29 POUNDS OF FAT A YEAR
The team was able to investigate how the microbiome shift affected the animals’ metabolism by using a novel piece of equipment—a total calorimetry machine—invented by Grobe. The apparatus allows precise measurements of energy intake, oxygen consumption and carbon dioxide output, and heat production in a single animal to determine the total energy change, or “delta G,” of the mouse.
The researchers discovered there was no change in aerobic (oxygen-dependent) resting metabolic rate for mice fed risperidone compared to control mice, but there was a significant decrease in non-aerobic resting metabolic rate sufficient to account for the animals’ weight gain.
“It’s about a 16 percent change in resting metabolic rate, which is enormous,” Grobe says. “It would be 29 pounds of fat gained every year for an average human.”
“That is the equivalent of eating one additional cheeseburger every single day,” adds Kirby.
MORE PROOF IT’S THE MICROBIOME
To prove that it was the “shifted” microbiome that was responsible for this metabolic change and the weight gain, the researchers transferred the microbiome from risperidone-fed mice into control mice and saw the same effect: decreased resting metabolic rate and increased weight gain.
Moreover, they found it wasn’t just the bacteria that could produce this effect. Transferring just a bacteriophage (phage)—a type of virus that infect microbiome bacteria—was sufficient to reduce resting metabolic rate and cause weight gain in the control mice.
The results may suggest that manipulating resting metabolic rate, specifically by targeting the gut microbiome, could represent a new approach to treating obesity. Alternatively, preventing unhealthy changes to the microbiome may prove beneficial for patients undergoing risperidone treatment.
The National Heart, Lung and Blood Institute, the National Institute for Allergy and Infectious Diseases, the American Heart Association, the American Diabetes Association, the National Science Foundation, and the University of Iowa Fraternal Order of Eagles Diabetes Research Center funded the study.
Republished as a derivative work from Futurity.org under the Attribution 4.0 International license. Original article posted to Futurity by Jennifer Brown-Iowa.
Featured Photo Credit: Aweisenfels via wikimedia, CC BY SA 4.0