salt; sodium; chloride;
The salt that we eat is called sodium chloride.
It consists of 40% sodium and 60% chlorine joined together chemically to make a compound we call salt. Both sodium and chloride are not safe by themselves, but when they join together they are not dangerous.
The body can't make the sodium and chlorine that are in salt by itself but they are essential to keep the body working and healthy.
Here are some of the important jobs sodium has in the body.
- It helps other nutrients be absorbed in the small intestine.
- It helps send messages along the nerves.
- It helps balance the amount of water in the body.
- Too much or too little sodium can affect blood pressure.
Chloride is also essential. Some jobs are:
- It helps to regulate the balance of acid in the body.
- Helps the body to absorb potassium.
As sodium chloride is so very important to humans and animals let's find out more about it.
How we get sodium chloride
There are 3 main ways of getting sodium chloride, which is the salt we use in our food.
- Deep shaft mining. This is like tunnelling for coal or other ores. A tunnel is dug down into the ground, and then side tunnels are made when the salt is dug out. This salt was left here many thousands of years ago when that part of the earth was under the sea.
- Solution mining. If salt is found underground, rather than digging it out, wells are tunnelled down into the salt layer, and then water is pumped down to dissolve the salt – the water that comes back up has salt in it. This water is boiled and cleaned so that when it dries the salt will be pure enough to eat.
- Solar evaporation. This is where salty sea or lake water is allowed to dry out in the sun in shallow ponds. When there is enough dry salt, it is collected, and cleaned ready to use.
The hard 'rock' salt that is collected in all these ways is crushed so that it becomes the salt you would get in a salt shaker and it is easy to pour out.
Sometimes iodine is added to salt, because in many places in the world there is not enough iodine in food, which can cause problems for the thyroid gland (a child's brain might not grow well, or a person might have very low energy levels).
Salt and your body
Our kidneys keep the balance of water and chemicals by controlling the amount of water in the body.
- If there is more water in our body than is needed, the extra water is collected by our kidneys and more urine is made.
- If not enough water is coming in – we have not been drinking quite enough water or other drinks - then little if any urine will be allowed out.
- If you sweat a lot, like on a hot day or if you are doing a lot of exercise, then you are sweating out salt as well as water.
- If you were dehydrated and feeling sick and dizzy then you might need to replace salt as well as water.
- Kids rarely exercise enough to need sports drinks. If you are thirsty after playing sport, but you have not been sweating a lot or working really hard you do not need salty drinks like sports drinks. Plain water and something to eat is enough.
If you have too much salt in your body then you could feel very thirsty and need to drink more water so that your kidneys can get rid of the extra salt by making more urine.
Having too much salt in the body can lead to heart problems such as high blood pressure.
Having far too much to drink can cause the salt level in your blood to drop too much and cause damage to your brain. This can sometimes happen when young people use some illegal drugs – they feel really thirsty, drink too much water or other drinks and their brain can swell up (sometimes this is called 'drowning' their brain).
We need to help our kidneys do their job by watching how much salt we have.
How much salt do you need?
Many people eat a lot more salt than they need. This is easy to do.
- Many processed foods already have salt in them.
- Fast foods often have a lot of salt in them.
- Canned foods often have salt.
- Packet foods such as biscuits often have salt.
- Packet foods like potato crisps and corn chips have a lot of salt in them.
There is often a lot of salt in foods because people have learned to like the taste of salty food – but too much is not good for you.
Sometimes the word salt is not mentioned but sodium is. Remember that salt is sodium and chloride?
If you know how much sodium is in the food you can find how much salt that is by multiplying the amount of sodium by 2.5.
The daily recommended maximum for salt for kids depends on their age.
- 1-3 years - 2g salt a day
- 4-6 years - 3g
- 7-10 years - 5g
- 11 and over - 6g.
You do not need any more salt than this.
Most foods that we cook at home do not need added salt as they already have salt in them, and we also do not need a salt shaker on the table to add even more salt.
When mum or dad is cooking then ask them not to add any salt to your food. You will find the food still tastes really good. It can also help mum or dad to cut down to a healthier level of salt.
Interesting stuff about salt
Salt has been important to humans throughout history.
- Salt is used to help make food last longer. Many foods have been pickled in brine (salty water) or have had a lot of salt rubbed into them to make the food last longer.
- The words salary and soldier come from old Latin words to do with giving or getting salt.
- Taxes on salt have led to wars, and a tax was one of the reasons why the French people revolted against their king in the French Revolution.
- Salt was so important to keep food safe in the Middle Ages that special salt roads were built to get salt from the ports to the cities and towns of the time. They were guarded by soldiers to stop the salt being stolen.
- Long ago people would boil seawater in a clay pot then collect the salt which was left when the water had boiled away. It was a long slow job to get little salt. In some very poor countries people are still forced to get their salt this way.
- Some people believe that salt can protect against demons.
- Some people believe that using salt can purify people and objects - that is free them from evil.
- In ancient times an invading army might 'salt the earth' to stop crops growing and make their enemies surrender faster.
- Salt crystallisation pans at Dry Creek produce about 285,000 tonnes of salt every day from 4,000 hectares.
- The world's largest salt flat is Salar de Vyani in Bolivia. This has 13,337 km of salt!
Some other things about salt
- Salt can be used to clean teeth, to rub on skin to make it smooth or added to a relaxing bath.
- Salt is often added to biscuits and sweets to 'improve' the flavour! Sounds yuk? Look at the list of ingredients!
- Humans and animals need salt to help their bodies work well. Often farmers, or hunters, will make a salt lick so the animals can get the salt that they need. Animals really like salt so that's why hunters may use a salt lick to attract animals to that area.
- In many countries including Australia, iodine is added to table salt to stop people getting thyroid gland problems.
Dr Kate says
Sometimes it can be hard to work out how much salt is in a product. You can help your body by looking out for salt.
- Look for salt in soups, pasta meals, pizza, take- away meals, sauce, mayo, sauce, chips, biscuits and cakes.
- Taste your food before adding salt or sauce – you will probably find you do not need to add the salt.
- Chose less salty snacks, bacon, cheese, pickles and smoked fish.
Some people like the taste of sea salt or salt from some rivers. They may taste a little different to other table salt but they are still all the same type of salt.
We've provided this information to help you to understand important things about staying healthy and happy. However, if you feel sick or unhappy, it is important to tell your mum or dad, a teacher or another grown-up.