There is a truism in health care: When you don't fully understand or can't act on information about your health care, you are more likely to be in poorer health.

Nearly all of us, about 9 of every 10 American adults, have some problems with health literacy.

Health literacy is not only about reading. It's about understanding difficult health terms and issues. Even highly educated people can have trouble understanding health care information. For example, learn more.