What role does calcium play in maintaining strong bones?

Question

Hello doctor,

I am a 24-year-old female. I learned that I have low calcium levels in my body after doing my routine blood investigations.

What are the primary functions of calcium inside the body?
How does calcium contribute to various physiological processes and support overall well-being?
What role does calcium play in maintaining strong and healthy bones?
How does the body absorb calcium, and what factors can enhance its absorption?
What are the dietary and lifestyle considerations that individuals should be aware of to optimize calcium absorption?
What are the potential health consequences of calcium deficiency, and how do you manage it?

Please help.

Thank you.

Answer 1

Hello,

Welcome to icliniq.com.

I understand your concern.

Hypocalcemia is defined as a total serum calcium concentration less than 8.8 mg/dL (less than 2.20 mmol/L) in the presence of normal plasma protein concentrations or as a serum ionized calcium concentration less than 4.7 mg/dL (less than 1.17 mmol/L). Hypocalcemia may be acquired or hereditary. Acquired causes include a variety of illnesses (eg, hypoparathyroidism (insufficient production or secretion of parathyroid hormone (PTH) by the parathyroid glands), liver disease, kidney disease, and COVID-19), diet, medication, and surgery.

Calcium regulation is critical for normal cell function, neural transmission, membrane stability, bone structure, blood coagulation, and intracellular signaling. The essential functions of this divalent cation continue to be elucidated, particularly in head injury or stroke and cardiopulmonary disorders. Ionized calcium is the necessary plasma fraction for normal physiologic processes. In the neuromuscular system, ionized calcium facilitates nerve conduction, muscle contraction, and muscle relaxation. Calcium is necessary for bone mineralization and is an important cofactor for hormonal secretion in endocrine organs. At the cellular level, calcium is an important regulator of ion transport and membrane integrity.

Calcium turnover is estimated to be 10-20 mEq/day. Approximately 500 mg of calcium is removed from the bones daily, and replaced by an equal amount. Normally, the amount of calcium absorbed by the intestines is matched by urinary calcium excretion. Despite these enormous fluxes of calcium, the levels of ionized calcium remain stable because of the rigid control maintained by parathyroid hormone (PTH), vitamin D, and calcitonin through complex feedback loops. These compounds act primarily at bone, renal, and GI (gastrointestinal) sites.

Calcium levels are also affected by magnesium and phosphorus. Most hypocalcemia cases are mild, and patients require only supportive treatment and further laboratory evaluation. On occasion, severe hypocalcemia may result in seizures (sudden, uncontrolled electrical disturbances in the brain causing changes in behavior), tetany (involuntary muscle contractions and spasms), refractory hypotension (severe low blood pressure), or arrhythmias (irregular heartbeats) that require a more aggressive approach. To effectively treat hypocalcemia in patients with concurrent magnesium deficiency, hypomagnesemia should be corrected first.

I hope this helps. Kindly follow up if you have more concerns.