Reducing daily salt intakes by one gram could reduce sugar-sweetened beverage consumption by 27 grams per day, report the researchers in Hypertension: Journal of the American Heart Association.
"If children aged four to 18 years cut their salt intake by half (i.e., an average reduction of three grams a day), there would be a decrease of approximately two sugar-sweetened soft drinks per week per child, so each child would decrease calorie intake by almost 250 kcal per week," said Feng He, lead author of the study.
"Not only would reducing salt intake lower blood pressure in children, but it could also play a role in helping to reduce obesity."
Obesity is currently thought to affect more than 64 per cent of the US's adult population and 16 per cent of children, and has been repeatedly linked with an increased risk of other health conditions such as heart disease and diabetes.
The research could increase pressure on the food industry to reduce salt content in a wide range of foods, and adds to previous studies linking dietary salt intake to an increase fluid consumption in adults (Progress in Cardiovascular Diseases, Vol. 49, pp. 59-75).
However, the British Soft Drinks Association (BSDA) was quick to respond to the new results. A spokesperson told FoodNavigator.com: "This study seeks to address the need to lower the salt intake of children but does not take into account that 61 per cent of all soft drinks are now low calorie or no added sugar and that a number of studies have shown no direct link between obesity and soft drinks consumption.
"Furthermore, research shows that 40 per cent of 11-18 year olds are not drinking the FSA's recommended daily minimum amount of 1.2 litres a day (Source: Expert Group on Hydration). Children are at greater risk of feeling the effects of dehydration, such as headaches, lethargy, reduced concentration and digestive problems so we should be encouraging them to be drinking more fluid not less."
"Sugar-sweetened soft drinks are a significant source of calorie intake in children," explained He. "It has been shown that sugar-sweetened soft drink consumption is related to obesity in young people. However, it is unclear whether there is a link between salt intake and sugar-sweetened soft drink consumption."
The researchers, from St George's, University of London, analysed data from the Great British National Diet and Nutrition Survey (NDNS) - anationally representative sample of more than 2,000 people between four and 18. Dietary intakes for 1,600 subjects of salt and fluid were recorded using a seven-day dietary record, with all food and drink consumed weighed on digital scales.
"We found that children eating a lower-salt diet drank less fluid," said He. "From our research, we estimated that one gram of salt cut from their daily diet would reduce fluid intake by 100 grams per day."
And the fluid intake included sugar-sweetened soft drinks. He and co-workers predicted that reducing salt intake by one gram each day would reduce sugar-sweetened soft drink consumption by 27 grams per day, after considering other factors such as age, gender, body weight and level of physical activity.
"Our results, in conjunction with other evidence, particularly that from experimental studies where only salt intake was changed, demonstrate that salt intake is an important determinant of fluid and sugar-sweetened soft drink consumption during childhood," stated the researchers.
"Currently, salt intake in young people is unnecessarily high because of, in most countries, hidden salt added to food by the food industry," they concluded.
Co-author of the study, Professor Graham MacGregor is also chairman of Consensus Action on Salt and Health (CASH) and professor at St George's Hospital.
In an accompanying editorial, Myron Weinberger from Indiana University Medical Center, said that reductions in salt and sweet-beverage consumption among children, coupled with an increase in physical activity, "could go a long way in reducing the present scourge of cardiovascular disease in our industrialized society. Obviously, each step in this progression requires further definition and confirmation. This presents a formidable challenge as we move into the 21st century."
Published online, doi: 10.1161/HYPERTENSIONAHA.107.100990
"Salt Intake Is Related To Soft Drink Consumption in Children and Adolescents A Link to Obesity?"
Authors: F.J. He, N.M. Marrero, G.A. MacGregor
Published online, doi: 10.1161/HYPERTENSIONAHA.107.104471
"Are Children Doomed by What They Eat and Drink?"
Author: M.H. Weinberger