Calcium is the most abundant mineral in our body and plays a role in many essential functions, from strengthening bones to nerve transmission. When its level in the blood is too low, it is referred to as “calcium deficiency,” and when it is too high, it is called “hypercalcemia.” Both imbalances may affect the muscles, heart, and nervous system. The causes of deficiency or excess are investigated, appropriate treatments are planned, and if necessary, diet, supplementation, or medical intervention is applied.

Key Takeaways

  • Calcium balance is essential for bone strength, muscle function, heart rhythm, and nerve transmission.
  • Both low calcium (deficiency) and high calcium (hypercalcemia) can cause serious symptoms and require medical evaluation.
  • Early diagnosis and appropriate treatment help prevent long-term complications and protect overall health.

What is Calcium?

Calcium is the most common mineral in the body and primarily forms the structure of bones and teeth. In addition, it plays a role in vital processes such as muscle contraction, nerve signal transmission, and blood clotting. Blood calcium levels are tightly regulated by hormones. Adequate intake is important for overall health.

What Are the Functions of Calcium in the Body?

Calcium is necessary not only for bone health but also for muscle movement, heart rhythm, and nerve transmission. Approximately 99% of the calcium in the body is stored in bones and teeth, while the remaining portion in the blood and soft tissues regulates vital functions. Its level in the blood is maintained within a narrow range because even small changes may lead to serious health problems.

Supports bone and tooth structure

Most of the calcium in the body is found in bones and teeth and provides their hardness. When sufficient calcium is not consumed, the body draws calcium from the bones to maintain balance in the blood. In the long term, this may lead to decreased bone density and an increased risk of osteoporosis.

Regulates muscle contractions

Muscle contraction and relaxation occur through calcium. When a nerve signal reaches the muscle cell, calcium enters the cell and initiates contraction. The heart muscle, in particular, requires proper calcium balance to function regularly.

Plays a role in nerve transmission

Communication between nerve cells occurs through chemical signals, and calcium is involved in this process. At insufficient levels, the nervous system may not function properly, and symptoms such as numbness and tingling may occur.

Contributes to blood clotting

Calcium helps activate the factors involved in the blood clotting process. When there is not enough calcium, the clotting mechanism may be affected, and bleeding time may be prolonged.

What is Calcium Deficiency?

Calcium deficiency is the condition in which the level of this mineral in the blood falls below the normal range. It may occur due to long-term inadequate intake or hormonal imbalances. Although mild deficiencies often do not produce noticeable symptoms, severe deficiencies may lead to muscle spasms and bone weakness.

What are the symptoms of calcium deficiency?

When calcium levels decrease, nerve and muscle functions are affected. Symptoms such as tingling in the hands, muscle cramps, and abnormal heart rhythm may be observed. In the long term, bone density may decrease.

Calcium deficiency symptoms can be listed as follows:

  • Muscle cramps, weakness
  • Tingling sensation in the fingers
  • Irregular heart rhythm
  • Low bone density/osteoporosis

What causes calcium deficiency?

Calcium deficiency is generally caused by insufficient intake through the diet. Vitamin D deficiency, kidney problems, or hormonal disorders may also impair absorption and lead to deficiency. Some medications and gastrointestinal surgeries may also reduce absorption.

Causes:

  • Low calcium intake
  • Insufficient Vitamin D
  • Hormonal imbalances
  • Health conditions affecting absorption

Who is at risk for calcium deficiency?

Calcium deficiency can occur at any age, but risk groups are distinct. Bone loss is more rapid, especially in postmenopausal women. In cases such as lactose intolerance or vegan diets, adequate calcium may not be consumed.

Calcium deficiency risk groups:

  • Postmenopausal women
  • Individuals with lactose intolerance
  • Those following a vegan or low-calcium diet
  • Older adults

What is Calcium Excess (Hypercalcemia)?

Hypercalcemia is the condition in which blood calcium levels rise above normal. It is generally associated with hormonal disorders, certain medications, or conditions such as cancer. This condition may have negative effects on many systems in the body.

What are the symptoms of high calcium levels?

When calcium is excessive, the digestive system, muscles, and heart may be affected. Constipation, fatigue, and irregular heart rhythm are among the most commonly reported symptoms

Symptoms of high calcium levels:

  • Constipation, nausea
  • Excessive fatigue
  • Weak muscle function
  • Heart rhythm disturbances

What causes high calcium levels?

Hypercalcemia most commonly results from hormonal disorders such as hypoparathyroidism or from certain types of cancer. In addition, excessive supplement use may increase blood levels.

Causes:

  • Hormonal imbalances
  • Certain cancers
  • High-dose supplement use

How is high calcium treated?

Treatment of high calcium levels primarily depends on identifying the underlying cause. Calcium levels are reduced through fluid therapy, diuretics, or medications. In severe cases, hospital monitoring may be required.

Treatment methods:

  • Treatment of the underlying cause
  • Maintaining fluid and electrolyte balance
  • Medication therapy

What is the Daily Calcium Requirement?

Daily requirements vary according to age, sex, and life stage. In general, it is around 1000–1200 mg for adults. This amount may be slightly higher in children, adolescents, and pregnant or breastfeeding women.

Which Foods Contain Calcium?

Calcium is found in many foods, especially milk and dairy products. In addition, green leafy vegetables, calcium-fortified beverages, canned fish, and other calcium rich foods are good sources.

Sources:

  • Milk, yogurt, cheese
  • Sardines and canned fish
  • Green leafy vegetables
  • Calcium-fortified products

Which Diseases are Associated with Calcium?

Calcium balance is associated with many chronic diseases. Osteoporosis, in particular, is directly linked to bone density loss. It has also been associated with heart and kidney diseases.

Diseases associated with calcium:

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Medicana Web and Editorial Board

Created at

03.03.2026 08:47

Updated at

03.03.2026 09:01

Creator

Medicana Web and Editorial Board

Frequently Asked Questions About Calcium

Calcium absorption varies depending on its form; for the carbonate type, taking it with food is generally better.

Current scientific evidence does not clearly support that calcium directly causes weight gain.

There is no strong evidence that calcium deficiency directly causes hair loss; however, severe nutrient deficiencies may affect hair health.

Most supplements may be divided into small doses throughout the day and taken with meals to increase absorption.

Calcium supplements are generally used if adequate mineral intake cannot be achieved through diet or if recommended by a doctor. Professional medical consultation is always required.