Sodium

What is sodium?

Sodium is an essential nutrient that regulates water balance, maintains blood volume, controls muscles and nerve function and helps to maintain our body temperature. Because it is an essential nutrient, a small amount of sodium needs to be eaten regularly.

Sodium is added to foods to enhance flavour, preserve food, and improve processing. The majority (approximately 90 percent) of dietary sodium is in the form of sodium chloride commonly known as salt.

What is the difference between sodium and salt?

Salt is made up of 40 percent sodium, and 60 percent chloride.

Because the majority of sodium in our diet comes from salt, people often use the term salt instead of sodium. However, it is the sodium within the salt that is bad for your health. It is also important to remember that the amount of sodium and salt within a food is not the same. For example, 1 gram of sodium is equal to 2.5 grams of salt.

  • To convert sodium to salt multiply by 2.5
  • To convert salt to sodium multiply by 0.4

Sodium and health

A person that eats a diet high in sodium increases their risk of developing heart, blood vessel and renal diseases. In some people it is also associated with an increased risk of stomach cancer, and poor bone health. By reducing the amount of sodium you eat, you can reduce your risk of developing some of these diseases.

How much sodium should New Zealanders be eating?

The New Zealand Ministry of Health recommends a suggested dietary target of 1,600 milligrams per day of sodium (equivalent to 4 grams of salt) and an upper level of intake of 2,300 milligrams per day of sodium (equivalent to 6 grams of salt) for older children and adult New Zealanders. Children need less depending on their age. The suggested dietary target is recommended for those wishing to maintain a low blood pressure over their lifetime. The upper level of intake is the highest daily amount of sodium in the diet that is likely to pose no adverse health effects.

Both the suggested dietary target and upper level of intake are much higher than the amount of sodium required for basic health requirements; this is referred to as an adequate intake.

Life stage Age Al UL SDT
    (milligrams sodium per day)
Infants 0 - 6 months 120 - -
  7 - 12 months 170 - -
Children and adolescents 1 - 3 years 200 - 400 1,000 -
  4 - 8 years 300 - 600 1,400 -
  9 - 13 years 400 - 800 2,000 -
  14 - 18 years 460 - 920 2,300 1,600
Adults 19+ years 460 - 920 2,300 1,600
Pregnancy 14+ years 460 - 920 2,300 -
  14+ years 460 - 920 2,300 -

AI = adequate intake, UL = upper level of intake, SDT = suggested dietary target (Source: NHMRC & NZMoH, 2006).

How much sodium do New Zealanders eat?

An accurate estimate of how much sodium New Zealanders are eating is not currently available. Best estimates suggest the amount may be about 3,600 milligrams per day of sodium (equivalent to 9 grams of salt). Better information on how much sodium New Zealanders are eating will be available when results of the New Zealand Ministry of Health's 2008-09 Adult Nutrition Survey are released sometime in 2011.

Key foods that contribute the most sodium to New Zealanders' diets are estimated to be breads and processed meats (bacon, ham, corned beef and sausages). Meat pies, pizza, instant noodles, cheese, sauces and takeaway foods also contribute a significant amount of sodium to New Zealanders' diets.

The food industry has been reducing salt in various products to reduce sodium levels. For example, sodium levels in bread, cheese and milk were lower in the latest New Zealand Total Diet Survey compared to previous surveys. However, sodium levels are still high in some foods, so it is important to be aware of the sodium content of the foods you eat.

Nutrition Survey (External website)

New Zealand Total Diet Study (Food Safety website)

How can I reduce the amount of sodium I eat?

To reduce the amount of sodium you eat the New Zealand Ministry of Health recommends choosing foods low in salt, and limiting the addition of salt in cooking or at the table. If using salt, choose iodised salt.

Remember that most sodium is hidden in foods and that many foods high in sodium won't necessarily taste salty (e.g. breakfast cereals). Checking food labels is a good way to keep an eye on how much sodium is in the foods you eat. On the food label the ingredients list will list salt and any other sodium-containing additives, and the nutrition information panel will tell you how much sodium is present in the food product. When looking for food products with the lowest sodium content, use the nutrition information panel to compare the levels of sodium per 100 grams of food, and choose the food with the lowest sodium level.

Food Labelling

Iodine and fortification

Food and Nutrition Guidelines (External website)

How do I know if a product is low or high in sodium?

Some foods are labelled as 'low sodium' or 'low salt' foods. A low sodium or low salt claim can only be made when a food has no more than 120 milligrams of sodium per 100 grams of food. Other claims that assist with the choice of lower sodium foods include 'reduced' sodium/salt, sodium/salt 'free', and 'no added' sodium/salt. Reduced sodium/salt means the food must have at least 25% less sodium/salt than a comparable food.

There are some foods for which there are only high sodium options and it is recommended that these foods are eaten less often and/or limited in the diet. Some examples of high sodium foods include; takeaways, salami, bacon, olives. As a guide a high sodium food is one with more than 600 milligrams of sodium per 100 grams of food.

For further guidance on how to choose lower salt foods check out the "Slash the Salt" pamphlet and wallet card.

Slash the SALT - pamphlet (2.85 MB PDF) (External website)

Slash the SALT - wallet card (713 KB PDF) (External website)