Taking antibiotics? Skipping sweets may help protect your gut

By Stephen Beech

Eating less sugar could protect the stomach during antibiotic treatment, suggests a new study.

Researchers found that skipping dessert while taking a course of antibiotics causes less disruption to the gut microbiome.

Researchers in the United States say their "surprising" findings could lead to new treatment methods for cancer patients and potentially others taking antibiotics.

The team analyzed more than 9,400 meals and 1,000 stool samples for the study, linking sugar-rich foods to greater antibiotic-related microbiome disruption in stem cell transplant patients.

They explained that the gut microbiome is the community of trillions of microorganisms living in the digestive tract.

The study, published in the journal Nature, was conducted by scientists at California-based City of Hope, a nonprofit cancer and diabetes research and treatment center.

Researchers followed patients with blood cancer who were going through an intensive treatment called allogeneic hematopoietic cell transplant, a group at particularly high risk for severe gut microbiome disruption and associated side effects.

The team says the findings connect to the idea of "food as medicine" during cancer care and the ways diet can help people prevent and recover from illness.

Study co-senior author Dr. Marcel van den Brink said: "Antibiotics disrupt the diversity of our gut bacteria, or microbiomes, which play an essential role in supporting our immune systems and overall health.

"Our research supports emerging evidence that avoiding sugary foods during antibiotic treatment may protect the microbiome.

"Preserving microbiome diversity has previously been linked with improved clinical outcomes for patients with cancer."

Antibiotics are often used to treat infections, but previous studies have shown that they also broadly destroy good bacteria in the gut — allowing the overgrowth of harmful microbes.

The five-year study followed patients who were hospitalized for several weeks to receive intensive chemotherapy, sometimes with radiation, to wipe out their immune systems and then undergo a stem cell transplant.

To prevent and treat infections, each patient took at least one antibiotic during their hospital stay, with 80% of them taking one or more of the broad-spectrum antibiotics that exert the strongest effect on the microbiome by targeting many types of bacteria.

Researchers tracked 9,419 meals eaten by 173 hospitalized patients.

They profiled the microbiome diversity — a key indicator of a healthy gut — in stool samples from 158 patients.

Every time patients ordered a meal from the hospital kitchen, the tray arrived with a questionnaire asking them to record the amount of each item that they ate and drank.

The researchers recorded more than 40,000 food items, creating an unprecedented dataset with a level of detail that's rarely possible in nutrition research.

For each patient, the researchers tracked between eight and 128 meals across a period from 12 days before to 49 days after transplantation.

The team also analyzed more than 1,000 patient stool samples to monitor changes in the gut microbiome.

Dr. van den Brink said: "Unlike past nutrition studies that rely on patients' memories of what they ate or other imprecise surveys, we had meticulous dietary records collected in real time.

"This enabled us to look for patterns that otherwise might be impossible to detect."

The researchers scoured the data in search of patterns linked to injury to the gut microbiome.

Dr. van den Brink said: "No matter how we analyzed the data, the same strong signal kept appearing.

"The patients who consumed more sweets while taking antibiotics were more likely to experience a loss of microbiome diversity as aggressive microbes crowded out other strains of bacteria."

He says one organism, Enterococcus, stood out.

When Enterococcus takes over the microbiome, patients undergoing transplant face a higher risk of bloodstream infections and other life-threatening complications.

The combination of high-sugar foods and broad-spectrum antibiotics appeared to multiply injury to the microbiome, leading to a substantial 24% drop in bacterial diversity for every 100-gram increase in sweets — the equivalent in sugar content to a large milkshake.

Researchers also tested their hypothesis that sugar exacerbates microbiome injury by giving broad-spectrum antibiotics to healthy mice and feeding them a range of diets.

Mice that ate a high-sucrose diet quickly developed an overgrowth of Enterococcus in their guts.

But mice that ate the high-sugar diet without antibiotics maintained normal bacterial diversity.

Dr. van den Brink said: "The fact that animal studies support associations we found in patient data provides a compelling rationale for future clinical trials to evaluate whether reducing sugar intake during antibiotic use would protect the microbiome.

"The microbiome is emerging as an important factor in cancer care.

"The better we understand what supports and disrupts it, the more opportunities we have to reduce treatment side effects while improving how patients respond to and recover from therapy."

He noted that, for cancer patients, the findings reinforce diet as a "strong influence" on the microbiome and as one of the most practical ways hospitals can support recovery during treatment.

Dr. van den Brink said: "Many of the foods and drinks we encourage hospitalized patients to consume, like nutritional shakes, smoothies and sports drinks, are high in sugar content.

"That's something we'll need to evaluate when prescribing antibiotics.

"Our study demonstrates that some antibiotics disrupt beneficial gut bacteria more than others."

He added: "It's premature to recommend everyone taking antibiotics avoid sugar.

"On the other hand, we don't have strong evidence that probiotics help preserve or restore microbiome diversity and many people choose to take them anyway.

"There's no harm in limiting sugar in your diet, and it's an easy thing to try."

DECK

"Researchers who tracked more than 9,400 hospital meals eaten by stem cell transplant patients linked sugar-rich foods to greater gut microbiome disruption during a course of antibiotics."

META WARNING. Keep grafs 1, 2 and 6 out of the meta description. Graf 1 carries the "stomach" problem, graf 2 carries the causal "causes," the doubled "the" and the British idiom, and graf 6 carries the City of Hope attribution. The clean graf is graf 4, "The team analyzed more than 9,400 meals and 1,000 stool samples."