Scientists in Spain report that white bread, a much-maligned food, looks like it can encourage the growth of some beneficial gut bacteria. Their research (“Pilot Study of Diet and Microbiota: Interactive Associations of Fibers and Polyphenols with Human Intestinal Bacteria”) was published in the Journal of Agricultural and Food Chemistry.
Sonia González from the University of Oviedo and colleagues note that our gut microbiomes play an important role in our health. When certain populations of bacteria drop, people become more prone to disease. One of the most effective ways to maintain a good balance of the microbiome is through our diets.
To figure out what dietary ingredients promote helpful bacteria, several studies have looked at the effects of individual fibers and probiotics. But few researchers had investigated the role of polyphenols, which are common in much of what we consume (spices, teas, fruits, and vegetables), or how polyphenols and fibers together help balance our gut microbes. González's team wanted to fill that gap.
To do so, they asked 38 healthy adults questions about their diets and figured out which bacteria were present in the participants' stool samples. Their analysis revealed that pectin, a compound in citrus fruits, lowers the levels of some helpful bacteria. This is contrary to previous research on pectin alone. The researchers suggest that pectin interacts with other substances in oranges, leading to this unexpected effect.
Their most novel finding, they said, was that white bread boosted Lactobacillus, a group of beneficial bacteria.
“Because some effects on intestinal microbiota attributed to isolated fibers or polyphenols might be modified by other components present in the same food, future research should be focused on diet rather than individual compounds,” concluded the investigators in their article.