🧬 Family & Essentiality

🌿 Plain-Language Summary

Potassium is the body’s main intracellular electrolyte. It works with sodium to regulate nerve signalling, muscle contraction, and blood pressure. Adequate potassium from whole foods helps counter sodium’s blood pressure–raising effects, supporting heart and vascular health.

⚗️ Molecular & Chemical IDs

• Element: K (Potassium)
• Atomic number: 19
• Common salts: potassium chloride, potassium citrate, potassium bicarbonate

⚡ Functions

• Maintains membrane potential for nerve impulse conduction
• Regulates muscle contraction, including cardiac rhythm
• Helps maintain acid–base balance
• Counterbalances sodium’s effects on fluid and blood pressure

🍽️ Absorption & Bioavailability

🥗 Food Sources

• Banana, citrus fruits, avocado
• Pulses, potatoes, leafy greens, tomatoes
• Dairy and meats (smaller contributions)

🇦🇺 Australian NRVs (NHMRC)

• AI (Men): 3800 mg/day
• AI (Women): 2800 mg/day
• No UL set for food potassium
• Supplemental use requires medical oversight (esp. kidney disease, medications)

🚨 Deficiency & Excess

Deficiency (Hypokalaemia)

Causes weakness, cramps, constipation, arrhythmias. Often due to losses from diuretics, vomiting, or diarrhoea.

Excess (Hyperkalaemia)

Risk in renal impairment or with ACE inhibitors, ARBs, or K-sparing diuretics. Can cause dangerous cardiac conduction abnormalities.

🧪 Testing & Monitoring

• Serum potassium (normal ~3.5–5.0 mmol/L) — note haemolysis can falsely elevate
• ECG changes with significant disturbances (e.g., peaked T waves in hyperkalaemia)
• Urinary potassium useful for assessing renal losses

🔄 Interactions

• ACE inhibitors/ARBs & K-sparing diuretics ↑ potassium
• Loop/thiazide diuretics ↓ potassium
• Magnesium depletion can make hypokalaemia harder to correct

📊 Evidence Snapshot

• 🔬✅ Well-established: Higher dietary potassium linked with lower blood pressure (in those with normal kidney function)
• ⚠️ Clinical caution: Potassium supplements should only be used under medical advice when comorbidities or medications are present