A bowl of beans or whole grains is often promoted as a healthy choice, yet not everyone receives the same health benefits.
Scientists have now discovered one possible reason. A study published in Microbiology Spectrum shows that the tiny organisms living in our intestines may decide how well our bodies use certain types of dietary fibre.
The human gut is home to trillions of bacteria. Many of these microbes help digest food that our own digestive system cannot fully process.
In return, they produce helpful substances that support digestion, the immune system and overall health.
Resistant starch is one form of dietary fibre that depends heavily on gut bacteria. It is found in foods such as legumes, whole grains and some cooked and cooled starchy foods. Because the body cannot fully digest it, gut bacteria must break it down.
Researchers have often reported mixed results when studying resistant starch. Some people experience better blood sugar control and other health improvements, while others see little change. This has made scientists suspect that gut bacteria play a key role.
Angela Poole and colleagues at Cornell University examined this question by studying samples of gut bacteria collected from more than 50 volunteers. Participants ate crackers containing different types of resistant starch as well as ordinary starch for comparison.
The team used advanced genetic testing to examine bacteria in much greater detail than older techniques allowed. Rather than simply identifying bacterial species, they were able to identify individual strains and the genes they carried.
One bacterium attracted particular attention. It is called Bifidobacterium adolescentis, a common resident of the healthy gut. The researchers discovered that one strain could process resistant starch well, while another strain of the same species could not.
The scientists also identified several previously unknown bacteria that appeared to become active when resistant starch was eaten. These microbes may also help digest fibre, although more research is needed to understand exactly how they work.
The findings suggest that future diet advice could become much more personalised. Before recommending a particular high-fibre diet, doctors may first examine a person’s gut bacteria to see whether they have the right strains to benefit from that food.
Such personalised advice could become valuable for people living with diabetes or other diseases where healthy blood sugar levels are important. Instead of relying on trial and error, treatment plans may one day match foods to each person’s unique gut microbiome.
The researchers caution that this approach is still in its early stages. More studies involving larger groups of people will be needed before gut bacteria testing becomes part of routine nutrition care.
This research provides strong evidence that nutrition is more complex than previously thought. It reminds us that healthy foods do not always produce identical results because each person’s gut microbiome is unique.
Even so, the study should not discourage people from eating fibre-rich foods, which continue to offer many proven health benefits. Instead, it opens the door to a future where healthy eating advice is tailored to each individual rather than following a one-size-fits-all approach.
If you care about health, please read studies about how Mediterranean diet could protect your brain health, and the best time to take vitamins to prevent heart disease.
For more health information, please see recent studies that olive oil may help you live longer, and vitamin D could help lower the risk of autoimmune diseases.
Source: Cornell University.
