June 2006 

Sodium is essential to life but most of us eat more sodium than required for good health. Health experts advise limiting total daily sodium intake to 2.4g /day, which is equivalent to 6g salt/day. Most of the sodium we consume comes from the foods we eat as table salt or other sodium compounds. 

This is especially the case in Asia where up to twice the recommended maximum intake has been recorded in some population*.  

Limiting dietary sodium intake can help in the prevention of high blood pressure, which in turn substantially decreases the risk of developing heart disease or stroke.  

In addition, other modifications to lifestyle and diet can also help to lower blood pressure and promote good health. These include increasing dietary intake of calcium and potassium; maintaining a healthy weight or lose weight if overweight; consume moderate quantities or no alcohol; do some physical activity every day. 

There is also some evidence that high intakes of salted, smoked and pickled foods increase the risk of gastric and naso-pharyngeal cancers.  

* Zhou et al (2003) J Human Hypertension 17:623-30

Understanding blood pressure numbers

Blood pressure is the force in the arteries when the heart beats (known as systolic pressure) and when the heart is at rest (diastolic pressure). It is measured in millimetres of mercury (mmHg). High blood pressure, also known as hypertension is usually defined in an adult as a blood pressure greater than or equal to 140mmHg systolic pressure or greater than or equal to 90 mmHg diastolic pressure.

Sodium in the Diet

Sodium is found in many forms but the most common, and concentrated source of sodium in the diet is sodium chloride, more commonly known as salt. 2.5 grams of salt contains 1 gram of sodium.   

Salt has been used as a preservative and a flavouring agents for centuries; Foods such as ham, sausages, bacon and other preserved meat and fish products, canned vegetables in brine, pickled products, salted fish, cheese, bread, savoury snack foods, condiments and traditional Asian flavourings such as oyster sauce, fish sauce and prawn paste are all high in salt and therefore sodium. Some ingredients for savoury dishes and quick meals such as stock cubes and canned soups may also contain high levels of salt. 

Sodium is also found in some food additives such as monosodium glutamate (a flavour enhancer), sodium saccharin (a sweetener), sodium nitrite (a preservative), sodium ascorbate (an antioxidant, sodium bicarbonate (baking soda) and in some medicinal products (e.g. antacids) but these are not usually major contributors to total dietary sodium intake. 

Dietary tips to reduce sodium consumption

• Cut down the use of salt, high sodium condiments and sauces in cooking.
• Choose lower sodium products such as reduced salt soy sauce or oyster sauce.
• Check food labels to select lower salt options where possible.
• Limit consumption of salt-preserved foods such as bacon, canned soups and vegetables, as well as salty snack foods such as salted nuts, preserved plums
• Avoid adding salt at the table, and select low sodium dipping sauces.

 

High-sodium foods: Eat Occasionally and In Moderation
Food Serving	Sodium (mg)
2 slices of hard cheese (60g)	300
2 rashers bacon, pan fried (80g)	1170
1 slice cheese pizza (100g)	480
1 packet potato chips (50g)	298
1 cup instant noodles	1400
hamburger on bun, plain take away	560
½ cup Chinese salted cabbage (100g)	1510
small can button mushrooms (100g)	560
1 salted duck egg,	360
bowl of cornflakes (75g)	200
fish sauce, 1 tablespoon	1390
oyster Sauce, 1 tablespoon	490
soy Sauce, 1 tablespoon	900

Taken from USDA ARS Nutrient Data Laboratory tables www.ars.usda.gov

And ASEAN Food Composition Tables (2000) ISBN 974-664-480-