Cosmos Magazine: Why and how does salt make food taste so good?

Salt is made up of both sodium and chlorine, which - although you shouldn't eat them separately - are molecules that humans need to survive.

But that doesn't explain why we like it. We need lots of things in broccoli too - vitamin C, vitamin K, iron, and potassium for example - and yet cravings for raw broccoli are rare.

Salt is particularly special because not only does it make things salty, it can also enhance the flavour of other flavours. This works for both savoury and sweet foods, which is probably why we end up eating so much of it.

The response time to putting salt on our tongue is also incredibly fast. Our tongue's nerve cells light up in just 50 milliseconds - a quarter of the time it takes for an eye to blink.

In 2016 a team of Australian researchers looked at how salt can touch our brain's reward system.

They stopped giving mice salt (effectively starving them of the stuff), then administered different opioid blockers and giving the rodents access to both salty and non-salty water.

While most of the salt-starved mice drank the salty water, the animals given a blocker, called naloxonazine, barely touched it.

Scientists already knew that salt cravings are regulated by the opioid system in the brain. This is the section of the brain where we process rewards, pain and addiction.

For example, if we eat when we're hungry, our brain rewards us with natural opioids, like endorphins for doing such a good job.

External opioids can also work the same way. Drugs like heroin work on these pathways, and this is why the drug can be extremely addictive and drive cravings.

But that the opioid blocked mice didn't want the salty water suggests that the receptors that naloxonazine binds to are responsible for the salt reward circuit.

This means salt could work the same way as an opioid, giving us that 'rush' when we get it.

Unfortunately, as delicious as it is, too much salt isn't good for us.

When we eat salt, the amount of sodium in our blood goes up and our body then draws more fluid into the blood to get the sodium concentration to the right level.

However, the more fluid in the blood, the higher the pressure against the blood vessel walls.

This is what causes high blood pressure, which can lead to heart attacks, strokes, or heart failure. And, as delicious as it is, nearly everyone in the world is eating too much salt.

Luckily, there could be a solution - salt substitute. Instead of just sodium chloride, a salt substitute includes more potassium chloride, meaning there's less sodium to raise your blood pressure.

Researchers in 2021 looked at 21,000 adults in China with a history of stroke or blood-pressure issues.

Half the group was given salt to use in their cooking, while the other half was given salt substitute.

In the group that had the substitute, that stroke incidents dropped by 14 per cent, heart attacks and other cardiovascular events dropped by 13 per cent and premature deaths dropped by 12 per cent.

The team suggest that if salt was switched for salt substitute worldwide, these results would add up to million of early deaths prevent each year.

Best of all, it's not that much more expensive than salt, and if you wanted to try it out most grocery stores already stock it.

If you want even more salty facts, find out about why sugar tastes so good, and find out if MSG is bad for you, keep an ear out for an episode on salt and sugar for the 'Huh? Science Explained' podcast anywhere you get your podcasts.

Originally published by Cosmos as Why salt makes things taste so good - or does it?