Potassium, Sodium, and a 21,000-Person Salt Substitute Trial

A trial run across 600 villages in rural China randomized more than 20,000 people with a history of stroke, or who were age 60 or older with high blood pressure, to cook with either regular salt or a substitute that replaced a quarter of the sodium chloride with potassium chloride. The salt substitute group had 14% fewer strokes, 13% fewer major cardiovascular events, and 12% fewer deaths over about five years.¹ The intervention changed the household salt product without adding a separate sodium-reduction program.

That trial, known as SSaSS, is the strongest evidence yet that potassium deserves equal billing with sodium in any conversation about blood pressure and cardiovascular risk. Most people already know their sodium number is too high. Almost nobody tracks whether their potassium number is too low, even though the two minerals work as a pair inside every cell in the body.

01How potassium and sodium work on blood pressure

Sodium and potassium sit on opposite sides of the cell membrane. Sodium dominates outside the cell and drives extracellular fluid volume, the acute lever behind blood pressure spikes and exercise hydration. Potassium dominates inside the cell, where it maintains the electrical gradient that fires nerves and contracts muscle, including the heart.²

Potassium helps the kidney excrete more sodium in urine, a process called natriuresis, and it relaxes the smooth muscle lining blood vessel walls.³ A diet high in sodium and low in potassium stacks two effects that both raise blood pressure. Raising potassium can blunt some of the pressor effect of the sodium already in the diet.

The modern Western dietary pattern pairs high sodium from packaged and restaurant food with low potassium from too few fruits, vegetables, legumes, and dairy. Both sides of that equation are adjustable, and addressing both captures more of the blood pressure opportunity.

02The SSaSS trial and its stroke results

The Salt Substitute and Stroke Study enrolled 20,995 adults across rural Chinese villages, most with a prior stroke or a diagnosis of high blood pressure, and randomized them by village to cook with either standard salt (100% sodium chloride) or a substitute blended at roughly 75% sodium chloride and 25% potassium chloride.¹ Participants used the product as their normal household salt for an average of 4.74 years. No behavior change was required beyond swapping the product in the kitchen.

The results were large enough to stop discussing salt substitutes as a fringe idea. Compared with the regular-salt group, the substitute group had a 14% lower rate of stroke, a 13% lower rate of major cardiovascular events, and a 12% lower rate of death from any cause.¹ The rate of serious adverse events attributed to hyperkalemia, elevated blood potassium, did not differ significantly between groups in this trial population, which mattered because hyperkalemia risk is the standard objection to potassium-enriched salt.

The population matters when reading this table. Participants were older, at elevated baseline cardiovascular risk, and living in communities where discretionary salt use was high. The trial establishes salt substitution as a treatment target for this defined population. Its size and duration cannot erase the uncertainty around younger adults, lower-risk populations, or countries where most sodium arrives in packaged and restaurant food.

03Better potassium sources than bananas

Potassium's public image is fused to bananas, and the fusion undersells better sources. A medium banana provides roughly 420 mg of potassium.² One cup of lentils or one medium baked potato provides substantially more.

Against an adult Adequate Intake of 3,400 mg per day for men and 2,600 mg for women, a banana covers roughly one eighth to one sixth of the daily target.² Beans, potatoes, and lentils do more work per serving, carry fiber alongside the potassium, and fit easily into the macro tracking most readers already do. A repeatable plate built around a legume or potato contributes more than relying on one fruit.

04Broader potassium and blood pressure evidence

SSaSS is the largest and most direct test of potassium-enriched salt substitution. A 2013 systematic review and meta-analysis in BMJ pooled randomized and observational data and found that higher potassium intake reduced blood pressure in adults and was associated with a lower risk of stroke. The evidence for broader cardiovascular disease and coronary heart disease outcomes was weaker and less consistent across studies.³

A 2026 network meta-analysis reached a similar practical conclusion. Salt substitutes containing 25% to 40% potassium chloride probably reduce systolic blood pressure and cardiovascular and all-cause mortality compared with regular salt.⁵ The authors also emphasized that the outcome evidence remains dominated by SSaSS, which limits confidence outside Chinese populations with high discretionary salt use.

The American Heart Association's diet-first guidance for adults with elevated or high blood pressure sets a target range of 3,500 to 5,000 mg of potassium per day, ideally from food rather than supplements, alongside sodium reduction.⁴ That range overlaps with the DASH eating pattern, which combines more fruit, vegetables, legumes, low-fat dairy, fish, nuts, and whole grains with less sodium and fewer ultra-processed foods. DASH also increases calcium and magnesium, so the independent contribution of potassium to the pattern's blood pressure effect cannot be determined.²

05Who needs caution before raising potassium

The SSaSS result gets misread if it turns into blanket advice to add potassium everywhere. Potassium handling depends on kidney function, and several common conditions and medications blunt the kidney's ability to excrete a potassium load.²

Healthy adults with normal kidney function generally handle potassium-rich foods well. Deliberate increases through salt substitutes or supplements require more caution because those products can deliver concentrated potassium. Anyone on the medications above, or with a kidney or heart condition, should bring a specific intake question to the clinician managing that condition.

06Salt substitutes help most in home cooking

For otherwise healthy adults with elevated or high blood pressure, potassium-enriched salt substitutes can reduce sodium intake when most salt is added during home cooking.⁴⁵ People with kidney disease or medications that affect potassium should ask a health care professional before using them. NIH's Office of Dietary Supplements notes that these products vary widely, from roughly 440 to 2,800 mg of potassium per teaspoon depending on the brand and blend, which is a wide enough range that checking the label matters.²

The swap works best in home cooking, where the household controls how much salt goes into the pot. Its value falls when most sodium arrives pre-added in restaurant meals and packaged food. For that reader, the higher-leverage move is comparing labels and choosing lower-sodium defaults using the practical ranges in the sodium intake reference.

Clinicians also use potassium citrate in some kidney stone prevention protocols and potassium chloride tablets in specific medical contexts. Those products require a medical plan.

07Potassium, exercise, and muscle cramps

Readers coming from why muscle cramps happen during exercise already know that a cramp mid-workout rarely diagnoses a potassium problem. Sweat carries very little potassium compared with sodium.² Exercise-associated muscle cramps commonly occur late in competition when fatigue is greatest, and current evidence does not support diagnosing them from potassium status alone.⁶ The blood pressure question operates over the longer timeline of the dietary pattern.

The two threads connect at the food level. Someone eating enough potatoes, beans, and yogurt to hit a potassium target is also eating foods that support post-workout glycogen and protein needs covered in the complete guide to hydration. Ordinary meals establish potassium sufficiency across the week.

08A food-first way to raise potassium

Cover potassium through food most days. Build meals around at least one potassium-dense anchor, a legume, a potato, a leafy green, or dairy, and let fruit fill in around it. Track your sodium the way you already do, and give the potassium side of the ratio equal attention.

For most healthy adults without kidney disease or the medications listed above, that food-first pattern shifts intake in the same direction as the 21,000-person trial. SSaSS turns the sodium number into a two-mineral decision and gives home cooks a practical way to change both.