The relationship between diet/nutrition and the mental health of immigrants in Western societies through a holistic bio-psycho-socio-cultural lens: A scoping review

Epidemiological evidence suggests that diet and nutrition not only impact individuals' physical health but also shape their mental health (MH). The nutrition/diet-MH relationship may be critical among immigrants due to socioeconomic and sociocultural factors. Despite the complex nutrition/diet-MH relationship, most scholarship in this area employs a biomedical perspective. This scoping review of 63 studies deployed a holistic bio-psycho-socio-cultural framework to examine the relationship between diet/nutrition and immigrants' MH. Five automated databases (Embase, PubMed, Medline, PsycINFO and Anthropology Plus) were systematically searched for relevant articles from Western countries. A bio-psycho-socio-cultural conceptual model guided the analysis of the multi-faceted diet/nutrition-MH relationship. Consumption of fruit/vegetables, unsaturated fats, vitamin D-rich foods and whole grains was significantly positively related to MH. Reported pathways included enhanced self-esteem and ability to stay physically active. Energy-dense food consumption emanating from unhealthful dietary acculturation to the Western lifestyle was associated with poor MH through various mechanisms, including exhaustion and worry about developing non-communicable diseases. Food insecurity and related hunger were significantly positively associated with depression and anxiety among immigrants through different pathways, including family conflicts, homesickness, social exclusion, feelings of shame/stigma, and helplessness related to not affording nutritious foods that meet one's cultural dietary requirements. Ethnic food consumption appeared to mitigate MH issues and enhance immigrants' well-being. A bio-psycho-socio-cultural-informed model is needed to gain an in-depth and encompassing understanding of immigrant MH as it relates to diet/nutrition. The first iteration of such a model is presented in this review alongside an illustration of how it may be used to strengthen an analysis and understanding of the multi-faceted diet/nutrition-MH relationship amongst immigrants and inform public health professionals and dieticians/practitioners.