Giving young babies tiny tastes of smooth peanut butter between four and six months of age could dramatically reduce peanut allergies by up to 77%, according to new research. The study, published in the Journal of Allergy and Clinical Immunology, suggests that the weaning period offers a crucial window to prevent around 10,000 of the 13,000 annual peanut allergy cases in the UK.
Researchers from the University of Southampton, King's College London, and the National Institute for Health and Care Research analysed the optimal timing for introducing peanut-based foods. They found that starting between four and six months yields the greatest benefit, while delaying until one year old cuts allergy cases by only 33%. For babies with eczema—a known risk factor—the investigators recommend starting at four months, provided the infant is developmentally ready.
Current NHS guidance advises that peanut (crushed, ground, or as butter) can be introduced from around six months, but the government's official weaning advice recommends no solids until around six months. Experts argue this needs updating to reflect the new evidence. Parents are advised to start with small amounts of fruit or vegetables, then introduce around three heaped teaspoons of smooth peanut butter per week, mixed with breastmilk if needed, and maintain this for years.
Peanut allergy affects an estimated one in 50 children in the UK, with rates rising. The condition occurs when the immune system mistakenly treats peanut as a threat, leading to potentially life-threatening reactions. Historically, families were advised to avoid peanut until age three, but evidence over the past 15 years has reversed this thinking. Early exposure helps the immune system learn to recognise peanut as food, especially when first encountered in the gut rather than on the skin.
Professor Graham Roberts from the University of Southampton emphasised that decades of avoidance advice had caused parental fear and confusion. He described the approach as a "simple, low-cost, safe intervention" that could deliver vast benefits for future generations. Experts caution that whole or chopped nuts and peanuts remain a choking risk for children under five and should not be given.
