Researchers found that a probiotic consisting of both Lactobacilli and Bifidobacteria helped to alleviate hay fever symptoms and improved quality of life during allergy season.
First study author Jennifer Dennis, of the Department of Food Science and Human Nutrition at the University of Florida, and colleagues recently reported their findings in the American Journal of Clinical Nutrition.
Hay fever, also called allergic rhinitis, is estimated to affect around 40-60 million people in the United States. It occurs when the immune system overreacts to airborne allergens.
Seasonal allergic rhinitis usually occurs in spring, summer, and early fall, and it is most commonly triggered by grass, tree, and weed pollens, as well as mold spores. Symptoms include runny nose, sneezing, itchy eyes, mouth, or skin, nose congestion, and fatigue.
Antihistamines and decongestants can help to alleviate the symptoms of hay fever. However, as with all medications, they may cause side effects. These include drowsiness, dizziness, blurred vision, nausea, and vomiting.
However, according to the results of the new study, there may be an alternative treatment for people with seasonal allergies: probiotics.
Probiotic combination improved allergy symptoms, quality of life
Previous studies have investigated the effectiveness of probiotics against seasonal allergies, but results have varied significantly depending on the bacterial strains used.
According to Dennis and team, past studies have shown that the “friendly” bacteria Lactobacilli and Bifidobacteria can help to maintain a healthy gut and immune system.
With this in mind, the researchers set out to determine how a probiotic containing a combination of Lactobacillus gasseri, Bifidobacterium bifidum, and Bifidobacterium longum affects seasonal allergy symptoms and life quality.
The team enrolled 173 healthy adults, all of whom reported having mild to moderate seasonal allergies. The subjects were then randomly allocated to one of two groups. One group was given the combination probiotic in the form of a capsule, to be taken twice daily, while the other group received a placebo.
Participants were not using any other allergy medications during the 8-week study period, and the study took place at the peak of spring allergy season.
Compared with participants who took the placebo, those who took the combination probiotic reported a reduction in allergy symptoms and improvements in quality of life, as determined by weekly telephone surveys.
“Not all probiotics work for allergies. This one did,” says Dennis.
Subjects with mild seasonal allergies reported the greatest benefits from the combination probiotic, the team reports.
Combination probiotic might boost levels of regulatory T cells
While further studies are needed to pinpoint precisely how the combination probiotic might alleviate symptoms of seasonal allergies, the team hypothesizes that it might be down to an increase in regulatory T cells, which could boost tolerance to such symptoms.
In conclusion to their findings, the researchers state that:
“Our study demonstrates a potential benefit for healthy adults with self-identified seasonal allergies when the probiotic is administered starting at the greatest level of allergy symptoms.
Future research should focus on the molecular mechanism by which probiotics modulate immune function. If elucidated, this information may lead to a more complete understanding of the role of commensal microorganisms in developing and maintaining immune balance.”