system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are food allergies so common in kids but not common in adults over 30?
gpt
No one really knows for sure.  According to a study released in 2013 by the Centers for Disease Control and Prevention, food allergies among children increased approximately 50% between 1997 and 2011.

Also some allergies can be outgrown, like milk, eggs, and soy.  Meaning there would be more children with these allergies than adults.