Food allergies are immune-mediated adverse reactions to specific foods that can range from mild symptoms to life-threatening anaphylaxis. Over recent decades, the prevalence of food allergies has increased globally, particularly among children, making it a significant public health concern (Turner et al., 2015). Unlike food intolerances, which involve non-immune mechanisms, food allergies are characterised by abnormal immune responses to normally harmless food proteins. This article explores the biological basis, common allergens, diagnostic methods, management strategies, and broader psychosocial implications of food allergies, drawing on textbooks, peer-reviewed research, and reputable health organisations.
1.0 The Immunological Basis of Food Allergies
Food allergies are typically classified as IgE-mediated hypersensitivity reactions, although non-IgE-mediated and mixed forms also exist (Kumar, Abbas and Aster, 2020). In IgE-mediated allergies, the immune system mistakenly identifies a food protein as harmful and produces immunoglobulin E (IgE) antibodies.
Upon re-exposure to the allergen, IgE antibodies bind to mast cells and basophils, triggering the release of histamine and other inflammatory mediators. This cascade results in symptoms such as:
- Urticaria (hives)
- Angioedema
- Gastrointestinal distress
- Respiratory difficulty
- Anaphylaxis
Anaphylaxis is a severe, systemic reaction that can involve airway obstruction, hypotension, and cardiovascular collapse. Immediate treatment with intramuscular adrenaline (epinephrine) is essential (NICE, 2011).
2.0 Common Food Allergens
Although many foods can cause allergic reactions, a limited number account for the majority of cases. In the United Kingdom and European Union, the primary allergens include:
- Peanuts
- Tree nuts
- Milk
- Eggs
- Wheat
- Soy
- Fish
- Shellfish
- Sesame
These are commonly referred to as the “major allergens” and are subject to mandatory labelling regulations (Food Standards Agency, 2023).
For example, peanut allergy is one of the most common and potentially severe allergies, often persisting into adulthood. In contrast, milk and egg allergies are more common in children and frequently resolve with age (Turner et al., 2015).
3.0 Prevalence and Epidemiology
Recent epidemiological studies estimate that food allergies affect approximately 6–8% of children and up to 3–4% of adults in Western countries (Turner et al., 2015). The reasons for rising prevalence are multifactorial and may include:
- Changes in diet
- Reduced microbial exposure (the hygiene hypothesis)
- Altered gut microbiota
- Genetic susceptibility
The hygiene hypothesis proposes that reduced exposure to infectious agents in early life may impair immune system development, increasing the risk of allergic disease (Kumar, Abbas and Aster, 2020).
4.0 Diagnosis of Food Allergies
Accurate diagnosis is crucial to avoid unnecessary dietary restrictions or life-threatening exposures. Diagnosis typically involves:
- Clinical history
- Skin prick testing (SPT)
- Serum-specific IgE testing
- Oral food challenge (gold standard)
According to NICE (2011), oral food challenges conducted under medical supervision remain the most reliable method for confirming diagnosis. However, they carry risk and must be carefully managed.
It is important to note that positive IgE tests alone do not confirm clinical allergy; correlation with symptoms is essential.
5.0 Management and Treatment
5.1 Allergen Avoidance
The primary management strategy remains strict avoidance of the offending allergen. This requires careful label reading and awareness of cross-contamination risks.
For example, individuals with severe nut allergies must avoid products labelled “may contain nuts”.
5.2 Emergency Preparedness
Patients at risk of anaphylaxis are prescribed adrenaline auto-injectors (e.g., EpiPen). Education on early symptom recognition and prompt administration is critical (NICE, 2011).
Schools and workplaces increasingly implement allergy management policies to protect individuals.
5.3 Oral Immunotherapy (OIT)
Emerging treatments such as oral immunotherapy aim to desensitise patients through gradual exposure to small amounts of the allergen. Studies suggest OIT can increase tolerance thresholds, particularly in peanut allergy (Nurmatov et al., 2017).
However, OIT carries risk of adverse reactions and is not universally effective.
5.4 Early Introduction and Prevention
Recent research challenges older recommendations of delayed allergen introduction. The LEAP (Learning Early About Peanut Allergy) trial demonstrated that early introduction of peanuts in high-risk infants significantly reduced peanut allergy development (Du Toit et al., 2015).
Consequently, UK guidelines now encourage early introduction of allergenic foods under appropriate supervision (NHS, 2023).
Psychological and Social Impact
Food allergies extend beyond physical symptoms and significantly affect quality of life. Anxiety related to accidental exposure, social isolation during shared meals, and fear of severe reactions are common (Turner et al., 2015).
Children with food allergies may experience bullying or exclusion, highlighting the need for inclusive policies and education.
From a health psychology perspective, chronic vigilance may increase stress levels, necessitating psychological support where appropriate (Taylor, 2021).
Food Labelling and Public Health Policy
Clear food labelling is central to allergy prevention. In the UK, “Natasha’s Law” (2021) mandates full ingredient labelling on pre-packaged foods prepared on site, following the tragic death of Natasha Ednan-Laperouse due to undeclared sesame.
The Food Standards Agency (2023) provides guidance to ensure consumer safety and transparency.
Public awareness campaigns and improved healthcare training also contribute to reducing morbidity and mortality associated with food allergies.
Distinguishing Myths from Evidence
It is important to distinguish between scientifically validated allergies and self-diagnosed sensitivities. Misinterpretation can lead to unnecessary dietary restriction and nutritional imbalance.
Professional assessment ensures evidence-based management and prevents confusion between allergy and intolerance.
Food allergies represent complex immune-mediated conditions with potentially severe consequences. Advances in immunology, epidemiology, and clinical practice have improved understanding, diagnosis, and management. While strict allergen avoidance remains central, innovations such as oral immunotherapy and early introduction strategies offer promising developments.
Beyond physiological mechanisms, food allergies influence psychological wellbeing and social participation, underscoring the need for comprehensive care. Continued research, public education, and policy enforcement remain essential to address the growing global burden of allergic disease.
References
Du Toit, G. et al. (2015) ‘Randomized trial of peanut consumption in infants at risk for peanut allergy’, New England Journal of Medicine, 372(9), pp. 803–813.
Food Standards Agency (2023) Food allergen labelling and guidance. Available at: https://www.food.gov.uk.
Kumar, V., Abbas, A.K. and Aster, J.C. (2020) Robbins and Cotran pathologic basis of disease. 10th edn. Philadelphia: Elsevier.
NHS (2023) Food allergy overview. Available at: https://www.nhs.uk.
NICE (2011) Food allergy in children and young people: Diagnosis and assessment. London: National Institute for Health and Care Excellence.
Nurmatov, U. et al. (2017) ‘Allergen-specific oral immunotherapy for peanut allergy’, The Lancet, 389(10066), pp. 1599–1609.
Taylor, S.E. (2021) Health psychology. 11th edn. New York: McGraw-Hill.
Turner, P.J. et al. (2015) ‘The epidemiology of food allergy’, Journal of Allergy and Clinical Immunology, 135(3), pp. 618–633.
