White bread may encourage the growth of beneficial gut bacteria, according to a recent study,

Researchers found that gut bacteria, or microbiomes, play an important part to overall health. They also revealed that considering the whole diet, not just individual ingredients, is critical when looking at the effects of food gut bacteria.

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 microbes living in our guts is through our diets, researchers said in their study.

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.

For the study, Sonia Gonzalez and her colleagues asked nearly 40 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.

Researchers said their most novel finding was that white bread boosted Lactobacillus, a group of beneficial bacteria.

The results were surprising because white bread is a much-maligned food.

The findings were recently published in American Chemical Society's Journal of Agricultural and Food Chemistry.