Can Hay Fever Affect Your Gut? The Link Between Pollen, Histamine and Digestion
R.Parnell (ANutr, MSc)
For many people, pollen season means sneezing, itchy eyes and a runny nose. But some people also notice their digestion feels more unsettled at the same time, with bloating, cramping, looser stools, constipation or a gut that feels more reactive than usual.
This may seem surprising, but the gut and immune system are closely connected. One possible link is histamine.
What is histamine?
Histamine is a natural chemical made by the body. It is best known for its role in allergy symptoms, including itching, sneezing and watery eyes.
But histamine also has important roles in the gut. It can influence gut movement, fluid secretion, immune signalling and how sensitive the nerves in the gut feel.
Histamine is not “bad”. It is part of normal immune function. Problems may arise when histamine activity becomes too high, poorly regulated or difficult for the body to break down efficiently.
Why pollen can affect the gut
When someone with hay fever is exposed to pollen, the immune system can respond by activating mast cells. These immune cells release histamine and other inflammatory compounds.
Mast cells are found not only in the nose and airways, but also in the gut lining. This means allergy-related immune activity may also influence the gut in some people.
In people with hay fever, pollen exposure can trigger histamine release as part of the allergic response. Because histamine also acts in the gut, this may help explain why some people notice more bloating, urgency or discomfort during high pollen periods, especially if they already have a sensitive gut.
Histamine can also come from food and bacteria
Histamine can come from several sources. Certain foods contain higher amounts of histamine, including aged cheeses, fermented foods, cured meats, wine and some fish.
Some bacteria in the gut can also produce histamine. This is why strain-level identification matters, especially for people who are sensitive to histamine and are choosing to supplement with live bacteria: not all strains behave in the same way.
EVIDOSE® Live Biotic Daily+ is formulated with four clinically studied live bacteria strains and based on genomic analysis, none of the strains carry the genes required to produce histamine:
- Lacticaseibacillus rhamnosus GG
- Bifidobacterium lactis BB-12
- Lactobacillus acidophilus NCFM
- Bifidobacterium lactis HN019
Each strain is included at its studied dose, alongside vitamin D3, which contributes to the normal function of the immune system.
Why the gut microbiome matters
The gut microbiome plays an important role in gut and immune health. It interacts with the gut barrier, immune cells and chemical signals involved in inflammation and tolerance.
A well-supported gut microbiome will not “cure” hay fever or histamine intolerance. However, supporting the microbiome may help maintain a healthier gut environment and support normal gut–immune communication.
During pollen season, simple habits may help support the gut:
- eat a varied, fibre-rich diet where tolerated
- stay hydrated
- keep meals and sleep routines consistent
- consider a histamine sensitive friendly probiotic supplement
- track whether symptoms change on high-pollen days
Some people may also choose to reduce high-histamine foods during peak pollen periods, although restrictive diets should ideally be done with professional guidance.
The takeaway
Pollen season may affect more than your nose and eyes. In some people, allergy-related histamine release and immune activity may coincide with digestive changes, especially in those with sensitive guts.
The science is still evolving, but we know the gut and immune system are closely connected. Supporting the gut microbiome helps maintain a healthy gut environment, an important foundation for normal immune function, particularly during pollen season.
References
1. Smolinska, S., Winiarska, E., Globinska, A., & Jutel, M. (2022). Histamine: A Mediator of Intestinal Disorders-A Review. Metabolites, 12(10), 895. https://doi.org/10.3390/metabo12100895
