Lowering salt intake in children
Deakin PhD student Carley Grimes recently took part in the University's Three Minute Thesis competition final. This is an edited version of her presentation.
Australian children are frequently exposed to highly salted foods. For example a hot dog alone would provide about 80% of an eight year old's maximum daily salt limit.
Past studies have demonstrated that salt raises blood pressure in children, which in turn increases their risk of adult hypertension and future cardiovascular disease.
Currently in Australia we have no accurate measure of salt intake in children.
Part of my research is to find this out by using 24-hr urine collections. Each day all of the salt we consume is excreted in our urine thus, this method is the most accurate measure of salt intake.
This is a picture of some of my first participants from a local school, this was taken after the 24-hr urine collection and I hope you will notice that although a little nervously, they are all still smiling.
Results from the first cohort of 60 participants show alarmingly high levels of salt consumption, with 72% of children exceeding the recommended daily Upper Limit.
This raises the question: Where is all this salt coming from? And how could we potentially lower salt intake?
Using data from a large representative sample of Australian children I have found that the major sources of salt are bread, breakfast cereals, processed meats, & cheese.
As a strategy to lower salt intake I have used dietary modelling to examine the effect of applying salt content targets to Australian foods.
A salt content target basically means there is a limit on the amount of salt permitted in manufactured foods.
I have found that the application of internationally recognised salt targets on Australian foods would lower daily salt intake in Australian children by up to 20%.
Finally I have used this same large dataset to examine the relationship b/w salt intake and another cardiovascular risk factor, obesity. You may be thinking salt isn’t like fat or sugar, it doesn’t provide calories, so how can it be related to obesity.
The mechanism behind this relationship lies in the homeostatic trigger of thirst, in response to the ingestion of dietary salt. In brief a child consumes salty foods, thirst is triggered, in an environment where soft drinks are readily available the child satisfies their thirst with a soft drink, beverages which are associated with weight gain.
My findings confirm this hypothesis, indicating that dietary salt intake is positively associated with SD consumption and that SD consumption is associated with increased risk of obesity.
In summary These novel findings indicate that salt reduction strategies may assist in childhood obesity management, my research provide Australia with the first accurate measure of salt intake in children and I’ve also demonstrated that the implementation of salt content targets on Australian foods would be a healthy start to salt reduction.