What is already known
Diet is known to play a key role in health, and previous studies have shown that specific dietary components — known as dietary xenobiotics — interact with gut microbes. However, how individual dietary compounds influence the microbiome and overall health remain less clear.
What this research adds
Researchers mapped the interactions between the gut microbiota and about 150 compounds found in fruit and vegetables. The study identified three key patterns through which these dietary xenobiotics are broken down. Some compounds were generally non-toxic, while others inhibited bacterial growth and altered microbial communities. Specific bacteria, such as Eggerthella lenta, are able to detoxify harmful compounds and prevent microbial disruptions.
Conclusions
The findings highlight the complex interactions between some dietary compounds and the gut microbiota, suggesting that microbial variations can impact health in different ways.
Diet can influence microbes in the gut, where specific nutrients and compounds interact with microbial communities, affecting digestion, metabolism and overall health. Now, researchers found that some dietary components interact with the gut microbiota in ways that vary between individuals, influencing how these compounds impact health.
The findings, published in Cell, highlight the complex interactions between some dietary compounds and the gut microbiota, suggesting that microbial variations can impact health in different ways.
Previous studies have shown that specific dietary components — known as dietary xenobiotics — interact with gut microbes. How people react to dietary components can vary based on the microbial metabolites their gut bacteria produce, but how individual dietary compounds influence the microbiome and overall health remain less clear.
To explore the interaction between the microbiota and dietary xenobiotics, Elizabeth Culp at Yale University School of Medicine in New Haven, Connecticut, and her colleagues studied how gut bacteria are influenced by dozens of compounds found in fruit and vegetables.
Varied effects
First, the researchers examined how 22 different dietary xenobiotics impacted the growth of 29 human gut microbiome samples and their community composition. They identified three key patterns through which these dietary xenobiotics are broken down. For example, glycosidic compounds — which are molecules formed from the reaction of a sugar with another substance — were readily broken down, while other compounds were not. Different microbial communities produced diverse metabolites from the same parent compound, the team found.
When the researchers expanded their investigation to 161 dietary xenobiotics, they discovered that most compounds did not inhibit bacterial growth, suggesting that toxicity can vary between parent compounds and their microbial metabolites.
Finally, the team tested 140 dietary xenobiotics on four different gut microbial communities. Of these compounds, 25 altered at least one microbial community, with 10 compounds showing disrupting effects across all four communities.
Community properties
Next, the researchers explored two phenomena that emerge when microbes grow in a community: cross-sensitization, where exposure to one compound increases sensitivity to another compound, and cross-protection, which occurs when exposure to a non-toxic compound improves the ability of microbial communities to detoxify a toxic compound.
For example, polydatin — a common dietary xenobiotic — was found to be converted into a toxic compound in certain microbial communities, inhibiting the growth of susceptible bacterial species. However, communities containing species that could metabolize these compounds were able to transform them into non-toxic forms.
Specific bacteria, such as Eggerthella lenta, were able to detoxify harmful compounds and prevent microbial disruptions. Microbial communities lacking E. lenta showed disruptions characterized by the expansion of Escherichia coli bacteria.
Several clinical trials are exploring how individual differences in the gut microbiota relate to dietary impacts, but more work is needed to optimize nutrition strategies for therapeutic purposes, the researchers say. “The maps we have generated and mechanisms that they illuminate are one step toward this goal.”
