Causes of Food Allergy
The causes of food allergy are related to the immune system mistakenly identifying certain food proteins as threats. Food allergy can develop at any age, but it most commonly begins in infancy or early childhood. The reasons why some people develop food allergies while others don’t are not fully understood, but a combination of genetics, environment, and immune system development play key roles.
Immune System Reaction
The immune system produces IgE antibodies in response to a food protein
On subsequent exposure, these antibodies trigger the release of histamine and other chemicals, leading to allergic symptoms
This reaction happens quickly—within seconds to minutes of eating the allergen
Genetic and Family Factors
Food allergies often run in families
If one parent has an allergy, the child has an increased risk; if both do, the risk is even higher
Children with eczema, hay fever, or asthma are more likely to develop food allergies
Early Life Exposure
Delayed introduction of allergenic foods in infants was once common but may increase risk
Recent guidelines recommend early, gradual introduction (e.g., of peanut butter) under medical guidance in high-risk infants
Breastfeeding and gut health may influence immune tolerance, although the evidence is still evolving
Environmental Factors
Western lifestyles may contribute to rising allergy rates due to reduced exposure to microbes
The “hygiene hypothesis” suggests a lack of exposure to everyday germs may skew the immune system towards allergic responses
Pollution and changes in the food supply may also influence sensitisation
Other Risk Factors
Severe eczema in infants is a strong predictor of future food allergies
Existing allergies (e.g., to dust mites or pollen) may increase sensitivity to certain plant-based foods due to cross-reactivity
Some children with milk or egg allergies are more likely to develop multiple food allergies over time
Causes of Food Allergy
Understanding the causes of food allergy helps guide prevention efforts, early diagnosis, and research into better treatments. While some risk factors can’t be changed, others—like early food exposure and dietary diversity—are now being studied for their protective potential.
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