'Good' Bacteria May Ease Hay Fever

Study Shows Probiotics Can Change Immune Response to Grass Pollen

Medically Reviewed by Louise Chang, MD on June 04, 2008
From the WebMD Archives

June 4, 2008 -- If springtime's splendor leaves you sniffling, "good" bacteria may one day provide relief. New research suggests probiotics can alter the body's immune response to grass pollen -- a common cause of seasonal allergic rhinitis, or hay fever.

The landmark study published in Clinical and Experimental Allergy suggests that in the future, "good" bacteria, or probiotics, may potentially offer a treatment option to the estimated 35.9 million people in the U.S. who have seasonal hay fever.

Probiotics are beneficial bacteria similar to those that naturally occur in the human gut and help promote a healthy digestive system. Changes in the delicate balance of intestinal bacteria have been linked to certain allergic disorders, leading scientists to theorize that probiotics may affect the body's immune system.

For the current study, researchers with the Institute of Food Researchers randomly assigned 10 volunteers to drink a daily glass of regular milk or milk containing the probiotic Lactobacillus casei Shirota. Lactobacillus casei has been widely studied for its health benefits. The volunteers drank the milk each day and were followed for five months.

The research team took blood samples from each volunteer before, during, and after grass pollen season, checking for antibody levels of immunoglobulin E (IgE). If you have hay fever or other allergies, your immune system produces IgE in response to exposure to pollen. IgE is a key player in allergic reactions.

The blood tests revealed similar levels of IgE between both groups of volunteers at the start of the study. However, those who drank the probiotic drink had significantly lower levels of IgE specific for grass pollens and other allergy-related immune substances at peak season and afterward.

"The probiotic strain we tested changed the way the body's immune cells respond to grass pollen, restoring a more balanced immune response," Kamal Ivory of the division of Gastrointestinal Biology and Health at the Institute of Food Research says in a news release.

"This was a pilot study based on small numbers of patients, but we were fascinated to discover a response," research leader Claudio Nicoletti says. "The probiotic significantly reduced the production of molecules associated with allergy."

However, the researchers admit further studies are needed to determine if probiotic supplementation results in fewer hay fever symptoms. Phase II of the study will address that question.

Show Sources


News release, Norwich BioScience Institutes.

Ivory, K. Clinical and Experimental Allergy, 2008; pp 1-8.

American Academy of Allergy Asthma & Immunology web site: "Rhinitis and Sinusitis Statistics."

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