Meet Elijah Price, also known as Mr. Glass—a genius with a body as delicate as fine china. In Unbreakable, M. Night Shyamalan introduces us to Elijah, who lives with osteogenesis imperfecta, a rare condition that makes his bones so fragile that even a small fall can shatter them. While his condition is genetic, it’s a poignant reminder of the importance of bone strength—something many of us unknowingly compromise due to low calcium levels, or hypocalcemia. 

Hypocalcemia doesn’t just affect your bones; it can impact your entire body. At first, the symptoms might feel minor—muscle cramps, tingling fingers, or constant fatigue—but these are your body’s way of saying, “I need more calcium!” Ignoring these signs can lead to more serious problems, like brittle bones, irregular heartbeats, or even seizures.

The good news? We don’t have to wait for our bones to reach their breaking point to take action. By eating calcium-rich foods, supplementing wisely, and ensuring we get enough vitamin D, we can keep our bones strong and resilient—no superpowers required. 

Captain Calcium

Calcium is an essential mineral in the body, playing a crucial role in numerous biochemical processes. It is vital for maintaining proper cardiac function, ensuring the structural integrity of bones, facilitating muscle contraction, and acting as a signaling molecule in various enzymatic pathways. The regulation of calcium levels in the body is a tightly controlled process, managed by the parathyroid hormone (PTH), calcitonin, and calcitriol (the active form of vitamin D). 

Since calcium cannot be synthesized by the body, it must be obtained from dietary sources. Its absorption in the gastrointestinal tract is influenced by PTH and calcitriol (1,25- dihydroxyvitamin D). Calcium levels in the blood can be assessed through a venous blood sample, with normal physiological ranges being 8.8–10.4 mg/dL for total calcium and 4.7–5.2 mg/dL for ionized calcium. 

From Bones to Biochemical Pathways

Calcium, the fifth most abundant element in the human body, is a cornerstone of health. In an average adult weighing 70 kg, the body contains approximately 1 kg of calcium. Most of this— around 99%—is stored in the skeleton, where it provides structural support in the form of crystals similar to hydroxyapatite. The remaining 1% is distributed between soft tissues, extracellular fluids, and blood. 

In the bloodstream, calcium exists in three forms:

• Free (Ionized Calcium): This biologically active form makes up about 50% of circulating calcium.
• Protein-Bound: About 40% binds to proteins like albumin and globulins.
• Bound to Small Molecules: The remaining 10% attaches to small anions such as bicarbonate, lactate, or citrate.

Calcium plays a dual role in the body, classified as either intracellular or extracellular:

• Intracellular Calcium: Though present in trace amounts inside cells, it is crucial for vital functions like muscle contraction, hormone release, energy metabolism, and cell division.
• Extracellular Calcium: This form is essential for bone mineralization, blood clotting, and stabilizing cell membranes. It also regulates neuromuscular activity—low levels can cause muscle spasms (tetany), while high levels reduce excitability.

Let’s see what calcium does to your body

The Real MVP for Bones and Muscles That Work Hard

Bone tissue acts as a reservoir for calcium, storing it as hydroxyapatite crystals. This storage and release of calcium are tightly regulated by the endocrine system, particularly the thyroid and parathyroid glands. When calcium levels in the blood rise, the thyroid gland secretes calcitonin, a hormone that inhibits bone breakdown by suppressing osteoclast activity. Conversely, when calcium levels drop, the parathyroid hormone (PTH) comes into play.

PTH's effects depend on its mode of action:

• Continuous Exposure: Stimulates osteoclast activity through the RANKL pathway, leading to bone resorption and potential bone loss, increasing the risk of osteoporosis.
• Intermittent Exposure: Activates osteoblasts, promoting bone formation and strengthening bones. 

If PTH levels remain chronically low, bone remodeling diminishes, leading to weak and brittle bones over time.

Calcium is equally vital for muscle function. It facilitates muscle contraction by regulating the interaction between actin and myosin, the proteins responsible for movement. Under resting conditions, tropomyosin blocks the binding site where actin and myosin interact, preventing contraction. When calcium is released from the sarcoplasmic reticulum within muscle cells, it binds to troponin, shifting tropomyosin away and allowing actin and myosin to engage. This interaction generates the force needed for muscle contraction. 

Keeping Your Cardiovascular System on Track 

Calcium plays a critical role in heart function by stabilizing the membrane potential of heart muscle cells. During the plateau phase of myocardial contractility, calcium influx regulates the pacemaker potential, controlling the heart's rhythm. Disruptions in calcium or potassium levels can throw this balance off, potentially leading to arrhythmias. For example, if a patient presents with severe hyperkalemia, order an electrocardiogram to evaluate for abnormal changes, and

Administration of calcium gluconate is the initial step to stabilize the myocardium and prevent arrhythmias. While prospective cohort studies have not shown a direct link between dietary calcium intake and the risk of heart disease, myocardial infarction, or death, the role of calcium supplements in cardiovascular health remains unclear. Further research is needed to determine whether calcium supplements affect cardiovascular risks.

Calcium is a key cofactor in the coagulation cascade and is essential for proper coagulability, playing a crucial role in platelet adhesion during primary hemostasis. When tissue is injured, von Willebrand Factor (vWF) is released, acting as a bridge between the endothelium and platelet GpIb receptors to ensure proper platelet adhesion. Once platelets adhere to the endothelium, calcium is released to help activate other coagulation factors in the clotting cascade. The tissue factor from subendothelial tissue binds to calcium and Factor VII, promoting thrombin formation. Calcium also plays a key role in the formation of the prothrombinase complex, which converts prothrombin into thrombin, ultimately leading to the creation of insoluble fibrin that stabilizes the blood clot.

Don't Let Calcium Slip Through the Cracks!

Insufficient calcium can weaken the bones, increasing the risk  of osteoporosis—characterized by fragile bones that are prone to fractures. In children, calcium deficiency may cause rickets, where the growth cartilage fails to properly mineralize, leading to irreversible skeletal deformities. In both children and adults, chronic calcium deficiency can result in osteomalacia, a condition where bones become soft and brittle due to improper mineralization.

Rickets and osteomalacia are closely linked to low calcium levels, but the interplay between calcium and vitamin D is crucial. If vitamin D levels are low, more calcium is needed to prevent these disorders.

Hypocalcemia, or low blood calcium levels (less than 8.5 mg/dL or an ionized calcium level below 4.61 mg/dL), is often caused by a vitamin D or magnesium deficiency, poor parathyroid hormone production (hypoparathyroidism), or other underlying health conditions. It can also be triggered by certain medications, including bisphosphonates, cisplatin, and proton pump inhibitors.

Common Symptoms of Hypocalcemia

• Increased neuromuscular irritability
• Perioral numbness (tingling or numbness around the mouth)
• Tingling or numbness in the hands and feet
• Muscle spasms or cramps
• Renal calcification or kidney injury
• Brain calcification
• Neurologic symptoms such as depression or bipolar disorder
• Cataracts
• Congestive heart failure
• Paresthesia (abnormal sensations like tingling or prickling)
• Seizures
• In rare cases, coma

Say Cheese! (But Also, Say Supplements)

Calcium supplementation is indicated when dietary calcium intake is insufficient, as determined by a patient's dietary history. Potential indications for calcium supplementation include osteoporosis, osteomalacia, hypocalcemic rickets, hypoparathyroidism, and hypocalcemia from chronic kidney disease. The most common indication for calcium supplementation is to prevent or slow the progression of osteoporosis. Aiming to achieve the RDA of calcium through dietary sources and considering supplemental calcium only for individuals consuming less than 800 mg/d are recommended, especially for individuals who cannot increase their calcium intake from food. 

Introducing RediClinic’s Calcium Supplement with Magnesium, Zinc, & Vitamin D3 for Stronger Bones – 60 Capsules

RediClinic’s Calcium Supplement is carefully formulated to support your bone health and enhance your daily wellness routine. Each bottle contains 60 easy-to-swallow capsules, designed to provide your body with the essential nutrients it needs for stronger, healthier bones.

Whether you're looking to boost your bone density or prevent conditions like osteoporosis, this supplement is a great addition to your wellness regimen.

Key Ingredients:

• Calcium Citrate Malate (500 mg): Provides a highly bioavailable form of calcium for improved absorption.
• Magnesium Oxide (100 mg): Vital for bone mineralization and helps support calcium function in the body.
• Zinc (15 mg): Contributes to bone density and strengthens the immune system.
• Vitamin D3 (400 IU): Essential for proper calcium absorption and supports overall bone health.
• Cissus Quadrangularis (250 mg): An herbal extract known for promoting bone healing and strength.

RediClinic’s Calcium Supplement is gluten-free and dairy-free, making it perfect for those with dietary restrictions. Take two capsules per day to help support your bone health and feel your best.

Don’t go overboard- too much can backfire!

Although no absolute contraindications are stated for calcium supplementation, some conditions should be considered. These conditions include patients with renal impairment or chronic kidney disease and a history of calcium-containing kidney stones. High calcium intake may also elevate the risk of cardiovascular disease and prostate cancer, although findings across studies are inconsistent.

Lessons from Elijah Price

Supervillains may be tough, but even they need strong bones to pull off their evil plans! Calcium’s job isn't just about giving you strong bones—it helps with muscle function, keeps your heart beating like a pro, and makes sure your nervous system isn’t throwing a tantrum. So, whether you’re saving the world or plotting a grand scheme, make sure you’re getting enough calcium to keep your body in top form—because even the most fearsome villain can’t afford to let their bones break down.

Frequently Asked Questions(FAQ's)

1. Why is calcium so important?

Calcium is the foundation of strong bones and teeth. It’s also vital for muscle function, nerve signaling, and blood clotting. If you’re not getting enough calcium, your body will take it from your bones to maintain necessary functions. Over time, this can lead to weakened bones and an increased risk of fractures.

2. How much calcium do I actually need?

Not too much, not too little—your bones are picky. For adults, aim for about 1,000 mg daily (1,200 mg if you’re over 50).

3. Are calcium supplements safe? What if I overdo it?

Calcium supplements can be safe when taken in the recommended amounts, but it's important to be cautious. While calcium is essential for strong bones, muscle function, and heart health, taking too much can cause problems. Excess calcium can lead to kidney stones or contribute to the hardening of your arteries. It’s important to stick to the recommended dosage and consult with a healthcare provider before increasing your intake.

4. What else do I need with calcium?

Calcium works in combination with other nutrients like vitamin D, magnesium, and sometimes vitamin K2 to be effective. Vitamin D is especially important because it helps the body absorb calcium. Without enough of these supporting nutrients, calcium supplementation may not work as well and could even lead to imbalances in the body.

5. Signs and Symptoms of Overdose

Hypercalcaemia may present with polyuria, anorexia, nausea, constipation, mood disturbances, cognitive dysfunction, coma, shortened QT interval, dysrhythmias, nephrolithiasis, pancreatitis, peptic ulceration, hypertension, cardiomyopathy, muscle weakness, and band keratopathy.

Dr. Swathy N, BAMS

Dr. Swathy N Ravindran, BAMS, graduate from the prestigious Vaidyaratnam P.S. Varier Ayurveda College in Kottakkal