Does salt cause high blood pressure — is that still the science?

Dietary sodium intake above 2,300 mg/day increases blood pressure in "sodium-sensitive" individuals (approximately 50–70% of hypertensive men and 25–40% of normotensive men) through volume expansion and altered vascular tone mechanisms, but the magnitude of the blood pressure reduction from sodium restriction in unselected populations is 2–3 mmHg on average, making blanket universal sodium restriction less impactful than often portrayed, while in sodium-sensitive hypertensives the reduction can be 8–10 mmHg (Intersalt Cooperative Research Group, BMJ, 1988).

The sodium-hypertension relationship is real but variable. Men with salt-sensitive hypertension (more common in older individuals and in Black men) experience substantial blood pressure benefit from sodium restriction. Men with salt-insensitive normal blood pressure see minimal benefit from sodium restriction. The clinical determination of sodium sensitivity requires deliberate dietary intervention and blood pressure monitoring, not universally available, so the practical approach is: if you have hypertension above 135/85 mmHg, sodium reduction below 2,300 mg/day is worth a 3-month trial with blood pressure monitoring.

Honesty Scale: Solid (1) for sodium restriction reducing blood pressure in hypertensives. Promising (2) for universal sodium restriction in normotensive men.

What to do: The primary sodium sources in the American diet are not table salt but processed foods (bread, processed meats, canned goods, restaurant food). Reducing processed food consumption reduces sodium without requiring careful dietary tracking. Track blood pressure with home monitoring before and after a 4-week sodium-reduction experiment.

For the full picture, read The Blood Pressure Deep Dive