Key Takeaway:
- Sugar may worsen antibiotic-related gut disruption, reducing microbiome diversity and increasing Enterococcus levels.
- The study involved seriously ill cancer patients, so the findings may not directly apply to otherwise healthy people.
- More clinical research is needed to determine whether reducing added sugar during antibiotic treatment improves health outcomes.
A Nature study links sugar-rich foods eaten during broad-spectrum antibiotic treatment with greater gut microbiome disruption in hospitalized cancer patients, though researchers say more studies are needed.
Researchers Track Sugar, Antibiotics And Gut Changes
Researchers analyzed 9,419 meals and 1,009 stool samples from 173 adults hospitalized for blood cancer and undergoing allogeneic hematopoietic cell transplantation. All participants received antibiotics during the study period, and 158 had paired microbiome samples suitable for analysis.
The study, published Sept. 30 in Nature, found that consuming sweets and sugar during broad spectrum antibiotic exposure was associated with lower gut microbiome diversity and increased levels of Enterococcus, a group of bacteria that can cause infections in vulnerable patients.
For every additional 100 grams of sweets consumed during antibiotic exposure, the researchers’ model predicted an additional 24.1% decrease in average microbiome diversity compared with samples without previous antibiotic exposure. The study found the association was strongest when sugar consumption occurred alongside broad-spectrum antibiotics.
The researchers also found an increase in Enterococcus faecium, a species associated with antibiotic-resistant bloodstream infections. In mouse experiments, adding sucrose to the diet increased antibiotic-associated Enterococcus expansion by 16.3-fold on day three and prolonged the effect.
Sugar May Give Surviving Bacteria An Advantage
The researchers say antibiotics can substantially alter the gut ecosystem by removing susceptible bacteria. Sugar consumption during that disruption may create conditions that favor organisms able to survive antibiotic exposure.
“Antibiotics can clear away many of the organisms that keep that ecosystem balanced,” said Marcel van den Brink, a co-senior author of the study and physician executive at City of Hope, according to Prevention.
Jonas Schluter, the study’s lead author and an assistant professor of microbiology at NYU Langone Health, said people taking antibiotics should be mindful of their sugar intake, while noting that the study did not establish whether the combination directly increases symptoms such as diarrhea in otherwise healthy people.
The researchers caution that their human findings come from a medically complex population. Participants were undergoing intensive cancer treatment, chemotherapy and transplantation, and many received broad-spectrum antibiotics because of fever or suspected infections. Those factors make it difficult to apply the findings directly to people taking antibiotics for routine infections.
Researchers Call For More Studies On Diet
The findings do not show that sugar alone causes harmful microbiome changes or that avoiding sugar will prevent antibiotic side effects. The researchers say prospective clinical trials are needed to determine whether reducing simple sugar during antibiotic treatment improves health outcomes.
For now, nutrition experts quoted in Prevention recommend limiting concentrated added sugars from sugary drinks, candy and desserts while emphasizing varied plant foods, fiber-rich choices and adequate nutrition during antibiotic treatment. They also caution against eliminating naturally occurring sugars in whole fruits or plain dairy solely because of the study.
The study’s authors describe reduced simple sugar during antibiotic treatment as a potentially modifiable factor that warrants further investigation, rather than an established treatment for protecting the gut microbiome.
