A study of more than 4,000 people shows that gut bacteria fluctuate throughout the day and that this occurs to a lesser extent in people with type 2 diabetes. Doctors could potentially use these patterns to predict and diagnose diabetes.
Circadian rhythms, which people sometimes refer to as the “body clock,” regulate patterns of sleep, alertness, temperature, and blood pressure, among other factors. These daily biological rhythms likely evolved to coordinate with light and food availability, but they also regulate internal metabolic processes.
Circadian rhythms are important to human health, and experts believe their long-term disruption to have various adverse consequences.
Building on this, a new study appearing in Cell Host & Microbe shows that diabetes is also associated with changes to the daily rhythms of the gut microbiome.
A team of researchers that the Technical University of Munich in Germany led showed that people with type 2 diabetes have fewer daily fluctuations in some of their gut bacteria and that these changes may serve to predict and diagnose the condition.
For many years, scientists have known that the circadian clock is crucial to human physiology. However, it is only recently that they have discovered its role in relation to the microbiome, which is the community of bacteria, viruses, and fungi that live in and on people — for instance, on the skin or in the gut.
Recent studies, for example, show that the community of gut bacteria fluctuates during the day, just like other circadian processes.
Some researchers believe that these regular changes to the microbiome are likely beneficial and that the loss of this daily rhythm could contribute to metabolic disorders, perhaps explaining the connection between circadian rhythms and diabetes.
To investigate this further, the team started by analyzing the microbiomes of almost 2,000 people over a period of 24 hours. Their results confirmed the regular oscillations of gut bacteria.
They then focused the study to include only the people with metabolic disorders, including obesity (defined as a body mass index, or BMI, of 30 or above), prediabetes, and type 2 diabetes.
They found that people with obesity and type 2 diabetes lost the rhythmic patterns of their gut bacteria. They also noted specific changes to the gut bacteria in people with diabetes.