High Sugar Intake Linked to Reduced Gut Microbiome Health
Patients on antibiotics saw greater losses in bacterial diversity when their sugar intake was higher.
Updated on Sept. 30, 2026 in Nutrition
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Would you limit your sugar intake if you were prescribed a course of antibiotics?
Researchers have identified a link between high sugar consumption and reduced gut microbiome diversity in patients undergoing antibiotic treatment. This study analyzed diet and health data from 158 individuals with blood cancers.
Why it matters
Antibiotics clear out both harmful and beneficial gut bacteria, and this research suggests that sugar may serve as a fuel source for opportunistic pathogens during this vulnerable period. These findings could lead to new dietary guidelines for patients who are prescribed antibiotics.
In a study of 158 people with blood cancers, researchers tracked 40,000 food items to correlate sugar intake with microbiome changes. Preclinical experiments in mice also demonstrated that a high-sucrose diet led to significant spikes in Enterococcus populations after biapenem use.
The players
Memorial Sloan Kettering Cancer Center
A comprehensive cancer treatment and research institution that conducted the human study.
NYU Langone Health
An academic medical center that provided research contributors for the study.
University of Trento
An Italian research university that contributed to the study of microbiome diversity.
The details
When antibiotics eliminate broad swaths of the gut microbiome, the balance of the internal ecosystem is disrupted. High sugar intake provides an abundant energy source that allows surviving, potentially pathogenic bacteria like Enterococcus faecium to rapidly proliferate in the absence of competing microbial flora. The mouse experiments confirmed this effect, showing that the population of these bacteria expanded over 33-fold within six days of the high-sugar, antibiotic regimen.
Timeline
Sugar consumption was measured during antibiotic treatment.
Mice showed a 16.3-fold increase in Enterococcus populations by day three.
Mice showed a 33.4-fold increase in Enterococcus populations by day six.
Health Landscape
This study advances the microbiome research initiatives at Memorial Sloan Kettering Cancer Center by highlighting the impact of dietary choices during clinical treatment. It adds to a growing body of evidence that identifies the gut-diet-drug triad as a critical factor in patient recovery.
If you are currently prescribed a course of antibiotics, consider discussing your dietary habits with your physician to see if reducing sugar intake is advisable for your specific treatment plan. Paying attention to sudden changes in digestion while on medication is also worth noting and reporting to your care team.
The takeaway
The study suggests that limiting sugar intake during antibiotic therapy may help protect the diversity of your gut microbiome. If you are starting an antibiotic, ask your doctor if any temporary dietary adjustments are appropriate for your health needs.
Further reading
You can find more on the evolving science of how diet affects the body in our Nutrition section.
Live Poll
Would you limit your sugar intake if you were prescribed a course of antibiotics?
