Scientists have discovered that changes in the bacteria living inside our gut may predict type 2 diabetes years before the disease appears.
The research, led by Chalmers University of Technology in Sweden and published in Cell Reports Medicine, suggests that a simple stool sample could one day help doctors identify people at high risk and encourage early lifestyle changes before serious health problems develop.
Type 2 diabetes is one of the fastest-growing health problems in the world. According to the World Health Organization, the number of adults living with diabetes has more than doubled since the 1990s.
Today, around 800 million people have diabetes, and more than 90% have type 2 diabetes. The disease develops when the body becomes resistant to insulin or cannot make enough insulin to keep blood sugar under control. High blood sugar can damage the heart, kidneys, eyes, nerves, and blood vessels if it is not treated.
Doctors already know that obesity, family history, unhealthy eating habits, and lack of physical activity increase the risk of type 2 diabetes. However, scientists have recently become interested in another possible risk factor: the gut microbiome.
The gut microbiome is the huge community of bacteria and other tiny organisms living in our digestive system. These microbes help digest food, produce vitamins, support the immune system, and influence many parts of human health.
As part of the European HealthFerm project, researchers followed 4,685 Swedish adults. Stool samples were collected to study their gut bacteria, and participants were monitored for about five years. During that time, 383 people developed type 2 diabetes.
When the researchers compared the participants, they found nine types of bacteria that were linked to a higher or lower risk of future diabetes. These differences were already present years before the disease was diagnosed, suggesting that changes in gut bacteria may happen early rather than being caused by diabetes itself.
One surprising finding involved Akkermansia muciniphila. This bacterium is often considered beneficial because it normally feeds on dietary fiber and helps support a healthy gut. However, the researchers found that high levels of this bacterium were linked with future diabetes.
They believe this may happen when people eat too little fiber. Without enough fiber, the bacterium may begin breaking down the protective mucus layer lining the intestine instead. This could allow harmful bacteria to reach the gut wall, causing inflammation and changes that may contribute to insulin resistance.
Another bacterium called Coprococcus catus also attracted attention. Very low levels were linked to a greater risk of diabetes, while higher levels appeared to remove this risk. These findings show that the balance of bacteria may be more important than simply having or not having a certain species.
The scientists believe that one day stool testing could be combined with traditional risk factors such as weight, family history, and blood sugar measurements to better predict who is likely to develop diabetes. Since gut bacteria can be changed through diet and lifestyle, the microbiome may become a target for future prevention programs.
The researchers stress that more studies are needed before these bacteria can be used in hospitals. However, their findings support existing advice to eat plenty of fiber-rich foods, including fruit, vegetables, beans, legumes, and whole grains, because these foods help nourish healthy gut bacteria.
This large study is valuable because it followed thousands of healthy people before diabetes developed, making the findings stronger than studies that only compare patients after diagnosis. While the research does not prove that gut bacteria directly cause diabetes, it suggests they may play an important role.
Future studies in different countries will be needed, but the work opens the possibility of using the gut microbiome to predict disease earlier and develop more personalized prevention strategies.
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Source: Chalmers University of Technology.
