What Illness Causes Low Magnesium?

December 31, 2025 •

3 min read

According to the National Institutes of Health, while dietary intake is a factor, low magnesium levels (hypomagnesemia) are most often caused by underlying health conditions, chronic alcoholism, or medication use. A deficiency in this essential mineral can disrupt numerous bodily functions and lead to serious health complications.

Quick Summary

Hypomagnesemia often results from excessive loss or malabsorption rather than insufficient dietary intake. Common causes include chronic alcoholism, type 2 diabetes, gastrointestinal disorders like Crohn's disease, and certain kidney diseases.

Key Points

Diabetes Mellitus: Poorly controlled type 2 diabetes leads to increased urinary excretion of magnesium due to high blood glucose levels.
Chronic Alcoholism: Heavy alcohol use causes poor dietary intake, malabsorption, and increased renal magnesium wasting through its diuretic effect.
Gastrointestinal Disorders: Conditions like Crohn's disease, celiac disease, and gastric bypass surgery cause malabsorption of magnesium from the intestines.
Medication Side Effects: Long-term use of certain drugs, including proton pump inhibitors, diuretics, and some chemotherapy agents, can deplete magnesium.
Kidney Disorders: Genetic or acquired kidney diseases, such as Gitelman syndrome, can lead to excessive loss of magnesium in the urine.
Acute Pancreatitis: During acute inflammation of the pancreas, magnesium can be sequestered in areas of fat necrosis, dramatically lowering its availability.

Understanding the Root Causes of Low Magnesium

Low magnesium, or hypomagnesemia, is a condition where the serum magnesium concentration falls below normal limits. Magnesium is a crucial electrolyte involved in over 300 enzymatic reactions, including energy production, muscle and nerve function, and blood pressure regulation. The kidneys play a key role in maintaining magnesium balance, so persistent deficiency usually indicates an underlying medical issue affecting absorption or excretion. Identifying and addressing the root cause is vital for managing low magnesium. The primary conditions and factors leading to this deficiency are detailed below.

Gastrointestinal Disorders

Illnesses affecting the digestive tract can impair magnesium absorption, as the mineral is primarily absorbed in the intestines.

Chronic Diarrhea and Vomiting: Prolonged episodes can lead to rapid electrolyte loss, including magnesium.
Malabsorption Syndromes: Conditions like Crohn's disease, celiac disease, and IBD cause intestinal damage that hinders nutrient absorption.
Gastric Bypass Surgery: Procedures altering the small intestine can result in significant malabsorption.
Acute and Chronic Pancreatitis: Acute pancreatitis can cause magnesium to be sequestered, while chronic pancreatitis can lead to malabsorption.

Chronic Alcoholism

Chronic alcohol abuse is a frequent cause of magnesium deficiency due to multiple factors.

Poor Nutritional Intake: Often leads to insufficient magnesium consumption.
Gastrointestinal Problems: Vomiting and diarrhea can increase magnesium loss.
Increased Renal Excretion: Alcohol acts as a diuretic, causing the kidneys to excrete more magnesium.

Type 2 Diabetes

There is a significant link between type 2 diabetes and low magnesium, involving both insulin resistance and kidney function.

Increased Urinary Loss: High blood sugar in uncontrolled diabetes leads to greater magnesium excretion by the kidneys.
Insulin Resistance: Magnesium is important for insulin sensitivity; deficiency can worsen resistance, creating a cycle of impaired insulin function and further magnesium loss.

Kidney Diseases and Inherited Renal Disorders

The kidneys regulate magnesium balance, and certain conditions can cause excessive loss in the urine (renal magnesium wasting).

Inherited Renal Tubular Disorders: Genetic conditions like Gitelman and Bartter syndromes impair the kidneys' ability to reabsorb magnesium.
Chronic Kidney Disease (CKD): While advanced CKD can increase magnesium, earlier stages or certain medications used in CKD can lead to hypomagnesemia.

Medications That Cause Magnesium Loss

Several medications can increase the risk of hypomagnesemia, particularly with long-term use.

Proton Pump Inhibitors (PPIs): Long-term use of acid reducers like omeprazole may decrease magnesium absorption.
Diuretics: Loop and thiazide diuretics increase kidney excretion of electrolytes, including magnesium.
Chemotherapy Drugs: Certain drugs, notably cisplatin, can cause significant renal magnesium wasting.
Aminoglycoside Antibiotics: This class of antibiotics can also increase renal magnesium loss.

Comparison of Key Hypomagnesemia Causes


Cause Category	Mechanism Leading to Low Magnesium	Example Conditions
Gastrointestinal Loss	Impaired intestinal absorption, chronic expulsion from the body via diarrhea or vomiting.	Crohn's disease, Celiac disease, Gastric bypass, Chronic pancreatitis.
Renal Loss	Kidneys excrete too much magnesium in the urine due to impaired reabsorption.	Type 2 diabetes, Alcoholism, Inherited disorders (Gitelman syndrome), Diuretic use.
Medication-Induced	Interference with magnesium absorption in the gut or increased excretion via the kidneys.	Proton pump inhibitors (PPIs), Diuretics, Cisplatin, Aminoglycoside antibiotics.
Nutritional Deficiency	Severe malnutrition or starvation where dietary intake is inadequate.	Anorexia nervosa, Critically ill patients on certain IV fluids.

What to Do If You Suspect Low Magnesium

If you have risk factors or experience symptoms like muscle cramps, fatigue, or irregular heartbeat, consult a healthcare provider. A blood test can measure serum magnesium, but this may not always reflect total body stores. Your doctor can determine the best course of action, which may include treating the underlying condition, adjusting medications, or recommending supplements.

Early intervention is crucial to prevent severe complications affecting the nervous system and cardiovascular health. For further details on magnesium function and disorders, refer to the National Institutes of Health Fact Sheet for Health Professionals.

Conclusion

While diet plays a role, low magnesium is most often caused by underlying medical conditions or medications. Chronic diseases like alcoholism, diabetes, and gastrointestinal disorders, along with specific prescription drugs, can disrupt magnesium balance. Recognizing these potential causes is key to effective management. A medical professional can diagnose the issue and create a targeted treatment plan to address the root cause, restore magnesium levels, and prevent serious complications.

Frequently Asked Questions

Symptomatic magnesium deficiency from low dietary intake alone is uncommon in healthy individuals because the kidneys are efficient at limiting urinary excretion to conserve the mineral.

Early symptoms can include nausea, vomiting, fatigue, and weakness. As the deficiency worsens, it can cause muscle contractions, cramps, tremors, numbness, tingling, and an irregular heartbeat.

Diagnosis is typically made through a blood test to measure serum magnesium levels. However, because most magnesium is stored in the bones and cells, this measurement may not fully reflect total body stores.

Treatment depends on the severity. Mild cases may be managed with oral supplements and dietary changes, while severe deficiency may require intravenous magnesium administration. Addressing the underlying illness is critical for long-term management.

Medications that can cause low magnesium include proton pump inhibitors (e.g., omeprazole), loop and thiazide diuretics (e.g., furosemide), and certain chemotherapy drugs (e.g., cisplatin).

Yes, long-term (typically over one year) use of proton pump inhibitors (PPIs) has been associated with an increased risk of hypomagnesemia.

Chronic alcoholism contributes to magnesium deficiency through poor diet, gastrointestinal issues like vomiting and diarrhea, and a direct diuretic effect that increases urinary magnesium excretion.