Nutrient density and cost of commonly consumed foods: a South African perspective

Food-based dietary guidelines promote consumption of a variety of nutritious foods for optimal health and prevention of chronic disease. However, adherence to these guidelines is challenging because of high food costs. The present study aimed to determine the nutrient density of foods relative to cost in South Africa, with the aim to identify foods within food groups with the best nutritional value per cost. A checklist of 116 food items was developed to record the type, unit, brand and cost of foods. Food prices were obtained from the websites of three national supermarkets and the average cost per 100 g edible portion was used to calculate cost per 100 kcal (418 kJ) for each food item. Nutrient content of the food items was obtained from the South African Food Composition Tables. Nutrient density was calculated using the Nutrient Rich Food (NRF9.3) Index. Nutrient density relative to cost was calculated as NRF9.3/price per 100 kcal. Vegetables and fruits had the highest NRF9.3 score and cost per 100 kcal. Overall, pulses had the highest nutritional value per cost. Fortified maizemeal porridge and bread had the best nutritional value per cost within the starchy food group. Foods with the least nutritional value per cost were fats, oils, foods high in fat and sugar, and foods and drinks high in sugar. Analysis of nutrient density and cost of foods can be used to develop tools to guide low-income consumers to make healthier food choices by identifying foods with the best nutritional value per cost.