Nutritional strategies to support seasonal allergy symptoms

Seasonal allergies are no longer a minor inconvenience for a small subset of the population. Allergic rhinitis, more commonly known as hay fever, now affects a substantial proportion of adults and children in the UK, with prevalence continuing to rise year on year. In recent research around 49% of people reported suffering with hay fever symptoms.[i] Beyond the familiar sneezing, itchy eyes and nasal congestion, hay fever is associated with poor sleep, daytime fatigue, reduced concentration and impaired quality of life, particularly during spring and summer months.

While antihistamines and steroid sprays are often used to manage symptoms, many people experience side effects such as drowsiness, dry mouth, or sleep disturbances. This has led to growing interest in nutritional and lifestyle strategies that support the body’s natural ability to cope with seasonal allergies.

Hay fever is not immune weakness, it is poor immune regulation

A key concept that is often misunderstood is that hay fever is not caused by a weak immune system. Instead, it reflects a poorly regulated immune response.
In a healthy, well-regulated immune system, harmless environmental substances such as pollen are recognised and tolerated. In people with hay fever, this tolerance breaks down. Thie immune system misidentifies pollen as a threat and mounts an exaggerated inflammatory response.

This means the immune ‘accelerator’ is pressed to hard, while the immune ‘breaks’ the mechanisms that normally calm inflammation and switch reactions off, are not working effectively. As a result, symptoms can escalate quickly and persist throughout the pollen season. Understanding hay fever in this way is important, because it shifts the goal from stimulating immunity to supporting immune balance and regulation.

What happens in the body during hay fever?

When pollen is inhaled, it meets immune cells lining the nasal passages, in susceptible individuals, this exposure triggers the production of immunoglobulin E (IgE) antibodies. [ii]

IgE binds to specialised immune cells called mast cells, which sit just beneath the surface of the nasal and respiratory tissues.

On re-exposure to pollen, IgE molecules on mast cells cross-link, triggering the release of histamine and other inflammatory mediators. Histamine increases mucous production, blood vessel permeability and nerve sensitivity, leading to symptoms such as –

• Sneezing and nasal itching
• Runny or blocked nose
• Watery, itchy eyes
• Coughing or wheezing in some individuals

Crucially, in people with hay fever, regulatory immune pathways that should dampen this response are under-active, allowing inflammation to persist and intensify with repeated pollen exposure.

Why preparation matters – start before symptoms begin

Because hay fever is predictable and seasonal, timing is critical. Supporting immune regulation before pollen levels peak is far more effective than trying to calm inflammation once symptoms are already established.

Different pollens dominate at different times of the year –

• Early spring: tree pollens such as birch, alder, hazel and ash.
• Late spring to summer: grasses and agricultural crops, including rapeseed
• Mid-to late summer: weeds, nettles and mould spores.

Many individuals react to more than one pollen type, resulting in symptoms that last month's rather than weeks. A proactive approach allows the immune system to be better regulated before allergen exposure becomes intense.

Nutritional strategies to support immune balance

Diet plays a major role in shaping immune responses and allergic sensitivity. Diets rich in plant fibres support microbial diversity and the production of metabolites that promote immune tolerance, while excessive intake of ultra-processed foods, alcohol and refined sugar has been associated with increased inflammation and immune dysregulation. Because mast cell activity and histamine release are influenced by the overall inflammatory environment, dietary patterns can meaningfully affect how strongly the body reacts to allergens.

Alongside these dietary foundations, several specific nutrients and bioactive compounds have been studied for their ability to support mast cell stability, immune regulation and inflammatory balance. These nutrients do not suppress the immune system; rather, they help calm excessive immune signalling and support a more proportionate response during allergy season.

Quercetin: supporting mast cell stability.

Quercetin is a naturally occurring flavonoid found in foods such as onions, apples, berries and green tea. It is widely researched for its antioxidant and anti-inflammatory properties and is often described as a natural mast-cell stabiliser.

Rather than blocking histamine after it is released, quercetin helps to reduce mast cell activation, limiting histamine release in the first place. [iii] This upstream support aligns well with the concept of immune regulation rather than symptom suppression.

Quercetin is frequently combined with vitamin C to improve stability and absorption.

Vitamin C: histamine breakdown and inflammatory control.

Vitamin C plays several roles in allergic regulation, including –

• Supporting mast cell stability
• Promoting the breakdown of histamine
• Reducing inflammatory cell activity in nasal and respiratory tissues

Vitamin D: immune modulation, not stimulation.

Vitamin D is increasingly recognised for its role in immune modulation, helping the immune system respond appropriately rather than excessively. Immune cells, including mast cells and regulatory T cells, express vitamin D receptors.[iv]

Low vitamin D status has been associated with increased allergic sensitivity, and insufficiency is common in the UK following winter months with limited sunlight exposure. Supporting adequate vitamin D levels into spring and summer may help promote a more balanced immune response.

The gut-immune-airway connection.

A significant proportion of immune activity occurs in the gut, making digestive health a key consideration for hay fever support. Research increasingly highlights a close connection between the gut microbiota and immune tolerance, often referred to as the gut-airway axis or the gut-lung axis.

Disruptions to the gut microbiome, known as dysbiosis, can impair immune regulation and increase inflammatory responses elsewhere in the body, including the nasal passages and lungs.

Targeted probiotic strains, particularly certain Lactobacillus and Bifidobacterium species [v], have been studied for their ability to –

• Support immune tolerance
• Improve nasal symptoms
• Enhance quality of life during allergy season

One well-researched unique strain – Lactobacillus acidophilus L92 which is a heat treated lactobacillus strain that has been shown to alleviate hay fever symptoms by balancing immune responses Th1/Th2 – a key consideration in the prevention and management of allergic conditions.[vi]

Stress, adrenal health and allergies.

Chronic stress can worsen allergic responses by altering cortisol signalling and immune regulation. The adrenal glands are closely linked to both stress resilience and inflammatory control.
Supporting adrenal health may include –

• Adequate Vitamin C and B-vitamin intake
• Adaptogenic herbs such as ashwagandha
• Reducing caffeine and alcohol during peak allergy season
• Prioritising sleep, relaxation, and recovery.

Lifestyle measures are not optional extras

Lifestyle factors play a critical role in immune regulation, particularly in conditions such as hay fever where the immune system is over-reactive rather than weak. One of the most overlooked influences on allergic responses is the body’s circadian rhythm, the internal 24-hour clock that coordinates immune activity, hormone release, and inflammatory signalling.

Allergic conditions, including allergic rhinitis (hay fever), display clear night-day patterns, with symptoms often worsening overnight or in the early morning.[vii] This is not coincidental. Immune cells involved in hay fever, including mast cells, are regulated by internal clock genes and show circadian variation in their activity and histamine release. Disruption of normal circadian rhythms has been shown to increase mast cell reactivity and impair immune regulation, contributing to more intense and persistent allergic symptoms.

Light exposure is a primary regulator of circadian rhythm. Regular exposure to natural daylight in the morning helps synchronise the immune system with the external environment, while excessive artificial light in the evening, particularly blue light from screens, can disrupt melatonin production and immune timing. Melatonin is not only a sleep hormone (as well as a powerful antioxidant), but it also plays an important role in modulating inflammation and immune balance.

Irregular sleep patterns, late nights, shift work, excessive evening screen use and inconsistent meal timing can all disturb circadian signalling, effectively removing another layer of immune ‘braking’ In contrast, support circadian alignment through consistent sleep-wake times, morning daylight exposure, reduced evening light, and regular meal patterns can help stabilise immune responses and reduce inflammatory load during allergy season.

In the context of hay fever, these lifestyle foundations work synergistically with nutritional strategies to support immune tolerance, mast cell stability and inflammatory control, rather than simply chasing symptoms once they appear.

A whole-body approach to hay fever

Hay fever is best understood as a systemic condition of immune dysregulation, rather than a simple nasal issue. Addressing nutritional foundations, supporting gut and adrenal health, and calming inflammatory pathways before pollen levels peak can help reduce symptom severity and reliance on medications.

By focusing on immune regulation, not immune stimulation, it is possible to support a calmer, more resilient response to seasonal allergens and enjoy the warmer months with greater comfort and clarity.

References

[i] Allergy UK (2023) Statistics and figures: Allergy UK: National Charity, Allergy UK/National Charity. Available at Statistics and Figures | Allergy UK | National Charity

[ii] Galli SJ, Tsai M. IgE and mast cells in allergic disease. Nat Med. 2012 May 4;18(5):693-704 

[iii] Jafarinia M, Sadat Hosseini M, Kasiri N, Fazel N, Fathi F, Ganjalikhani Hakemi M, Eskandari N. Quercetin with the potential effect on allergic diseases. Allergy Asthma Clin Immunol. 2020 May 14;16:36.

[iv] Fulgheri G, Malinowski B, Bergmann K. Association Between Vitamin D Deficiency and Allergic Diseases. EJIFCC. 2011 Jul 20;22(2):39-44. PMID: 27683389; PMCID: PMC4975286.

[v] Yang G, Liu ZQ, Yang PC. Treatment of allergic rhinitis with probiotics: an alternative approach. N Am J Med Sci. 2013 Aug;5(8):465-8.

[vi] Torii A, Torii S, Fujiwara S, Tanaka H, Inagaki N, Nagai H. Lactobacillus Acidophilus strain L-92 regulates the production of Th1 cytokine as well as Th2 cytokines. Allergol Int. 2007 Sep;56(3):293-301

[vii] Smolensky MH, Reinberg A, Labrecque G. Twenty-four hour pattern in symptom intensity of viral and allergic rhinitis: treatment implications. J Allergy Clin Immunol. 1995 May;95(5 Pt 2):1084-96.