The average salt content of packaged bread sold in the UK has fallen by 20 per cent over the past decade. But salt levels still vary widely, indicating that further targets are required, finds research published in BMJ Open.

Bread is the biggest contributor of dietary salt in the UK, providing almost a fifth of the total derived from processed foods. The recommended daily intake for UK adults is a maximum of 6 g, with the current average 8.1 g a day.

Excess dietary salt can lead to high blood pressure, and an increased risk of heart attack, stroke, and kidney disease, as well as to other health problems. And the evidence shows that curbing dietary salt at the population level is one of the most cost effective means of improving public health.

The researchers base their findings on an analysis of the salt content of various packaged breads available in UK supermarkets between 2001 and 2011. They analysed salt levels in 40 products in 2001; in 138 products in 2006; and in 203 products in 2011.

In 2001, the average salt level in packaged bread was 1.23 g per 100 g. By 2006 this had fallen to 1.05 g, and by 2011 this had fallen further still to 0.98 g/100 g, equivalent to a reduction in salt levels of around 20% over the decade. The salt content of 18 products analysed at all three time points fell by 17%.

And, overall, the number of products meeting the Department of Health’s 2012 target – of less than or equal to 1 g of salt per 100 g – rose from under a third (28%) in 2001 to almost three quarters (71%) in 2011.

But wide variations in salt content persisted in similar products, and between supermarket own-label and branded products, the results showed.

In 2001, 38% of supermarket own-label loaves met the 2012 target compared with just 17% of branded products. By 2011, the equivalent figures were 89% and 42%, respectively.

Little difference in salt content was found between white, wholemeal, and brown loaves “despite the common perception that wholemeal and brown bread are healthier alternatives to white bread,” note the authors.

The variations in salt content indicate that there is further scope to lower levels even further in bread, say the study authors. “This requires further progressive lower targets to be set, so that the UK can continue to lead the world in salt reduction and save the maximum number of lives,” they write.

But they caution: “While a voluntary target based approach works to encourage industry reductions, the targets need to be coupled with the forceful government or quasi-government agency to ensure that all sectors of the food industry are aware of the targets and reducing salt in their products to meet [them].”

A target based approach does work, they conclude, adding: “Other countries around the world need to follow the UK’s lead and set salt targets.”