Women are much more likely than men to suffer from irritable bowel syndrome (IBS), a chronic condition that causes digestive problems, abdominal pain and bloating.
Now scientists at UC San Francisco may have discovered why. Estrogen, the researchers report Scienceactivates previously unknown pathways in the colon that can cause pain and make the female intestine more sensitive to certain foods and their breakdown products.
When male mice were given estrogen to mimic the levels of females, their sensitivity to intestinal pain increased to match that of females.
The findings not only explain female dominance in intestinal pain disorders, but also point to possible new ways to treat the conditions.
“Instead of just saying that young women suffer from IBS, we wanted rigorous scientific explanations as to why,” says Holly Ingraham, Ph.D., the Herzstein Professor of Molecular and Cellular Pharmacology at UCSF and co-senior author of the study. “We answered that question and identified new potential drug targets in the process.”
The research also suggests why low-FODMAP diets – which eliminate certain fermentable foods, such as onions, garlic, honey, wheat and beans – help some IBS patients, and why women’s gut symptoms often fluctuate with their menstrual cycle.
“We knew that the gut had a sophisticated pain-sensing system, but this study shows how hormones can increase that sensitivity by tapping into this system through an interesting and powerful cellular connection,” says co-senior author David Julius, Ph.D., the Morris Herzstein Chair in Molecular Biology and Medicine and chair of Physiology.
Julius won the 2021 Nobel Prize in Physiology or Medicine for his work on pain sensation.
