Salt shaker on a table

Salt and Health: How Much Is Too Much and Where It Hides

10 min read

In our view, salt is not something to fear. Your body needs sodium, one of the two parts of salt, to work. The NHS says it is easy to have too much salt, and that eating too much can cause high blood pressure, which increases the risk of heart attacks and strokes. The useful question is how much you need and where it comes from.

This guide covers why your body needs sodium, how much salt the NHS and the World Health Organization (WHO) advise, what trials show about cutting salt, the debate over low intakes, where salt hides in everyday food, and how to cut back without losing flavour.

6 g
The NHS daily salt limit for adults and children aged 11 and over, around 1 teaspoon
NHS, Salt in your diet
3/4
Share of the salt we eat that comes from packaged and everyday foods we buy
NHS, Salt in your diet
5.4
Average fall, in mmHg, in the top blood pressure number in people with high blood pressure who cut salt for 4 weeks or more (average cut across all trials about 4.4 g a day)
He et al. 2013, Cochrane review of 34 trials
14%
Lower stroke rate with a potassium salt substitute, about 4.5 fewer strokes per 1,000 people a year, in people in rural China who had had a stroke or were 60 or over with high blood pressure
Neal et al. 2021, 20,995 people
Sources: NHS. He et al. 2013, BMJ. Neal et al. 2021, New England Journal of Medicine.

Why your body needs sodium

The WHO describes sodium as an essential nutrient. Your body needs it to keep the right volume of blood plasma, to balance acids and bases, to send nerve signals and for normal cell function. Salt is sodium chloride. The WHO treats 2 g of sodium as about 5 g of salt, so to turn a sodium figure into salt, multiply by 2.5.

The issue for most people is the opposite of too little. The WHO reports that the average adult worldwide ate about 11 g of salt a day in 2021, and that too much sodium was linked with an estimated 1.7 million deaths in 2023. It calls high sodium a well-established cause of raised blood pressure and higher risk of cardiovascular disease.

How much salt to aim for

The NHS advises adults and children aged 11 and over to eat no more than 6 g of salt a day, around 1 teaspoon. Younger children need less: no more than 5 g at age 7 to 10, 3 g at age 4 to 6, 2 g at age 1 to 3, and less than 1 g for babies under 1. The WHO recommends less than 5 g of salt a day for adults.

These limits include the salt already in food. The NHS reports that around three quarters of the salt we eat comes from packaged and everyday foods we buy, so most of your intake arrives before you pick up the salt shaker.

What trials show about cutting salt

A 2013 Cochrane review in the BMJ by Feng He and colleagues pooled 34 randomised trials with 3,230 people who cut their salt for at least 4 weeks. On average, salt intake fell by about 4.4 g a day. The top blood pressure number, systolic pressure, fell by 5.4 mmHg (millimetres of mercury, the unit blood pressure is measured in) in people with high blood pressure and by 2.4 mmHg in people with normal blood pressure. Larger cuts in salt were linked with larger falls in systolic blood pressure.

A 2021 trial in the New England Journal of Medicine by Bruce Neal and colleagues tested a salt substitute, 75% sodium chloride and 25% potassium chloride, against regular salt in 600 villages in rural China. The 20,995 people taking part had either had a stroke or were aged 60 or over with high blood pressure, and were followed for an average of 4.7 years. The salt substitute group had a 14% lower rate of stroke, a 13% lower rate of major cardiovascular events and a 12% lower death rate. Serious problems from high blood potassium were not significantly more common with the substitute in this trial. That does not show it is safe if you have kidney disease or take medicines that raise potassium (see Who should take care below).

Cutting salt lowers blood pressure Average fall in systolic blood pressure, mmHg, 34 randomised trials High blood pressure 5.4 All participants 4.2 Normal blood pressure 2.4 0 3 6
Source: He et al. 2013, BMJ, Cochrane systematic review. Salt intake fell by about 4.4 g a day on average, over at least 4 weeks. 3,230 participants in total.

The debate over low salt intakes

Some studies suggest risk might rise at low sodium intakes as well as high ones. One large example is the 2014 PURE study in the New England Journal of Medicine by Martin O'Donnell and colleagues. It estimated daily sodium from a single morning urine sample in 101,945 people across 17 countries and followed them for an average of 3.7 years. Compared with people whose estimated sodium was between 4 and 6 g a day (between about 10 and 15 g of salt), people at 7 g of sodium or more (about 17.5 g of salt) had a higher risk of death and major cardiovascular events, and the link was strongest in people with high blood pressure. People below 3 g of sodium a day (about 7.5 g of salt) also had a higher risk. That low group includes people eating within the NHS limit of 6 g of salt, which is why the finding is debated.

PURE was observational, so it shows links, not cause and effect. In our view, a single morning urine sample is a rough estimate of what people usually eat, and the design cannot rule out that people who were already ill ate less. The trials in the Cochrane review measured blood pressure, not deaths. The salt substitute trial did measure deaths, but it tested swapping some sodium for potassium in high-risk people, not eating less salt. So neither settles this question on its own. The NHS and WHO limits remain in place. In our view, PURE is not a reason for most UK adults to add salt, since the WHO reports that the average adult worldwide eats about 11 g a day, more than double its limit of less than 5 g.

Where salt hides

The NHS lists foods that are often high in salt: bread, breakfast cereals, meat products and ready meals, as well as takeaways and restaurant meals. It suggests eating cured meats and fish, cheese, olives and pickles less often, and not using too much soy sauce, gravy granules, ketchup, mustard, mayonnaise or brown sauce. Some dissolvable tablets, such as certain painkillers, vitamins and prescription medicines, may be high in salt.

How to cut back

These steps come from NHS advice, with our own notes marked.

1
Read the front label
The NHS suggests choosing products with green and amber colour-coded labels on the front of the pack, and lower-salt versions of foods and sauces.
2
Flavour without salt
Use herbs, spices, black pepper, garlic, chilli or lemon juice. Taste your food before adding salt, and take the salt shaker off the table.
3
Swap the hidden sources
Choose tinned foods in water instead of brine, and snacks such as fruit, vegetable sticks, plain rice cakes or unsalted nuts.
4
Cook more meals yourself
In our view, cooking from basic ingredients gives you control over how much salt goes in, since most salt comes from food you buy.

Who should take care

The WHO suggests that adults in the general population replace regular table salt with lower-sodium salt substitutes that contain potassium. Its guideline does not apply to pregnant women, children, people with kidney problems or people with other conditions that affect how the body clears potassium. In our view, ask your GP (general practitioner) or pharmacist before you use a potassium salt substitute if you have kidney disease, heart failure or diabetes, or take medicines that can raise potassium, such as some blood pressure and heart medicines or potassium supplements.

The NHS advises speaking to your GP before changing any medicines, including dissolvable tablets that may be high in salt. In our view, if you have high blood pressure, kidney disease or heart failure, follow the salt advice your GP or specialist gives you. In our view, if you train for long periods in the heat and sweat heavily, talk to a sports dietitian about fluids and salt rather than guessing.

Frequently asked questions

How much salt should I eat a day?
The NHS advises no more than 6 g of salt a day for adults and children aged 11 and over, around 1 teaspoon. The WHO recommends less than 5 g for adults.
Does cutting salt help if my blood pressure is normal?
In the 2013 Cochrane review, cutting salt lowered systolic blood pressure by 2.4 mmHg on average in people with normal blood pressure, a smaller fall than the 5.4 mmHg seen in people with high blood pressure.
Is eating too little salt risky?
The PURE study linked low estimated sodium intakes with higher risk, but it was observational and used a single urine sample to estimate intake. The NHS says it is easy to have too much salt, and the WHO reports that the average adult worldwide eats about 11 g a day, more than double its limit of less than 5 g.
Do salt substitutes work?
In a 2021 trial of 20,995 people in rural China who had had a stroke or were 60 or over with high blood pressure, a potassium salt substitute lowered the stroke rate by 14%, about 4.5 fewer strokes per 1,000 people a year. It is not known if the benefit is the same in younger, healthier people. The WHO guideline on these substitutes excludes pregnant women, children, people with kidney problems and people with other conditions that affect how the body clears potassium. If you take blood pressure or heart medicines, ask your GP (general practitioner) or pharmacist first.
Where does most of my salt come from?
The NHS reports that around three quarters of the salt we eat comes from packaged and everyday foods, such as bread, breakfast cereals, meat products and ready meals.

The bottom line

Your body needs sodium, but the NHS says it is easy to have too much salt, and around three quarters of the salt we eat comes from packaged and everyday foods. Randomised trials show that cutting salt lowers blood pressure, more so in people with high blood pressure, and a large trial found that a potassium salt substitute lowered stroke in older, high-risk adults. The NHS limit for adults is 6 g a day. In our view, reading front labels, cooking more meals yourself and flavouring food with herbs and spices are practical ways to get there, and anyone with a heart or kidney condition, or who takes blood pressure medicines, should check with their GP before cutting salt hard or using a potassium salt substitute.

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Related reading

Sources

  • He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ 2013;346:f1325. pubmed.ncbi.nlm.nih.gov/23558162
  • Neal B, Wu Y, Feng X, et al. Effect of salt substitution on cardiovascular events and death. New England Journal of Medicine 2021;385(12):1067-1077. pubmed.ncbi.nlm.nih.gov/34459569
  • O'Donnell M, Mente A, Rangarajan S, et al. Urinary sodium and potassium excretion, mortality, and cardiovascular events. New England Journal of Medicine 2014;371(7):612-623. pubmed.ncbi.nlm.nih.gov/25119607
  • NHS. Salt in your diet. Last reviewed 17 April 2023. nhs.uk
  • World Health Organization. Sodium reduction fact sheet. 11 May 2026. who.int
  • World Health Organization. Use of lower-sodium salt substitutes: WHO guideline. 27 January 2025. who.int
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