Dr Carly Grimes

Packing a school lunch box can sometimes feel a little overwhelming these days. Trying to pack foods that are nutritious, liked by children, as well as following school guidelines on high allergen foods, such as nuts, can be tricky.  What most of us don’t realise is that salt can be lurking in many popular foods in children’s lunchboxes.

Our research at the Institute for Physical Activity and Nutrition (IPAN) at Deakin University obtained the first accurate measure of how much salt Victorian children are eating. We did this in over 600 children aged 4-12 years by collecting their urine over 24-hours. Sounds bizarre, but the salt we eat each day is excreted in our urine, making this the best way to measure salt intake. The results may shock you – we found that on average children were eating 6 grams of salt per day, which is far too high!

The recommendation is 3.5 grams per day for children aged 4-8 years and 5 grams per day for children aged 9-13 years. Seven out of ten children were eating more salt than recommended. When we asked the children to describe all the foods they ate in one day we found that about one quarter of a child’s daily intake of salt comes from food eaten at lunch time. We also know that some of the main sources of salt in children’s diets include bread, cheese and deli meats. This provides a great opportunity to make some simple changes to foods packed in school lunches to cut down on salt.

A lot of children enjoy bread, cheese and deli meats, and both bread and cheese are part of healthy eating. But what is important to know is that there is a lot of variation in the amount of salt in different brands of these foods. By checking the nutrition label you can find options that have less salt. If you have tried reading food labels, you may have noticed that salt is not listed, instead, sodium is shown. Sodium is part of salt, so when you want to find a food which has less salt look for the sodium information per 100 grams listed on the label. To help find the best options for these popular lunch-time choices, we recommend looking out for products that have less sodium (i.e. salt).

Switching to foods with less sodium can make a  big difference to the amount of salt your child eats. Take a look at these two lunch boxes – lunch box # 1 contains foods that are higher in sodium, whereas the foods in lunch box # 2 are lower sodium options.

Lunch Box Comparisons

Lunch Box #1 Salt Content (g) Lunch Box #2 Salt Content (g)
2 slices of bread
(sodium 490mg per 100g)
0.8 2 slices of bread
(sodium 323mg per 100g)
1 slice of processed cheese
(sodium 1472mg per 100g)
0.8 1 slice of low-fat cheddar cheese
(sodium 570mg per 100g)
Lettuce 0 Lettuce 0
Tomato 0 Tomato 0
2 slices of leg ham
(sodium 1500mg per 100g)
2 2 slices of leg ham
(sodium 316mg per 100g)
Margarine spread 0.3 Margarine spread 0.3
Cheese dip with crackers 0.6 Hummus dip with carrot and cucumber sticks 0.3
Banana 0 Banana 0
Total salt content (g) 4.5 Total salt content (g) 1.8

In total, lunch box # 1 provides 4.5 grams of salt which is 2.5 times more than lunch box #2 which has only 1.8 grams of salt. As you can see from these two lunchboxes, simple swaps to foods with less salt can really add up.

You can also download the FoodSwitch app, which you can use to scan the barcode on a food product and it will tell you the nutritional information of the product – including its salt content. It will also give you options for healthier alternatives.

Remember, fresh foods, like fruits and vegetables, lean meats, and eggs are best and don’t have any added salt. Try to pack these into lunchboxes to cut salt even further.  For example, instead of using deli meat swap to home-prepared roast chicken or egg and lettuce for a tasty sandwich filling. Use the sodium targets to help you at the supermarket to switch to foods with less salt.

Dr Carley Grimes is an Alfred Deakin Postdoctoral Research Fellow and is a member of the Institute for Physical Activity and Nutrition at Deakin University.