Sodium is commonly found in food as salt (sodium chloride). A small amount of sodium is required by the body as it plays an important role in keeping our fluids and electrolytes balanced.
You need some sodium as it helps maintain normal blood pressure, supports the work of your nerves and muscles, and regulates your body's fluid balance. However, the naturally occurring salt in our food is usually enough to meet your sodium needs.
There are strong links between salt and heart health. Too much salt in our diet is linked to an increased risk of high blood pressure. High blood pressure is a risk factor for heart disease, stroke and kidney disease. Reducing salt is an important goal and is now thought to be more important in its impact on reducing the risk of heart attacks and strokes than stopping smoking. So it's important to know just how much sodium your body needs.
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How much sodium (salt) do I need?
To reduce the risk of chronic disease it is recommended you eat no more than 5 g of salt a day (2000 mg sodium). That's less than 1 tsp of salt. People with diagnosed health conditions, high blood pressure or heart failure need to be extra careful when it comes to salt intake.
Why is too much sodium bad for me?
Too much sodium raises blood pressure and increases the risk of heart disease and stroke. How your blood pressure is affected depends on genetics, age, ethnicity, medications and any health conditions such as Type 2 diabetes.
- If you are older, overweight or have high blood pressure, diabetes or chronic kidney disease you are more likely to be sensitive to the blood pressure-raising effects of salt.
- If others in your family have raised blood pressure in response to higher levels of sodium chloride, you may be more likely to as well.
- For people who do not have raised blood pressure, reduced sodium intake can decrease the risk of developing hypertension.
What foods are high in sodium (salt)?
Over 75% of the salt we eat comes from processed and packaged foods. Salt is added to many foods to add flavour and can help to preserve food to make it last longer.
Foods high in salt include:
- processed meats
- tinned fish in brine
- packaged snack foods
- easy-cook packet foods such as instant noodles and rice risottos
- bread and many types of crackers
- pre-made sauces and flavour sachets
- table salt.
When you're shopping, the following targets can be a good guide to sodium levels:
- high sodium/salt foods = >600 mg sodium per 100 g
- medium sodium/salt foods = 120–600 mg sodium per 100 g
- low sodium/salt foods = <120 mg sodium per 100 g.
How can I cut back on salt?
- Eat fresh foods where you can.
- Use fresh herbs and spices to flavour food instead of salt, stocks or soy sauce.
- If you add salt to your food, do so after cooking and once you’ve tried the food first so you don’t add too much.
- Limit packaged and processed foods as they will include salt added to flavour and preserve the food.
- Find low-salt snacks you enjoy such as fruit, unsalted nuts, plain & unsalted popcorn, yoghurt, biscuits and crackers low in sodium.
- Limit intake of salami, sausages, ham and other processed or cured meats.
- Choose vegetables and fish canned in spring water instead of brine.
- When shopping, read labels for sodium content of foods.
- Limit takeaways which are often high in salt. Make them at home instead, using fresh ingredients. If you do but them, ask for no added salt.
Salt and iodine
When you do want to add salt to a dish, always choose iodised salt. Fancy, and often expensive sea salt and rock salts don't contain iodine. Although only required in very small amounts, iodine is an essential nutrient for everyone. Table salt in New Zealand is iodised to ensure we avoid the damaging effects of iodine deficiency, which was common here before the 1950s.
Sodium NZ Nutrition Foundation
Salt and blood pressure NZ Heart Foundation
Slash the salt NZ Stroke Foundation
How to cut back on salt to boost your heart health NZ Heart Foundation
Sodium NZ Nutrition Foundation, 2022
Sodium position statement NZ Heart Foundation, 2022
How to cut back on salt to boost your heart health NZ Heart Foundation, 2020
Hyponatremia – symptoms and causes Mayo Clinic, US, 2022