Salt Reduction Saves Lives

14 April 2014

From the fall in blood pressure that was due to salt reduction, there has been a saving of approximately 18,000 stroke and heart attack events a year, 9,000 of which would have been fatal

Background

Raised blood pressure throughout its range is the single biggest cause of death through the strokes and heart disease it causes (e.g. 62% of all strokes and 49% of heart disease). A high salt intake is the major factor that puts up our blood pressure.

Most products in the supermarket have now been reduced from 20 to 40%. These reductions have been made slowly, and there have been no loss of sales to the food industry, and the public are largely unaware of these reductions.

Results

From 2003 to 2011:

• Average population salt intake fell by 15%, from 9.5g/day to 8.1g/day (P<0.05)
• Average population blood pressure fell by 3mm Hg systolic and 1.4mm Hg diastolic (P<0.001)
• Stroke and heart disease deaths fell by approximately 40% (P<0.001)

Salt

Salt intake was measured by 24hr urine collections, measuring the amount of sodium in a random sample of the population in the National Diet and Nutrition Survey (NDNS) and fell from 9.5g per day in 2003 to 8.1g per day in 2011 i.e. a 15% reduction.

Blood Pressure

Over the same time period, blood pressure was measured in the Health Survey for England using a standardised protocol using the same validated electronic sphygmomanometer. Blood pressure fell in the adult population by 3mm Hg systolic and 1.4mm Hg diastolic (P <0.0001). As part of this fall could be attributed to better treatment in those who have high blood pressure, the study then looked at individuals who were not on any drug treatment for blood pressure and a correction was made for all other variables that could have influenced blood pressure, apart from salt [REF 5]. There was still a fall in adult population blood pressure of 2.7mm Hg systolic/ 1.1mm Hg diastolic, (P <0.0001). This reduction in blood pressure can therefore be attributed to the fall in salt intake.

Deaths

From the Office for National Statistics, which records deaths, over the same time period 2003 – 2011, stroke and heart disease deaths have fallen by 42% and 40% respectively. Several other risk factors for cardiovascular disease other than salt intake have also changed for the better during this time, including a reduction in smoking and cholesterol, however average body mass index (BMI) rose. Nevertheless it can be concluded that the fall in salt intake that led to a fall in blood pressure will have played an important role in both stroke and heart disease deaths. Indeed from this fall in blood pressure that has occurred, we can predict that approximately 18,000 stroke and heart attacks have been prevented each year – 9,000 of which are fatal [REF 6].

“This is great news for the UK, and shows just how effective the salt reduction policy is” says one of the paper’s authors, Sonia Pombo. “The food industry has worked hard to reduce levels of salt across many of their products, and as a result, average intakes of salt have gone down. The brilliance of the programme means that shoppers can still buy their favourite foods, just with less salt in them!”

Reduction in stroke and heart attack deaths occurred in England from 2003 – 2011, with the fall in blood pressure that has occurred in England over this time, taken from the Health Survey for England. *p<0.05, ***p<0.001 for trend.

Further Action

However UK salt intake remains high, at 8.1g/day, and is way above the target of 6g/day. The results of this study indicate that we need to redouble our efforts in the UK, in particular to get the food industry to act faster and more aggressively to save the maximum number of people from suffering and dying from stroke and heart disease. 

"This is great news, as it shows that the salt reduction plan is working and saving lives” says Graham MacGregor, Professor of Cardiovascular Medicine at Queen Mary University of London, Wolfson Institute of Preventive Medicine, and Chairman of Blood Pressure UK. “It is vital that we continue to get the maximum reduction of salt from the food industry. The Department of Health must take a much more robust attitude to the food industry, forcing them to reduce salt intake quicker and across the board in order to assure a level playing field. If they do not, we must regulate the salt targets to ensure that the maximum number of lives are saved and the maximum cost savings are made for the NHS”.

REF 1 – Salt Reduction in England from 2003 to 2011: its Relationship to Blood Pressure, Stroke and Ischaemic Heart Disease Mortality

Feng J He, Sonia Pombo-Rodrigues, Graham A MacGregor, BMJ Open 2014;4:e004549 DOI:10.1136/bmjopen-2013-004549

1. actiononsalt.org.ukfor further information about UK salt reduction