Potassium and blood pressure: the mineral most people under-consume

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Sodium reduction gets most of the public-health attention. The flip side — inadequate potassium — produces nearly as much blood-pressure burden in industrialised populations and is easier to fix without taste-acceptability problems. The 2021 Salt Substitute and Stroke Study (SSaSS) is one of the most consequential cardiovascular trials of the decade, and it changed how many cardiology bodies think about sodium-potassium balance.

What the recommended intake actually is

The 2019 National Academies updated Dietary Reference Intakes set the Adequate Intake (AI) for potassium at 3,400 mg/day for adult men and 2,600 mg/day for adult women — a downward revision from the prior 4,700 mg/day reference that had been criticised as unrealistically high (PMID: 30844145).¹ Despite this revision, NHANES analyses show that fewer than 5 percent of US adults meet the AI on usual intake. Median US potassium intake is 2,700 mg/day in men and 2,100 mg/day in women — meaningful gaps in both sexes.

SSaSS: the salt-substitute trial that mattered

The 2021 Salt Substitute and Stroke Study (SSaSS) by Neal and colleagues randomised 20,995 adults at high cardiovascular risk in rural China to use a 75 percent NaCl / 25 percent KCl salt substitute or regular salt for cooking and seasoning. Over 4.74 years, the salt-substitute arm had a 14 percent reduction in stroke (HR 0.86, 95% CI 0.77-0.96), a 13 percent reduction in major adverse cardiovascular events, and a 12 percent reduction in all-cause mortality (PMID: 34491761).² This was a hard-endpoint trial — not a surrogate-marker study — and the effects were driven by lower sodium and higher potassium in tandem. A subsequent 2024 individual-participant-data meta-analysis confirmed mortality benefits across populations (PMID: 38986011).³

The biological case

Potassium intake affects blood pressure through several mechanisms: increased natriuresis, vasodilation via Na/K-ATPase regulation in vascular smooth muscle, reduced arterial stiffness, and reduced sensitivity to sympathetic activation. A 2017 Cochrane meta-analysis pooled 22 RCTs of potassium supplementation in hypertensive adults and found a placebo-adjusted reduction of −5.0 mmHg systolic and −3.4 mmHg diastolic at intake increases of 1,500-3,000 mg/day (PMID: 28379581).⁴ Effects are larger in those with higher baseline sodium and in Black populations. The 2020 ISH Global Hypertension Guidelines specifically recommend increased dietary potassium as a non-pharmacologic intervention (PMID: 32319175).⁵

Food sources beat supplements for most people

Bananas (~420 mg per fruit), potatoes (~900 mg per medium baked), beans (~600 mg per cup), spinach, tomatoes, yogurt, salmon, and avocados are dense sources. The DASH diet — built around potassium-rich produce — delivers 4,500-5,000 mg/day and reduces SBP by 5-10 mmHg in classic trials (PMID: 9099655).⁶ Supplemental potassium tablets are FDA-limited to 99 mg per tablet (about 2.5 percent of daily intake) for a reason: rapid bolus dosing of supplemental potassium can cause GI mucosal injury and arrhythmia. Salt substitutes (NaCl/KCl blends) are a practical middle ground that increases dietary potassium with everyday meals, validated by SSaSS.

Who must be careful

Patients on potassium-sparing diuretics (spironolactone, eplerenone, amiloride), ACE inhibitors, angiotensin receptor blockers, direct renin inhibitors, or non-selective beta-blockers; patients with CKD stages 4–5; patients on heart-failure regimens with multiple RAAS-active drugs; and patients with adrenal insufficiency should not increase potassium intake without monitoring. Pre-existing hyperkalemia is a contraindication. A 2024 KDIGO update on potassium management in CKD emphasised that potassium liberalisation may be appropriate in earlier CKD with good baseline control, but is risky in advanced CKD (PMID: 38942488).⁷

Where the field is going

Public-health agencies are increasingly framing sodium reduction and potassium repletion as a single intervention rather than separate priorities. The 2025 AHA scientific statement on dietary interventions for hypertension reiterates that the sodium-to-potassium ratio is a stronger predictor of cardiovascular risk than either alone (PMID: 39836398).⁸ The recently advancing low-sodium-high-potassium salt substitutes are likely the most evidence-based cardiovascular product on the consumer aisle that the average person can adopt without prescription.