Why salt is bad for you - and how to spot hidden sodium

When it comes to eating healthily, we’ve all heard that we should cut down on our salt intake. But how much is too much - and why is sodium so bad for you, anyway?

‘We all need a bit of salt in our diets for our bodies to function properly,’ says Sonia Pombo (opens in new tab), nutritionist at Consensus Action on Salt and Health (CASH) (opens in new tab) - but too much of the white stuff can lead to a host of serious health implications. 

Crucially, it can make your body hold on to too much water. This extra fluid can then increase blood pressure, putting a strain on our kidneys, arteries, heart and brain. Over time, this can result in kidney and heart disease and elevate our risk of stroke, while also leading to brittle bones and dementia. 

• How to lower your cholesterol: expert tips to help keep your heart healthy
• How to reduce your sodium intake in 7 easy steps
• Best heart rate monitors to keep track of your ticker

What's more, a new study reveals that consuming too much salt can also weaken your immune system. Volunteers who ate double the recommended daily allowance showed significant immune deficiencies and decreased ability to fight off bacterial infections. 

We’re not born with a preference for salty food, however - instead it’s something we develop. Sonia explains: ‘Like sugar, the more salt we eat, the more our taste buds adapt to the flavour, and the more we need. It’s been shown that if children eat a high-salt diet, they’ll continue doing so as adults. 

‘By reducing your salt intake or, ideally, cutting it out completely, you can retrain your taste buds in a few weeks.’ 

How much sodium per day is OK?

In the US, the Dietary Guidelines for Americans recommend limiting intake of sodium to less than 2300mg per day (opens in new tab). Meanwhile in the UK, NHS guidelines (opens in new tab) state that we should be eating no more than 6g of salt a day.

However, the reality is we typically eat up to 50% more a day on both counts - 3400mg of sodium in the US and 9g of salt in the UK.

Salt vs sodium: is there a difference?

Salt and sodium are often used interchangeably, however there is a distinction. Sodium is a mineral that is found naturally in some foods. Meanwhile, salt is a mineral compound that is composed of sodium and chlorine. In both cases, however, it’s the sodium that raises our blood pressure and causes problems.

Somewhat unhelpfully, the two terms are measured slightly differently, too. Where sodium is listed on food packaging, multiply the figure by 2.5 to calculate the salt content. 

In the USA, FDA regulations require nutritional information - including sodium - to be listed on most foodstuffs (baring meat and poultry). Meanwhile, new regulations now mean all food products sold in Europe have to display the salt content.

Beware hidden sodium

Even if you don’t add salt to your food during cooking or after, hidden salts in processed foods can ramp up our intake - often without us realising it. 

‘Up to 75% of the salt in our diets is hidden in processed foods,’ says Sonia. ‘And this doesn’t just include salty foods like cheese and bacon, but everyday foods that don’t necessarily taste salty, such as bread, pasta, gravy and other savoury sauces.'

Her advice? 'Always check the label, and give anything with a high sodium or salt content the swerve.'

Should I eliminate salt completely?

Despite its negative connotations, salt is an essential nutrient, which is important for a number of body functions. 

‘It’s a vital component in our blood and moderate consumption helps support healthy heart function,’ says Dr Riccardo Di Cuffa (opens in new tab), founder of Your Doctor

This might seem to go against everything we’ve been told, but these little grains are responsible for keeping our heart rate stable. The presence of sodium ions (found in salt) is essential for the contraction of muscles, including the largest and most important one of all – our heart.

It’s also key for bone health, sleep, preserving proper brain and nerve function and aiding digestion. 

What’s more, it also plays a big role in keeping us hydrated. This might seem counterintuitive, but salt can actually help us retain water in our cells, ensuring we maintain the correct fluid balance in our bodies. That’s why it’s key to replace lost salt, as well as water, after a hard workout – isotonic sports drinks are
a good way to top up lost nutrients.