Changing the salt in a kitchen jar may seem like a small step. But in a large trial in rural China, a blend that replaced some sodium chloride with potassium chloride was linked to fewer strokes and other cardiovascular events among people at high risk.
The finding offers a practical way to think about blood pressure: reducing sodium is one approach, but replacing some of it with potassium may also matter. The results do not mean everyone should switch salts. Potassium-enriched substitutes can be risky for people whose bodies have trouble clearing potassium, so personal health and medications matter.
What the trial tested
The Salt Substitute and Stroke Study, published in 2021 in The New England Journal of Medicine, enrolled 20,995 adults in 600 villages in rural China. Participants had a history of stroke or were at least 60 and had high blood pressure. Researchers assigned villages to use either ordinary salt or a substitute made of 75% sodium chloride and 25% potassium chloride. The study followed participants for about five years.
Compared with ordinary salt, the substitute was associated with a 14% lower rate of stroke, a 13% lower rate of major cardiovascular events, and a 12% lower rate of death. These were differences between groups in a particular study population—not a promise that an individual will receive the same benefit. The trial also found no statistically significant increase in serious clinical events related to high potassium.
Why might the blend help? Sodium can raise blood pressure, while potassium can help the body manage sodium and support healthy blood pressure. Replacing some sodium with potassium may therefore shift intake in a favorable direction. But the trial tested a specific product and population; it did not show that simply adding potassium supplements or eating more of any one food produces the same results.
Why this is more than a salt-shaker story
In many diets, much of the sodium comes from packaged, prepared, or restaurant food rather than salt added at the table. A substitute used in home cooking cannot address every source. The trial’s implications are most direct for people and households who regularly use salt in cooking or at the table—and whose health makes a potassium-containing option appropriate.
The research was conducted in rural China, where participants were older or had already experienced a stroke, and where household salt use may differ from that in other places. That makes the study important, but not a one-size-fits-all prescription. It also helps explain why a seemingly simple intervention deserves careful interpretation: population-level benefits can coexist with real risks for particular people.
Who should be cautious
Potassium is essential, but too much can be dangerous when the kidneys cannot remove it effectively. People with chronic kidney disease, impaired kidney function, or other conditions that affect potassium handling should not assume a potassium-enriched salt is a safe substitute. Some medicines can also raise potassium, including certain drugs used for blood pressure or heart disease. The exact risk depends on a person’s health and treatment.
If you have kidney disease, take medication that affects potassium, or have been told to limit potassium, ask a clinician or pharmacist before using a salt substitute. Do not stop or change prescribed medicine to make room for a dietary change. For people without known risks, it can still be sensible to check with a health professional if they are unsure whether a product is suitable.
A measured takeaway
The trial makes potassium-enriched salt substitutes a noteworthy tool in blood-pressure prevention, especially for communities where salt is commonly added during cooking. It does not replace the broader work of managing blood pressure, choosing a balanced diet, and following an individual care plan.
For someone considering a switch, the useful first step is not to buy a product blindly: check its ingredients and ask whether potassium is appropriate for you. The research suggests that replacing some regular salt may help certain high-risk populations. It also underscores why a change that is beneficial for many can be unsuitable for some.
