Taking antibiotics? Sugar may be making the damage worse

Researchers studying hospitalized people with blood cancers found a link between sugar consumption and greater disruption of gut bacteria during antibiotic treatment. Antibiotics can remove helpful microbes along with harmful ones, leaving the gut more open to dangerous species.

The team, from NYU Langone Health, City of Hope and Memorial Sloan Kettering, analyzed 9,419 meals from 173 patients and tracked their microbiomes. Each extra 100 grams of sugar eaten in the two days before treatment was associated with a further 21% drop in bacterial diversity.

Patients who ate more sugar while receiving antibiotics also had higher levels of Enterococcus faecium, a bacterium associated with hard-to-treat infections. In experiments, mice given an antibiotic and sucrose likewise developed larger Enterococcus populations.

The findings, published in Nature, suggest that diet may influence the effects of antibiotics on the gut. The researchers say cutting back on sweets during and after treatment could help limit this disruption, but the study reports an association in patients.

The study focused on blood cancer patients because their meals and microbiomes could be closely monitored in hospital. Researchers say further work can clarify how food choices affect recovery and treatment outcomes, including for people receiving stem cell transplants.