WASHINGTON (dpa-AFX) - Cutting down on sugary foods during antibiotic treatment may help preserve healthy gut bacteria, particularly in patients undergoing treatment for blood cancer, according to a new study.
For the study, researchers examined 173 patients with blood cancers who were undergoing hematopoietic cell transplantation. They tracked what patients ate across 9,419 hospital meals and regularly collected stool samples to study changes in the bacteria living in their digestive systems.
The patients underwent intensive treatment before receiving their transplants. This included chemotherapy and, for some patients, radiation to destroy existing immune cells and prepare the body for the transplant. Antibiotics were also used throughout the hospital stay to prevent or treat infections. About 80% of the patients received broad-spectrum antibiotics, which can disrupt the gut microbiome because they target a wide range of bacteria.
Depending on the patient, the researchers recorded between eight and 128 meals. The monitoring period covered the time from 12 days before transplantation to 49 days afterwards. More than 1,000 stool samples were also examined to track changes in the gut microbiome.
The research team then analyzed the information to look for links between diet, antibiotic treatment and changes in gut bacteria.
They found that patients who consumed more sweets while receiving antibiotics were more likely to experience a reduction in the variety of bacteria in their gut. A diverse microbiome is generally considered important because different types of bacteria perform different functions and can help prevent harmful organisms from becoming dominant.
Enterococcus was of particular interest to the researchers. If this bacterium becomes overly abundant in the gut, transplant patients may face an increased risk of serious complications, including bloodstream infections and graft-versus-host disease.
The researchers found that the combination of high sugar intake and broad-spectrum antibiotics was linked to a substantial reduction in gut bacterial diversity. For every additional 100 grams of sweets consumed, bacterial diversity was estimated to decline by about 24%. The researchers noted that this amount contained roughly as much sugar as a large milkshake.
The team also carried out experiments in mice to investigate the possible role of sugar more closely. The animals were given broad-spectrum antibiotics along with different diets.
Mice that received antibiotics and a diet high in sucrose developed a rapid increase in Enterococcus in their intestines. In contrast, mice that consumed the same high-sugar diet without receiving antibiotics did not develop the same increase in the bacteria.
The findings suggest that sugar may have a greater impact on the gut microbiome when antibiotics have already disturbed the normal bacterial community.
However, the researchers stressed that the human study does not prove that eating sugar directly caused the loss of gut bacteria diversity. Further research will be needed to determine whether reducing sugar intake during antibiotic treatment can help protect the gut microbiome or lower the risk of serious infections.
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