Minerals

Calcium

Calcium (Ca)

Strong

Calcium is the most abundant mineral in the human body, with about 99% stored in bones and teeth. It is essential for bone structure, muscle contraction, nerve transmission, and blood clotting. Adequate intake throughout life is crucial for preventing osteoporosis.

How It Works

Calcium functions through multiple mechanisms:

Bone Structure: Forms hydroxyapatite crystals with phosphorus, providing bone hardness and structure.
Muscle Contraction: Calcium ions trigger muscle fiber contraction by binding to troponin and enabling actin-myosin interaction.
Nerve Transmission: Essential for neurotransmitter release at synapses.
Blood Clotting: Required for several steps in the coagulation cascade.
Cell Signaling: Serves as a secondary messenger in numerous cellular processes.
Enzyme Function: Activates various enzymes including lipases and ATPases.

Natural Food Sources

Food	Amount per Serving
Yogurt (plain)	415 mg per cup
Cheddar cheese	307 mg per 1.5 oz
Cheddar cheese	305 mg per cup
Milk	325 mg per 3 oz
Sardines (with bones)	349 mg per cup
Fortified orange juice	253 mg per 1/2 cup
Tofu (calcium-set)	94 mg per cup

Safety Information

Contraindications

Hypercalcemia – do not supplement
History of calcium-containing kidney stones - discuss with doctor
History of calcium-containing kidney stones – discuss supplementation with a clinician

Potential Side Effects

Constipation (especially with calcium carbonate) (common)
Bloating and gas (common)
Bloating and gas (uncommon)

Scientific Research

Vitamin D and Calcium Supplementation Reduces Cancer Risk

JAMA Network Open

This large analysis of multiple studies found that taking vitamin D supplements, especially along with calcium, may help reduce the overall risk of developing cancer. The protective effect was strongest when people took at least 1000 IU of vitamin D daily. While this is promising, more research is needed to understand which specific cancers might be prevented and who benefits most.

meta analysis

Typical Dosage

Optimal: 1000 mg
Range: 1000-2500 mg

RDA is 1,000 mg for adults under 50 and 1,200 mg for women over 50 and men over 70. Upper limit is 2,500 mg. Split doses for better absorption (no more than ~500 mg elemental calcium at once).

Quick Facts

Bioavailability: Calcium citrate is absorbed at roughly 20–25% regardless of stomach acid and is often preferred in people using acid-suppressing medications. Calcium carbonate is about 20% absorbed and requires stomach acid, so it should be taken with food. Absorption generally decreases with age.
Half-life: Serum calcium is tightly regulated by parathyroid hormone and vitamin D. Bone calcium turns over slowly over years, acting as a long-term reservoir.
Also known as: Calcium Carbonate, Calcium Citrate, Calcium Lactate, Calcium Gluconate

May Help With

Osteoporosis

Related Compounds

Disclaimer: The information provided is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare provider before starting any supplement regimen.