Antibiotics can disrupt the gut microbiome. New research suggests what people eat while taking them may influence how much that disruption occurs.
In a study published in Nature, researchers followed people undergoing stem cell transplants and found that higher intake of sugar-rich foods and drinks during broad-spectrum antibiotic treatment was linked to lower gut bacterial diversity and more growth of Enterococcus, a type of bacteria that can become problematic in this patient group.
The study does not show that everyone taking antibiotics should cut out sugar. The human findings were observational, and the participants were seriously ill cancer patients receiving intensive treatment. But mouse experiments supported the idea that sugar may make some antibiotic-related microbiome changes worse.
Researchers tracked 9,419 meals eaten by 173 hospitalized patients with blood cancers. Patients recorded how much of each meal they ate, and researchers also analyzed more than 1,000 stool samples to follow changes in their gut bacteria.
All participants received antibiotics during their hospital stay, and most received broad-spectrum antibiotics.
One pattern stood out: Patients who ate more foods in a category that included sweets, sugary drinks and some nutritional beverages while taking broad-spectrum antibiotics tended to have a greater loss of microbiome diversity.
Higher sugar intake was also linked to more Enterococcus.
Importantly, the same pattern was not seen when patients were not exposed to broad-spectrum antibiotics. That suggests the interaction between diet and antibiotics may matter more than sugar alone.
The researchers also tested the idea in mice. When mice received antibiotics along with added sucrose, Enterococcus increased much more than it did with antibiotics alone. Sugar by itself did not produce the same effect.
The findings are intriguing, but they come with important limits.
People undergoing stem cell transplantation are not typical antibiotic users. They may receive intensive chemotherapy, frequent medications and prolonged antibiotic treatment, all while dealing with side effects that can make eating difficult.
That matters because some of the sugar-rich products identified in the study included nutritional drinks and shakes that are often used to help sick patients get enough calories.
So the study should not be interpreted as evidence that cancer patients should avoid those foods.
“It’s premature to recommend everyone taking antibiotics avoid sugar,” said Marcel van den Brink, one of the study’s senior authors.
Instead, the research raises a question that can now be tested more directly: Could temporarily reducing some sugar-rich foods during antibiotic treatment help protect the gut microbiome?
Clinical trials would be needed to answer that, along with whether any microbiome benefit translates into better health outcomes.
Several authors reported financial relationships involving microbiome or biotechnology companies.
The research was supported by the National Cancer Institute, National Heart, Lung and Blood Institute, National Institute of Allergy and Infectious Diseases and other nonprofit and academic research programs and foundations.