Salt…. Do you know the facts? How does it impact heart disease and why should we be on a low salt diet?

Before you ask for “extra salt with that” make sure you know the facts about salt and how much you should be having in your diet, particularly if you suffer from or are at risk of high blood pressure or heart disease.

Nutritionist, Chloe Steele, gives us the ins and outs about salt. Why too much is bad for you, what it actually is and what it does, and top tips to help reduce your intake.

How much salt should we actually be having?

The World Health Organisation and the Australian National Health and Medical Research Council recommend that adults should consume less than 2g of sodium per day1, (which roughly equates to less than one 5g teaspoon of salt per day). However, the average Australian is consuming far above this, at approximately 3.6g1 of sodium, which is more than our bodies can use. Our ancestors consumed approximately 1.73g of salt per day, and it is unlikely that humans have had sufficient time to adapt to higher levels. As a result, high dietary salt intakes may be linked to several diseases, including high blood pressure and heart disease.

What is salt and what does it do?

Salt is a compound comprising of approximately 40% sodium and 60% chloride; and it is the sodium component, which is of the most concern. High sodium intakes have been associated with the development of high blood pressure and heart disease, but despite it being potentially harmful in excessive amounts, sodium is necessary for several biological processes. The body only requires 0.5g of sodium per day to properly function and when consumed within the healthy range of less than 2g of sodium per day, it is involved in a healthy functioning immune system, it ensures water balance in the blood, it enables the nerves and muscles to function properly, and it is required for normal heart function2.

Why is too much sodium bad for you?

Doctors will normally recommend a low salt or low sodium diet to individuals who have heart disease, or who are at high risk from getting it, but why?

When we eat more sodium than can be used, the body needs to find a way of getting rid of it.  Research has suggested that by raising the blood pressure, the body may increase the amount of sodium that is processed in the kidneys and excreted in the urine3. However, an unfortunate side effect of continually high blood pressure is that the arteries, which carry the blood, become stiff and unable to effectively deliver blood to the heart, resulting in the development of heart disease. For individuals who already have heart disease, continual high salt intakes can be an added burden and increase your risk of having a heart attack.

High dietary salt intake and its resulting increased blood pressure may also cause thickening and stiffening of the heart’s main pumping chamber, which affects its ability to contract and pump the blood around the body. This can increase your risk of heart failure, which is another form of heart disease2. Diets low in salt have been associated with a regression of the thickening of the arteries of the heart4, so even if you have this condition, there is something you can do to help.

Top tips to reduce sodium intake 

Be mindful of what you eat

Most of the sodium intake in the average Australian diet is from ultra-processed foods and cutting these out will ensure that you lower your risk for heart disease5. Sodium is often used as a preservative and flavour enhancer, and processed foods and those with a long shelf life are likely to have added sodium. Even supposedly sweet foods can have high amounts, so don’t be fooled! For this reason, the following foods should be avoided:

  • Packaged and processed foods such as pizza, pies, sausage rolls, and fast food 
  • Processed meats such as ham, salami, bacon, sausages, burgers, and chicken nuggets
  • Tinned foods with added salt (tomatoes, beans, and vegetables)
  • Salted nuts, chips, and crackers
  • Yeast extract spreads such as Vegemite
  • Sauces such as fish sauce and soy sauce.
  • Eat plenty of fresh fruits, vegetables, and whole grains

Fruits, vegetables, and whole grains are naturally low in sodium and diets high in these are associated with a lower risk for developing heart disease6. Fruits, vegetables, and whole grains may also contain additional nutrients, called phytonutrients, which can be of further benefit to heart health.

Read the ingredients

If you buy food that comes in packaging, then it will have an ingredients list. Most often salt will be listed as sodium, and it is important to keep total daily levels below 2g per day. Choose foods labelled as “no-added salt” and look at the total you are consuming per serve. Try to choose foods with less than 120mg per 100g.

When looking at food labels, the column labelled quantity per 100g is useful, as it helps you to compare the sodium content of similar foods and make low sodium swaps, regardless of the serving size. For example, here are the ingredients listed on the back of two different brands of tinned tomatoes with differing serving sizes. The tin that is lower in sodium is an easy swap for the one you would normally purchase.

Make your own and remove salt from your cooking

Many people will say that they prefer salty or sweet foods, and the good news is that these are not in-built tastes but learned behaviours. Making your own food from scratch is the best way to be mindful of your sodium intake, whilst reducing your consumption of ultra-processed foods. If you add salt when you are cooking or at the table, then ensure that you find some way of measuring it and gradually decrease it until you aren’t adding any at all. Find other ways to flavour your food, using garlic, herbs, and spices. Your taste buds will start to adapt to the new, no salt flavour and you will ensure that you lower your risk for heart disease at the same time.

Nutritionist Chloe Steele has provided this information for Heart Research Australia Heart Health Club members. If you are not a member you can sign up here.

For more information about Heart Disease and tips for being heart health, check out our Heart Hub here.

1.        National Health and Medical Research Council. Sodium (Updated 2017). Nutr Ref Values Aust New Zeal Incl Recomm Diet Intakes. 2017;(September):210-216.

2.        Patel Y, Joseph J. Sodium intake and heart failure. Int J Mol Sci. 2020;21(24):1-12. doi:10.3390/ijms21249474

3.        Garfinkle MA. Salt and essential hypertension: pathophysiology and implications for treatment. J Am Soc Hypertens. 2017;11(6):385-391. doi:10.1016/j.jash.2017.04.006

4.        Hummel SL, Mitchell Seymour E, Brook RD, et al. Low-sodium dietary approaches to stop hypertension diet reduces blood pressure, arterial stiffness, and oxidative stress in hypertensive heart failure with preserved ejection fraction. Hypertension. 2012;60(5):1200-1206. doi:10.1161/HYPERTENSIONAHA.112.202705

5.        Chen X, Zhang Z, Yang H, et al. Consumption of ultra-processed foods and health outcomes: A systematic review of epidemiological studies (Consumo de alimentos ultraprocessados ​​e resultados para a saúde: uma revisão sistemática de estudos epidemiológicos). Nutr J. 2020;19(1):1-10.

6.        Rosato V, Temple NJ, La Vecchia C, Castellan G, Tavani A, Guercio V. Mediterranean diet and cardiovascular disease: a systematic review and meta-analysis of observational studies. Eur J Nutr. 2019;58(1):173-191. doi:10.1007/s00394-017-1582-0