The 2011 Fukushima nuclear disaster placed health professionals and the public in the centre of an ‘infodemic’. We introduced health literacy training for health professionals to improve communication skills when facing a health crisis. By 2019, one in four public health nurses – our gatekeepers of community health – had been trained in Fukushima. Follow-up evaluations showed that the trained nurses applied their newly learned skills in practice, with more positive attitudes toward – and increased confidence in – their interactions with community residents. We also found that older residents and those unfamiliar with health services were more likely to notice improvements in written health information from the trained health workers. Health literacy training enhances communication between professionals and the public and makes health information more equitably accessible. This training has been incorporated into medical and nursing education, and also into primary school education, with participatory health-related activities for children in Fukushima and beyond. Our health literacy initiative covers the two arcs of health literacy: health professionals’ ability to communicate health information and people’s (including children’s) ability to use the information.