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By Chimnonso Onyekwelu with Melissa Smith
The topline
- Allergies are rising rapidly, with around one in three people now living with an allergic condition in many Western countries.
- The causes go far beyond genetics, with growing evidence linking allergies to changes in diet, gut health, environmental exposures and our relationship with the microbial world.
- Managing symptoms isn’t enough — understanding and addressing the root causes is essential if we want to reverse the allergy epidemic rather than simply live with it.
How many people do you know who live with at least one allergy? If it feels like the answer is “almost everyone,” you’re not imagining it. The real question is: why have allergies become so common?
For many people, allergies have become part of everyday life.
Spring brings streaming eyes and relentless sneezing.
A meal out can require careful scrutiny of every ingredient.
Parents carry adrenaline auto-injectors wherever they go, while millions rely on daily antihistamines or inhalers simply to get through the day.
What was once considered a relatively uncommon health problem has become one of the defining chronic health challenges of modern life.
Globally, allergic conditions such as asthma, eczema, hay fever and food allergies now affect an estimated 10-30% of the population, placing them among the four most common chronic diseases worldwide.
In the U.S., around 1 in 3 adults (31.8%) and 1 in 4 children (27.2%) report living with an allergic condition, affecting more than 100 million people with symptoms ranging from mildly irritating to potentially life-threatening.
The picture in the U.K. is equally striking. Around 1 in 3 people now lives with at least one allergic condition, giving the U.K. one of the highest allergy rates in both Europe and the world.
Far from being a seasonal inconvenience, allergies can disrupt sleep, restrict diets, limit social lives and require constant vigilance against triggers that may provoke severe asthma attacks or even anaphylaxis.
Yet despite this growing burden, much of modern healthcare remains focused on managing allergic reactions rather than asking a more fundamental question:
Why are allergies becoming so common in the first place?
Antihistamines, inhalers and immunotherapies undoubtedly improve quality of life and can be lifesaving, but they do little to explain why the immune system is increasingly reacting to substances it once ignored.
Meanwhile, the allergy industry continues to expand. The global food allergy market alone is projected to grow from $44.1 billion in 2025 to $73.2 billion by 2035, reflecting a healthcare model that is becoming ever more centred on long-term disease management.
Increasingly, research suggests the answers may lie not simply in pollen counts or genetics, but in the profound changes that have taken place in how we live, eat and interact with the microbial world around us.
When the immune system mistakes friend for foe
An allergy develops when the immune system mistakes a harmless substance — such as pollen, foods, dust mites or animal dander — for a dangerous threat.
Instead of peacefully tolerating these everyday exposures, the immune system launches a defence.
In sensitised individuals, exposure to an allergen stimulates the production of IgE antibodies, triggering the release of histamine and other inflammatory chemicals. The result may be hayfever, hives, eczema or asthma, while in severe cases it can lead to life-threatening anaphylaxis.
But this raises an important question.
Human genes have changed very little over the past few decades, yet allergies have increased dramatically.
Genetics alone cannot explain such a rapid rise.
Instead, a growing body of research (here and here) points toward changes in the environment and modern lifestyles. Air pollution has intensified. Antibiotic use has become widespread, particularly during early life.
Diets have shifted towards refined sugars, saturated fats and ultraprocessed foods. Early microbial exposure has changed, while disruption of the gut microbiome has become increasingly common.
Other theories suggest that greater pet ownership, alongside children’s reduced exposure to soil, dirt and diverse environmental microbes, may also influence how immune tolerance develops.
Although these factors may appear unrelated, they share a common thread.
Allergies are increasingly understood as disorders of immune tolerance — situations in which the immune system loses its ability to distinguish harmless substances from genuine threats.
The gut: The immune system’s training ground
Much of the immune system’s education happens somewhere many people rarely associate with allergies at all: the gut.
Around 70%-80% of the body’s immune cells reside within the gastrointestinal tract, where they are in constant conversation with food, microbes and countless environmental particles. It is here that the immune system learns one of its most important skills — recognising which substances should be tolerated and which require a defensive response.
This process, known as immune tolerance, is fundamental to healthy immune function.
When that educational environment becomes disrupted, the immune system may begin reacting to harmless exposures instead of ignoring them, creating the conditions in which allergic disease can develop.
Modern diets appear to be playing an increasingly central role in shaping this process. The modern Western diet — typically high in refined sugars, saturated fats and ultraprocessed foods but low in fiber-rich plant foods — has been shown to alter both the composition of the gut microbiome and the way the immune system communicates (research here and here).
Today, ultraprocessed foods account for almost half of total calorie intake in both the U.K. and the U.S. Many also contain additives, emulsifiers and artificial ingredients capable of disturbing microbial balance and promoting inflammatory responses.
Emerging evidence increasingly links these dietary changes with allergy risk.
A 2019 study from the COCOA birth cohort in South Korea followed more than 1,600 infants and found that mothers consuming diets high in baked and sugary processed foods during pregnancy were significantly more likely to have children who developed food allergies.
Early-life antibiotic exposure may further compound this by altering microbial communities during critical periods of immune development.
Encouragingly, the reverse also appears true.
Diets rich in whole foods and dietary fiber are consistently associated with healthier immune function and better long-term health. The Zutphen Study in the Netherlands, which followed 1,373 men for four decades, found a 9% reduction in total mortality for every additional 10 grams of daily fiber consumed.
Similarly, research in an Israeli population reported a 43% lower risk of death among individuals consuming at least 25 grams of fiber each day.
Taken together, these findings reinforce an important message.
The gut does far more than digest food.
It helps educate the immune system throughout life.
When that training ground is compromised, immune tolerance may begin to break down — and allergies can become one of the consequences.
Why controlling symptoms isn’t always enough
Modern allergy medicine has transformed the ability to control allergic reactions.
Antihistamines, corticosteroids, inhalers and emergency adrenaline have saved countless lives and continue to play an essential role, particularly during severe reactions.
But while these treatments suppress inflammation, they rarely restore the immune balance that gave rise to the allergy in the first place.
A 2026 study of people with T2-high asthma illustrates this challenge. Although inhaled corticosteroids significantly reduced inflammatory markers including IgE and eosinophils, long-term improvements in lung function were limited, suggesting that reducing inflammation on its own doesn’t necessarily resolve the underlying immune dysfunction.
Long-term medication use can also carry important considerations.
High-dose inhaled corticosteroids have been associated with suppression of growth-related hormones, metabolic changes and raised blood sugar levels, with one analysis reporting a 34% higher risk of developing diabetes among long-term high-dose users.
Antihistamines, while highly effective for symptom relief, may also affect daily functioning. In one clinical study, drowsiness occurred in 54% of patients taking chlorpheniramine and 39% taking levocetirizine, alongside measurable reductions in attention and psychomotor performance.
Even allergen avoidance, long considered the cornerstone of food allergy management, may not always be straightforward.
Emerging evidence suggests that complete avoidance can sometimes hinder the development of immune tolerance.
In a 2018 clinical study, 22 of 30 patients developed allergies to foods they had previously tolerated after following elimination diets. More than half (52%) experienced anaphylaxis, while 70% had begun avoiding those foods before symptoms had even appeared.
These findings do not diminish the importance of avoiding genuinely dangerous allergens where medically necessary. Rather, they highlight an important limitation of a purely symptom-focused approach.
Managing allergic reactions is not always the same as restoring healthy immune function.
Restoring the conditions for immune balance
Allergies are complex, and there is no single solution that applies equally to every individual. Food allergies, environmental allergies, reactions to medications and allergies to animals each involve different triggers and varying biological mechanisms.
Yet one consistent theme continues to emerge across the scientific literature.
The gut and the immune system sit at the centre of how allergic responses develop.
Supporting these interconnected systems may therefore offer one of the most constructive ways to encourage greater immune tolerance over time.
Simple lifestyle choices can make a meaningful difference:
- Choose whole foods more often. Prioritize fiber-rich foods while reducing ultraprocessed products, additives and excess sugar that may disrupt the gut microbiome and promote inflammation.
- Increase plant diversity. Vegetables, fruits, legumes, nuts and seeds nourish beneficial microbes while exposing the immune system to a broader range of natural compounds.
- Support your microbiome. Fermented foods and carefully selected probiotics may help strengthen microbial diversity and immune regulation.
- Stay well hydrated. Adequate hydration supports digestion, the gut lining and healthy immune function.
- Moderate alcohol and excess caffeine. Both can disturb gut balance and contribute to digestive stress.
- Manage stress. Chronic stress influences both gut function and immune regulation, increasing inflammatory reactivity.
- Prioritize restorative sleep. Healthy sleep helps regulate immune responses and may reduce allergic susceptibility.
- Move regularly. Moderate physical activity supports healthy immune turnover and helps regulate inflammation.
- Check key nutrients. Adequate levels of vitamin D, zinc and omega-3 fats all contribute to balanced immune function.
As our understanding of allergies continues to evolve, it is becoming increasingly clear that they cannot be viewed solely as isolated reactions to pollen, foods or pets. They are also reflections of the environments in which our immune systems develop and the lifestyles that shape them throughout life.
Modern medicine has become highly effective at treating allergic symptoms — and those treatments remain essential for many people. But reducing the growing burden of allergic disease is likely to require something more.
A healthier future for allergy care may depend not only on suppressing symptoms, but on restoring the biological conditions in which immune tolerance can flourish once again.
Originally published by Alliance for Natural Health International.
Chimnonso Onyekwelu serves as a legal researcher at Alliance for Natural Health International, where she does high-level policy analysis and interpretation of legal frameworks in the health and nutrition sector.
Melissa Smith is an outreach and communication officer at Alliance for Natural Health International.
