New research shows that children can play an important role in lowering families' salt intake
- Primary schoolchildren can help their families reduce salt intake through app-based learning, according to a new study in China
- Over a 12-month period, salt intake was significantly reduced by 8% (0.82g/day) in adult family members which was accompanied by a significant fall in systolic blood pressure
- It is estimated that this novel approach, if scaled up across China, would prevent approximately 250,000 stroke and heart disease events per year, and also have major implications for other countries
- Reducing salt is the single most cost-effective measure to reduce blood pressure, i.e. the leading causes of death worldwide through strokes and heart disease it causes. In developing countries where most of the salt is added by the consumer, an app-based education could play a very important role in helping to reduce salt intake.
A new study published today in The BMJ (1) and carried out by researchers funded by the National Institute for Health Research (NIHR) at Queen Mary University of London and The George Institute for Global Health at Peking University Health Science Center, has shown that schoolchildren can help their families to successfully reduce salt intake via smartphone app-based learning.
The controlled trial, conducted in northern, central and southern China where salt intake is high amongst both children and adults, included 54 primary schools with over 590 children (aged 8-9 years) and over 1180 adult family members (including parents and grandparents with an average age of 46). During the study, children, parents and grandparents were taught about the dangers of eating too much salt and how to reduce it using a smartphone app, known as AppSalt. Salt reduction education, together with the routine health education curriculum, was integrated into the AppSalt system. The app was installed on parents’ or grandparents’ smartphones. Children’s homework was to remind their parents and grandparents to complete the learning and tasks with them, following the step-by-step guide in the app. Salt intake was measured at the beginning and 12 months into the app-based education, each involving two consecutive 24-hour urine collections. School teachers organized the evaluation and facilitated the salt reduction education by communicating with children and their families through virtual chats or in-personal meetings.
The average baseline salt intake (i.e. before the salt reduction education) was 5.5 g/d for 8-9 years-old children, and 10.0 g/d for adults which is double the World Health Organization (WHO) recommended level. After one year of education, salt intake fell by 8% (0.82 g/d, P<0.001) in adults which was accompanied by a fall of 1.6 mmHg (P<0.05) in systolic blood pressure. In children, there were small falls in salt intake and blood pressure, but they were not significant.
Salt reduction is one of the most cost-effective public health measures as it lowers blood pressure, the leading cause of cardiovascular disease (strokes, heart disease and heart failure) (2). Approximately 80% deaths from cardiovascular disease occur in developing countries (3). Whilst China is the largest developing country in the world, there were ≈2.2 million stroke deaths and ≈1.9 million heart disease deaths in China during 2019 (4). This continues to rise due to the rapid epidemiological and economic transitions.
Salt intake in China is very high and approximately 80% of the salt is added by the consumers during cooking or in sauces (5). So far, no country has demonstrated a successful salt reduction programme in such settings.
Professor Feng He, Professor of Global Health Research at Queen Mary University of London and lead author said: “This study provides a novel and feasible approach to reducing salt intake in the population where most of the salt in the diet is added by the consumers. Nationwide implementation could support salt reduction efforts, leading to a reduction in salt intake in the Chinese population and therefore a reduction in strokes and heart disease.”
Professor Puhong Zhang, associate director at The George Institute for Global Health at Peking University Health Science Center and joint lead author said: “Primary school is a well-organised place where salt reduction education could be integrated into the existing health education curriculums and nearly all the families could receive the education through schoolchildren in a long run. This will help salt reduction across the whole population in China”.
Dr Yuan Li, Head of Nutrition and Lifestyle Program at The George Institute for Global Health at Peking University Health Science Center and co-author said: “The app-based education is well accepted by children, parents and teachers. With proper training and supervision, even individuals with minimal knowledge on the technology can learn to successfully use the app to acquire knowledge, set goals and monitor progress. Importantly, the app-based education could reduce workload for school teachers and ease the pressure on the already-busy school curriculum in China”.
Professor Graham MacGregor, Chairman of WASSH (World Action on Salt, Sugar and Health), Professor of Cardiovascular Medicine at Queen Mary University of London and co-author said: “This study has achieved a reduction in salt intake and blood pressure with the use of a smartphone app. Given the devastating impact salt has on health, all countries should adopt measures to reduce salt intake, including apps like AppSalt. In settings where most of the salt comes from processed foods, the industry also needs to reduce the huge and unnecessary amounts of salt they add to food. The best way of doing this is to set mandatory salt reduction targets, e.g. South Africa and Argentina.”
Mhairi Brown, Programme Lead of WASSH at Queen Mary University of London said: “Although this study was carried out in China, the methods could potentially be adapted by many other countries. Even in developed countries where most of the salt in the diet is from processed food, kids can still play a role in helping their family to reduce salt, e.g. by selecting food with less salt when shopping with their parents using a free app like FoodSwitch (6) and getting them to reduce the amount of salt they add to their food”.
Ends
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Notes to editors:
World Action on Salt, Sugar and Health (WASSH) are a global group with the mission to improve the health of populations throughout the world by achieving a gradual reduction in salt, sugar and excess calorie intake. Based at Queen Mary University of London, WASSH were established in 2005 to translate the success of the UK’s salt reduction programme worldwide, providing resources and expert advice to enable the development and implementation of salt reduction programmes in high-, middle- and low-income countries. WASSH have a network of more than 600 members in 100 countries, all of whom are working towards reducing population salt, sugar and calorie intake in their country.
References
- He FJ, Zhang P, Luo R, et al. App based education programme to reduce salt intake (AppSalt) in schoolchildren and their families in China: parallel, cluster randomised controlled trial. BMJ 2022;376:e066982
- He FJ, Tan M, Ma Y, MacGregor GA. Salt Reduction to Prevent Hypertension and Cardiovascular Disease: JACC State-of-the-Art Review. J Am Coll Cardiol 2020;75:632-47
- Mozaffarian D, Fahimi S, Singh GM, et al. Global sodium consumption and death from cardiovascular causes. N Engl J Med 2014;371:624-34
- GBD 2019 Diseases and Injuries Collaborators. Global burden of 369 diseases and injuries in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet 2020;396:1204-22
- Anderson CA, Appel LJ, Okuda N, et al. Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: the INTERMAP study. J Am Diet Assoc 2010;110:736-45.
- FoodSwitch. http://www.foodswitch.co.uk/.
