ASSESSING METHODS TO ESTIMATE THE COST OF ADHERENCE TO A DIETARY APPROACHES TO STOP HYPERTENSION (DASH) DIET PATTERN FOR LOW-INCOME ADULTS IN SOUTH AFRICA

Access to affordable health-promoting food is critical for the management and prevention of cardiovascular disease. However, health-promoting diet patterns often cost more than widely accessible ultra-processed foods.This study aimed to estimate food expenditure, relate it to the Dietary Approaches to Stop Hypertension (DASH) index, and identify associations with sociodemographic factors that would promote healthful eating in Langa, a low-income township in Western Cape, South Africa. Our approach uses prices derived from nationally representative food purchase data from South Africa and links those prices to dietary intake data.First, we assessed three new pricing methods using barcode-level data to reflect the diverse range of products available in the South African food system. We then described food group and nutrient consumption in this population and investigated the sociodemographic associations with DASH accordance. Finally, we estimated food expenditures by applying prices derived earlier to determine spending on food and beverages consumed in this context. We assessed the relationship between total expenditure and diet quality and pursued positive deviance approaches to estimate the cost of accordance to the DASH pattern in this resource-constrained environment. We found that average-based methods that are less resource-intensive perform as well as methods meant to align with purchase behaviors among those with low income. Fruit, vegetable, nut, legume, and dairy consumption was low in Langa and confirms apparent disparities in diet quality. Reading labels for sugar content and higher diet diversity were associated with higher DASH scores, while sedentary behaviors (such as TV watching) were associated with lower scores. We found that expenditure was highest for the lowest DASH accordance tertile group. There were no differences by tertile group when adjusting for grams of food, but when further estimating expenditure per 2000kcal we found that higher quality diets tend to be more expensive. We found a small, yet statistically significant association weakly supporting our hypothesis that increasing the amount of money people spend on food would improve diet quality.These findings represent a better approximation of resources needed to secure a DASH diet in this resource-constrained environment which can inform possible cash transfer and nutrition education programs.