Background Health care organisations have traditionally aimed for community health by offering treatment and prevention services. Increasingly health care and public health strategists invite us to look at health care organisations as not just care providers but as anchor institutions (i.e., large community-rooted organisations with significant impact on local economy, social fabric, and overall community wellbeing). In response, this study explored how health care organisations can effectively operate as anchor institutions and improve the social determinants of health of people living in their local communities.

Methods We conducted four case studies in secondary healthcare organisations in England including mental health and community services. The studied sites were diverse in terms of offered services, size, geography and anchor activity strategy and they were all based in socio-economically deprived areas. We collected our data through semi-structured interviews with staff members or external partners of the studied organisations who were actively engaged in the organisations’ anchor institution strategy. We synthesised the data using a realist approach which focuses on how things work in specific contexts. In line with realist methodology, we produced a set of explanations (programme theory) of how health care organisations can improve and promote the social determinants of health of local communities.

Results Our findings showed that a framework for effective anchor activity includes four building blocks: employment, spending, estates, and sustainability, held together by organisational ethos and local partnerships. Specifically, health care organisations – as anchor institutions- can improve the social determinants of health for their local communities through enabling accessible paths for local community recruitment and career progression; empowering local businesses to join supply chains boosting income and wealth; transforming organisational spaces into community assets; and supporting local innovation and technology to achieve their sustainability goals. These blocks need to be integrated across organisations on the basis of a population health approach promoted by supportive leadership, and in collaboration with a diverse range of local partners.

Conclusion Policy makers should support health care organisations to leverage employment, spending, estates, and sustainability to help address the unequal distribution of the social determinants of health.