New research investigating the effect of gut microbiota on the efficacy of type 2 diabetes drugs suggests that the composition of gut bacteria may explain why diabetes medications work for some people and not others.

According to some estimates, over 415 million people worldwide currently have type 2 diabetes, which has led some scientists to refer to the condition as a "global pandemic."

Although there is no cure for diabetes yet, treatment and lifestyle changes can help those living with the disease.

However, diabetes drugs have varying rates of success, which depend on the form of administration and may vary from person to person.

New research, led by Hariom Yadav, PhD, an assistant professor of molecular medicine at the Wake Forest Baptist Medical Center in Winston-Salem, NC, investigates one of the possible causes behind such varying success rates—the gut bacteria.

Previous studies quoted by Yadav and colleagues in their paper show that the gut bacteria can "instigate" obesity and type 2 diabetes, and that people living with diabetes have an imbalance in the composition of their gut bacteria.

Also, as Yadav explains, some diabetes drugs are effective when given intravenously but do not work when taken orally. The bacteria in the gut are key to regulating how a person metabolizes drugs.

"For example," explains the lead researcher, "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," he continues, "metformin, a commonly used anti-diabetes drug, works best when given orally but does not work when given through an IV."

So, based on these observations, the researchers wondered whether the composition of the gut bacteria influences the efficacy of certain diabetes medications.

To this end, Yadav and colleagues reviewed over 100 studies of rodents and humans and published their results in the journal EBioMedicine.

How the microbiome can influence drugs

The research focused on how the microbiome either boosted or inhibited the effectiveness of the drugs. It found that modulating the gut microbiome with drugs could help boost, change, or reverse the efficacy of drugs for type 2 diabetes.

The study's lead researcher sums up by saying, "We believe that differences in an individual's microbiome help explain why drugs will show a 90% or 50% optimum efficacy, but never 100%."

"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."

—Hariom Yadav

However, more studies are needed to continue to decipher the interactions between the gut bacteria and diabetes drugs in clinical practice, caution the authors.

"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," Yadav adds.

According to the latest report from the Centers for Disease Control and Prevention (CDC), over 100 million adults in the US are currently living with diabetes or prediabetes.