Food allergies in children have more than doubled in a generation: what's going on?

Food allergies in children are on the rise, according to data from NHS digital. “The numbers of babies and children with food allergies currently stands at between six and eight per cent, whereas only three per cent of adults have a food allergy,” explains Lucinda Miller, specialist in child nutrition and clinical lead of NatureDoc Clinic, a team of UK-wide Nutritional Therapists. “In a generation it has more than doubled.”

It turns out that well-meaning parents following the best-available medical advice might have contributed to the increase. Like many parents, I delayed giving my daughter foods containing nuts, thinking I needed to wait until she was at least a year old. But this is outdated advice.

Last week the American Academy of Pediatrics last week updated their guidelines to call for "purposeful feeding" of four to six-month-old babies who are at high-risk for developing food allergies, those who have a relative with an allergy, or who have severe eczema or an egg allergy.

Their recommendations are built on results of a major study completed in the UK by researchers at Guys and Thomas’s and King's College London. It found that of the parents who introduced peanuts (one of the most common allergens in the developed world) to their children at an early age, only 1.9 per cent of the children developed an allergy. Of those who waited until their child was five years old, 13.7 per cent of the kids developed an allergy.

“The findings showed that holding back on giving babies allergenic foods could in fact increase the risk of developing allergies,” Dr Adam Fox, a consultant paediatric allergist at Evelina London Children’s Hospital, and one of the UK’s leading food allergy expert, explains.

The American advice is slightly different to the official UK advice. In the UK the NHS’s advice, in line with World Health Organisation guidelines, recommends that children be exclusively breast fed until the age of six months and weaned onto food – alongside breast-milk – after that, with the introduction of allergenic foods such as peanut and egg not delayed.

Why we develop allergies

How you become allergic, is, Dr Adam Fox explains, complicated. Our knowledge of the origin of allergies in general is based on models of peanut allergies, with further research suggesting it is similar for other foods, such as egg and sesame. How an allergy starts is that a baby, typically with eczema, will come into contact with the nut protein first via the skin (perhaps an over enthusiastic peanut-butter-sandwich eating toddler kissing her brother or sister). The body creates antibodies to peanut and produces antibody-secreting plasma cells, or as Dr Fox explains, “the skin immune system makes a bad decision to become allergic; basically it gets the wrong signal.” Then, later, when the baby eats a peanut (or other allergen) for the first time, the body recognises it from the previous exposure and releases histamine – which causes the symptoms of an allergic reaction.  

If the baby has eczema, their risk is increased: one study found that children with mild eczema had a three times increased risk of food sensitization, and those with severe eczema had a six-time risk increase compared to children without the skin condition.

If the child is diagnosed with an allergy, they may yet outgrow them: milk and egg are usually outgrown in early childhood, around 20 per cent will outgrow a peanut allergy, usually by the age of 11, while tree, nut, fish or shellfish allergies are more often allergies for life.

How to prevent allergies

If, however, your child’s gut experiences a peanut before their skin does, then “it’s immune system tends to make a good decision.” Dr Fox says. He says that even children with bad eczema can swerve a nut allergy if they get “early exposure by mouth”.

The good news for mothers who are used to being told that everything is essentially their fault, Dr Fox says, “what’s clear in the data is that what mothers eat during pregnancy or while they’re breastfeeding doesn’t impact on allergies.”

It’s not, however, something that is communicated particularly well to new parents. Miller agrees: “many of the weaning books and online advice is not always up to date,” she says. Nor, I found, was any advice particularly forthcoming from GPs or community midwives: while I’ve now found my own resources (specifically this one), no one that I saw routinely actively advised me on weaning and introducing nuts into my baby’s diet.

“This is where we need to get the information out to as many mothers to be as possible,” Miller says. “This is not easy, as nuts are often unwelcome in children’s environments such as nurseries, because of the serious effect they can have on children with genuine allergies.”

So how do you introduce potential allergens to your baby’s diet? “When embarking on weaning it is still very important to introduce every new food one at a time and to feed your baby that food at least twice before you can be sure that the food has not been tagged by their immune system as an allergen,” Miller advises.

The upshot is that it’s not as scary as it might at first seem, but that parents do have to take an active role in helping to prevent allergies. Like the parenting journey in general it requires a leap into the unknown, pushing boundaries and careful monitoring at first – and then hopefully a smooth ride from there.

Allergies and weaning in a snap shot

• Introduce potential allergenic foods around the time the baby starts eating whole foods, at the age of six months. Make sure they are crushes to avoid choking hazards
• Give the baby new foods one at a time, and at least twice
• If your baby has an allergic reaction, call 999
• Only give infant-safe foods, for example unsalted or sweetened nut butters. Try the baby-friendly brand Nuttery Buttery