Does early exposure to peanuts prevent allergy development?
Once, healthcare experts, especially those dealing with children at risk of allergies to foods like peanuts, advised keeping them away from these foods. But a recent long-term study has arrived at a different conclusion. Will the tolerance last a lifetime?
This long-term study overturns previous advice on handling allergies: Introducing peanut protein to children as early as their first year of life significantly reduces the risk of a peanut allergy - and this effect lasts at least through adolescence. Infants who have regular contact with the food since infancy have a lifelong risk of developing this allergy that's more than 70% lower than those who don't consume such products. This is reported by a research team from Britain and the United States in the medical journal "NEJM Evidence."
"The evidence is clear," says study leader Gideon Lack from King's College London. "Introducing peanuts into a child's diet early leads to long-term tolerance and protects them from an allergy until adolescence." This practice could potentially prevent over 100,000 cases of peanut allergy per year worldwide.
"This study confirms that eating peanut products regularly since infancy allows for the development of a stable tolerance," says Germany's Kirsten Beyer. In some countries like Germany, about 0.4% of children under two have a peanut allergy - significantly less than in the U.S., Australia, or Britain, where peanut products are more common. Symptoms can range from itching and hives to vomiting and breathing problems, all the way to a life-threatening reaction. The allergy usually starts in the first three years of life and typically lasts a lifetime.
For years, experts have advised parents, especially those with high-risk children, to avoid giving their children peanuts. "Decades of advice to prevent giving peanuts to children made parents fear giving them peanuts at a young age," says Lack. This avoidance, Lack suspects, might have even contributed to the increase in allergies. The same sentiment is shared by Beyer.
The study we're discussing is a long-term continuation of the LEAP study (Learning Early About Peanut Allergy), whose initial findings were published in 2015 and caused a worldwide sensation. It involved over 640 infants aged 4 to 11 months who had eczema or a strong allergy to egg white and were thus considered at higher risk. Those with a suspected peanut allergy were excluded.
Out of these infants, one-third were given peanut protein in the form of powder or paste at least twice a week from the age of four months, while the other two-thirds weren't. The researchers discovered that 17.3% of children who hadn't had contact with peanuts developed a peanut allergy, while only 3.2% who were given frequent peanut products had one. This translates to an 81% risk reduction.
"These findings were unparalleled and had the power to transform approaches to preventing food allergies," remarked allergologist Anthony Fauci, who was the Director of the US National Institute of Allergy and Infectious Diseases (NIAID) at the time. The agency had to re-evaluate its recommendations for dealing with a peanut allergy. The guidelines in Germany were also amended, adds Beyer.
The follow-up study, called LEAP-Trio, included approximately 500 other participants who were now six and older. They could eat peanuts at their discretion, regardless of whether they had abstained from peanuts during the initial phase or not. By the time they were thirteen, approximately 15% of the 250 children who had previously abstained from peanuts still had a peanut allergy. In the consumption group, this was only 4%.
The protective effect had somewhat diminished, but still amounted to 71%. The team explains this by the fact that nine children in the abstinence group later tolerated peanuts during the study. Only one child who had already had contact with peanut products developed an allergy after the age of six.
The protective effect remained constant, regardless of whether and how much peanut products the respective children consumed during the study period. This means that a tolerance acquired in early childhood still persists even if there's no consistent contact with a food later on. The study's lead author, George Du Toit, from King's College, adds, "It's a safe and highly effective measure that can be implemented at four months." The infant should be developmentally ready for weaning.
"While this is a landmark study in food allergies for the past ten years, it completely changed the way we look at things," says allergist Lars Lange from the allergological ambulance of the GFO clinics in Bonn. "It shook the world."
In Australia, the effects of the LEAP study led to an increase in hospital treatments for children who had aged swallowed or inhaled peanuts or other nuts in subsequent years. A research team from Melbourne reported this in the "Journal of Allergy and Clinical Immunology" in 2021.
"By no means should small children be given whole peanuts," cautions the Bonn allergist Lange. "Australia saw a rise in hospital treatments for children who accidentally inhaled peanuts in the years following the study."
Expert recommends parents with high-risk babies suffering from eczema to introduce peanut products into their weaning diet if their families regularly consume them. It's crucial to make this a regular practice, says Beyer, "If you only offer it occasionally, it's better to leave it out." This ensures that the child is exposed to peanuts consistently. Prior to introducing peanuts, a pediatrician should rule out peanut allergies through a blood test for antibodies.
The nutrition expert also suggests parents to give their children the same food they eat at home, regularly. This includes eggs. However, in contrast to peanut allergies, which are much less common in Germany, around 2% of children have egg allergies. In this case, Beyer advises against serving soft-boiled or scrambled eggs and recommends baking or frying them instead.
