Sodium — The Controversy

•Observational— Cohort vs. guideline tension; salt-sensitivity is real

The tension

• RCTs of BP consistently show that lower sodium reduces blood pressure, more in salt-sensitive individuals.
• Cohort studies of mortality (PURE in particular) show a U-shape: both very low (<2 g/day) and very high (>5 g/day) sodium associate with higher mortality.

The two evidence types are not necessarily contradictory. RCTs measure short-term BP responses; cohorts measure long-term outcomes including non-cardiovascular endpoints. Both have methodological caveats (cohorts struggle with measurement; RCTs with adherence).

The salt-sensitivity dimension

Individual sodium-BP response varies dramatically:

• Salt-sensitive: BP rises with sodium load.
• Salt-resistant: BP barely changes with sodium load.

There’s no validated clinic test for salt sensitivity; African-American ancestry, older age, baseline hypertension, CKD, and obesity correlate with salt sensitivity.

Practical translation

• If hypertensive, CKD, CHF, or salt-sensitive: target the guideline range (1.5–2.3 g/day).
• If normotensive and active: 3–5 g/day sodium is probably fine; electrolyte balance (especially during exercise and heat) matters more than rigid restriction.
• Eat less ultra-processed food — this single change accomplishes most of what sodium restriction is supposed to do, because UPF delivers ~70–80% of dietary sodium.

Related entries

Blood pressure, Hypertension, DASH diet, Hydration & electrolytes.