A new Nature study links sugar-rich eating during antibiotic treatment with deeper disruption of the gut microbiome. The human findings are observational, supported by controlled mouse experiments—not proof that avoiding sugar improves patient outcomes.
What changed
Researchers tracked 9,419 meals consumed by 173 adults hospitalized for blood-cancer stem-cell transplantation; 158 had paired longitudinal stool samples. During antibiotic exposure, greater intake of sweets and simple sugars predicted lower microbial diversity and greater expansion of Enterococcus. An institutional analysis estimated an additional 21% reduction in alpha diversity for each 100 grams of sugar consumed during the preceding 48 hours. In mice, sucrose also amplified and prolonged antibiotic-driven Enterococcus expansion.
How strong is the evidence?
The detailed meal records and repeated microbiome sampling strengthen the human association, while the mouse experiments support biological plausibility. But patients were not randomized to high- or low-sugar diets. Microbial diversity and bacterial abundance are surrogate outcomes, not symptoms, infections, recovery, or survival.
What remains uncertain
These patients also received chemotherapy and intensive hospital care, so the result may not apply to otherwise healthy people taking a short antibiotic course. Illness severity, changing appetite, and incompletely recorded outside foods could still confound the association. A prospective human dietary trial is needed.
Why it matters
The study identifies diet as a potentially modifiable influence on antibiotic-related microbiome injury, but it does not justify stopping antibiotics or prescribing a special diet. It is a strong rationale for clinical trials rather than a treatment recommendation.
Sources
Original Nature study and NYU Langone report, both published September 30, 2026.
Illustrative stock photo by Daniel Kraus on Unsplash; it does not depict the study, its participants, or its results.
