Allergy season will soon be upon us—spelling misery for many. Antihistamines and decongestants can reduce the symptoms of hay fever—but not without side effects such as sleepiness, dizziness, blurred vision, nausea, and vomiting.
A better answer to seasonal allergies may be to take a daily probiotic! According to a new study conducted at the University of Florida, a daily probiotic may greatly reduce allergy symptoms. But not all probiotics have this effect. In this study, researchers found that a probiotic containing Lactobacilli and Bifidobacteria was effective in calming hay fever symptoms and boosting quality of life during allergy season. The findings were reported in the American Journal of Clinical Nutrition.
Quick Facts on Hay Fever
Also called allergic rhinitis, hay fever happens when the immune system overreacts to airborne allergens causing runny nose, sneezing, itchiness of the eyes, moth, or skin, nasal congestion, and fatigue. The condition affects between 40 and 60 million people in the United States and typically occurs in spring, summer, and early fall. Common allergens include pollens from grass, trees, and weeds, as well as mold spores.
A Breakthrough Study
Earlier research has examined probiotics against seasonal allergies with widely varied results depending on the bacterial strains contained in the probiotics. Past studies have shown that the “friendly” bacteria Lactobacilli and Bifidobacteria can help to maintain a healthy gut and immune system. Considering these past studies, the Florida team 
chose to test a combination of Lactobacillus gasseri, Bifidobacterium bifidum, and Bifidobacterium longum.
The study was conducted over 8 weeks at the peak of allergy season with 173 healthy adults with mild to moderate seasonal allergies. The subjects were randomly assigned to two groups. The first group was given the combination probiotic in the form of a capsule, to be taken twice daily. The second group was given a placebo. None of the participants were using any other allergy medications.
Over the 8-week study period, subjects were surveyed by telephone weekly about their symptoms. Those who took the probiotic reported improved allergy symptoms and better quality of life. Those whose seasonal allergies were mild reported the greatest benefits from the combination probiotic.
“Not all probiotics work for allergies. This one did,” said the researcher team lead.
Probiotic Combination Might Boost T cells
More research is needed to determine exactly how the combination probiotic worked to reduce seasonal allergies. For now, however, the team believes it might be due to an increase in regulatory T cells. Such cells may improve tolerance to allergy symptoms.
“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,” the researchers said. “Future research should focus on the molecular mechanism by which probiotics modulate immune function … this information may lead to a more complete understanding of the role of commensal microorganisms in developing and maintaining immune balance.”
