Dietary intake of the African-PREDICT study population

Abstract

Background: Ethnicity and socioeconomic status (SES) contribute to the dietary intake of individuals, which, in turn, plays an important role in the development of non-communicable diseases (NCDs). South Africa (SA) is currently in the middle of a health transition characterised by a quadruple burden of NCDs, communicable diseases, and perinatal- maternal- and injuryrelated disorders, as well as experiencing a nutrition transition (NT). The NT causes individuals to shift to a westernised diet consisting of unhealthier dietary choices leading to various metabolic conditions related to NCDs. Comparisons between the different ethnic groups and the different socioeconomic groups will give a better understanding of the dietary intake differences of these groups. Objectives: The aim of this study was to determine the difference in dietary intake between the different SES groups and the two ethnic groups (black and white population) of the baseline of the African-PREDICT study population. Design and Methods: The African-PREDICT study is a prospective observational study which stretches over a follow-up period of 10 years. Data included in this study are the baseline data collected from 2013-2016 and include 904 participants. Each participant completed three 24-hour dietary recall interviews. After the three 24-hour dietary recalls were completed, they were coded and household measures were converted to grams. The nutrient and food analysis of the baseline dietary data was conducted by the South African Medical Research Council using the food composition tables for SA. After the food and nutrient intake were determined the Mann-Whitney U test were used for the comparison between the two populations within the three SES groups, and the Kruskal-Wallis test was used for the comparison of the three SES groups within the two populations. Exploratory factor analysis was used to determine nutrient patterns. Results: Clear differences were seen between the dietary intake of the black and the white population across all SES classes. The white population had a diet consisting of a larger variety of nutrients, while the black population's diet was very monotonous. The black population had a greater consumption of foods such as cooked maize porridge and atchar while the white population preferred rice and pasta as their starch. Both populations had high intakes of bread. SES also played a role in the food choices of the study population. The high SES groups had a higher intake of vegetables and fruits, as well as milk and milk products, whereas the low SES groups had low intakes of fruit and vegetables (leading to low intakes of fibre, calcium, magnesium, folate and vitamins A, C and E) and higher intakes of refined starches and carbonated cold drinks. Three nutrient patterns were identified in the study population which explained 63.3% of the variance in the diet. These patterns were named according to the largest positive loadings on nutrients namely: plant protein, carbohydrates and folate nutrient pattern, the calcium, phosphorus and potassium nutrient pattern and finally the vitamin E and unsaturated fats nutrient pattern. Conclusion: There were clear differences between the black and white populations and the different SES groups. The high SES groups follow a diet consisting of healthier options which includes vegetables and fruit as well as milk and milk products. Whereas the low SES groups consumed less vegetables, fruits and milk and also tend to buy cheaper products, which are also the less healthy options. These unhealthy dietary choices can lead to various metabolic conditions, such as hypertension or overweight/ obesity, all related to NCDs and contributing to the disease burden of SA.