There’s been a lot of press about gut health in recent health and fitness news. The evidence keeps stacking up on just how important it is to eat foods with plenty of healthy, “good” bacteria (also called gut microbes). A brand-new study, conducted at Boston Children’s Hospital, compiled data on how gut microbes influence metabolism.

The study, led by Paula Watnick, MD, PhD, of the Division of Infectious Diseases at Boston Children’s Hospital, was published in the journal Cell Metabolism. The study found a surprising way that good bacteria–in fruit fly intestines–influenced metabolism. The intestines of fruit flies share a similar structure and function with humans.

The recent fruit fly study discovered a connection between the digestive cells in the stomach, pancreas, and intestines, and the cells that regulate glucose metabolism. This immune pathway is known as IMD.

Metabolism and Immune Pathways

A pathway is a linked series of chemical reactions occurring within a cell. In metabolism, this pathway involves breaking down of nutrients (such as glucose) into energy.

Past studies have shown that the digestive system is part of the body’s immune system, acting as the first line of defense against harmful bacteria.

Previous Fruit Fly Studies on Metabolism

Watnick and the research team realized that in previous studies, performed by Norbert Perrimon, PhD, at Harvard Medical School, bacteria in the intestines of the flies helped to produce healthy fats—essential to the flies’ fat metabolism. Flies that had no healthy gut bacteria accumulated unhealthy fat droplets in their digestive cells. Watnik explained, “When there’s a problem processing glucose [blood sugar] or lipids [fats], fats get stuck in these droplets in cells that are not designed for fat storage,” she says.

Study Findings

Watnick’s study found that flies with mutations in the IMD immune pathway had the unhealthy fat droplets in their intestines. Watnick explained that these fat droplets are a sign of fatty liver (a condition that is an underlying contributor in diabetes). Watnick also commented that these flies are likely to have metabolic syndrome (associated with obesity and diabetes).

“We know bacteria control our metabolism, but no one realized that bacteria were interacting with innate immune signaling pathways in enteroendocrine cells [cells of the stomach, intestines and pancreas],” says Watnick. “Maybe these pathways are really a system that allows cells to recognize bacteria for different reasons.”

Watnick and colleagues hypothesize that eating more fermentable foods may promote good metabolism. “Such foods may help counteract imbalances in our gut bacteria, such as those caused by protracted [long-term] antibiotic use,” Science Daily.


If you are trying to lose weight, and want to influence your metabolism, consider taking probiotic supplements, and eating more foods with healthy bacteria, including yogurt, kefir, fermented foods (such as sauerkraut) and more. Keep in mind that when you take any type of supplements, it’s best to choose pharmaceutical grade supplements, and always consult with the physician beforehand.