The salt content of cheese sold in UK supermarkets remains high, despite many products meeting the recommended government targets on salt reduction, finds research published in the online journal BMJ Open.
And salt content varies widely, even within the same type of cheese, the findings show, prompting the researchers to call for much tougher targets on salt lowering.
A high dietary salt intake is linked to high blood pressure, which is a risk factor for stroke, heart attacks, heart failure and kidney disease. It also increases the risk of stomach cancer and osteoporosis, and is indirectly linked to obesity.
Salt reduction is widely recognised to be one of the most cost effective ways of improving public health, and at the 66th World Assembly, all countries unanimously agreed to cut their salt intake by 30% towards a target of 5 g/day by 2025.
The current recommended dietary salt intake in the UK is 6 g/day, but is widely exceeded, according to dietary surveys. Cheese is a major contributor to dietary salt intake, with the average person consuming 9 kg of cheese every year.
The researchers analysed the salt content (g/100 g) of 612 different cheeses produced in the UK or imported from overseas and sold in the seven major UK supermarket chains in 2012. This information was collected from the product packaging and nutritional information panels.
In general, salt content was high, averaging 1.7 g/100 g of cheese. But salt levels varied widely - and not only among different types of cheese, but also within the same type.
Halloumi and imported blue cheese contained the most salt (2.71 g/100 g), while cottage cheese contained the least (0.55 g/ 100 g).
Among the 394 cheeses with salt reduction targets, most (84.5%) had already met them for 2012.
Cheddar and cheddar-style cheeses are the most popular/best-selling lines and 250 of these products were included in the analysis.
On average, salt content tended to be higher in branded (1.78 g/100 g) than in supermarket own label (1.72 g/ 100 g) cheddar and cheddar-style cheeses.
And more of the supermarket own-label cheeses in this category met the 2012 target for salt reduction than did the branded products: 90% compared with 73%.
"Our finding of a high salt content in cheeses sold in the UK is similar to those observed in the USA, Australia, France, Belgium, Canada, New Zealand, South Africa, and Brazil, showing that high levels of salt in cheese is a global challenge," write the authors.
But they suggest that UK salt reduction targets could be more ambitious.
"The results indicate that much larger reductions in the amount of salt added to cheese could be made, and more challenging targets need to be set," they conclude.