A decade after a landmark study proved that feeding peanut products to young babies could prevent development of life-threatening allergies, new research finds the change has made a big difference in the real world. About 60,000 children have avoided developing peanut allergies after guidance first issued in 2015 upended medical practice by recommending introducing the allergen to infants starting as early as 4 months. “That’s a remarkable thing, right?” said Dr. David Hill, an allergist and researcher at Children’s Hospital of Philadelphia, and author of a study published Monday in the medical journal Pediatrics.