Why gastrointestinal disorders afflict women more often

Women are more likely to have irritable bowel syndrome and other gastrointestinal (GI) disorders than men are. Although this could be because men and women handle the condition differently— "toughing it out" versus getting it checked out—studies suggest that the GI system behaves differently in women because of sex-related features in the brain. Tanja Babic, a researcher at Penn State Hershey College of Medicine, found that the nerve cells that control the movement of food through the intestines are more sluggish in response to brain inputs in women than in men.

"Women are more likely to develop gastrointestinal disorder than men, but very little research has been done to investigate the reasons behind this," Babic says. "Females also show differences in brain structure and function compared to males, including higher levels of GABA (γ-aminobutyric acid), an inhibitory neurotransmitter. Since GABA influences the activity of neurons that control digestion, I wanted to investigate whether GABA activity in these neurons is different in males and females. If we can selectively change the activity of these neurons in females, we would have a potential therapeutic target for better treatment of GI disorders in women."

To identify these differences, Babic measured the type of nerve signal received from the brain and the nerves' responsiveness to the signals in rats. She found that the nerves in female rats received more signals that suppress the intestinal movement of food. The nerves were also less responsive when stimulated. According to Babic, the data support that the nerves controlling the intestines in females are less excitable and receive more inhibitory signals from the brain, offering one explanation of why digestion problems are more common in women.