Taking a probiotic combination could reduce hay fever symptoms, according to a study at the University of Florida.
The researchers wanted to test the hypothesis that a combination of lactobacilli and bifidobacteria would help alleviate allergy symptoms. They believe that probiotics, or live bacteria, work by increasing the body’s percentage of regulatory T-cells, which might increase tolerance to hay fever symptoms.
During the study, which was carried out in the spring, 173 healthy adults who suffer seasonal allergies were split into two groups. One took the combination probiotic while the other group took a placebo. Over the course of eight weeks, volunteers filled in a regular online survey to report their discomfort level.
The researchers also analysed DNA from stool samples to determine how the bacteria changed. This confirmed which participants were taking the placebo.
Those who took the probiotic reported improvements in quality of life, compared to those taking the placebo. For example, they reported fewer allergy-related nose symptoms.
The researchers say that currently available allergy medications have unwanted potential side effects, such as a dry mouth and drowsiness, which is why there is a need for an alternative.
The study, published in the American Journal of Clinical Nutrition, concludes that the combination probiotic showed clinical benefit for those with mild seasonal allergies.
Hay fever is non-threatening but can be extremely debilitating, often requiring antihistamines and other medications that themselves have their own side effects but that are also sometimes of minimal use.
The 179 study participants were randomised to two groups, with one group receiving probiotic supplements and the other placebo for the eight-week duration of the trial. A major potential confounder of the trial was identified in the form of consumption of fermented foods and participants had to agree to not include them as part of their diets.
Throughout the course of the trial, comparable numbers of people in both arms guessed that they were in the active medication/placebo arm. This is important as the mental state of a patient can often be one of the determinants of a medication’s usefulness and a number of trials have documented clinical effect after placebo use that has no other explanation.
An objective scoring system was used to compare symptoms and improved scores were seen in the probiotic group, ie, the group on probiotics noted reduced symptoms overall compared to the placebo group. The difference was statistically significant and was more profound in women than in men. Less constipation was also noted.
A change was seen in the intestinal bacterial count and type in those taking probiotics. This may account partly for the results as the probiotic strains used have been found to produce anti-inflammatory fatty acids and other metabolites that may lessen the inflammation involved in hay fever. The actual molecular mechanisms that may be at play are yet to be elucidated.
This is an interesting study and, while it is premature to suggest anyone with hay fever immediately start supplementing with probiotics, it would probably do no harm once the issue has been discussed with a doctor.
Research score: 4/5