PKU vs. Aspartame

The Dangers of this Artificial Sweetener for PKUers

Since the 1960s, diet sodas have been allowing people to drink their favorite carbonated, caffeinated beverage without feeling bad about their calorie intake. Instead of using actual sugar—sucrose—diet sodas use some form of sugar substitute, known as an artificial sweetener, to sweeten the drink without adding any (or many) calories. One of the more common of these artificial sweeteners is aspartame.

Aspartame is 200 times sweeter than sugar, and so a much smaller amount is needed to provide the same level of sweetness. Its use in various products has been approved by the FDA, and it’s used in, in addition to diet sodas, chewing gum, sugarless candies, some children’s cold and flu medication, light ice creams, sugar-free puddings and gelatins, and the tabletop sweetener Equal. Aspartame is considered safe for consumption by all individuals…well, almost all individuals.

Aspartame is made from two amino acids: aspartic acid and phenylalanine (Phe). When ingested, aspartame is broken down into these two components. If you remember from the last newsletter (You can read it here!), individuals with phenylketonuria (PKU) can’t break down Phe, and they must remain on a low-Phe diet for life to prevent negative health effects.

Fruits and vegetables, most of which are naturally low in Phe, make up a large part of a PKUer’s diet.

Because they can’t consume Phe, PKUers can’t consume products with aspartame. And because of the health risk if they would consume these products, the FDA requires that products, including diet sodas, containing aspartame have a statement on the label warning individuals of the presence of Phe.

But not all diet sodas contain aspartame. In recent years, largely prompted by the claims of negative health effects linked to aspartame consumption, manufacturers have begun using other sweeteners to flavor their diet sodas. Splenda (sucralose) is used in Diet Coke with Splenda and Diet Pepsi (they changed their recipe in 2020), while Coca-Cola Life contains a blend of cane sugar and stevia, both natural sweeteners. Zevia also uses stevia leaf, while Hansen’s diet sodas are sweetened using sucralose and another artificial sweetener called acesulfame potassium (ace-K).

So PKUers finally have some options when it comes to calorie-free carbonated, caffeinated beverages, which is really important for individuals who don’t have a lot of options when it comes to their diet. However, it’s still important for them to check the label to ensure what they’re drinking is safe, just as it is for anyone that requires diet modifications.

Are you a fan of diet sodas? Have you tried any of the diet sodas that use a sweetener other than aspartame? Let me know in the comments below!