Sodium (Na)

Sodium’s chemical symbol, Na, comes from the Latin name natrium, itself from Greek νάτριον and Egyptian natron, a natural source of soda compounds used historically. The English name “sodium” derives from soda (soda ash). Modern chemistry adopted Na as the element’s official symbol to reflect its historical Latin root while keeping the English name sodium in common use.

Sodium (Na) is an essential electrolyte that helps maintain fluid balance, blood pressure, and acid–base equilibrium. It enables nerve impulse transmission and muscle contraction, supports nutrient absorption in the gut (e.g., glucose), and aids kidney function in regulating electrolytes. Both deficiency and excess can cause health problems, so intake should be balanced according to guidelines.

Sodium is the chemical element represented by the symbol Na. In neutral elemental form it’s written as Na, but in biological fluids and most compounds (for example table salt, NaCl) it exists as the positively charged sodium ion, Na+. Clinically and physiologically, “sodium” almost always refers to Na+, the ion responsible for fluid balance, nerve conduction and blood pressure regulation.

Sodium (Na) in a blood test is a key electrolyte that helps regulate fluid balance, nerve impulses and muscle function. It’s measured in mmol/L, with a typical reference range about 135–145 mmol/L. Low sodium (hyponatremia) or high sodium (hypernatremia) can indicate dehydration, kidney or heart issues, hormonal imbalances, medication effects or conditions like diabetes insipidus and requires medical evaluation.

Sodium causes the body to retain water, increasing blood volume and raising blood pressure. Excessive intake worsens hypertension risk, especially in salt‑sensitive individuals, older adults, and those with kidney disease. Reducing sodium can lower blood pressure and cardiovascular risk; common guidance is to limit daily sodium to about 2,300 mg (roughly 6 g salt) or less, and follow clinician advice.

No. Na (sodium) is an element; "salt" usually means sodium chloride (NaCl). Salt is about 39.3% sodium by mass, so 1 g sodium ≈ 2.54 g salt, and 1 g salt ≈ 0.393 g sodium. Sodium also occurs in other compounds and processed foods. Health advice focuses on limiting sodium because excess intake can raise blood pressure and cardiovascular risk.