Reducing salt intake around the world by 15 per cent could prevent almost nine million deaths between 2006 and 2015, says a new meta-analysis covering 23 countries.
Low- and middle-income countries carrying 80 per cent of the burden for chronic disease were used in the analysis, led by Perviz Asaria from Kings Fund London, UK and published in The Lancet Chronic Diseases Series.
The startling figures presented in the analysis looks set to increase pressure on the food industry to reduce salt levels in products intended for these countries.
Numerous scientists are convinced that high salt intake is responsible for increasing blood pressure (hypertension), a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe.
Salt is of course a vital nutrient and is necessary for the body to function, but campaigners for salt reduction, like the Consensus Action on Salt and Health (CASH) consider the average daily salt consumption in the western world, between 10 and 12g, far too high.
The pressure has been mounting on food manufacturers to reduce the salt content of their foods and the UK's food standards agency (FSA) recommendation of six grams of salt per day for the general population is understood to be more a realistic target for the next five years than the ideal healthy limit.
The reviewers state that simple dietary changes could reduce salt intake by 30 per cent, but focused their analysis on the potential benefits from a 15 per cent reduction.
Only the blood-pressure-dependent effects of sodium intake on cerebrovascular and hypertensive diseases mortality were modeled by the researchers. They did not take into account other possible complications mediated by high blood pressure, such as renal failure.
The reductions in salt intake could be achieved at relatively little cost, said the authors.
"The main costs of the strategy to reduce salt consumption would be awareness campaigns through mass-media outlets and regulation of food products by public-health officers, with a total cost ranging from $0·04 to $0·32 per person for the countries analysed," they wrote.
And when combined with key elements of WHO's tobacco control framework, the total reduction in chronic disease related deaths was calculated to be 13.8 million. The majority of such death was from cardiovascular disease (75.8 per cent), followed by respiratory disease (15.4 per cent), and cancers (8.7 per cent).
"Our investigation has highlighted… the large number of potentially avertable deaths from cerebrovascular and hypertensive diseases in regions of high salt consumption," wrote the authors.
"Analysis of the global goal presented in the first paper of this series suggests that [people in whom deaths are averted] might survive for 18 years on average.
"Although the absolute numbers of deaths that would be averted with these selected interventions are substantial, they nevertheless account for only a small fraction of the total burden of deaths from chronic diseases," they concluded.
Commenting on the research, Professor Graham MacGregor, chairman of CASH, said the study showed the importance of a relatively small reduction in salt intake.
"But bigger reductions in salt intake would save even more lives," he said.
"The onus is now on the global food industry to save these lives by slowly removing the salt that they currently add to manufactured foods and to reduce salt intake worldwide to less than five g/day.
"Furthermore, the paper clearly shows that compared to other public health interventions, salt reduction is cheap and, importantly, can be achieved in many countries by the food industry without having to require individuals to change their behaviour.
"The UK food industry is now acting. The rest of the world needs to follow," concluded MacGregor.
Indeed, a spokesperson for the Food and Drink Federation, a UK-based industry association, told this website: "Salt reduction is a priority for the industry as part of its ongoing efforts to reformulate products where technologically possible, safe and acceptable for consumers.
Industry's efforts have been praised by the FSA, the Government and others, and we are seen to be leading the world on this issue."
The spokesperson highlighted several milestones achieved to date, including cutting sodium levels in bread by about 25 per cent since the 1980s, a 38 per cent reduction in sodium levels in breakfast cereals from 1998 to 2006, and a 25 per cent reduction in sodium levels in potato crisps.
"Members of the Biscuit Cake Chocolate & Confectionery Association have achieved salt reductions of between 16 - 50 per cent in all biscuit and cake categories, since February 2006," added the spokesperson. "This is in addition to the significant reductions that had been made previously."
In the UK, Ireland and the USA, over 80 per cent of salt intake comes from processed food, with 20 per cent of salt intake coming from meat and meat products, and about 35 per cent from cereal and cereal products.
Source: The Lancet Chronic Diseases Series
Published Online December 5, 2007, doi:10.1016/S0140-6736(07)61698-5
"Chronic disease prevention: health effects and financial costs of strategies to reduce salt intake and control tobacco use"
Authors: P. Asaria, D. Chisholm, C. Mathers, M. Ezzati, R. Beaglehole