Allergies – Could LGG help?
Allergies are a real inconvenience for any who suffer from them. From milder allergic reactions to pollen in the form of seasonal hay fever, through to severe allergies to foods or other triggers, this is a very broad area of medicine, and can range from mild inconvenience through to life threatening. So, scientists asked the question, can LGG affect allergies? It can affect the immune system after all, and allergies are typically an immune response, so it’s not a far-fetched idea.
When it comes to skin and allergy research, Lactobacillus rhamnosus GG (LGG) is one of the most studied bacterial strains in the world, and while much of the early work focused on infants and early-life development, a growing number of studies have also explored how LGG behaves in adults, particularly in relation to seasonal allergies and skin conditions that come as a result of allergies.
Most of the studies in this area were conducted as randomised double blind placebo control trials, maintaining a very high standard of clinical research. This means the results are unbiased and trustworthy, and we’d expect nothing less from this marvellous microbe’s body of evidence.
Studies you say? Tell me more
There is more than one area in the field of allergies that has been studied for it’s interaction with LGG, but typically they focus on seasonal allergies and immune balance, so let’s see what they found.
In a recent RCT published in Microbiology Spectrum (2025), researchers studied adults with seasonal allergic rhinitis, more commonly known as hay fever.
Participants took a slow-release chewable containing LGG throughout the pollen season, while a control group received an identical placebo. The results from this group were very promising indeed.
LGG was shown to successfully reach the upper airways, where pollen reactions begin, and was detected in 77% of participants’ throats and 41% of nasal passages. This is important as it shows this bacterium is capable of not just surviving but remaining in the upper air passages, so it’ll stick around.
Those taking LGG also showed lower levels of key, inflammation-related immune markers, including IL-4 and IL-13, compared with the placebo group, indicating that the LGG could have helped to bring inflammation and irritation down.
So, this study found some promising results: the LGG showed a real ability to reduce inflammatory markers, indicating that it can help to reduce inflammation, a major part of allergies. It also was found to stay in the upper airways once it was there, so any positive effect it does have may last since it’ll stick around!
Sometimes pollen allergies can come alongside food allergies, so researchers decided to examine this group, and see how LGG might have an effect here as well. Another randomised, double-blind trial explored how LGG might influence the body’s natural defences in adults with birch-pollen allergy, a variation of hay fever, and oral allergy syndrome, a condition where certain foods can trigger mild reactions in pollen-sensitive individuals.
Over a period of five and a half months, adults who took LGG daily showed increased levels of allergen-specific IgA (Immunoglobulin A) antibodies in their saliva compared with those on placebo. IgA antibodies are part of the body’s first line of immune defence, helping to stabilise mucosal surfaces such as the mouth, nose, and throat, and to neutralise threats by bonding to bacteria or viruses.
This is a very encouraging finding. IgA is widely regarded as one of the most important immune markers, and in the digestive tract is often associated with a strong gut barrier. Not only this, but it is typically linked with calming the immune system, and preventing overreaction. Finding high levels of it in the saliva suggests that, thanks to LGG, the mouth and throat are more prepared to deal with any incoming threats, and should the immune system overreact to something like pollen, the IgA may help calm that overreaction.
So how does it apply to me?
Across the adult studies, a consistent picture emerges, and it’s very encouraging.
LGG has been shown in gold-standard clinical trials to interact with the immune system in measurable ways. It has demonstrated local effects in the mouth, throat, and nasal passages, helping to maintain calm immune communication in response to allergens, and was found to survive well in the mouth and throat, sticking around to do its work.
Some participants experienced improved immune balance in the form of higher IgA during high-pollen seasons, with no reported side effects!
Allergies can be a persistent inconvenience for any of us unfortunate enough to suffer them, and Lactobacillus rhamnosus GG is one of the few bacterial strains studied across all life stages, from infancy to adulthood, so it was an strong contender for research into this area.
In adults, it has shown promising results in helping the body maintain immune stability and mucosal balance in the face of common allergens, with studies using rigorous gold-standard testing methods and showing measurable biological changes compared with placebo. So, in preparing the body to deal with allergies appropriately, LGG could be a very promising microbe indeed!
References (the science) – Don’t just take our word for it:
- Laursen, R.P., Larnkjær, A., Ritz, C., et al. (2021) Probiotic effects on allergic disease: systematic review. Clinical & Translational Allergy, 11(7), e12071. https://pubmed.ncbi.nlm.nih.gov/34385933
- Kalliomäki, M., Antoine, J.M., Herz, U., et al. (2010) Guidelines for the evaluation of probiotics in food. FAO/WHO Expert Consultation Report. https://www.fao.org/3/a0512e/a0512e.pdf
16. De Boeck, I., Spacova, I., Cauwenberghs, E., et al. (2025) ‘Lacticaseibacillus rhamnosus GG in a chewable colonizes the nose and facilitates local immune benefits in allergic rhinoconjunctivitis patients’, Microbiology Spectrum, 13(10), e00773-25. doi: 10.1128/spectrum.00773-25. Available at: https://pubmed.ncbi.nlm.nih.gov/40891819/
17. Piirainen, L., Haahtela, S., Helin, T., Korpela, R., Haahtela, T. and Vaarala, O. (2008) ‘Effect of Lactobacillus rhamnosus GG on rBet v1 and rMal d1 specific IgA in the saliva of patients with birch pollen allergy’, Annals of Allergy, Asthma & Immunology, 100(4), pp. 338–342. doi: 10.1016/S1081-1206(10)60596-0. Available at: https://pubmed.ncbi.nlm.nih.gov/18450119/
