In a study published yesterday in the Journal of Infectious Diseases, researchers showed that Heliobacter pylori, an intestinal microbe that co-evolved with humans, appears to protect children from asthma.H. pylori sound better than hookworms to control my allergies.
Asthma rates have nearly doubled in the United States since 1970, and are swelling in the developing world. Underlying the rise is a constellation of causes -- and one of these may be the loss of H. pylori, a vanishing member of the rich bacterial ecosystems in our stomachs. Nearly universal at the advent of modern antibiotics, it's now present in just one-fifth of young Americans.
Blaser and NYU colleague Yu Chen analyzed the medical histories and stool samples of more than 7,400 people enrolled in the National Health and Nutrition Examination Survey. After controlling for other variables, they found that the presence of H. pylori was associated with a 25 percent fall in asthma rates among people under 20 years old. The drop was even more significant in H. pylori-positive children aged 3 to 13: They were 59 percent less likely to develop asthma.
Kids with H. pylori were also less likely to have eczema and hay fever -- disorders that often accompany asthma, and likely share the same roots in immune systems that are excessively sensitive to everyday contaminants.
Blaser said the bacteria's presence triggers the production of Th17 cells, a type of regulatory cell that determines the body's response to foreign bacteria and pollution.
There is, however, a positive side to the loss of H. pylori: the bacteria has been linked to stomach ulcers and gastric cancers.