The South African salt story: where are we and where are we heading?

Abstract

Background and objectives: The mortality and morbidity burden caused by hypertension are preventable and therefore, efforts need to be taken to address this burden. Excess dietary sodium intake is associated with increased blood pressure and the reduction thereof is considered as one of the best investments for public health. As a first step the South African (SA) government has implemented a mandatory regulation (R.214) pertaining to the reduction of sodium in foodstuffs as part of a wider sodium reduction strategy. Monitoring of different aspects of such a strategy is crucial to establish effectiveness and was the main aim. Objectives included (i) establishing baseline sodium and potassium excretion; (ii) investigating appropriate monitoring methods in terms of sodium intake and (iii) to evaluate sodium content in foodstuffs set out in R.214. Methods: We collected 24-hour urine samples and spot urine samples from three population groups i.e. White, Black and Indians in SA. Sodium and potassium were analysed. Three formulas were used to estimate sodium excretion i.e. Kawasaki, Tanaka and INTERSALT. To evaluate the sodium content of foodstuffs we randomly selected ten food products from each of the categories and measured the sodium through atomic absorption spectrometer. Results: In total, 692 and 681 24-hour and spot urine collections were collected. Median sodium and potassium excretion was 122.9 and 33.5mmol/day, and median salt intake was 7.2g/d. The majority (92.8%) of the population did not meet the recommended potassium intake per day and 65.6% consumed more than 6g/d of salt. The Kawasaki and Tanaka formula showed significantly higher (p≤0.001) estimated sodium values than the measured 24 hour excretion in the whole population (5677.79mg/d and 4235.05mg/d vs. 3279.19mg/d). The majority of the food products tested complied with the 2016 targets (72%) and 42% with the 2019 targets. Conclusions: These findings support the SA government’s sodium reduction legislation. Estimated sodium excretion from the three formulas should be used with caution. The sodium content in foodstuffs provides valuable information with regard to monitoring and evaluation. SA is doing well in terms of the strategy but a lot still needs to be done