The number of food allergies in the UK is increasing, with hospital admissions for allergic reactions and anaphylactic shock in England having risen by a third in the past five years. Latest estimates indicate around 1 to 2% of UK adults and 5 to 8% of children (roughly 2 children per classroom) living with a diagnosed food allergy. While the reason is not known, there are a number of theories that may explain the rise.
The lack of early childhood exposure to certain micro-organisms in the natural environment results in a less diverse microbiome (the population of microbes that live on and in our bodies) and a weaker immune system, which makes us more susceptible to allergies. Modern lifestyles mean we live large amounts of time indoors in clean environments, including home, school and work and less time outdoors, so our exposure to a diverse range of good and bad bugs is lower.
Delaying the introduction of allergenic foods for the first years of life may actually increase the risk of allergy rather than reduce it, as was previously thought. Those who started eating peanuts before they were 1 year old were less likely to have an allergy by age 5 than those who avoided peanuts.
The NHS currently advises introducing cow's milk, eggs, fish, shellfish, wheat, nuts (not whole) and seeds before the age of one, adding them in small amounts to babies diets one at a time after the age of six months.
There is also a strong link between childhood eczema and food allergy risk. The earlier the onset and more severe the symptoms, the more likely a child is to develop a food allergy. It is thought that sensitization to food can occur through the skin, and having dry skin may increase the risk. To reduce the risk it is recommended to apply emollients to protect the skin's barrier.
Another theory links food allergy to reduced exposure to sunlight, an important source of vitamin D. Babies with vitamin D deficiency are three times more likely to have an egg allergy and eleven times more likely to have a peanut allergy.
Source: feature in Good Housekeeping, March 2019
