By Peter Russell WebMD Health News Reviewed by Farah Ahmed, MD May 7, 2015
The so-called “friendly bacteria” known as probiotics may help take some of the misery out of hay fever, or seasonal allergies, according to a new review of studies. But the doctors who did the review say more research is needed before they’d be able to recommend probiotics as a treatment option.
Some scientists think the rise in allergies may be caused by a lack of bacteria in the gut due to cleaner living conditions. Living in a super-clean environment that doesn’t put you in contact often enough with microscopic living things called microbes might make your immune systems go haywire when it has to deal with harmless allergens, their theory goes.
Probiotics are live microbes that can increase the amount of good bacteria in the intestines.
Researchers from Vanderbilt University Medical Center examined 23 studies involving a total of 1,919 people. The quality of the studies varied, but two were “randomized controlled studies,” which are considered the gold standard by scientists.
The researchers say 17 of the studies showed that people with seasonal allergies who took probiotics had some improvement in at least one aspect – such as milder symptoms or better quality of life – compared to people who had allergies but were given a “fake” treatment called a placebo.
Six studies showed probiotics didn’t improve symptoms of hay fever, the researchers report in the International Forum of Allergy & Rhinology journal.
The review shows promise, but one of the reasons the researchers can’t yet recommend probiotics to treat seasonal allergies is because the studies used different probiotic strains and different study groups.