When it comes to calcium, the immediate association is usually with bone health. While this relationship is correct, it is incomplete. Calcium is one of the most abundant minerals in the human body and performs fundamental functions that go far beyond the skeletal structure.

For the health professional, understand the Functions of calcium in the body in an integrated way, it is essential for a more accurate clinical approach, especially in metabolic, hormonal and digestive settings.

Calcium as a metabolic regulator

About 99% of the body's calcium is stored in bones and teeth, but the remaining 1% plays critical roles in physiological regulation. Even small variations in serum calcium concentrations can have significant impacts on cellular functioning.

In energy metabolism, calcium acts as a second intracellular messenger, participating in processes such as:

• enzyme activation;

• muscle contraction;

• release of neurotransmitters;

• cell signaling.

This regulatory role explains why the body keeps blood calcium levels under strict control, even at the expense of bone mobilization when necessary.

Relationship between calcium and the hormonal system

Calcium metabolism is profoundly influenced by the endocrine system. Hormones such as parathyroid hormone (PTH), active vitamin D, and calcitonin regulate intestinal absorption, renal excretion, and bone mobilization.

In addition, calcium indirectly participates in hormonal modulation by influencing:

• insulin secretion;

• release of thyroid hormones;

• contraction of smooth muscle cells, including those involved in vascular function.

Imbalances in calcium metabolism may therefore reflect broader hormonal and metabolic changes, even in the absence of obvious bone symptoms.

Calcium and muscle function: beyond contraction

Muscle contraction is directly dependent on intracellular calcium. It is responsible for allowing the interaction between actin and myosin, both in skeletal muscle and in cardiac and smooth muscle.

When calcium intake or regulation is impaired, manifestations such as:

• muscle fatigue;

• cramps;

• reduced contractile efficiency;

• changes in heart rate, in more extreme cases.

Therefore, calcium should not only be seen as a structural nutrient, but as a fundamental functional element for movement and physiological performance.

The role of calcium in digestion and nutrient absorption

In the gastrointestinal tract, calcium participates in the activation of digestive enzymes and in the signaling that regulates intestinal motility. Its absorption occurs mainly in the small intestine and depends on factors such as:

• presence of vitamin D;

• adequate intestinal pH;

• integrity of the intestinal mucosa.

Digestive changes, intestinal inflammation, or low bioavailability can compromise calcium absorption, even when dietary intake seems sufficient. This point is especially relevant in clinical practice, as nonspecific digestive symptoms can coexist with functional mineral deficiency.

In what situations does calcium deserve special attention?

Although the need for calcium varies according to age, sex, and clinical condition, some profiles deserve attention:

• climacteric and post-menopausal women;

• the elderly;

• individuals with low dietary intake;

• people with intestinal absorption disorders;

• patients with high muscle or metabolic demand.

In these settings, evaluating total calcium intake — diet, supplementation, and bioavailability — is more relevant than focusing solely on intake alone.

Supplementation: criterion above the trend

With the advancement of formulations, calcium supplements began to consider not only the amount of the mineral, but also its chemical form, absorption, and gastrointestinal tolerability.

In professional practice, supplements can be considered as part of a broader nutritional strategy, especially when the diet does not meet the needs or when there are physiological absorption limitations. The choice should always be guided by individual assessment, and not by generic protocols.

Conclusion

Calcium is a systemic mineral with a direct impact on metabolism, hormonal function, digestion, and muscle contraction. Reducing it solely to bone health limits understanding of its true role in the body.

For health professionals, taking an expanded view of calcium allows for more assertive decisions, both in dietary guidance and in the assessment of the need for supplementation. Taking care of calcium is taking care of the body as a whole.

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