Final answer:
The nutrient that the nurse would advise the breastfeeding client with phenylketonuria to avoid in foods is phenylalanine.
Step-by-step explanation:
The nutrient that the nurse would advise the breastfeeding client with phenylketonuria to avoid in foods is phenylalanine.
Phenylalanine is an amino acid that is found in high concentrations in certain foods, including animal products, certain starches, and artificial sweeteners like aspartame. People with phenylketonuria have a deficiency of the enzyme phenylalanine hydroxylase, which is needed to break down phenylalanine. Consuming foods high in phenylalanine can lead to toxic levels of phenylalanine in the body, causing damage to the central nervous system and brain.