The gut of human like many other vertebrates is mostly dominated by two groups of bacteria, Bacteroidetes and Firmicutes along with some minor populations of Actinobacteria, Fusobacteria, and Cyanobacteria species as part of a complex microbial community.
Bacteroidetes is composed of three large classes of Gram-negative, non-spore forming, anaerobic, and rod-shaped bacteria and the Firmicutes include all Gram-positive bacteria, spore-forming, round/rod shaped bacteria.
In terms of numbers these microbial population has 10 times more number of cells than our own body cells. Our well being is almost dictated by this intestinal flora and hence can be considered as an “exteriorized organ”.
As you know, asthma is caused by inflammation of the bronchi, the small tubes that carry air in and out of the lungs. The inflammation can be triggered by exercise, cold air or smoke, for example, or it can be caused by allergies to things such as house dust mites or pollen.
Recently, a team of researchers led by Benjamin Marsland from Lausanne University Hospital has shown in experiments with mice that the lack of fermentable/soluble fibers in diet can lead to allergic inflammatory reactions in the lungs.
Benjamin Marsland’s work showed that when we take enough soluble\fermentable fiber containing food such as pectin, it favors the growth of bacteria that produce circulating short chain fatty acids and this can influence the production of immune cells in the bone marrow that could have major implications in suppressing allergies.
The microbes take "soluble" fiber such as pectin—found in apples, pears, berries, citrus fruits, and onions—and ferment it into specific types of fatty acids called short chain fatty acids (SCFAs) such as propionic acid that interact with immune cells, helping keep inflammation in check. These fatty acids are able to circulate through the bloodstream, perhaps hooking up with immune cells throughout the body. Levels of the immune cells known as eosinophils, and of the antibody immunoglobulin E—both usually increased in allergies and asthma—were almost halved, and the mice showed less constriction of their airways.
Tests showed that the immune cells generated in the bone marrow of mice given one of these SCFAs were less able to trigger allergies in the airways. To see if the gut bacteria were responsible for the fiber-mediated benefits, the scientists analyzed the feces of mice on normal, low-, and high-fiber diets.
In the animals given pectin, the kinds of bacteria best able to produce the anti-inflammatory fatty acids were about twice as prevalent as those of other bacteria more common in a low-fiber diet.
On closer examination, the researchers found proportionally higher amounts of the fatty acids not only in the stool of the pectin-eating mice, but also in their blood. To find out, the researchers injected the mice with propionate, one of those short chain fatty acids. After 2 weeks, the rodents again showed reduced inflammatory responses and less constriction of the airways in response to the dust mite treatment.
This means that bacteria in the gut have an effect on allergic airway disease in the lung! The soluble fibre food helps in the growth and survival of these beneficial bacterial species!
Eat more soluble fibre food to avoid allergic responses!
Further Reading: http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3444.html
Bacteroidetes is composed of three large classes of Gram-negative, non-spore forming, anaerobic, and rod-shaped bacteria and the Firmicutes include all Gram-positive bacteria, spore-forming, round/rod shaped bacteria.
 |
| The above picture shows the various regions of the GI tract, the Microbial population size and types |
In terms of numbers these microbial population has 10 times more number of cells than our own body cells. Our well being is almost dictated by this intestinal flora and hence can be considered as an “exteriorized organ”.
As you know, asthma is caused by inflammation of the bronchi, the small tubes that carry air in and out of the lungs. The inflammation can be triggered by exercise, cold air or smoke, for example, or it can be caused by allergies to things such as house dust mites or pollen.
Recently, a team of researchers led by Benjamin Marsland from Lausanne University Hospital has shown in experiments with mice that the lack of fermentable/soluble fibers in diet can lead to allergic inflammatory reactions in the lungs.
Benjamin Marsland’s work showed that when we take enough soluble\fermentable fiber containing food such as pectin, it favors the growth of bacteria that produce circulating short chain fatty acids and this can influence the production of immune cells in the bone marrow that could have major implications in suppressing allergies.
The microbes take "soluble" fiber such as pectin—found in apples, pears, berries, citrus fruits, and onions—and ferment it into specific types of fatty acids called short chain fatty acids (SCFAs) such as propionic acid that interact with immune cells, helping keep inflammation in check. These fatty acids are able to circulate through the bloodstream, perhaps hooking up with immune cells throughout the body. Levels of the immune cells known as eosinophils, and of the antibody immunoglobulin E—both usually increased in allergies and asthma—were almost halved, and the mice showed less constriction of their airways.
Tests showed that the immune cells generated in the bone marrow of mice given one of these SCFAs were less able to trigger allergies in the airways. To see if the gut bacteria were responsible for the fiber-mediated benefits, the scientists analyzed the feces of mice on normal, low-, and high-fiber diets.
In the animals given pectin, the kinds of bacteria best able to produce the anti-inflammatory fatty acids were about twice as prevalent as those of other bacteria more common in a low-fiber diet.
On closer examination, the researchers found proportionally higher amounts of the fatty acids not only in the stool of the pectin-eating mice, but also in their blood. To find out, the researchers injected the mice with propionate, one of those short chain fatty acids. After 2 weeks, the rodents again showed reduced inflammatory responses and less constriction of the airways in response to the dust mite treatment.
This means that bacteria in the gut have an effect on allergic airway disease in the lung! The soluble fibre food helps in the growth and survival of these beneficial bacterial species!
Eat more soluble fibre food to avoid allergic responses!
- Dr. P. Kumarasamy
Further Reading: http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3444.html
