🧬 Family & Essentiality

🌿 Plain-Language Summary

Magnesium is required for over 300 enzyme reactions. It supports energy production, muscle and nerve stability, heart rhythm, and blood sugar regulation. It also plays roles in sleep quality, stress resilience, and mental wellbeing, making it one of the body’s most versatile nutrients.

⚗️ Molecular & Chemical IDs

• Element: Mg (Magnesium)
• Atomic number: 12
• Common supplement forms: citrate, glycinate, oxide, chloride

⚡ Functions

• Cofactor for ATP-dependent enzymes (energy metabolism)
• Stabilises neuromuscular excitability and cardiac rhythm
• Supports glucose and insulin metabolism
• DNA, RNA, and protein synthesis
• Brain & mood: regulates NMDA receptors and GABA activity → linked to anxiety, depression, and stress resilience
• Sleep: contributes to melatonin production and relaxation of nervous system pathways
• Cardiovascular: supports blood vessel relaxation, blood pressure control, and healthy heart rhythm

🍽️ Absorption & Bioavailability

🥗 Food Sources

• Nuts, seeds, legumes, whole grains
• Leafy greens, cocoa, avocado
• Mineral waters (varies by brand)

🇦🇺 Australian NRVs (NHMRC)

• RDI (Men): 400–420 mg/day
• RDI (Women): 310–320 mg/day
• Pregnancy: 350–360 mg/day
• Lactation: 310–320 mg/day
• UL (supplemental Mg): 350 mg/day (from non-food sources)

🚨 Deficiency & Excess

Deficiency

Can cause muscle cramps, tremor, arrhythmias, fatigue. Often overlaps with low potassium. Low magnesium has been linked with poor sleep, higher stress, anxiety, and depressed mood.

Excess

Usually from supplements. Magnesium oxide can cause diarrhoea. Severe hypermagnesaemia occurs mainly in renal impairment, leading to hypotension and slowed reflexes.

🧪 Testing & Monitoring

• Serum magnesium often appears normal despite deficiency
• RBC magnesium or clinical context may provide better insight
• Monitor in arrhythmias, chronic diuretic or PPI use, and unexplained fatigue/anxiety

🔄 Interactions

• PPI use and diuretics can reduce magnesium
• Can chelate medications (e.g., tetracyclines, levothyroxine) — separate dosing
• Low magnesium worsens hypokalaemia and hypocalcaemia

📊 Evidence Snapshot

• 🔬✅ Well-established: Correction of deficiency improves neuromuscular stability and heart rhythm
• 💤 Emerging: Supplemental magnesium may improve sleep quality and relaxation, particularly if low baseline status
• 🧠⚖️ Mental health: Observational links between low magnesium and higher rates of depression/anxiety; trials show mixed but promising results
• ❤️ Cardiovascular: Higher dietary intake associated with lower blood pressure and reduced cardiovascular risk