Health literacy refers to a set of abilities that allow people to read and evaluate information, fill out forms, understand and follow directions, navigate health care facilities, communicate with health professionals, and use information to make decisions about their health. Low health literacy has been linked with poor health outcomes [8]. Ratzan and Parker describe health literacy as “the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions” [7]. The Canadian Expert Panel on Health Literacy defines it as “the ability to access, understand, evaluate and communicate information as a way to promote, maintain and improve health in a variety of settings across the life-course.” The panel recognizes the role of education, culture, language, the communication skills of professionals, the nature of the materials and messages, and the settings in which education is provided as important factors in the uptake of health information [9].

In the USA it has been estimated that nearly 50 % of the adult population, or 90 million people, have trouble reading and understanding health information [10]. Six out of ten Canadians do not have the skills to obtain, understand, and act upon health information and services, or to make appropriate health decisions on their own [11]. Canada’s Expert Panel on Health Literacy estimated that more than half of working-age adults in Canada (55 % or 11.7 million) have inadequate health literacy skills and seven out of eight adults over the age of 65 (88 % or 3.1 million) are in the same situation [12]. In 2011, the European Health literacy survey reported that among the eight participating European countries, nearly one of two individuals had inadequate or low health literacy [13]. Those most vulnerable are the elderly, minority groups, immigrants whose first language is not the language of the majority, the less educated, and the poor [7].

Health care professionals tend to underestimate the prevalence of low health literacy because it is not possible to identify this patient population by appearance. Most people with low literacy skills are of average intelligence and able to compensate for their lack of reading ability. People with low functional health literacy may have feelings of shame and inadequacy, so may not admit their lack of understanding or ask for help [14]. While it is not possible to predict low health literacy from a person’s behavior, certain clues may point to it. Patients may fill out forms incompletely or inappropriately. They may be unable to name their medications or the indications for taking them. They may bring someone with them to do the reading or they may avoid having to read in front of others by saying, “I forgot my glasses” or “I’ll read this later” [10]. Although low levels of literacy predispose people to low health literacy, people who are good readers may also have low health literacy skills. In the context of health care, they may not be able to translate medical jargon and terminology into standard English that makes sense to them [15].

Communication between health care providers and patients can be improved. Weiss suggests that clinicians slow down, use plain, nonmedical language, show or draw pictures, limit the amount of information, use the teach-back or show-me technique, and create a shame-free environment [6]. Other strategies include prioritizing clear communication within one’s organization and using a “universal precautions” approach to communication.