Every cook knows the moment. A stew is tasted, something seems to be missing, and a hand reaches for the salt cellar. A pinch, followed by another, just in case.
Few people realise that this everyday gesture involves a delicate balance. On one side is sodium, found in ordinary table salt and responsible for its characteristic salty taste. On the other should be potassium, a mineral abundant in fruit, vegetables and pulses. For decades, we have piled up the first until it threatens to tip the scales, while the second has remained almost forgotten. Where that balance lies has much to do with our blood pressure.
When Salt Was Worth a Salary: There was a time when salt was a treasure. Caravans crossed the Sahara to trade it for gold, and the English word salary derives from the Latin salarium, the allowance received by Roman soldiers which, according to tradition, was associated with the purchase of salt. Historians still debate whether soldiers were actually paid in salt or received money to buy it.
Today, the situation has been reversed. Salt is so cheap and readily available that we have ended up consuming too much of it. The World Health Organization (WHO) recommends no more than five grams a day, roughly one teaspoon. In Spain, a reference study conducted in 2009 estimated average daily consumption at 9.8 grams, almost twice that amount. According to the WHO, excessive dietary sodium was associated with approximately 1.7 million deaths worldwide in 2023.
Why is it so harmful? Imagine a hose through which water flows under excessive pressure for years. Its walls eventually come under strain and may deteriorate. Something similar happens to our arteries when blood pressure remains persistently high. Hypertension is precisely this sustained elevation of the pressure exerted by blood against the artery walls. It rarely causes symptoms, and this very lack of symptoms means that many people have it without knowing. Over time, it increases the risk of stroke, heart attack, heart failure and kidney disease.
Two Sides, Two Destinies: Table salt is sodium chloride. When we consume too much sodium, the body tends to retain water. The volume of circulating fluid increases, which in turn favours a rise in blood pressure.
Potassium plays a complementary role. It helps the kidneys eliminate sodium through the urine and contributes to the regulation of blood vessel tone, encouraging the vessels to relax. This is why the two minerals are closely linked in the control of blood pressure.
The WHO recommends that adults consume at least 3.5 grams of potassium a day. A substantial proportion of the population falls short of this amount. The result is an unbalanced scale, with too much sodium and insufficient potassium.
Potassium-enriched salts are designed to address both sides of this imbalance. They replace part of the sodium chloride with potassium chloride. The proportions vary from one product to another, but generally range from about 15 to 50 per cent. Each pinch therefore delivers less sodium and more potassium than conventional salt.
In shops, these products appear under different names, such as “low-sodium salt”, “potassium salt” or “mineral salt”. It is worth checking the ingredients, as the proportions of the two minerals differ considerably between products.
Researchers are still investigating how much of the cardiovascular benefit comes from reducing sodium and how much from increasing potassium. Both are likely to contribute, although the question remains open.
The Experiment of 600 Villages: For years, we have known that these salts help lower blood pressure. What remained unanswered was a more important question: whether that reduction also translated into fewer cardiovascular events and fewer deaths.
The answer came from the SSaSS trial — the Salt Substitute and Stroke Study — one of the largest clinical trials to investigate this question. It was a cluster-randomised trial, meaning that entire villages, rather than individual participants, were randomly assigned to one of the two groups.
The study involved 20,995 people from 600 rural villages in China, with an average age of 65. Almost three in four had previously suffered a stroke, and 88 per cent had hypertension. Residents of 300 villages were given a salt substitute containing 25 per cent potassium chloride and 75 per cent sodium chloride. The remaining 300 villages continued to use ordinary salt.
After an average follow-up of 4.7 years, the group using the substitute experienced 14 per cent fewer strokes, 13 per cent fewer major cardiovascular events and 12 per cent fewer deaths from any cause. Systolic blood pressure — the upper reading — was, on average, about 3.3 mmHg lower in the substitute group. Study 1 · Study 2
Evidence from other studies points in the same direction. A meta-analysis — a study that gathers and statistically combines the results of several trials — examined 21 studies involving 31,949 participants from 15 countries.
It found reductions in overall mortality, cardiovascular mortality and cardiovascular events. These findings nevertheless need to be interpreted with some caution, as only five of the 21 trials reported clinical outcomes, and much of the evidence came from SSaSS itself.
Analyses of blood pressure changes found no significant differences according to age, sex or a history of hypertension. This observation does not, however, establish that the benefits in terms of cardiovascular events are identical across all these groups.
In Peru, a trial conducted in six communities in the Tumbes region found that, among people who were not hypertensive at the outset, using the substitute was associated with a 51 per cent relative reduction in the risk of developing hypertension. Across all participants, the average reduction in systolic blood pressure was more modest, at 1.29 mmHg.
What the WHO Says and What It Leaves Open: In January 2025, the WHO published a specific guideline on the use of lower-sodium salt substitutes. Its recommendation is more nuanced than some headlines suggest. WHO guideline
The first recommendation remains to reduce sodium intake to below two grams a day, equivalent to five grams of salt. In addition, for adults who use table salt, the WHO suggests replacing ordinary salt with a product in which part of the sodium chloride has been replaced by potassium chloride.
The recommendation applies to the salt we add at home, either at the table or during cooking. It does not cover the salt already present in packaged foods or used in restaurant meals. Nor does it apply to people with kidney disease or other conditions that impair potassium elimination. The WHO also makes no recommendation for children or pregnant women, because the available evidence is insufficient to draw conclusions about these groups. This does not mean that the substitutes have been shown to harm them.
The Stowaway in the Supermarket: Here comes the less comfortable part. Between 70 and 75 per cent of the salt we consume comes from processed foods and ready-made meals. In other words, it travels as a stowaway in bread, cured meats, cheese, canned foods, prepared dishes and snacks.
A bag of crisps may contain a considerable amount of salt, although the figure varies by brand and product. Changing the salt in the cellar shifts the balance in the right direction, but it does not, by itself, solve the problem.
To uncover the stowaway, we need to get into the habit of reading food labels. In the European Union, manufacturers must declare the salt content, although sodium may also be listed separately. In that case, simply multiply the sodium figure by 2.5 to obtain the equivalent amount of salt. As a reference, the British traffic-light labelling system — a voluntary scheme widely used in the United Kingdom — classifies a food as high in salt if it contains more than 1.5 grams per 100 grams, and as low in salt if it contains no more than 0.3 grams. The latter is also the threshold for describing a product as “low in salt” under EU rules.
The Garden’s Counterweight: Food remains the best source of potassium. Bananas have a reputation as champions, but many other foods contain even more.
Per 100 grams, dried white beans provide approximately 1,700 milligrams of potassium; dried chickpeas, around 1,000; and lentils, about 700. Among fresh foods, avocado stands out with roughly 485 milligrams, spinach with 466, potatoes with 400 and bananas with 358.
It is important not to compare dried and cooked foods directly. Pulses absorb water during cooking, so their potassium content per 100 grams decreases accordingly. Even so, a 60-gram portion of dried white beans can provide around 1,000 milligrams, almost a third of the recommended daily intake.
Cooking also holds a secret. Potassium dissolves in water. When we boil potatoes, vegetables or pulses in plenty of water and then discard it, we may lose a considerable proportion of this mineral. Depending on the cooking method, losses can reach 75 per cent.
These techniques are useful for people who need to restrict their potassium intake. For healthy people, however, it makes sense to preserve as much of it as possible by steaming vegetables or incorporating the cooking liquid into other dishes.
When the Counterweight Weighs Too Much: Every mineral essential to life has a less friendly side. An excessive concentration of potassium in the blood is known as hyperkalaemia, and it can be dangerous because the heart is particularly sensitive to changes in potassium levels.
In severe cases, hyperkalaemia can cause potentially fatal arrhythmias. It may produce symptoms such as muscle weakness, tingling or cramps, although it can also go unnoticed. For this reason, it is difficult to identify from symptoms alone.
Healthy kidneys remove excess potassium efficiently. Problems arise when kidney function is impaired or when certain medicines interfere with this process.
Before using these salts, it is advisable to consult a doctor if you have chronic kidney disease, diabetes — particularly when it affects the kidneys — or any other condition that favours potassium accumulation. The same caution applies to people taking potassium-sparing diuretics, such as spironolactone, potassium supplements, or medicines belonging to the ACE-inhibitor and ARB families. Potassium-sparing diuretics increase urine output while reducing potassium excretion. These medicines are widely used to treat hypertension, heart failure and other cardiovascular conditions.
The prescribing information for spironolactone — the official document describing the medicine and its precautions — expressly warns of the risk of severe hyperkalaemia when it is combined with potassium supplements or salt substitutes containing potassium. Since declining kidney function can progress without obvious symptoms, a blood test measuring potassium levels and kidney function can identify risks that might otherwise go unnoticed.
There is also a household detail worth bearing in mind. The cooking pot is shared, and whatever goes into it is eaten by everyone. If someone in the family needs to avoid excess potassium, the WHO advises against using these substitutes to prepare food for that person.
The SSaSS trial excluded people with severe kidney disease — a term the study did not define precisely — and those taking potassium-sparing diuretics or potassium supplements. Among the selected participants, no increase in serious episodes of hyperkalaemia was observed. Several commentators have nevertheless highlighted an important limitation. Potassium levels in the blood were not measured regularly, so some episodes may have gone undetected.
Salts With a Premium Image: It is tempting to think that Himalayan pink salt or sea salt offers a solution. It does not.
Both ordinary salt and Himalayan pink salt consist mainly of sodium chloride. In terms of sodium intake, the differences are small and of no practical significance. The minerals responsible for their colour are present in quantities too small to provide any meaningful nutritional benefit.
The most obvious difference is usually the price. Ordinary salt may cost around 0.50 euros per kilo, while some pink salts reach eight euros. Paying more does not mean eating more healthily. The main risk is that their appearance or supposed beneficial properties may encourage us to use them less sparingly.
Salts labelled “light” or “low-sodium” can indeed reduce sodium intake considerably, although their composition varies. Many replace part of the sodium chloride with potassium chloride and are therefore subject to the same precautions. The label should always be checked.
One final point concerns iodine, an essential element that enables the thyroid gland, located at the front of the neck, to produce its hormones and regulate many bodily functions. Non-iodised sea salt does not guarantee an adequate intake of this mineral. The WHO states that, where salt iodisation programmes exist, lower-sodium substitutes should be iodised in the same way as ordinary salt. It is therefore worth checking the packaging.
Taste, Purse and a Little Imagination: And what about taste? The findings are reassuring. In the SSaSS trial, more than 90 per cent of participants in the intervention group were still using the substitute after five years. When the proportion of potassium chloride is high, some people notice a metallic or bitter aftertaste. Mixtures with a lower concentration tend to be more palatable. The palate can also adapt over time to less salt, although the studies are small and do not all agree on how long this takes.
And what about the purse? Salt substitutes tend to be somewhat more expensive. In SSaSS, a kilo cost 1.62 dollars, compared with 1.08 dollars for ordinary salt. Prices vary by country, brand and potassium content. Since we use relatively small quantities, however, the additional cost is usually modest.
There is always another resource as well — imagination. Herbs, lemon and garlic bring character to dishes and make it easier to use less salt. Paprika, vinegar and spices help as well. The kitchen offers more possibilities than we tend to remember when our hand automatically reaches for the salt cellar.
This reflection has a precedent in these pages. In November 2023, I published Healthy Flavours: Alternatives to Salt, an article exploring how spices, aromatic herbs and other seasonings can enrich our dishes while reducing our reliance on the salt cellar. That proposal remains fully relevant. Today, we add another perspective, supported by new scientific evidence, which invites us to pay closer attention to the balance between sodium and potassium. Two different approaches, both leading to the same idea. Looking after our health also begins in the kitchen.
What the Balance Does Not Yet Know: It is important to acknowledge the limitations of the research. SSaSS was an open-label study, meaning that participants knew which type of salt they were using. It was conducted in a single country and involved an older population at high cardiovascular risk. Moreover, in those rural communities, much of the salt was used in home cooking, while processed foods were consumed relatively infrequently — a situation quite different from that in Western societies.
The trial’s lead investigator believes the findings are applicable to other populations. However, the editorial accompanying the study in the New England Journal of Medicine reminded readers that their generalisability remains difficult to predict. The magnitude of the benefit may vary according to dietary habits, sodium and potassium intake, and the characteristics of each population.
The meta-analysis also found considerable variation between studies. In addition, information on hyperkalaemia was limited. The evidence supports the use of these substitutes under appropriate conditions, but important questions remain unanswered.
Research offers valuable guidance, not a universal guarantee.
The Pointer of the Balance: A different salt does not cure hypertension, nor does it compensate for an unbalanced diet. But it can help tip the scales away from excess sodium and towards a little more potassium. This change should go hand in hand with eating pulses, vegetables and fruit, reducing the consumption of very salty products, and paying attention to the salt that reaches our table without our having added it.
Health is built through simple decisions, repeated day after day. Some go almost unnoticed, such as changing the salt in the cellar or choosing pulses instead of a fast-food meal. Their importance lies not in any single gesture, but in the consistency with which we make these choices part of our lives.
The next time your hand reaches for the salt cellar, it may be worth pausing for a moment. There is a balance we cannot see, but our arteries know it very well.
Nullius in verba