Sugar amplified antibiotic-related microbiome disruption in mice and was linked to similar changes in hospitalized transplant recipients. Digest
Antibiotics can weaken the gut microbial community that normally keeps potentially harmful bacteria in check. Researchers investigated whether sugar-rich foods amplify that disruption.
In 158 adults receiving stem cell transplants for blood cancers, researchers tracked daily food intake and collected stool samples over several weeks. For each sample, they examined associations between gut bacteria, average dietary intake, and antibiotic use during the preceding two days. In a separate experiment, mice received a single injection of a broad-spectrum antibiotic, which targets many types of bacteria, and standard chow with either a sucrose (table sugar) supplement or a matching supplement without sugar.
- In transplant recipients, higher sugar intake was linked to a greater loss of microbial diversity during broad-spectrum antibiotic treatment. Each additional 100 grams of daily sugar intake was associated with a further 20.6% decrease in diversity.
- Sugar-rich foods consumed during broad-spectrum antibiotic treatment were also associated with a larger share of Enterococcus faecium in the gut bacterial community. Enterococcus bacteria can cause antibiotic-resistant bloodstream infections.
- In mice, adding sucrose to antibiotic treatment raised stool Enterococcus counts 16.3-fold on day three and 33.4-fold on day six compared with antibiotic treatment without added sucrose. Sucrose alone did not increase these counts.
The researchers also explored why sugar might have this effect. Possible explanations include directly promoting Enterococcus growth or indirectly influencing gut bacteria through changes in metabolism or immune defenses. Interestingly, in mice carrying only Enterococcus faecalis, sugar had no significant effect, suggesting that interactions with other gut bacteria may also play an important role.
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The mouse experiments identify sugar as a modifiable amplifier of antibiotic-related microbial disruption. Whether reducing sugar intake during broad-spectrum antibiotic treatment can actually protect the microbiome and improve outcomes in transplant patients remains a question for future dietary trials.