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Science on salt

The Food Standards Agency has set a target of reducing the average salt consumption of adults to 6g a day by 2010. The Agency's advice on salt intake for adults and children is underpinned by the recommendations of the Scientific Advisory Committee on Nutrition (SACN). SACN is an independent expert committee that advises the Agency and the Department of Health.

Scientific Advisory Committee on Nutrition
In 1994, the Committee on Medical Aspects of Food and Nutrition Policy (COMA) recommended reducing the average salt intake of the population to 6g a day, in its report Nutritional Aspects of Cardiovascular Disease. This recommendation was based on evidence of a link between high salt intake and high blood pressure (also called hypertension).

In 2003 the Scientific Advisory Committee on Nutrition (SACN), in its report on Salt and Health, reviewed the evidence since 1994 to consider if COMA's previous recommendation to reduce the salt intakes of the population was still valid.

SACN concluded that the evidence for a link between salt intake and blood pressure had increased since 1994. The current high levels of salt habitually consumed by the population raise the risk of high blood pressure, which increases the risk of stroke and premature death from cardiovascular diseases. SACN confirmed that the population as a whole would benefit from reducing their intake to 6g per day. SACN also set lower recommended maximum levels of salt intake for babies and children for the first time.

In his preface to the report, Chair of SACN Alan Jackson states: 'Meeting these targets would be of major benefit to public health. Even a small reduction in salt intake could help to reduce the burden of high blood pressure on our population.'

The recommended maximum amounts of salt set for adults and children are achievable population goals, not ideal or optimum consumption levels.

Diet and blood pressure
Studies have shown that the greatest reductions in blood pressure are observed with a diet that is low in salt, total fat and saturated fat, and rich in fruit, vegetables, and low-fat dairy foods.

The Dietary Approaches to Stop Hypertension (DASH) trial (Appel et al, 1997) assessed the effects of dietary patterns on blood pressure. The results demonstrated that compared with a typical US diet, a diet rich in fruit, veg and low-fat dairy products (the DASH diet) significantly reduced average blood pressure by 5.5/3.0mmHg.

The DASH Sodium trial (Sacks et al, 2001) examined the combined effect of the DASH diet and reduced salt intake. The greatest reductions in blood pressure were observed with the DASH diet and low salt intake (3g) which reduced blood pressure by an average 8.9/4.5mmHg below the control diet (representing a typical US diet) at the high salt (9g) level.

The DASH Sodium trial also showed that reducing salt intake reduced average blood pressure levels of people eating the DASH diet or the control diet. The effects were observed in those with and without hypertension, in both sexes and across ethnic groups.

Maintaining a healthy weight, not consuming too much alcohol, and regular physical activity will also help to prevent and reduce high blood pressure.

See the Blood pressure page for more information on blood pressure.

Download the full SACN report, Salt and Health. To find out more about SACN, visit the SACN site.

A publication from the Medical Research Council (MRC) produced in 2005 summarises the evidence behind the public health target to reduce salt intakes to 6g a day. To read the report, visit the MRC website.