Chloride

Sodium's partner in salt, and the raw material for stomach acid.

Mechanisms, studies and evidence grades for each claim above.

What it is

Chloride (Cl⁻) is the primary extracellular anion and a major electrolyte that partners with sodium to regulate fluid distribution. See Sodium for the paired mechanism.

Why it matters

• Helps maintain hydration and blood volume (osmotic balance)
• Required for stomach acid (HCl) production
• Supports acid-base regulation (kidney + buffering)

Intake

Most chloride comes from salt (NaCl), so it's often tracked indirectly via sodium intake. Typical adequate intake for adults is roughly 2.3 g/day (varies by guideline); needs increase with high sweat loss and GI losses (vomiting, etc.).

Deficiency effects

Hypochloremia can occur with vomiting or diuretic use and may cause weakness, fatigue, and metabolic alkalosis; low stomach acid production can impair digestion in some contexts.

Lab signals

Low chloride often travels with metabolic alkalosis, diuretic use, or vomiting. High chloride can be seen with saline loads and may track with metabolic acidosis in some contexts.

Top foods

• Salt
• Olives
• Seaweed
• Bone broth

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