Food Intolerances in Adults: Symptoms, Triggers, and Therapeutic Approaches

Food allergies in adults represent a major clinical challenge characterized by an aberrant immune reaction to nutritional components. Unlike non-allergic food intolerances caused by enzymatic deficits (such as lactase deficiency), true food allergies are immunologically mediated. High-molecular-weight proteins and glycoproteins act as antigens that stimulate allergen-specific IgE antibody synthesis. Cross-linking of IgE on mast cells and basophils triggers rapid degranulation, releasing vasoactive and inflammatory mediators including histamine, tryptase, and leukotrienes. Manifestations span from localized urticaria and angioedema to systemic, life-threatening anaphylactic shock.

Epidemiological data indicate that adult food allergy prevalence ranges between 3% and 10%, with a steadily rising incidence in developed nations. The most prevalent eliciting allergens in adults include tree nuts, peanuts, crustacean shellfish, mollusks, finfish, and cow's milk, along with raw fruits and vegetables (e.g., celery, apples, carrots) associated with pollen food allergy syndrome. Key predisposing factors include personal or familial atopy, prior sensitization, environmental pollutants, and barrier dysfunction of the gut mucosa.

Accurate clinical diagnosis requires a structured approach combining detailed medical anamnesis, skin prick testing, serum-specific IgE quantitation (e.g., ImmunoCAP), and, when indicated, supervised double-blind placebo-controlled food challenges. Comprehensive management centers on strict dietary allergen avoidance, tailored nutritional counseling, and mandatory prescription of intramuscular epinephrine auto-injectors for patients at risk of severe anaphylaxis.

The development of a food allergy stems from an aberrant response of the adaptive immune system. In sensitized individuals, B-lymphocytes synthesize allergen-specific IgE antibodies directed against benign dietary proteins. Upon re-exposure, the offending food antigen cross-links cell-bound IgE antibodies on mast cells and circulating basophils, triggering the explosive release of histamine, leukotrienes, and pro-inflammatory cytokines.

Genetic predisposition represents a cornerstone of etiology: individuals with a family history of atopic conditions, including atopic dermatitis, allergic asthma, or allergic rhinitis, face a markedly elevated susceptibility. In adults, the most common triggering foods encompass tree nuts, peanuts, seafood, fish, and cross-reactive allergens present in raw vegetables and fruits.