<img height="1" width="1" alt="" style="display:none" src="https://www.facebook.com/tr?id=1573404252890905&amp;ev=PixelInitialized">

Phenylalanine in diet soda: Is it harmful?

Answer Section

Phenylalanine is an amino acid, a building block of protein. Most people don't need to worry about it. But it is an issue for people who have a genetic condition called phenylketonuria (PKU). Genetic conditions are passed through families.

In people with PKU, phenylalanine can cause intellectual disability, brain damage, seizures, and skin and other problems. Intellectual disability is slow learning and skill building.

Phenylalanine is in many protein-rich foods, such as milk, eggs and meat. Phenylalanine also is sold as a dietary supplement.

The artificial sweetener aspartame (Equal, NutraSweet) has phenylalanine. Aspartame is added to many medicines, diet foods and diet sodas.

In the United States, any product that has aspartame must carry a warning about the phenylalanine. This warning helps people with PKU avoid those products.

People who don't have phenylketonuria most likely don't need to worry about phenylalanine.

Use products with aspartame with care if you:

  • Take certain medicines. These include monoamine oxidase inhibitors, neuroleptics and medicines that contain levodopa (Sinemet, Rytary, others).
  • Have the muscle movement condition called tardive dyskinesia.
  • Have trouble sleeping, anxiety or another mental health condition. Phenylalanine might make you more anxious, sad or jittery.

If you aren't sure whether to worry about phenylalanine or aspartame, talk to a member of your health care team. A blood test can show if you have phenylketonuria. A blood test also screens newborns for the condition.

Last Updated: May 24th, 2023


© 2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of Use

2018JMHLogoWhite

Great Care Starts Here

Johnson Memorial Health is a nationally recognized network of physicians and advanced practice providers that provides healthcare to Johnson County and surrounding areas.

FIND A PROVIDER
Page-Mayo