For years, health experts have encouraged people to eat more plant-based foods.
The advice is supported by many studies showing that diets rich in vegetables, fruits, legumes, and whole grains help protect the heart, support healthy weight, and improve digestion.
Scientists are now uncovering another reason these foods are so beneficial.
Researchers from Ludwig Princeton investigated what happens after plant foods reach the intestines.
Inside the digestive tract, billions of bacteria feed on parts of plants that escape digestion. In return, these microbes produce chemicals that travel through the body and influence many organs.
The scientists carried out two related studies to understand where these chemicals come from and how diet changes their production. Their findings suggest that some of our ideas about the gut microbiome need to be updated.
One study found that plant fibre and a little-known group of hard-to-digest plant proteins work together to reshape the activity of gut bacteria. Rather than simply feeding the microbes, these nutrients changed which chemicals the bacteria produced.
The healthier chemicals increased, while compounds linked with kidney disease and poorer health became less common. The researchers found that plant proteins helped bacteria use dietary protein instead of breaking down proteins from the body’s own protective gut lining.
The second study investigated indoles and phenols, chemicals that have attracted attention because they may affect inflammation, cancer, bowel disease, and brain health. Scientists had widely believed these compounds came almost entirely from gut bacteria.
Surprisingly, isotope tracing experiments showed that human and animal cells can make many of these important compounds themselves. Antibiotics reduced only those chemicals that depended completely on bacteria, while many others continued to be produced by the body.
This discovery may influence future treatments. If some beneficial metabolites come mainly from our own cells, therapies may need to target both human metabolism and the gut microbiome rather than focusing only on probiotics or dietary supplements.
The work also introduces the idea that indigestible plant proteins could become a recognised nutrient alongside dietary fibre. Future food labels may even include this information if additional research confirms their health benefits.
Scientists caution that more human research is needed because many experiments were performed in laboratory models. Diet is also only one factor influencing the microbiome, alongside genetics, medicines, age, and lifestyle.
Overall, these studies provide important new insights into the relationship between food, gut bacteria, and human biology.
Their strengths include the use of sophisticated tracing techniques and two complementary investigations addressing different questions. The main limitation is that the findings still require confirmation in larger human studies.
Nevertheless, the research opens new opportunities for designing diets and future treatments that improve health by supporting both the microbiome and the body’s own metabolism.
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Source: Ludwig Princeton.
