It might feel counterintuitive, but research suggests introducing common allergens early—like peanuts, eggs, and dairy—around 4–6 months may actually help prevent food allergies from developing, rather than cause them. Studies show babies who eat allergen-containing foods early are less likely to develop allergies to those foods later. The window of opportunity is in infancy, when your baby's immune system is still developing and learning what's safe to eat. You don't need to avoid these foods during pregnancy or breastfeeding either—exposure seems protective. Talk to your pediatrician about the right timing and approach for your baby's situation, especially if allergies run in your family or your baby has eczema.