These reading habits are understandable characteristics of giftedness; gifted children are cognitively more developed than is normally expected. However, gifted readers need guidance in book selection. A child reading at a college level is not necessarily ready for college material. Just because a ten year old can comprehend Anne Rice's writing does not mean that a ten year old is ready to meet the Vampire Lestat.
This, then, becomes the difficulty for parents. Children of all reading abilities tend to enjoy books about people slightly older than they are, so a ten year old will relate to and be interested in books about thirteen year olds more than books about twenty year olds. Finding books written at a high interest, high ability level requires time and work.
Doing an advanced book search at Amazon.com and highlighting the appropriate age range is one tool. Amazon also provides book reviews, and reading those reviews is an excellent start. The reviews are usually written by adults, but sometimes there are child reviews. If there are no child reviews, beware: this is not a book for children.
Sometimes gifted children need to hear, “We'll put this book up until your life experience catches up to your reading level.” When parents say that, they need to drive directly to the library or bookstore and find a book that is of the appropriate interest level. Stephanie Meyer's Twilight Series is more a more appropriate vampire series than Interview with a Vampire or Dracula.
Helping gifted children pick out appropriate reading materials helps keep them in common experience with their peers and helps preserve childhood a little longer, which are admirable goals in themselves.