Using probiotics may help alleviate the symptoms of allergic rhinitis (AR), also known as seasonal or perennial allergies, according to a Vanderbilt study that reviewed 23 previous trials.

The results were published in April in the online version of the journal International Forum of Allergy & Rhinology.

“When you look at all the studies combined, there was a statistically significant improvement in both the rhinitis-specific quality of life of those patients and in their nasal specific quality of life,” said lead author Justin Turner, M.D., Ph.D., assistant professor of Otolaryngology. But he cautioned that “the jury is still out” and suggests the topic is ripe for future studies.

Probiotics are microorganisms that are thought to have gastrointestinal benefits when consumed.

They are present in some foods, such as yogurt, or can be taken as a dietary supplement. But comprehensive data about their effectiveness is more difficult to come by because they are regulated as a supplement and not as a drug, Turner said.

The study, which included Alexander Zajac, M.D. a resident in General Surgery and, Austin Adams, M.D., a resident in Otolaryngology Surgery, “represents the most comprehensive analysis to date on the use of probiotics for the treatment of AR,” according to the journal article.

“It was a systematic review where basically we just searched the medical literature for all studies that have evaluated treatment of allergic rhinitis with probiotics,” Turner said. “There was a lot of variability in the individual studies, but a majority of the studies did show at least some benefit with the use of probiotics compared to placebo.”

Of the 23 studies that were reviewed, 17 showed that probiotics were linked to improvement in at least one facet of a patient’s health — either rhinitis-specific quality of life or in symptoms. A total of 1,919 patients were involved.

“That means that six (studies) did not show any benefit at all, so it’s hard to make any firm conclusions about that,” Turner said. “We also found that the studies were very variable, so they used a lot of different bacterial strains and treatment durations.”

Allergic rhinitis is a common disease that affects between 10 and 30 percent of the general population.

Turner cautioned that probiotics are not a substitute for current medications used to treat symptoms.

“This is not by any means suggesting that this is a cure for allergies,” he said, but suggests that further studies on the topic are in order.