Public health messaging about blood pressure has focused almost exclusively on reducing sodium intake. The evidence for reducing sodium is genuine, but it is incomplete without addressing potassium. Potassium counteracts the blood pressure-raising effects of sodium through several mechanisms: it promotes sodium excretion by the kidneys, relaxes blood vessel walls by hyperpolarising smooth muscle cells, and reduces sympathetic nervous system activity. The sodium-to-potassium ratio in the diet is a stronger predictor of cardiovascular disease than sodium alone.
The Intake Gap
The recommended daily intake of potassium is 3,500mg in the UK. The average UK adult consumes approximately 2,700mg per day. This gap is primarily explained by low fruit and vegetable intake. Whole plant foods are potassium-rich by nature. The human kidney evolved to process very high potassium intakes from plant-rich diets alongside very low sodium intakes. Ultra-processed food diets reverse this ratio completely: high in sodium from added salt and low in potassium from minimal whole plant food content.
Best Dietary Potassium Sources
- Avocado: 975mg per avocado, one of the highest food sources
- Spinach: 840mg per 100g cooked
- Sweet potato: 440mg per medium sweet potato
- Lentils: 730mg per 200g cooked portion
- Salmon: 628mg per 150g portion
- Banana: 422mg per banana
- White beans: 1,000mg per 100g cooked