Salt Substitute (Potassium Chloride)
Food · Pantry & Condiment · Food, Typed Supps
One of the few dietary swaps with a hard trial outcome behind it — and a real contraindication.
Stage by stage
- Salty, with an edge (Taste): Potassium chloride reads as salty but slightly bitter, which is why blends work better than pure.
- Sodium down (Circulation): Lowering sodium lowers blood pressure — the mechanism behind the trial result.
- Potassium up (Extracellular fluid): The added potassium is beneficial in most people and dangerous in a defined minority.
- Kidney handling (Kidney): Excretion depends on renal function; below eGFR 30 the load can accumulate.
What the evidence supports
- Reducing stroke and cardiovascular events — strong evidence. SSaSS randomised 20,995 participants to a 75% NaCl / 25% KCl blend and reported reductions in stroke, major cardiovascular events and all-cause mortality over a mean 4.7 years — randomised outcome data with death as an endpoint.
- Evidence that it causes Hyperkalaemia in kidney disease or on RAAS blockade — moderate evidence. A genuine contraindication. SSaSS excluded participants with serious kidney disease or on potassium-sparing diuretics, which bounds the result.
Timing
No timing. The one thing to establish before starting is kidney function and whether you take an ACE inhibitor, an ARB or a potassium-sparing diuretic.
Time to effect
- 2–4 weeks: Blood pressure response to the reduced sodium.
- ~5 years: The stroke and mortality benefit observed in SSaSS.
Allergens
None of the fourteen major allergens. Derived from what this food is, not from a product label.
Eating patterns
Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Gluten-free. Depends on the product: Keto, Low-FODMAP.
Cost band
Cheap — roughly £1.5 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
Food vs. supplement
Almost every dietary recommendation rests on observational association. This one rests on a randomised trial of nearly 21,000 people with stroke and death as endpoints, which is why it is worth treating differently from ordinary nutrition advice.
Kitchen tip
Check with a clinician first if you take a blood pressure medication or have any kidney issue. For everyone else it is one of the better-evidenced changes available.
Common myth
“It’s just salt with less sodium, so anyone can use it.” In reality: For most people it is a genuinely good swap with randomised trial evidence behind it. For someone with advanced kidney disease, or taking an ACE inhibitor, an ARB or a potassium-sparing diuretic, the potassium it replaces the sodium with can rise to dangerous levels — the SSaSS trial specifically excluded those people. It is effective and it has a contraindication, and both halves need saying.
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