A recent study has revealed that consuming sugary foods while undergoing antibiotic treatment can harm the gut microbiome, potentially increasing susceptibility to serious infections.
This research, published in the journal Nature, utilized a unique opportunity. It examined cancer patients who were hospitalized and received continuous antibiotics before having stem cell transplants. Since these patients consumed only hospital-prepared meals, researchers had precise data on their food intake, avoiding the common issue of reliance on memory in nutrition studies.
The gut microbiome comprises trillions of bacteria, viruses, and various microbes residing in our intestines. These microorganisms are essential for digestion, vitamin production, and immune function, among other roles. Interestingly, they also interact with the brain to produce neurotransmitters like serotonin, which are vital for regulating mood, sleep, and stress.
Previous studies indicate that diet significantly influences the composition and variety of gut bacteria. Individuals who consume diverse, plant-based, and fiber-rich diets tend to possess a more varied gut flora compared to those who primarily eat processed foods. Typically, a more diverse microbiome correlates with better health, as a rich community of gut bacteria can help keep harmful pathogens at bay.
“This study offers a different perspective because the patients are experiencing both microbiome disruption and nutritional changes due to their cancer treatments,” explained Dr. Jonathan Peled, a physician scientist at Memorial Sloan Kettering.
Conducted by scientists from Memorial Sloan Kettering Cancer Center, NYU Langone Health, and City of Hope Cancer Center, the research explored the effects of certain foods on gut microbiome composition following the destabilization caused by antibiotics and hospital diets.
“We analyzed the data in various ways,” Peled noted.
They investigated the connections between major macronutrient categories—like fats, carbohydrates, and fiber—and gut bacteria types. Specific foods such as chicken, apples, and chocolate cake were also scrutinized.
“A recurring theme was that increased sugar intake, particularly from added sugars, had profoundly negative effects when combined with antibiotics on the microbiome,” Peled stated.
The study drew from over 1,000 stool samples from 173 patients who consumed more than 9,400 hospital meals.
The findings showed a direct correlation: the more intense the antibiotic treatment a patient received, the greater the decline in their microbiome diversity.
Interestingly, most food types did not significantly affect the diversity of gut bacteria; however, sweets—defined as sugars and sweetened products—differed noticeably. The study indicated that for every increase of 3.5 ounces in sweet consumption during antibiotic treatment, there was a corresponding 24% decrease in microbiome diversity.
This loss of gut bacteria diversity was linked to an increase in certain harmful bacteria, including Enterococcus faecium.
Enterococcus is usually harmless but can overgrow when antibiotics disrupt the balance of gut flora, potentially leading to serious conditions like sepsis if it enters the bloodstream.
“In the context of bone marrow transplants, we discovered that Enterococcus can exacerbate particular complications, known as graft versus host disease,” Peled remarked.
Graft versus host disease occurs when transplanted stem cells attack the recipient’s healthy tissues, perceiving them as foreign.
The research team also aimed to replicate these microbiome changes in mice. After administering a broad-spectrum antibiotic, there was a slight uptick in Enterococcus. However, adding sugar in their diet led to a dramatic increase in Enterococcus levels, multiplying significantly within just a few days.
This rapid increase in harmful bacteria could have serious consequences.
Overall, patients whose diets included more sugar after transplants exhibited a 12% higher risk of mortality compared to those who limited their sugar intake—a modest yet meaningful increase in risk.
“It represents a small change in their risk profile,” Peled commented.
Notably, the boost in Enterococcus levels persisted for about eight days post-antibiotic treatment.
“This is a pretty interesting study,” noted Dr. Anthony Maresso, a professor at the Baylor College of Medicine. “I suspect it’ll spark some discussions,” he added, despite not being part of the study.
“This is crucial for transplant patients, as hospitals are primarily concerned about the risk of infections,” Maresso highlighted. “It makes me think about whether hospital diets should be adjusted.”
He further questioned if the findings might also apply to people taking antibiotics in non-hospital settings. For instance, does a high-sugar diet while on antibiotics for something like an ear infection raise the risk of subsequent infections?
While Peled admitted that the study is intriguing, he emphasized that it lacks the rigor of a randomized clinical trial that would test various diets to identify those that could best protect patients on antibiotics.
Given that it’s generally advisable to limit sugar intake, he suggested it wouldn’t hurt to consider minimizing sugar consumption during antibiotic treatment.
“What our study implies is that it might not be necessary to avoid sugary foods entirely, but perhaps just during the antibiotic phase,” Peled concluded.
