Why Your Gum Says "Contains Phenylalanine"

For years, I've cultivated an addiction to Trident White, an addiction that has slightly freshened my breath and had no apparent effect on the whiteness of my teeth.

When discarding an old package of the good stuff, I'd always see the following warning under the ingredients:

 Phenylketonurics: Contains Phenylalanine.

What did any of that mean?

I considered making a Short about this topic but felt that, tonally, it was a bit too serious to be sandwiched in between algorithmically churned videos about Kendrick Lamar and NYC apartment rent. So I thought I'd write about it, because it happened to move me. I will take one moment to note, however, that my pronunciation of "phenylalanine" became surprisingly good, so...please clap.

This paper proved to be my decoder ring. Undiscovered until the 1930s, phenylketonuria made it tough for some people to process phenylalanine (these are the only two vocab words you need to know). Phenylalanine is a pretty run of the mill amino acid available in lots of stuff, but if you have phenylketonuria, it can cause significant learning disabilities. Basically, your body can't handle too much of it. Though rare (anywhere from 1/50,000 to 1/6,000 depending on the population and how you count), it's serious.

In the 1950s, mother Mary Rooney became concerned with the development of her daughter, Sheila. Sheila became one of the first babies the hospital tested for phenylketonuria, and they found it. While Sheila was initially treated as more of a scientific curio than a patient, her mother Mary understandably sought a cure, or at least something to alleviate Sheila's symptoms.

The doctors labored to create a diet that was low in phenylalanine (it's harder than it sounds and forced them to remove it from other foods and select alternatives extremely carefully. There was some chemistry involved). By all reports, what they came up with tasted bad but had great results: Sheila started to improve mentally and physically.

This next part was tough to even read about - the doctors wanted to test whether this laborious phenylalanine-free diet even worked, so they started giving Sheila phenylalanine again to see if their work had made a difference. It had. She began to suffer.

Fortunately, they didn't keep that stage of testing going long. Sheila was put back on her restricted diet immediately. Sadly, Sheila had to eventually stop her diet for a bunch of reasons, and she never progressed mentally above a small child's development level.

But her sacrifice (and her mother's dogged pursuit of a treatment) wasn't in vain. Phenylketonuria testing for infants became mainstream (typically infants will get a heel pinprick to check for it) and alternative diets significantly advanced. Understanding of phenylketonuria — and the ways to treat it — increased.

Smash cut to the 1970s. An artificial sweetener — cyclamates, covered by a renowned grey-haired YouTuber here - was removed from the market. A new sweetener, aspartame, proved to be a viable option. But there was a catch. Aspartame was made from aspartic acid and...phenylalanine.

Already gun shy from the cyclamate controversy, the FDA wanted to make sure any new sweeteners were safe. So, they said in regulations that manufacturers would have to include a warning to phenylketonurics that anything with Aspartame contained phenylalanine, including diet sodas, sweeteners, and, eventually, Trident white gum.

I know that every time I throw away a package of gum now, I'll think about the good fortune I have to dismiss that warning on the back, as well as the gratitude I have that the warning exists for those who need it. And, maybe, on my more pensive days, I'll also think about the people like Sheila and Mary Rooney who got us there.