← Nutrients · Metabolic Health

Sodium

ElectrolyteFoundationalTransportElectrochemical

Not just "salt": the gradient that runs your nerves, heart and nutrient absorption.

At a glance

Essential · don't fear salt
Strong human evidence

How to take it

  • Roughly 2–3 g a day, more if you sweat a lot
  • Salt your food, especially if you cook at home
  • Also: cheese, olives, bone broth

Watch out

  • Both too little and too much stress the body

Signs you're low

  • Headache, confusion
  • Seizures in severe cases
The Research

Mechanisms, studies and evidence grades for each claim above.

Intake

Roughly 2–3 g/day, increasing with sweat loss.

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Hydration

Regulates water retention, blood volume, and cellular hydration.1 Works with potassium and chloride to maintain osmotic gradients and membrane potential, keeping electrolytes in balance.3

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Heart

Electrical signaling in cardiac tissue depends on sodium gradients;3 also maintains blood volume and circulation.1

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Brain

Sodium influx generates action potentials (nerve signaling).2 Sodium-dependent transporters (SVCT2) also deliver vitamin C to neurons.4 Imbalance (hyponatremia) can cause neurological dysfunction.5

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Muscle and performance

Required for muscle contraction and prevention of dysfunction from electrolyte imbalance.3

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Gut

Sodium-dependent transport improves nutrient absorption and vitamin uptake, including SVCT1-mediated dietary vitamin C absorption in intestinal tissue.46 Also enables absorption of glucose and amino acids via sodium-coupled cotransporters. (the two citations originally linked for glucose/amino-acid cotransport point to Notion pages that no longer resolve — flagged rather than silently dropped)

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Longevity

Sodium balance influences hormonal regulation (RAAS, stress response) and circulatory stability;7 dysregulation in either direction (too low or too high) is a physiological stressor.7

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Oxidation / cellular stress

Indirectly supports antioxidant systems by enabling vitamin C transport into cells.4 See Vitamin C and Glycine / Collagen for where that connects to collagen synthesis.

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Deficiency effects

Hyponatremia: confusion, headache, seizures.

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Key insight

Sodium is not just "salt" — it's a central regulator of fluid balance, cellular energy systems, and nutrient delivery, especially for compounds like vitamin C that feed directly into collagen synthesis and antioxidant defense.8

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Top foods

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References

  1. Strazzullo and Leclercq, 2014 — sodium and fluid volume. PMID 24566466
  2. Grider et al., 2023 — action potential physiology. PMID 29262057
  3. Pirahanchi et al., 2023 — sodium potassium pump physiology. PMID 30020655
  4. Takanaga et al., 2004 — SVCT sodium-dependent vitamin C transport. PMID 12845532
  5. Hyponatremia and neurological dysfunction (overview). 2012. PMID 24493834
  6. Intestinal sodium-glucose cotransport (SGLT1) physiology. 2018. PMID 30231979
  7. RAAS / sodium balance and stress physiology. 2016. PMID 27434054
  8. SVCT1/2 vitamin C transport. 2003. PMID 12845532

TODO — the source page also cited two references for glucose and amino-acid sodium-cotransport that point to broken/deleted Notion pages (no longer resolvable). Worth re-sourcing those two claims directly against primary literature (SGLT1 for glucose, PMID 30231979 above is adjacent but not the original cite; amino acid cotransport has no substitute yet).