Can a Gut Bacteria Prevent Asthma?

Health Professional

Did you know we have more bacteria living on and within our bodies than we have  cells?   While most of us think of bacterial infections as bad, that's not always the case.   In fact, most bacteria have a symbiotic relationship with our bodies -- we both benefit.   A bacteria that lives in your stomach may even prevent a person from developing asthma.

Your stomach has acids in it to help your body digest foods.   A bacteria called Helicobacter Pilori, or H. Pylori, is able to flourish in such an environment.   Studies show that about 50 percent of humans are infected with this bacteria.    A  theory devised  is that a healthy level of H. Pylori may prevent asthma, and that a lack of H. Pylori may cause asthma.

This theory was first postulated when scientists observed asthma rates going up at the same time levels of H. Pylori in the gut were diminishing.  A study of animals seemed to confirm this theory, according to a report in the Journal of Clinical Investigation.*

The article notes that Asthma rates are considered to be higher in Western societies such as the United States and Europe, which tend to be more technologically developed. This theory postulates that this is occurring in part because our modern diet and medical practices are causing a decline in the H. Pylori population in our guts.

For one thing, a healthy level of H. Pylori is believed to be beneficial, yet when the H. Pylori level gets too high it's beleived to be linked to medical conditions such as  gastritis, stomach ulcers and even cancer.  So many physicians often prescribe antibiotics to kill off the bacteria.   This was once believed to be harmless, yet this new theory has scientists reconsidering.

Scientists now believe a  healthy balance of H. Pylori is  essential for the healthy development and maintenance of the immune system.  When H. Pylori isn't present the immune system will not mature in infants and this may cause asthma and allergies.  In adults this balance is needed  in order to keep the immune system healthy to prevent asthma and allergies, or so the theory goes.

For those interested in the scientific theory it goes something like this:  A healthy infection of H. Pylori in kids prevents the accumulation of dendric cells and triggers the accumulation of regulatory T-Cells that  suppress the bad immune response that cause asthma and allergies, according to the above article.

The article also notes that studies  show that when regulatory T-Cells were transferred from infected mice to non-infected mice, they too had the protection against allergies and asthma.  Unfortunately, mice that had a healthy infection early lost any protection afforded after the H. Pylori infection was depleted by antibiotics.

If such study results on mice prove to be true for humans, then scientists and doctors will need to cosider a healthy diet when attempting to help an asthmatic get his asthma under control.   Likewise, they may also want to reserve using antibiotics that kill H. Pylori to only those cases that show symptoms, and not prophylactically (to prevent symptoms).

The article also notes that historically 70-90 percent of children were born with H. Pylori in their guts, and this level has dropped to as low as 10 percent in Western nations.   Again, this decline occured as asthma rates in Western nations increased.

This research once again proves  three other theories I wrote about:  The Micro-flora theory of asthma and allergies,  the Hygiene Hypothesis, and that  antibiotics may cause asthma.

Surely nothing is etched in stone here, yet it's interesting what modern science is learning about what might cause asthma, and what might prevent it.

*Arnold, Isabelle C., et al.,  "Helicobacter pylori infection prevents allergic asthma in mouse models through the induction of regulatory T-cells," The Journal of Clinical Investigation, 121:8, 3088-3093, 1 July 2011