Changes in the sodium content of bread in Australia and New Zealand between 2007 and 2010: implications for policy

It is well established that excess dietary sodium consumed throughout life causes blood pressure to rise with age1,2 and greatly increases the risks of cardiovascular diseases.3,4 With average population sodium consumption accepted to be well above recommended dietary intakes in both Australia5 and New Zealand,6 efforts are increasingly focused on reducing population sodium intake.7,8 There is particular interest in strategies involving the food industry because some three-quarters of the sodium in Australian and New Zealand diets derives from processed foods.9 In both countries, bread is one of the biggest contributors, providing about a fifth of daily sodium intake.6,9

In 2007, the New Zealand Heart Foundation and the Australian Division of World Action on Salt and Health each launched new efforts to engage industry in new programs to reduce the sodium content of bread.10 More recently, in 2010, the Australian Government’s Food and Health Dialogue announced a voluntary sodium target for Australian breads.11 Several bread manufacturers have made commitments to reducing the salt content of their breads in both countries,10,11 and reformulation to reduce the sodium content of food is now firmly on the agenda in Australia and New Zealand.12

The primary objective of this study was to establish the effectiveness of recent efforts to achieve reductions in the sodium content of bread products in Australia and New Zealand.11,13

Data on sodium content were collected for sliced packaged breads available for sale in Australia and New Zealand in 2007 and 2010. Data were obtained directly from the mandatory Nutrition Information Panel (NIP) of all packaged breads identified during visits to two major supermarket chains in each country (Coles and Woolworths in Australia and Pak’n Save and Foodtown/Countdown in New Zealand).

For each bread product, the brand name, product name, manufacturer and sodium content per 100 g were recorded on paper data collection forms in the supermarket and subsequently entered into an electronic spreadsheet. Each bread product was categorised as “white”, “wholemeal” or “mixed grain”.

In Australia, sodium content data were available for 94 sliced bread products in 2007 and 99 in 2010. For New Zealand, the corresponding numbers were 63 and 68. For every bread type, sodium content per 100 g varied substantially across years and countries, indicating marked initial and subsequent variation in bread composition (Box 1).

Our findings demonstrate the potential for voluntary salt reduction programs, implemented as collaborations between non-governmental agencies and industry, to effect changes in the sodium content of bread. Our data also highlight the need for sustained action, because there is still substantial room for improvement. While the concerted efforts over 4 years of these agencies and their collaborating manufacturers has reduced the mean sodium content of New Zealand breads, there has been no corresponding reduction in mean levels in Australia. The proportion of breads meeting targets did rise in both countries, but an isolated change in this parameter is unlikely to translate into large health gains. There remains substantial scope for improvement,11,14 with the mean sodium content of breads in Australia and New Zealand still far higher than that in the United Kingdom (397 mg/100 g).15,16

The wide range of sodium levels we identified (115 mg/100 g to 770 mg/100 g) indicates that it is possible to manufacture and market breads with low sodium content, and suggests that the barriers are mostly not technical.17 Coordinating salt reduction efforts may have significant potential for delivering improvements. This is highlighted by the disparities observed for the two manufacturers in this study that operate in both Australia and New Zealand (George Weston Foods and Goodman Fielder). In 2010 in Australia, the breads of George Weston Foods had a lower mean sodium content than the breads of Goodman Fielder, but the reverse was true in New Zealand. George Weston Foods also decreased the sodium content of its breads to a greater extent in Australia than in New Zealand, while the sodium content of breads made by Goodman Fielder rose in Australia and fell in New Zealand. The absence of government leadership is an important reason for this disparity, and while non-governmental organisations can have some impact, they lack the authority and resources of government. Strong government leadership has been a central feature of the successful ongoing salt reduction programs in the UK,15 Finland,18 the United States19 and Canada.20

Ongoing monitoring of sodium levels in bread is required to assure effectiveness of any new program that is implemented. Our analysis highlights the need for careful review and interpretation of the data, with findings for Australia requiring detailed consideration in terms of their public health impact. Specifically, between 2007 and 2010 there was no change in the mean sodium concentration of breads in Australia, despite a significant improvement in the proportion of breads meeting the 400 mg/100 g target. The explanation is a shift in the range and distribution of sodium levels in Australian breads, so that in 2010 there were no longer any breads with very low sodium contents available (the lower end of the range has increased from 115 mg/100 g to 235 mg/100 g), and there were new breads with high sodium content on the market (the upper end of the range increased from 620 mg/100 g to 770 mg/100 g). It is unlikely that an improvement in the proportion meeting the 400 mg/100 g target (with no corresponding improvement in mean salt levels) will have reduced the total quantity of salt delivered to the Australian population in bread. In New Zealand, where there were improvements in both the proportion of products meeting the target and the overall mean sodium level, there is likely to have been a real fall in the amount of salt delivered to consumers in bread, with associated gains in public health.

A limitation of our study is that we did not weight sodium data by sales. Market-share data for each product would have enabled an analysis that directly quantified the impact of the changes observed on the quantity of sodium in bread products sold.21 Reassuringly, the mean sodium levels in Australia were consistent with previous data reported from sales-weighted analyses done by the national Heart Foundation in 2009.22 It is also of note that the data we present here do not include unpackaged breads and breads sold from non-supermarket outlets. In Australia, for example, it is known that Bakers Delight products have sodium levels significantly above the average.23

In conclusion, our data provide the first objective, quantitative evaluation of progress in reducing the sodium content of bread products in Australia and New Zealand. While there has been some improvement in sodium levels in New Zealand, and while the companies actively engaged in salt reduction efforts are to be congratulated, our data also highlight the need for continued action. Better results are likely to be achieved if the governments of Australia and New Zealand take committed leadership of these programs.

3 Changes in the sodium content of bread, 2007–2010*

* Means were compared between years for each country using t tests.