Is the association between food insecurity and depression mediated by diet?

Background. Food insecurity is associated with depression. Food insecurity involves distinctive patterns of dietary intake, and recent evidence suggests that dietary intake affects mood. Thus, an important pathway from food insecurity to depression may be via dietary changes. Methods. We studied two observational datasets (one from the UK, and NHANES 2017-8 from the USA) with measurements of food insecurity and affective state, plus dietary data from 24-hr food recalls. We examined variables concerning dietary composition and intake timing, as well as affective state, by food-insecurity status. Results. In both datasets, people experiencing food insecurity had significantly worse affective states. They showed dietary differences, notably more meal skipping, less regular timing of the first meal, and lower dietary diversity. A set of dietary variables (meal irregularity, night eating, dietary diversity, fruit and vegetable intake, and protein intake) partially mediated the association between food insecurity and affective state, accounting for 23% and 6% of the total association. Discussion. Dietary intake represents one pathway via which food insecurity can negatively affect mental health. Our findings suggest that while dietary intake plays a role in the association between food insecurity and poorer mood outcomes, it does not predominate.