Newly emerging research seeks to investigate the effect of gut microbiota on the efficacy of type 2 diabetes drugs, suggesting that the composition of gut bacteria may illuminate why certain diabetes medications work for some people—and not others.

Estimates indicate that over 415 million people across the globe have type 2 diabetes, a statistic leading some scientists to refer to the condition as a “global pandemic.” While there is no current cure for diabetes, treatments and lifestyle changes can help those living with the disease. Yet pharmaceutical drugs for diabetes have varying rates of success, contingent on the form of administration, and results often vary from person to person.

The research, led by Hariom Yadav, PhD, an assistant professor of molecular medicine at the Wake Forest Baptist Medical Center in Winston-Salem, investigates one of the possible causes behind such varying success rates: the gut bacteria. Previous studies cited in the paper published by Yadav and colleagues demonstrate that the gut bacteria can “instigate” obesity and type 2 diabetes, and that people living with diabetes have an overall imbalance in the composition of their gut bacteria.

Moreover, as Yadav explains, there are some drugs for diabetes that are only effective when given intravenously, but not when delivered orally: leading him to believe that gut bacteria are critical in regulating how a person metabolizes drugs. “For example, certain drugs work fine when given intravenously and go directly to the circulation, but when they are taken orally and pass through the gut, they don’t work. Conversely, metformin, a commonly used anti-diabetes drug, works best when given orally but does not work when given through an IV.”

Based on these observations, the researchers sought to understand whether or not the composition of gut bacteria directly influences the efficacy of certain diabetes medications. Yadav and colleagues reviewed over 100 studies of rodents and humans, and published their findings in the journal EBioMedicine.

How the microbiome can influence drugs

The research focused on the ways in which the microbiome either enhanced or reduced the drugs’ effectiveness, finding that regulating the gut microbiome with drugs could help alter, enhance, or even reverse the success of drugs for type 2 diabetes. Yadav summarized the findings by stating: “We believe that differences in an individual’s microbiome help explain why drugs will show a 90 or 50 percent optimum efficacy, but never 100 percent…our review showed that the metabolic capacity of a patient’s microbiome could influence the absorption and function of these drugs by making them pharmacologically active, inactive, or even toxic.”

Nevertheless, researchers must conduct additional studies to “continue to decipher the interactions between the gut bacteria and diabetes drugs” in clinical practice and further applications. Yadav adds, “This field is only a decade old, and the possibility of developing treatments derived from bacteria related to or involved in specific diseases is tantalizing.”

The latest report from the Centers for Disease Control and Prevention (CDC) indicates that over 100 million adults in the United States are currently living with diabetes or prediabetes.