Some of the most common breads we see in the supermarket contain almost half the recommended day's worth of salt in just two slices. That's before you've even added any Vegemite.
Our new analysis looked at the salt content of 1,439 bread products sold in four major supermarkets since 2010.
What most surprised us was that the breads often thought to be the healthiest actually contain the most salt. For example, some rye breads in the survey contained twice as much salt as a serving of sea salt chips.
Wraps on average contained 33% more salt than sliced white bread. Some wraps had eight times as much salt as others.
This is important because while we've been trying to minimise sugar and fat intake, it seems we've been overlooking one of the biggest dietary killers of all – salt.
Heart disease is the leading cause of non-communicable disease deaths worldwide. Globally, it has been estimated more than 1.65 million heart-related deaths per year are attributed to excessive dietary salt intake.
The forgotten killer
Salt is sometimes called the "forgotten killer", and it's easy to see why. We're eating way too much of it, often without even realising. It's hidden in the processed and packaged foods we buy, and in foods we don't even think of as being salty.
The average Australian has a salt intake of around 8g to 9g per day. That's almost double the World Health Organisation's recommendation of less than 5g per day.
According to the most recent Australian Health Survey, the highest contributors of salt to the diet include bread and bread rolls (12.8%), processed meat (6.7%), ready-to-eat breakfast cereals (2-3%) and sauces, dips and condiments (6%).
We found rye breads contained on average 20% more salt than the voluntary sodium reduction targets that the Australian government set in 2009, to be achieved in three major food categories (ready-to-eat breakfast cereals, breads and processed meats) by 2013.
The results from our research show the targets have worked, with 81% of breads meeting them. Salt levels in breads and bread rolls had dropped by some 10% in seven years.
This is a promising start, but the bread targets covered only about two-thirds of the products analysed in this survey.
They did not cover flat breads – which had the highest average salt content. Breads such as wraps, naan, roti and tortillas also included unnecessarily high levels of salt. On average, these contained a third more salt than white bread.
This highlights the need for clear salt targets across all ranges of processed foods, as well as transparent monitoring systems to ensure all manufacturers are reducing salt across the product ranges.
Some of our other findings included:
Schwob's Dark Rye Sourdough contains twice as much salt as a serving of Kettle's Sea Salt Chips.
Mission Wholegrain Wraps contain eight times more salt than one Vitastic Sorj Healthy Soft Wrap Wholemeal.
The huge difference in the amount of salt in breads is alarming. We need all bread manufacturers to reduce the amount of salt in bread to the lowest possible levels, across all types of products.
A good public health initiative example is in Victoria. The Victorian Salt Reduction Partnership, led by VicHealth, is supporting national activities to reduce salt. This includes working with industry partners to identify and promote solutions to lowering salt in processed foods in parallel with behaviour change campaigns.
If you don't have the time to read nutrition information on packets of bread in the supermarket, then there is an app for finding find lower salt options: FoodSwitch.
Clare Farrand, Senior Project Manager, WHO CC Salt Reduction, George Institute for Global Health and Jacqui Webster, Associate Professor, Food Policy. Director of World Health Organization Collaborating Centre on Population Salt Reduction, George Institute for Global Health