If you read the labels on your foods… and you’re a diet soda drinker (like I am), you may have noticed a little warning: PHENYLKETONURICS: CONTAINS PHENYLALANINE. I always figured it was some sort of food allergy, mainly because the warning comes in the same place I usually see warnings about wheat, milk, egg, soy, and tree nut warnings.
Phenylketonuria (also called PKU) is an inherited disorder where a person can’t process one of the amino acids found in many foods: phenylalanine or “phe”. Because the body can’t process phe, it builds up in the body. In infants and children, too much phenylalanine in the brain can cause developmental delays. In teens and adults, too much phenylalanine can cause mood swings, depression, slow reaction time, and low IQ.
Symptoms of PKU in infants and children can include:
- Extreme crankiness or fussiness
- Inability to focus
- Anxiety
Symptoms of PKU in teens and adults can include:
- Low IQ
- Crankiness/irritability/mood swings
- A feeling of fogginess when thinking
- Slower reaction and response times
- Depression and anxiety
In a normal digestive system, the body uses a particular enzyme to break down phenylalanine and use it to make another amino acid (tyrosine). In people with PKU, the enzyme doesn’t break phenylalanine down, so the amino acid builds up in the body and brain. Some phe is essential for growth and development, but too much can cause damage to the brain noted above.
Managing phe levels is critical in infants and children with phenylketonuria. The brain is most likely to be damaged by high phenylalanine levels at a young age. Even as a teen or adult, PKU can cause problems if phe levels are not kept as low as possible.
Right now there is no cure for PKU. It can be managed with a low-phenylalanine diet and/or medication.
What foods contain phenylalanine? Lots of them. Phe is a building block for many proteins, including meats and dairy products. Vegetables, fruits, and some grains tend to have much lower phenylalanine levels. If you have PKU, a dietician can help you figure out a safe, low-phe diet. Online support groups may also be able to offer tips — but should not replace a medical professional’s advice.
For more information, visit PKU.com or PKUnews.org.