Surprising Fact: there’s a Link between Gut Microbiome and Seasonal Allergies

Surprising Fact: there’s a Link between Gut Microbiome and Seasonal Allergies

  • Gut Health

  • By Desiree Nielsen, Registered Dietitian

    After a chilly winter, the arrival of longer days and warmer temperatures can feel like such a gift - that is until the scratchy throat, watery eyes, and runny nose that are the telltale signs of seasonal allergies begin. Seasonal allergies, commonly known as hay fever, occurs when our immune system overreacts to pollens in the environment. The sneezing, congestion, mental fog and irritation that accompany allergies can really put a damper on all that fun in the sun!

    If seasonal allergies are a part of your life, grab your neti pot and consider this: allergies represent an imbalanced immune response. And, given that 80% of our immune function lies within our digestive tracts, perhaps we should shift some of our focus to nurturing better gut health all year long, not just during cold and flu season.


    How does an allergy develop?

    Seasonal allergies occur because your adaptive immune system labels otherwise harmless pollens as harmful. If you are prone to seasonal allergies, as you come into contact with pollens, white blood cells decide that these natural substances are invaders and trigger the development of Immunoglobulin E (IgE) antibodies matched to the offending pollens.

    Once this sensitization has occurred, these IgE antibodies now course through your system like the pollen patrol, initiating what is known as a TH2 inflammatory response every time you come in contact with the pollen. Antibodies bind to mast cells, causing them to release their stores of histamines in addition to triggering a host of other ‘complement’ proteins that are your body’s best effort to rid you of the pollen intruders.

    However, why these allergies occur in approximately ten percent of us is not entirely understood. The current, most accepted hypothesis, is known as the hygiene hypothesis. It proposes that environments with low microbial diversity predispose our immune systems to overreact1.

    The thinking behind this is that microbes that cause infection typically stimulate TH1 responses in the immune system, and suppress the TH2 response that can predispose us to allergy1,3.

    As a result, early life exposure to potentially infectious microbes appears to have a hugely beneficial effect, as do exposures to microbes that are part of the normal human microbiota, stimulating our immune system to learn which exposures are safe and which are harmful.

    Children born by natural delivery (which is baby’s first introduction to microbes), those who are breastfed, or have exposures to older siblings, pets or farm animals appear to have improved immune responses in the research1-3. Conversely, those born by caesarean section, require antibiotic use in early life, or are exposed to homes using antimicrobial cleaners may be more at risk1-3.


    How a healthy gut may help decrease allergic response

    Given that your immune system’s interaction with bacteria appears to be central to nurturing appropriate immune responses in seasonal allergy, it is only natural that taking care of your gut be part of your allergy defensive. The gut is where immune-microbe interaction is at its most potent: your gut-associated immune system is exposed to trillions of bacteria, yeasts, fungi and viruses on a daily basis. Normal interaction with a healthy bacterial community is known to have a beneficial impact on immunity, supporting it in forming appropriate responses to external stimuli. The early microbiota of children who develop allergy has been shown to be of lower diversity than those without allergy, with unique patterns of species growth3.

    How does this happen? Depending on the type of bacteria observed, researchers have demonstrated that beneficial bacteria can1-3:


    • help directly oppose the inflammatory response and improve immune tolerance
    • improve acquired immunity responses, demonstrated by increases in other immune cells such as IgG, IgA and IgM
    • secrete antimicrobial peptides and improve the gut mucus barrier to defend against harmful microbes
    • produce short-chain fatty acids that help feed immune processes


    Because of these effects, taking a daily probiotic, such as Bio-K+, can be a great strategy to support this beneficial interaction with microbes and decrease reactivity in the body. In fact, research has shown that introducing certain probiotic bacteria, including Lactobacillus species into the gut may help relieve seasonal allergy symptoms and help you feel better4.

    One 2015 review found that amongst 23 studies, probiotics significantly improved quality of life, while every human trial within the review noted improvement in at least one marker, including allergic symptoms themselves4. This positive trend towards benefit was echoed in a 2016 trial5. What’s interesting here is that despite the researchers noting the significant variation in the methods of current studies (which can create a variance in results), the trend was still towards the positive, meaning the link between probiotics and allergy is extremely promising!

    In addition to your daily dose of probiotics, take steps to lead a bacteria-friendly lifestyle. Eat a healthy diet filled with high fibre plant foods like vegetables and beans, to feed beneficial bacteria in the gut2. Enjoy fermented foods daily to keep that natural conversation between the external bacterial world and your immune system going. And avoid antibiotic use unless medically necessary – not all bugs need drugs – and reduce your use of antibacterial home and personal products.


    Seasonal allergies are nothing (and everything!) to sneeze at; supporting your immune system is critical to help minimize the toll allergies take on your health and wellbeing. If you suffer from seasonal allergies, remember the role that your gut plays in strengthening your body’s immune responses and tend your inner garden well.


    Do you have more questions on air allergies or gut health? Let us know in comments below! For more healthy inspirations, join our community. Click here to find your Bio-K+ closest point of sale. Contact us or find us on Facebook and Instagram.




    1. Stiemsma, Leah T et al. “The Hygiene Hypothesis: Current Perspectives and Future Therapies.” Immunotargets and Therapy4 (2015): 143–157. PMC. Web. 28 May 2018.
    1. Fujimura, Kei E., and Susan V. Lynch. “Microbiota in Allergy and Asthma and the Emerging Relationship with the Gut Microbiome.” Cell host & microbe17.5 (2015): 592–602. PMC. Web. 28 May 2018.
    1. Ipci, Kagan, et al. "The possible mechanisms of the human microbiome in allergic diseases." European Archives of Oto-Rhino-Laryngology274.2 (2017): 617-626.
    1. Zajac, Alexander E., Austin S. Adams, and Justin H. Turner. “A Systematic Review and Meta-Analysis of Probiotics for the Treatment of Allergic Rhinitis.” International forum of allergy & rhinology5.6 (2015): 524–532. PMC. Web. 28 May 2018.
    1. Güvenç, Işıl Adadan, et al. "Do probiotics have a role in the treatment of allergic rhinitis? A comprehensive systematic review and meta-analysis." American journal of rhinology & allergy30.5 (2016): e157-e175.

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    Desiree Nielsen Registered Dietitian
    About the author
    Desiree Nielsen is a registered dietitian, author and host of the vegetarian cooking sshow, The Urban Vegetarian. Desiree takes an evidence-based, integrative approach to her dietetics work, with a focus on anti-inflammatory, plant-centredcentered nutrition and digestive health.
    View all articles by Desiree Nielsen
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