by Ashley Giddens RD/LD
Q: My soft drink label reads “contains phenylalanine” near the ingredient list. What exactly does that mean?
A: Phenylalanine, which may sound quite intimidating, is actually an amino acid that is an extremely important component of the diet for individuals with phenylketonuria, or PKU. Since the mid-1960’s, newborns became routinely screened for PKU, which is an inherited error of metabolism in which the body is deficient in or even missing the enzyme that converts phenylalanine to tyrosine (another amino acid). If those with PKU then have too much phenylalanine in the blood, they can experience irreversible damage can be neurological, behavioral, or affect the skin, personality or learning.
At this time, there is no cure, but a few drugs have been introduced for treatment. Those with PKU must regularly monitor their blood levels of phenylalanine and follow a phenylalanine-restricted diet. Since amino acids are what make up protein, high protein foods must be avoided with PKU. A team of medical professionals is necessary for individualized treatment of PKU, which must be life-long. With early management starting in the first days of life, one born with PKU can experience normal growth and development.
Aspartame, which is often used as a sweetener by itself or in foods and beverages like diet soft drinks, also contains phenylalanine. So, what you are reading on your soft drink label is actually an alert to those with PKU to avoid this product. Otherwise, this should not be cause for concern if you do not have any condition that may be affected by phenylalanine or aspartame.
For nutritional counseling, Norman Regional Health System offers the guidance of registered dietitians. Those interested can schedule an appointment for an assessment with a referral from their family physician.