The team looked at healthy subjects who had various levels of antibiotic resistance genes and found those consuming high-fibre diverse diets that were also low in animal protein had fewer antibiotic resistance genes (ARG).
Those with the lowest ARG levels in the gut also had higher levels of anaerobic microbes, a hallmark of a healthy gut with low inflammation.
“The results lead directly to the idea that modifying the diet has the potential to be a new weapon in the fight against antimicrobial resistance,” explains Danielle Lemay, lead study author and Research Molecular Biologist at the ARS Western Human Nutrition Research Center in Davis, California.
“And we're not talking about eating some exotic diet either, but a diverse diet, adequate in fibre, that some Americans already eat."
The team began enrolling 290 healthy adults in the study, searching for specific links pointing to levels of antibiotic resistance genes in the microbes of the human gut with both fibre and animal protein in adult diets.
The researchers found regularly eating a diet with higher levels of fibre and lower levels of protein, especially from beef and pork, was significantly correlated with lower levels of ARG among their gut microbes.
The team also found that the bacterial species in the family Clostridiaceae were the most numerous anaerobes found.
However, the strongest evidence pointed to the association between a greater range of foods in the diet and lower ARG levels.
"Surprisingly, the most important predictor of low levels of ARG, even more than fibre, was the diversity of the diet,” Dr Lemay adds.
“This suggests that we may want to eat from diverse sources of foods that tend to be higher in soluble fibre for maximum benefit."
Further findings revealed those who had the highest ARG levels in their gut microbiome were found to have significantly less diverse gut microbiomes compared to groups with low and medium levels of ARG.
Modifying gut microbiome
"Our diets provide food for gut microbes. This all suggests that what we eat might be a solution to reduce antimicrobial resistance by modifying the gut microbiome," Dr Lemay says.
"But this is still just a beginning because what we did was an observational study rather than a study in which we provided a particular diet for subjects to eat, which would allow more head-to-head comparisons.
"In the end, dietary interventions may be useful in lessening the burden of antimicrobial resistance and might ultimately motivate dietary guidelines that will consider how nutrition could reduce the risk of antibiotic-resistant infections."
Published online: DOI: 10.1128/mbio.00101-22
“Association of Diet and Antimicrobial Resistance in Healthy U.S. Adults.”
Authors: Andrew Oliver et al.