In the quest of making the world a sanitized, squeaky clean place to live, humans have driven some bacteria to extinction. While this is indeed good when the bacteria cause illness, it may be a quite a loss to the humans as some bacteria may hold the key in preventing events like stroke and asthma.
A study conducted by researchers from NYU School of Medicine has found that a virulent strain of the gut bacterium Helicobacter pylori (H. pylori) may protect against stroke and even some cancers.
H. pylori were, till recently, living in the mucous layer lining of the stomach. At least half the world's population has the bacteria in their gastrointestinal tract. The bacterium is vanishing from the developed world due to better sanitation; however, it is still present in many developing countries. The most virulent strains have a gene called cagA.
The study was essentially a survey that included about 10,000 individuals over a 12 year period. Researchers found that people who carried the most virulent strain of H.pylori had a 55 percent lower risk of death from stroke and a 45 percent less risk of death from lung cancer.
Previous research from one of the study authors, Martin J. Blaser, found that the bacterium was associated with gastric diseases like gastritis and stomach cancer.
Blaser along with Yu Chen, another study author, have even found that the bacteria may protect against childhood asthma.
"This finding confirms earlier work, however, that gastric cancers are now uncommon in the United States. We also found that H. pylori was related to a reduced risk of stroke and lung cancer, and these effects were stronger for the cagA strain, suggesting its mixed role in human health," said Yu Chen, PhD, MPH, associate professor of population health and environmental medicine and one of the study authors.
"The most interesting finding was that there is a strong inverse association with stroke which could be protective. There is some precedent for this and it is possible that the same cells (T reg cells) that H. pylori induces that protect against childhood asthma could be the protective agents, however, the findings need to be confirmed," said Martin J. Blaser, MD, professor of internal medicine and professor of microbiology.