Cutting Sugar While on Antibiotics May Preserve Gut Microbiome Diversity

A study of 158 blood‑cancer patients in New York hospitals found that eating high‑sugar foods during antibiotic treatment sharply reduced gut microbiome diversity. Researchers recorded over 40,000 food items and linked each meal to stool samples taken before, during, and after chemotherapy and stem‑cell transplant. For every 100‑gram increase in sugary food or drink within 48 hours of an antibiotic dose, the loss of bacterial diversity rose by an average of 24 %. The same combination also boosted the abundance of Enterococcus faecium, a pathogen that can cause serious hospital infections. Parallel mouse experiments confirmed that a high‑sugar diet amplified Enterococcus growth when antibiotics were present, while a sugar‑free diet maintained diversity. The results suggest that clinicians may need to reconsider recommending sugary smoothies or milkshakes to patients on antibiotics, and that limiting sugar intake could be a low‑cost, low‑toxicity strategy to protect gut health during treatment.