Eating for Brain Health: Exploring barriers and facilitators of diet adherence in a dementia-risk sample in South Africa

Steenkamp, Kirsten

Eating for Brain Health: Exploring barriers and facilitators of diet adherence in a dementia-risk sample in South Africa

Thesis / Dissertation

2026

Publisher

University of Cape Town

Department

Department of Psychiatry and Mental Health

Faculty

Faculty of Health Sciences

Abstract

Background: The prevalence of dementia is increasing in low-and-middle-income countries, including in South Africa. It is driven by population ageing, with contributions from several noncommunicable diseases and lifestyle factors, including diet. The influential 2024 Lancet Commission suggests that modifiable risk factors across the lifespan may account for almost half of dementia cases. These risk factors include mid-life hypertension, diabetes mellitus, and dyslipidaemia. A significant proportion of the burden caused by these risk factors may be mitigated by diet. In addition, there is evidence that a brain-healthy diet may be part of a care package that could improve dementia outcomes once confirmed. The role of a healthy diet in reducing dementia risk and progression could be an important modifiable intervention. In South Africa, low-income households experience pervasive structural and psychosocial barriers to healthy eating, which result in chronic food insecurity and low dietary diversity. Additionally, reported adherence to national eating guidelines is low. Socio-cultural studies have shown that perceptions of health strongly influence dietary behaviour. There are currently no behavioural interventions to improve diet adherence in dementia-risk South Africans. The development of contextually informed interventions to improve diet adherence may significantly help reduce the burden of dementia. This includes an in-depth understanding of socio-cultural perceptions of healthy eating, which could facilitate dietary behaviour change for improved brain health. Aims: To explore contextually relevant factors influencing adherence to the South African FoodBased Dietary Guidelines (SA-FBDG). Specifically, readiness to change, food insecurity, and barriers to healthy eating were examined. In addition, this study aimed to explore, using in-depth interviews, how barriers and facilitators to a healthy diet might be mitigated and strengthened, respectively. Methodology: A cross-sectional, mixed-methods approach was used to measure SA-FBDG diet adherence and potential variables that are associated with adherence. The study recruited 120 dementia-risk persons from two primary healthcare facilities in Khayelitsha, Cape Town. In line with current evidence, dementia-risk was defined as persons over the age of 60 who were diagnosed with a chronic condition of either/and diabetes, hypertension or high cholesterol. Hereafter, qualitative semi-structured interviews were conducted with 13 subsampled participants to explore dietary behaviour and eating-related perceptions. Key findings: 1. Adherence to the Elderly SA-FBDG was moderate. 2. Diet adherence was significantly positively correlated with dietary readiness to change and negatively correlated with barriers to healthy eating. Results showed that diet adherence was not significantly associated with food insecurity. However, in the qualitative subsample, financial deprivation was reported as a key barrier to healthy eating. Additional barriers to healthy eating included limited food literacy and poor health awareness. Facilitators to healthy eating included having your own food garden, positive self-talk, a supportive community, and responsibilities towards family. 3. The data suggested that diet adherence was dependent on the monthly Older Person's Grant. Diet adherence was higher in the period after grant payment and lower for the remainder of the month, which is consistent with a pattern of food insecurity linked to income. Conclusions: In addition to strengthening interdisciplinary research and promoting clinical nutrition, the research will advance efforts towards achieving the Sustainable Development Goals by reducing food insecurity and the burden of nutrition-related non-communicable diseases in South Africa. Potential intervention targets are recommended to inform the development of dementia-informed dietary interventions and align future research with Africa's 6x5 dementia plan.