Allergy season is well under way for millions of Canadians. People sensitive to tree pollen can suffer from March through to July. Grass pollen is released from April to July and then ragweed hits from August all the way until November.
What are seasonal allergies?
Seasonal allergies, also known as hay fever, like all allergies, are an immune response to a protein. In this case, the protein is coming from plant pollen being inhaled. The body creates antibodies whenever it perceives a threat has invaded the body and in the case of allergies the immune system mistakenly creates antibodies to the harmless pollen proteins.
The antibodies associated with allergic reactions are called immunoglobulin E, or IgE antibodies. These antibodies are controlled by type 2 helper T cells, or Th2 cells. Th2 cells activate and recruit IgE antibodies which then attach to mast cells. Mast cells, which are abundant in the eyes, nose and lungs, are the cells that release histamine and the other chemicals responsible for creating the symptoms associated with hay fever.
How to Prevent Allergies and Reduce Symptoms
As described above, allergies are associated with a Th2 mediated response from the immune system. In order to prevent allergies it would be important to create a shift away from this pre-allergic Th2 response. This is done by creating a more even Th1/Th2 balance in the immune system.
It is believed that part of why more and more people are reaching for the Claritin is reduced microbial exposure at an early age. That is, we are too clean and our immune system is not taught how to properly respond to actual threats and instead starts creating reactions to harmless proteins such as pollen. Several studies show that infants exposed to pets in their first year of life grow up to have a lower risk of developing allergies and asthma. Sharing the floor with a cat or dog helps introduce babies' immune systems to more microbes and creates a more balances immune system.
If you are no longer an infant, there is much research showing the benefits of probiotics in preventing and reducing the symptoms associated with allergies. Probiotics help by down-regulating the immune system's Th2 response which in turn reduces the number of IgE antibodies that will be recruited to activate mast cell histamine production. Studies also show that lower diversity of healthy intestinal bacteria is associated with higher levels of circulating IgE. Therefore, it is likely beneficial to get probiotics from a variety of sources such as a daily supplement, yogourt, and other fermented foods and beverages.
If you already have allergies probiotics are still helpful at reducing symptoms and may help to prevent allergies from developing in the future.
Medicinal mushrooms such as Reishi and Chaga have been found to have similar immune modulating effects. Reishi has demonstrated the ability to down-regulate the Th2 response and reduce allergy symptoms to inhaled pollens. Chaga has also shown the ability to reduce the Th2 response and suppress IgE production.
Finally, research has shown that having higher blood concentrations of various carotenoids, reflecting a diet high in fruits and vegetables, is associated with lower incidence of hay fever.
Scott Figueroa and Holly Letourneau are naturopathic doctors and co-founders of Hart & Sol Integrative Healthcare.