Phenylalanine in diet soda: Is it harmful?


Phenylalanine is an essential amino acid, which means you need it in your diet. Amino acids are the building blocks of protein. Phenylalanine is especially important to young, growing children. Adults need less phenylalanine in their diet.

Phenylalanine is found in protein-rich foods, such as milk, cheese, nuts, seeds, poultry, fish, as well as some leafy vegetables and whole grains. It's also found in diet foods, such as diet soda, that contain aspartame.

Phenylalanine is safe to eat or drink unless you have phenylketonuria (PKU), a rare birth defect in which an enzyme needed to process phenylalanine is missing. PKU is usually diagnosed in infancy.

For infants and children with this disorder, consuming phenylalanine is dangerous. Adults with this disorder should consult their doctors regarding whether phenylalanine is a concern. If you do not have PKU, phenylalanine in foods is not a concern.