aCenter for the Research and Treatment of Arterial Hypertension and Cardiovascular Risk, Centro Hospitalar do Alto Ave, Guimarães bLife and Health Sciences Research Institute, School of Health Sciences, University of Minho, Braga cICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães dProfessora da Escola E.B.2,3 João de Meira, Bióloga, Mestre em Educação Ambiental, Guimarães eInstituto Ciências Biomédicas Abel Salazar, Universidade do Porto fFaculdade de Medicina, Universidade Porto, Oporto, Portugal.
The aim of the study was to evaluate the 24-h urinary sodium excretion in children of 10-12 years at a school in the north of Portugal and to examine the influence on salt intake and blood pressure of three different educational interventions for 6 months.
Blood pressure (BP) and sodium excretion in 24-h urinary samples (UNa) validated with urinary creatinine were measured in 155 children 10-12 years old belonging to nine classes at baseline and after 6 months of three educational interventions in students from three classes each after parents consent was obtained. Interventions consisted in no additional action [control (CTR)], weekly lessons about the dangers of high salt intake [Theoretical (THEOR)] and both lessons and working practices in the school garden of planting, collection of herbs for salt substitution at home [practical (PRACT)].
At baseline 139 students (76 girls and 63 boys) were eligible showing average 24-h UNa of 132 ± 43 mmol/24 h (mean salt intake of 7.8 ± 2.5 g per day) and BP of 118/62 (13/9) mmHg that did not correlate to each other. At the end of the study, versus baseline, BP decreased by 8.2/6.5 mmHg in CTR (n = 31), by 3.8/0.6 mmHg in THEOR (n = 43) and by 3.5/0.7 mmHg in PRACT (n = 53) and salt intake was reduced by 0.4 ± 2.4 g per day in CTR, by 0.6 ± 3.2 g per day in THEOR and by 1.1 ± 2.5 g per day in PRACT. It was observed that salt intake variation was not independent of the group (CRT, THEOR and PRACT) (χ, 9.982, P = 0.041). Salt intake was significantly reduced only in the PRACT group (1.1 g per day) and in the PRACT group the percentage of children who reduced salt intake by at least 1g per day from baseline to the end of the study was significantly higher (50.9%) than that of the other groups, THEOR, 48.8% and CTR, 32.2%.
Our data indicates that children 10-12 years old have a high salt intake that is well above the proposed recommendations and that a strategy based on theoretical and practical education may achieve in some children an important reduction in daily salt intake which, if maintained over time, may assume important public health implications. These results suggest that in those children a more complete theoretical and practical intervention is more productive and efficient towards reduction of salt intake than single theoretical or no intervention.
[Show abstract][Hide abstract] ABSTRACT: Since 2003/2004, the United Kingdom has implemented a salt reduction campaign; however, there are no data on salt intake in children as assessed by 24-hour urinary sodium, the gold standard method, to inform this campaign. We performed a cross-sectional study, involving South London school children across 3 age tiers: young children (5- to 6-year olds), intermediate-aged children (8- to 9-year olds), and adolescents (13- to 17-year olds). Dietary salt intake was measured by 24-hour urinary sodium excretion and compared with newly derived maximum salt intake recommendations. In addition, dietary sources of salt were assessed using a 24-hour photographic food diary. Valid urine collections were provided by 340 children (162 girls, 178 boys). The mean salt intakes were 3.75 g/d (95% confidence interval, 3.49-4.01), 4.72 g/d (4.33-5.11), and 7.55 g/d (6.88-8.22) for the 5- to 6-year olds, 8- to 9-year olds, and 13- to 17-year olds, respectively. Sixty-six percent of the 5- to 6-year olds, 73% of the 8- to 9-year olds, and 73% of 13- to 17-year olds had salt intake above their maximum daily intake recommendations. The major sources of dietary salt intake were cereal and cereal-based products (36%, which included bread 15%), meat products (19%), and milk and milk products (11%). This study demonstrates that salt intake in children in South London is high, with most of the salt coming from processed foods. Much further effort is required to reduce the salt content of manufactured foods.
[Show abstract][Hide abstract] ABSTRACT: Scientists worldwide have disseminated the idea that increased dietary salt increases blood pressure. Currently, salt intake in the general population is ten times higher than that consumed in the past and at least two times higher than the current recommendation. Indeed, a salt-rich diet increases cardiovascular morbidity and mortality. For a long time, however, the deleterious effects associated with high salt consumption were only related to the effect of salt on blood pressure. Currently, several other effects have been reported. In some cases, the deleterious effects of high salt consumption are independently associated with other common risk factors. In this article, we gather data on the effects of increased salt intake on the cardiovascular system, from infancy to adulthood, to describe the route by which increased salt intake leads to cardiovascular diseases. We have reviewed the cellular and molecular mechanisms through which a high intake of salt acts on the cardiovascular system to lead to the progressive failure of a healthy heart.
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