A nurse is teaching the parent of a toddler who has phenylketonuria about meal planning. Which of the following information should the nurse include in the teaching?

The correct answer is B: Avoid foods containing milk products. Toddlers with phenylketonuria lack the enzyme needed to break down phenylalanine, which is found in high-protein foods like milk products. Avoiding milk products helps prevent buildup of phenylalanine, which can be harmful. Aspartame (choice A) contains phenylalanine and should be avoided. Increasing protein consumption (choice C) would exacerbate the issue. Limiting foods high in iron (choice D) is not directly related to managing phenylketonuria.