The Minster Practice, Lichfield

2005/06 advice

The Food Standards Agency states that a high salt product contains 0.5g of sodium per 100g, medium salt 0.1-0.5g per 100g and low salt product 0.1mg & less per 100g of product.

Recommended salt intake is less than 6g per day . Food labels often list sodium which needs too be multiplied by 2.5 to convert to salt content as salt is 40% sodium. 6g of salt is 2.4g sodium.

Children:
up to 6 months: <1g per day
7 to 12 months: 1g per day
1 to 3 years: 2g per day
4 to 6 years: 3g per day
7 to 10 years: 5g per day
Over 11 as adult: 6g per day

Reduction in salt intake and blood pressure

This is now Government policy (see below re 1994 position). Average salt intake in England is around 11g per day for men and 8g per day compared to the recommended 6g per day and this is an important cause of raised blood pressure. Reduction of salt intake is particularly important for patients at high risk of heart disease such as the obese an dthose with type 2 diabetes. Most children eat too much salt.

Around 75% of salt is from processed foods such as ready meals, soups, sauces and savoury snacks. The salt content can be estimated by multiplying the sodium figure on the nutrition information label by two and a half. In addition to avoiding these sources, salt added to food during cooking should be reduced and never added at the table.

Raised blood pressure can also be avoided by

Further information www.foodstandards.gov.uk/healthiereating/dailydiet/salt/ and www.sacn.gov.uk

Referenced detailed information about salt

Salt does not have a direct effect on atherosclerosis but the amount of salt intake is associated with the level of blood pressure. Intersalt, an international multi-centre epidemiological study,[i] [ii] reported significant associations of urinary sodium excretion and BMI (direct), and urinary potassium excretion (inverse) with blood pressure. [iii] [iv] Each of these factors is independent of each other and of alcohol intake. The issue of salt intake remains a contentious issue but reductions in salt intake are particularly likely to be effective at reducing blood pressure in the elderly. [v] Three quarters of salt intake comes from processed and convenience foods and reduction in the amount of salt added to processed food would prevent 75,000 deaths from coronary heart disease and stroke each year.[vi] Salt may be listed on the label as 'sodium chloride' or 'monosodium glutamate'. Do not use low salt alternatives if there is kidney trouble.

 The Intersalt data was challenged by the Salt Institute[vii] but their own analyses of data were incorrect both statistically and biologically[viii] and ignored additional supporting data outside Intersalt[ix]. 65-85% of dietary salt comes from processed foods, but rather than reformulate their products, manufacturers lobby strongly to avoid official recommendations to reduce salt content. Salt is the main flavour in processed foods which would be unappetising without salt; other natural means of improving flavour would be expensive. In 1994, Sir Kenneth Calman, Chief Medical Officer at the DoH, specifically emphasised that reduction of salt intake was not government policy [x] and refused to endorse the statement of the third review from the cardiovascular group of the government’s advisory committee on medical aspects of food policy that people should reduce their salt intake by one third from 9g (150 mmol) to 6g (100 mmol).

 Further work on the Intersalt data[xi] confirmed that reducing sodium intake by 100 mmol would result in an adult systolic pressure lower by 3-6 mmHg. The slope of systolic pressure from age 25 to 55 would be 10mmHg less and for diastolic pressure 6mmHg less.

 Besides an association with BP, there is an independent association with CVA mortality[xii]. Salt intake also correlates closely with LVH irrespective of BP and a moderate reduction in salt intake causes regression of LVH [xiii]. It is not only smooth muscle in arteries that is salt sensitive. A controlled double blind study in asthmatics demonstrated improved symptoms and increased peak flow in men (but not women) after a moderate reduction in salt intake [xiv]. In a 2 year study of bone density in 124 postmenopausal women a modest reduction in salt intake had an equivalent effect as an increase in calcium intake of 900mg[xv]. There is also a suggestion that in young females a high salt intake (leading to increased calciuria) coupled with a low calcium intake may lead to a permanent reduction in peak bone mass[xvi].

 A literature review found not only that salt intake, as measured by 24 hour urinary sodium excretion, is correlated with damage to three target organs of hypertension (heart, kidney, and brain), but also that the correlation is partially independent of blood pressure. Another study from Japan supported these observations: Among 156 hypertensive patients assessed for sodium sensitivity and followed an average of seven years, sodium-sensitive patients had a two-fold increase in cardiovascular events compared with those who weren't sodium sensitive. This finding remained significant after adjustment for variables, including mean arterial pressure at baseline.

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