Health literacy is also influenced and defined by culture. Zarcadoolas et al (2006) state that as a component of health literacy, cultural literacy (i.e. the ability to understand and use culture and social identity to interpret and act on information) is clearly needed by all stakeholders in order to improve health care and health outcomes. As the Institute of Medicine (2004, p 9) states, ‘culturally influenced perceptions, definitions and barriers can affect how people interact with the health care system and help determine the adequacy of health literacy skills in different settings’. Furthermore, the Institute claims that health literacy is not just shaped by cultural differences between patients and providers but also between those who create the health messages and those who use them. Socio-cultural factors are therefore important for public health campaigns, especially when vulnerable groups are being targeted.