like to have a Diet Coke. I know that aspartame is bad, but the other
day I noticed the words "Phenylketonurics: Contains Phenylalanine" on
the label. What is this? And why does Coke see fit to print it in the
old "saccharine" manner? This raises my suspicions.
no reason for most people to worry about phenylalanine. The warning
you've seen is aimed at people with phenylketonuria (PKU), an inherited
disorder in which the enzyme that converts the amino acid phenylalanine
into another amino acid, tyrosine, is defective. If undetected, PKU can
lead to severe mental retardation and developmental problems in
children. Fortunately, there's a screening test administered shortly
after birth that detects the 1 in 16,000 newborns with the condition.
phenylketonuric requires that you maintain a diet free of
phenylalanine. This isn't so hard during infancy as there's special
formula to replace regular formulas and mother's milk, both rich in
phenylalanine. The difficulty comes later because phenylalanine is a
natural component of most foods containing protein and can turn up
anywhere, even, as you noticed, in diet cola. Consequently, the only
regular foods people with PKU can eat safely are vegetables.
some controversy over when, if ever, people with PKU can stop being
mostly vegetarian and switch to a diet higher in protein. Some doctors
feel that by 10 or 12 years old, most children with PKU can safely
switch to a normal diet. I'm not one of them.
evidence suggests that some adults with PKU develop Alzheimer's-like
symptoms when they eat typical diets. Then, when they resume the low
protein regime, symptoms vanish and normal intellectual capacity
resumes. Because PKU can pass from mother to child and lead to
irreversible brain damage as early as the first days after conception,
it's vital for women with the disorder to keep a very low protein diet
whenever there's a chance of becoming pregnant.
a long answer to your question, and probably one you didn't expect. The
short answer is that phenylalanine in diet soft drinks won't hurt you,
but the aspartame (NutraSweet) may be a different story.