The researchers recruited thirty-eight healthy adults who were asked to answer a questionnaire on their food habits. Scientists also analysed the participants’ stool samples. Unexpectedly, they found that those individuals who ate more white bread had higher levels of Lactobacillus, a group of beneficial bacteria that could ward off digestive disorders, in their digestive tracts.
It seems that white bread provides soluble hemicellulose (dietary fibre) and resistant starch in the diet. Both products have been positively related to a higher presence of Lactobacillus in the gut. “The prebiotic effect of cereals has been traditionally attributed to whole grain foods, because of their high fibres content. However, our results reveal that the consumption of refined grains, often undervalued in this regard, could beneficially modulate intestinal microbiota too”, explained the authors of this research in a press release.
However, they also warned that it was difficult to pinpoint how much resistant starch comes from bread intake, or from the diet in general. They believe effects on gut microbiota that are often attributed to isolated fibres or even polyphenols might be modified by other components in food. “Although the limited sample size and high variability of individuals do not allow firm conclusions to be established, our study highlights the importance of considering diet as a whole, rather than isolated components”, authors considered. This means that, in their opinion, future research should be focused on the broader diet, rather than on individual compounds.