Dietary intake and sources of sodium and potassium among Australian schoolchildren: results from the cross-sectional Salt and Other Nutrients in Children (SONIC) study

Abstract

ObjectivesTo examine sodium and potassium urinary excretion by socioeconomic status (SES), discretionary salt use habits and dietary sources of sodium and potassium in a sample of Australian schoolchildren.DesignCross-sectional study.SettingPrimary schools located in Victoria, Australia.Participants666 of 780 children aged 4–12 years who participated in the Salt and Other Nutrients in Children study returned a complete 24-hour urine collection.Primary and secondary outcome measures24-hour urine collection for the measurement of sodium and potassium excretion and 24-hour dietary recall for the assessment of food sources. Parent and child reported use of discretionary salt. SES defined by parental highest level of education.ResultsParticipants were 9.3 years (95% CI 9.0 to 9.6) of age and 55% were boys. Mean urinary sodium and potassium excretion was 103 (95% CI 99 to 108) mmol/day (salt equivalent 6.1 g/day) and 47 (95% CI 45 to 49) mmol/day, respectively. Mean molar Na:K ratio was 2.4 (95% CI 2.3 to 2.5). 72% of children exceeded the age-specific upper level for sodium intake. After adjustment for age, sex and day of urine collection, children from a low socioeconomic background excreted 10.0 (95% CI 17.8 to 2.1) mmol/day more sodium than those of high socioeconomic background (p=0.04). The major sources of sodium were bread (14.8%), mixed cereal-based dishes (9.9%) and processed meat (8.5%). The major sources of potassium were dairy milk (11.5%), potatoes (7.1%) and fruit/vegetable juice (5.4%). Core foods provided 55.3% of dietary sodium and 75.5% of potassium while discretionary foods provided 44.7% and 24.5%, respectively.ConclusionsFor most children, sodium intake exceeds dietary recommendations and there is some indication that children of lower socioeconomic background have the highest intakes. Children are consuming about two times more sodium than potassium. To improve sodium and potassium intakes in schoolchildren, product reformulation of lower salt core foods combined with strategies that seek to reduce the consumption of discretionary foods are required.

Dietary Intake and Sources of Potassium in a Cross-Sectional Study of Australian Adults

“…In this study, the Na:K by urine excretion was 1.9; and consequently this increases an individual's risk of CVD [14,15]. Na:K > 1 have also been reported in other adult populations in Australia [18,19,48] and the US [49,50]. Examination of nationally representative data in 2011-2012 from NHANES revealed that only approximately 10% of US adults have a Na:K consistent with WHO guidelines and therefore may have reduced risk of CVD-related mortality [49].…”

“…When categorised by sub-major food groups, the largest contributors of potassium were potatoes, dairy milk, dishes where cereal is the main ingredient, and coffee and coffee substitutes. Similarly, other recent Australian studies have also identified that vegetable produces/dishes (in particular, potatoes), breads and cereals, milk products/dishes and meat products/dishes are key contributors of potassium intake [18,48,53,54]. Potato as a key source of potassium is a common finding [18,48,53], however whilst other fruits and vegetables are also good sources of potassium, these are generally not featured in the same proportion as potato and represent an opportunity to improve food choices [48].…”

“…Individual foods were also classified as being a core or discretionary food as defined by the Australian Guide to Healthy Eating [32,33] using methods previously described [18]. Discretionary foods are those foods which are not a part of the five core food groups (vegetables; fruit; grain; lean meats, poultry, fish, eggs, tofu, nuts, seeds, legumes, beans; milk, yoghurt, cheese) and are not essential to the diet [33].…”

“…There is limited evidence using the objective measure of 24-h urine collections to assess potassium intake in Australians [18,19]. The aims of the current study were to assess potassium intake, as well as food sources of potassium (including level of processing, purchase origin of these foods); and the Na:K in a cross-section of Australian adults.…”

A High-Salt Diet Promotes Phosphorylated Tau and Cognitive Decline in Mice

“…5 Alarmingly, high salt consumption in contemporary societies extends to school children, with a recent Australian study estimating that 72% consumed more than the recommended upper limit. 6 High salt intake continues across many regions despite concerted health policy initiatives to raise awareness of the associated health risks (e.g. World Action on Salt & Health [WASH]) and the fact that over 75 countries have now adopted strategies to reduce population salt intake by 30% by 2025.…”