What is calcium?

Calcium (also called calcium) is a vital mineral and the most abundant mineral in the human body. Approximately 99% of total calcium is found in bones and teeth , where it provides strength and stability. The remaining 1% circulates in the blood and plays a crucial role in muscle contraction, nerve conduction, blood clotting, and hormone regulation .

Calcium is therefore not only a building block for a strong skeleton, but also a regulator of numerous metabolic processes . However, the body cannot produce calcium itself – it must be regularly supplied through food or supplements. Among the best natural sources are dairy products, almonds, broccoli, kale, sesame seeds, mineral water with a high calcium content, and fortified plant-based drinks.

How does calcium work?

Calcium fulfills both structural and functional roles in the body and is involved in almost all physiological processes.

Bones and teeth:
Calcium, together with phosphate, forms the mineral component of bone – known as hydroxyapatite. This compound gives the skeleton its hardness and stability. Bone tissue is constantly renewed throughout life; an adequate calcium intake is crucial to prevent bone loss and osteoporosis . Calcium is optimally incorporated into bones, especially when combined with vitamin D3, vitamin K2, and magnesium .

Muscle and nerve function:
Calcium acts as a "switching molecule" for muscle contraction . When a nerve impulse reaches a muscle, calcium causes the muscle fibers to contract. After contraction, it is returned to the storage cells – a cycle that only functions smoothly with an adequate supply. The heart, as the body's largest muscle, also relies on calcium to beat regularly.

Nerve transmission:
Calcium regulates the release of neurotransmitters, chemical messengers that transmit information between nerve cells. This supports concentration, reaction time, and mental performance.

Blood clotting and hormone regulation:
Calcium is an essential component of the coagulation cascade , which stops bleeding after injuries. It is also involved in the release of hormones and enzymes that regulate many metabolic processes.

Acid-base balance:
Calcium helps maintain a stable pH level in the blood. When the body becomes too acidic, calcium can be released from the bones to neutralize the acid – another reason why a balanced calcium level is essential.

Benefits of calcium

  • Supports strong bones and teeth

  • Contributes to normal muscle function

  • Promotes healthy heart and nerve activity

  • Supports blood clotting

  • Stabilizes the acid-base balance

  • Promotes the release of hormones and enzymes

  • Prevents bone loss (osteoporosis).

  • Works synergistically with vitamin D3 K2 and magnesium

Possible side effects and interactions

Calcium is generally safe when consumed through normal dietary intake. However, excessive intake – especially through high-dose supplements – can lead to hypercalcemia , meaning excessively high calcium levels in the blood. Possible symptoms include fatigue, nausea, constipation, or heart rhythm disturbances.

The right balance with other nutrients is important:

  • Vitamin D3 promotes the absorption of calcium in the intestine.

  • Vitamin K2 ensures that calcium is stored in the bones and not deposited in blood vessels.

  • Magnesium acts as an antagonist and prevents muscle cramps or calcifications.

People with kidney disease or a tendency to develop kidney stones should only take calcium supplements under medical supervision.

Conclusion

Calcium is far more than just a "bone mineral"—it's a versatile nutrient involved in almost all life processes. It ensures stability, energy, and responsiveness in both body and mind. Adequate intake through diet or supplements, combined with vitamins D3 and K2, and magnesium, is crucial for healthy bones, strong muscles, and a stable nervous system—throughout life.

Sources

  1. Heaney RP. (2000): Calcium, dairy products and osteoporosis. J Am Coll Nutr , 19(2 Suppl), 83S–99S.

  2. Beto YES. (2015): The role of calcium in human aging. Clin Nutr Res , 4(1), 1–8.

  3. Bronner F. (2003): Mechanisms of intestinal calcium absorption. J Cell Biochem , 88(2), 387–393.

  4. Cashman KD. (2018): Calcium intake, calcium bioavailability and bone health. Br J Nutr , 119(3), 291–302.