What disease depletes calcium? A Comprehensive Guide to Causes

October 2, 2025 •

4 min read

Did you know that hypoparathyroidism is one of the most common causes of low blood calcium? Understanding what disease depletes calcium is critical because the body's mineral balance is controlled by a delicate system that, when disrupted, can lead to serious health problems like hypocalcemia.

Quick Summary

Hypocalcemia, or low blood calcium, is caused by several diseases that interfere with the body's regulation of this vital mineral. These conditions include endocrine disorders, kidney disease, and issues with vitamin D and magnesium absorption, each leading to calcium depletion through various mechanisms that require medical attention.

Key Points

Hypoparathyroidism: An underactive parathyroid gland is a direct and common cause of low blood calcium by failing to produce enough parathyroid hormone (PTH).
Chronic Kidney Disease: Impaired kidney function prevents the activation of vitamin D, which is essential for calcium absorption, leading to depleted levels.
Vitamin D Deficiency: Without enough vitamin D, the body cannot absorb calcium from the diet, which can lead to weakened bones and conditions like rickets or osteomalacia.
Malabsorption Disorders: Conditions like celiac disease damage the intestinal lining, interfering with the body's ability to absorb calcium and other nutrients.
Low Magnesium (Hypomagnesemia): Adequate magnesium is crucial for PTH to function correctly; a deficiency can impair PTH secretion and cause calcium levels to drop.
Acute Pancreatitis: The severe inflammation can cause fats to bind with calcium, removing it from the bloodstream and leading to hypocalcemia.
Underlying Medical Conditions: Low blood calcium is typically a symptom of a larger health issue, not simply a lack of calcium in the diet, and requires proper medical diagnosis.

The Body's Calcium Control System

Calcium is a crucial mineral involved in more than just building strong bones and teeth. It plays a critical role in nerve signaling, muscle function, blood clotting, and heart rhythm. The body maintains a very tight control over blood calcium levels through the interplay of three key players:

Parathyroid Hormone (PTH): Secreted by the parathyroid glands, PTH acts to raise blood calcium levels by stimulating bone resorption, increasing kidney reabsorption of calcium, and activating vitamin D.
Vitamin D: This essential vitamin helps your body absorb calcium from the food you eat in the intestines. It is converted to its active form primarily by the kidneys.
The Kidneys: Beyond activating vitamin D, the kidneys filter the blood and excrete excess minerals. Their ability to regulate mineral balance is vital for calcium homeostasis.

When any part of this system is compromised by disease, the result can be a depletion of calcium, leading to the condition known as hypocalcemia.

Hypoparathyroidism and PTH Disorders

Perhaps the most direct answer to what disease depletes calcium is hypoparathyroidism. This condition occurs when the parathyroid glands don't produce enough parathyroid hormone (PTH).

Causes of Hypoparathyroidism

Surgical Damage: The most common cause is unintentional damage or removal of the parathyroid glands during neck surgery, such as a thyroidectomy.
Autoimmune Disorders: The immune system may mistakenly attack the parathyroid glands.
Genetic Factors: Some people are born with absent or non-functional parathyroid glands, known as idiopathic hypoparathyroidism.

How PTH Deficiency Causes Hypocalcemia

With insufficient PTH, the body cannot effectively mobilize calcium from the bones, reabsorb it in the kidneys, or activate vitamin D to absorb it from the gut. This leads to a persistent drop in blood calcium levels.

Chronic Kidney Disease (CKD)

Chronic kidney disease severely disrupts the body's mineral balance and is a major cause of calcium depletion. As kidney function declines:

Impaired Vitamin D Activation: The kidneys lose their ability to convert vitamin D into its active form (calcitriol), which is necessary for calcium absorption from the intestines. This leads to reduced calcium intake.
Hyperphosphatemia: The damaged kidneys cannot effectively excrete phosphate, leading to high phosphate levels in the blood. Excess phosphate binds with calcium, reducing the amount of free, active calcium available.
Secondary Hyperparathyroidism: The low calcium and high phosphate levels trigger the parathyroid glands to produce more PTH in a desperate attempt to compensate. This persistent overproduction of PTH can further contribute to bone loss over time.

Vitamin D Deficiency

While not a disease in itself, severe vitamin D deficiency is a significant contributing factor to calcium depletion because it cripples the body's ability to absorb calcium from food. Without adequate vitamin D, even a high-calcium diet can be ineffective. Prolonged deficiency can lead to bone-softening diseases:

Rickets: Occurs in children, causing bone deformities and impaired growth.
Osteomalacia: The adult equivalent of rickets, where bones become weak and painful.

Malabsorption Disorders

Many digestive system diseases can interfere with nutrient absorption, including calcium. Since the small intestine is where most calcium absorption takes place, any damage or dysfunction in this area is problematic.

Celiac Disease: An autoimmune disorder where consuming gluten damages the lining of the small intestine. This damage reduces the surface area available for calcium absorption, leading to deficiencies. For more information, you can consult the Cleveland Clinic's detailed resource on hypocalcemia here.
Crohn's Disease: A chronic inflammatory bowel disease that can affect any part of the digestive tract, impairing the absorption of essential nutrients.
Gastrointestinal Surgery: Procedures like gastric bypass can reduce the stomach's size and remove parts of the intestine, drastically limiting the body's ability to absorb calcium.

Other Conditions Causing Calcium Depletion

Several other medical conditions can also lead to hypocalcemia through various pathways:

Hypomagnesemia (Low Magnesium): Magnesium is required for the parathyroid glands to function correctly and secrete PTH. When magnesium levels are severely low, PTH secretion is impaired, causing calcium levels to drop.
Acute Pancreatitis: In severe cases, the inflamed pancreas releases enzymes that break down fats. This process can lead to the formation of calcium soaps, which sequester calcium and remove it from circulation.
Certain Cancers: Some cancers, such as metastatic breast cancer, prostate cancer, or leukemia, can trigger processes that reduce calcium levels in the blood.
Medications: Some drugs, including certain chemotherapy agents, bisphosphonates, and certain seizure medications, can interfere with calcium regulation.

Comparison of Diseases Causing Calcium Depletion


Disease	Primary Mechanism	Symptoms (in addition to hypocalcemia)
Hypoparathyroidism	Insufficient PTH production and release.	Muscle cramps, tingling in lips/fingers, seizures.
Chronic Kidney Disease	Impaired vitamin D activation; high phosphate binds calcium.	Fatigue, bone pain, secondary hyperparathyroidism.
Vitamin D Deficiency	Insufficient intestinal calcium absorption.	Bone pain, muscle weakness, risk of fractures.
Celiac Disease	Damage to intestinal lining reduces absorption.	Diarrhea, weight loss, digestive distress.
Hypomagnesemia	Impaired PTH secretion and target organ resistance.	Fatigue, muscle cramps, abnormal heart rhythms.
Acute Pancreatitis	Calcium chelation (soap formation) in the abdomen.	Severe abdominal pain, nausea, vomiting.

Conclusion

Understanding what disease depletes calcium is a critical step toward a correct diagnosis and effective treatment. While dietary intake plays a role in bone health, low blood calcium is most often caused by an underlying medical condition, not simply low calcium consumption. These conditions range from endocrine and kidney disorders to malabsorption issues and magnesium deficiency. If you experience symptoms of hypocalcemia, such as muscle cramps, tingling, or bone pain, it is essential to consult a healthcare professional. A proper medical evaluation can identify the root cause and ensure appropriate treatment is received to restore the body's vital mineral balance.

Frequently Asked Questions

While a poor diet can contribute to long-term bone density issues, it is rarely the sole cause of low blood calcium (hypocalcemia). Low blood calcium is most often a symptom of an underlying medical problem that affects how your body regulates or absorbs calcium.

Chronic kidney disease depletes calcium by impairing the kidneys' ability to convert inactive vitamin D into its active form. Active vitamin D is essential for absorbing calcium from food. Failing kidneys also retain phosphate, which binds to and lowers free calcium.

The four tiny parathyroid glands produce parathyroid hormone (PTH). When blood calcium levels are low, PTH is released to trigger the bones to release calcium, the kidneys to reabsorb more calcium, and vitamin D to activate, ultimately raising blood calcium.

Yes, celiac disease is a common cause of malabsorption. The condition causes damage to the lining of the small intestine when gluten is consumed, which reduces the surface area available to absorb nutrients like calcium and vitamin D.

Magnesium is a critical mineral for parathyroid gland function. Severe hypomagnesemia (low magnesium) can impair the secretion of parathyroid hormone (PTH). Without enough PTH, the body struggles to maintain normal blood calcium levels.

Symptoms of low calcium can range from mild to severe and include muscle cramps, particularly in the back and legs, tingling in the lips, fingers, and feet, dry skin, brittle nails, and, in severe cases, seizures or arrhythmias.

Diagnosing the cause typically involves a series of blood tests to measure levels of total and ionized calcium, parathyroid hormone (PTH), vitamin D, and magnesium. Kidney function tests and bone density scans may also be used.