they have shed some light on one of the eternal questions in nutrition: is it healthier to eat white bread or brown bread? Until now, nutrition experts often shunned white bread because of its low fibre content and potential to spike the blood sugar.

For the study, published in Cell Metabolism, Israeli researchers recruited 20 healthy people; half ate whole-wheat sourdough bread and the other half white bread for a week. Then both groups took a two-week break and switched bread diets.

Researchers measured 20 health markers and focused on blood sugar levels after eating, what is known as the glycaemic response, a biological measurement of how quickly the body can process glucose consumed in the food.

The scientists found that on average, neither of the breads emerged as less likely to affect blood sugar.

For first author Eran Elinav, “The findings of this study are not only fascinating but potentially very important, because they point toward a new paradigm: different people react differently, even to the same foods”.

So, according to the results of the study, individuals can differ in their response to the same food, in this case bread, due to individual differences in the gut microbiota. So there is no good or bad bread, but it depends on each person’s gut microbiota.

The findings of this new research are linked with other current research from the Weizmann Institute of Science and to a series of earlier studies that suggested diets should be tailored to each person’s gut microbiota in order to maximize health benefits.



Korem T, Zeevi D, Zmora N, et al. Bread affects clinical parameters and induces gut microbiome-associated personal glycemic responsesCell Metabolism. 2017. DOI: