An infant with phenylketonuria requires which of the following dietary alterations?

For an infant with phenylketonuria (PKU), the dietary management is crucial for preventing the adverse effects associated with this condition. PKU is a genetic disorder that results in the inability to metabolize phenylalanine, an amino acid found in many protein-containing foods.

The correct dietary alteration for an infant with PKU involves a low phenylalanine and high tyrosine diet. Since individuals with PKU cannot effectively process phenylalanine, it is important to limit its intake to prevent toxic accumulation in the body, which can lead to serious neurological issues. Tyrosine, on the other hand, is another amino acid that can be essential for individuals with PKU, particularly because the metabolism of phenylalanine can lead to a deficiency in tyrosine. Therefore, ensuring adequate intake of tyrosine while restricting phenylalanine is a key aspect of managing the diet of an infant with PKU, making this option the best choice.

This dietary alteration helps in fostering normal growth and development while mitigating the risks associated with the buildup of phenylalanine in the body.