Causes of Magnesium Deficiency

Low magnesium comes from too little intake, too much loss through the gut or kidneys, or a shift of magnesium into cells.

Low intake

• A diet low in whole grains, nuts, seeds, legumes and green vegetables
• Alcohol use disorder, a very common cause because alcohol increases loss and reduces intake
• Starvation and poor nutrition
• Long hospital stays without nutrition

Loss through the gut

• Long-term diarrhoea and vomiting
• Malabsorption such as coeliac disease, Crohn's disease and short bowel syndrome
• Pancreatitis and bowel surgery
• Long-term use of proton pump inhibitors (acid-reducing medicines such as omeprazole and pantoprazole)

Loss through the kidneys

• Medicines: loop and thiazide diuretics, some cancer drugs (cisplatin), amphotericin, calcineurin inhibitors and some antibiotics
• Poorly controlled diabetes, which makes the body pass more magnesium in the urine
• Kidney tubular disorders and inherited conditions such as Gitelman syndrome
• High calcium levels

Shifts and other causes

• Refeeding after starvation
• Severe burns
• Pregnancy, breastfeeding and heavy sweating, where needs rise
• Older age, where absorption falls

Associated problems

Low potassium and low calcium commonly occur with low magnesium.

Ayurvedic view

Ayurveda links poor nutrition, alcohol, digestive weakness and loss of fluids with Vata aggravation. This is traditional and not a modern explanation.

Key point

Alcohol, gut disease, diabetes and certain medicines are the most common causes.

Before your appointment

Note your symptoms, when they began, and what makes them better or worse. Mention alcohol use, diarrhoea, vomiting, diabetes, kidney disease, bowel conditions and any recent illness. List all medicines, especially diuretics, acid-reducing medicines, antibiotics, supplements and herbal products. Write down your usual diet and any antacids or laxatives you take. Ask about blood tests for magnesium, potassium and calcium, and whether an ECG is needed. Call 112 for seizures, fainting, severe weakness or a very irregular heartbeat.