A new study published in Nature Communications suggests that pregnant women who consume a high-fiber diet may reduce the risk of their unborn child developing asthma. It appears that eating this type of diet alters the gut bacteria in the mother. These bacteria produce anti-inflammatory substances that suppress genes related to asthma in the fetus.
The researchers started with studies that involved three control groups of pregnant mice that were fed three different diets with varying amounts of fiber during their third trimester. When the baby mice became adults, the researchers exposed them to house dust mites. Such mites are a common trigger for asthma in humans.
The offspring of mice whose mothers ate a high-fiber diet did not develop symptoms of asthma, while the offspring of mice fed the low-fiber diet did develop these symptoms.
The researchers examined the gut bacteria of the pregnant mice. Those on the high-fiber diet had specific microorganisms that produced anti-inflammatory compounds when the fiber was digested. These compounds traveled to the uterus in the bloodstream and suppressed genes linked to asthma development in the fetus.
Next, the researchers examined humans. They analyzed diet data and blood samples of 40 pregnant women and compared them with the babies’ frequency of visits to the doctor for respiratory symptoms during their first year. Women who had consumed a high-fiber diet during pregnancy also had anti-inflammatory compounds in their blood. In addition, their children were significantly less likely to have visited a doctor two or more times for respiratory complaints during their first year.
This could explain why children who grow up on farms appear to have a lower risk for asthma. The researchers speculate that this difference could be due to dietary differences or to exposure to microbes in the farm environment.