Scientists have found that introducing babies to peanuts, eggs and other potentially allergy-causing foods at an early age could prevent serious reactions later in life.
The study for the Food Standards Agency (FSA) of UK found that children who were introduced to peanut and egg-white proteins from the age of three months had a lower chance of developing food allergies than those who were only introduced to them at six months old – but only if the recommended quantity of allergenic food was consumed.
Scientists found that weekly consumption of the equivalent of approximately one-and-a-half teaspoons of peanut butter and one small boiled egg would lead to the prevention of an allergy to those food substances.
The research compared those infants who were breastfed and consumed allergenic foods from three months with those solely breastfed and given foods at six months.
Dubbed Eat (Enquiring About Tolerance), the study – published in the New England Journal of Medicine – involved 1,303 three-month-old children from England and Wales who were randomly split into two groups.
Mothers of children in the first group were asked to comply with current guidelines, which recommend that mothers breastfeed their children for the first six months of their lives before introducing them to allergenic foods if they so choose.
After testing their children for existing allergies, mothers of children in the second group were asked, in addition to breastfeeding, to introduce their offspring to six types of allergenic foods – cooked eggs, milk, wheat, peanuts, fish and sesame – from the age of three months. Both groups were then tracked over the next three years to see if they developed any allergies to those foods between the ages of one and three years old.
When the scientists looked at those mothers who had stuck strictly to the early introduction regime, the relative risk of developing a food allergy was 67% lower than for children who had just been breastfed to six months.
More specifically, the results reveal that prevalence of egg allergies was far lower, with just 1.4% of those exposed to them from the age of three months developing an egg-allergy, compared with 5.5% of those who were breastfed to six months.
For peanuts the effect was even greater: none of the 310 children in the early introduction group developed a peanut allergy, versus 13 of the 525 children who developed an allergy having been introduced to them from the age of six months.
However, early introduction to such foods only helped to avoid allergies later in life if the children were exposed to a sufficient amount of the potentially allergy-causing food. The authors conclude that a mean weekly consumption of 2g of peanut or egg-white protein was associated with the prevention of these two respective food allergies.
“Our study was looking at the introduction of multiple allergenic foods to infants recruited from the general population,” explained Dr Michael Perkin, one of the study’s authors. “This is about what’s the best way of introducing allergenic foods to all infants, not just a very selected subgroup. And that is absolutely unique. No one has done anything remotely like this.”
The study – which was run by researchers from St George’s University of London, King’s College London and Guy’s and St Thomas’ NHS foundation trust – builds on the earlier findings of the team’s Learning Early About Peanut Allergy (Leap) trial, which involved a cohort of infants at high-risk of developing peanut allergies. In that study, the scientists discovered that exposing such children to peanut protein in their first 11 months reduced the chance of them developing a peanut allergy by the time they reached five years of age.
“Leap was formed of a very focused group of children who were at really high risk of allergic reaction and was limited to peanuts,” said Dr Andrew Clark, a children’s allergy specialist at Cambridge University hospitals.
“The improvements in this study are that it is on a much wider spectrum of the general population. And the exciting finding is that they did find that early introduction of allergenic foods works in that it seems to reduce the prevalence of food allergies, tested at three years.”
However, the study does have limitations, he added. “It didn’t show an effect in the majority of children that they studied – it seems to show an effect only in those people who were really engaged with the process of introducing the foods early,” said Clark. “What we need to look at now is ways of identifying people for whom the early introduction is going to work best.”
Guy Poppy, chief scientific adviser at the FSA, said: “The FSA has an important role to play in helping consumers manage food allergies and this includes expanding our knowledge about how allergies develop. This research is an important part of that work. These findings will add to the body of scientific evidence that helps us inform public health policies and guidelines on infant feeding.
“While this study will be of interest to parents, we would advise them to continue to follow existing government infant feeding advice. It should also be emphasised that this research was carried out under guidance of allergy professionals.”
