What is Calcium (Ca)?

Calcium is essential for bones and teeth, heart, nerves, muscles, and blood clotting.

Calcium is the most abundant mineral element in your body, because it is the major element in bones. Serum and red blood cell calcium, however, do not represent bone mineral content or dietary adequacy.

Although most of the body’s calcium is stored in bones, some circulates in the blood. About 40% of the calcium in blood is attached to proteins in blood, mainly albumin. Protein-bound calcium acts as a reserve source of calcium for the cells but has no active function in the body.

Food sources of calcium:

Dark green vegetables, whole grains, nuts


Calcium’s actions are as wide ranging as neuronal excitation, neurotransmitter release, innate immunity, hormonal secretion, and tone of smooth muscle cells in the vasculature, airways, uterus, gastrointestinal (GI) tract, and urinary bladder.

Optimum calcium status can help prevent lead toxicity.


Erythrocyte calcium as a marker:

Erythrocyte (whole blood) calcium is a useful marker in the management of people with hypertension and arrhythmias, renal failure, and even pre-menstrual syndrome.

Calcium accumulation in hair:

Calcium accumulation in hair can reflect the end result of the process of chronic mobilization from bone.

High levels in hair:

High levels are associated with calcium loss, which may indicate early signs of osteoporosis, especially in females in the age range of 30-50 yrs. High hair calcium in younger women may, by inference, indicate calcium loss that has not yet shown as bone density decrease.

Low levels in hair:

Low hair calcium may indicate increased risk of myocardial infarction with increased associated aortic calcium concentrations. However, low hair calcium in children reflects calcium distribution and is not directly related to dietary intake of calcium. Low hair calcium accompanied by other low element levels such as chromium, cobalt, magnesium, and manganese may suggest malabsorption. Hair treatments such as permanent solutions, bleach, or dyes may contain calcium and cause high hair calcium levels.

Urinary levels:

High levels:

Kidney stone formers are characterized by high urinary calcium, and potassium appears to decrease stone formation by decreasing urinary calcium levels. Conversely, low potassium intake results in higher calcium urinary levels. Other tests that may be helpful when calcium is abnormal are: bone density analysis, vitamin D, Deoxypyridinoline (deoxyPYD), and parathyroid hormone.

Low levels in blood:

Hypocalcemia most commonly results when too much calcium is lost in urine or when not enough calcium is moved from bones into the blood. Causes of hypocalcemia include the following:

– A low level of parathyroid hormone (hypoparathyroidism), as can occur when the parathyroid glands are damaged during thyroid gland surgery

– Lack of response to a normal level of parathyroid hormone (pseudohypoparathyroidism)

– No parathyroid glands at birth (for example, in DiGeorge syndrome)

– A low level of magnesium (hypomagnesemia), which reduces the activity of parathyroid hormone

– Vitamin D deficiency (due to inadequate consumption or inadequate exposure to sunlight)

– Kidney dysfunction, which results in more calcium excreted in urine and makes the kidneys less able to activate vitamin D

– Inadequate consumption of calcium

– Disorders that decrease calcium absorption

– Pancreatitis

– Certain drugs

Potential treatment:

  • Calcium supplements
  • Sometimes vitamin D

Calcium supplements, given by mouth, are often all that is needed to treat hypocalcemia. If a cause is identified, treating the disorder causing hypocalcemia or changing drugs may restore the calcium level.


High levels in blood:

Hypercalcemia is a condition in which the calcium level in your blood is above normal. Too much calcium in your blood can weaken your bones, create kidney stones, and interfere with how your heart and brain work.


  • excessive thirst and frequent urination (kidneys have to work harder to filter calcium)
  • upset stomach, nausea, vomiting, constipation
  • bone pain, muscle weakness and depression (due to calcium leaching from bones)
  • confusion, lethargy, fatigue (calcium can interfere with brain functions)
  • palpitations, fainting, cardiac arrhythmia (severe hypercalcemia can disrupt heart functions in severe cases)


  • overactive parathyroid glands (hyperparathyroidism). check for benign tumor or enlargement in one of 4 parathyroid glands.
  • cancer (lung, breast, blood can increase risk)
  • tuberculosis or sarcoidosis can increase serum vit d levels and trigger GI tract to absorb more calcium.
  • genetic disorder (check for familial hypocalciuric hypercalcemia)
  • too much sitting/lying down.
  • severe dehydration
  • certain drugs
  • excessive amounts of calcium or vit d supplements.

Possible Treatment:

Treatment depends on the cause. Please consult your doctor and figure out what the cause is first.


The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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