Article 24 of the UNCRC says that healthcare for children and young people should be as good as possible, and also goes further than this by saying children and young people have the right to be both physically and mentally fulfilled.

Among other things, this implies that children and young people:

• should have good enough nourishment from their food
• should be able to live in a safe and healthy environment
• shouldn’t be in danger at work.

Article 24 also says that children and young people have a right to information about their health. They should have a say in how they get this and be able to say what they like and dislike about the information they get.

https://www.unicef.org/child-rights-convention/convention-text-childrens-version