Calcium, as an elemental mineral, ranks as the most abundant mineral within the human body. While commonly recognised for its role in promoting strong bones, calcium serves a far broader spectrum of functions. This article delves into the pivotal functions of calcium and its intricate workings within the human body.
Functions of Calcium in the Body
An adult typically harbours approximately 1.2 kilograms of calcium in their body, accounting for 1-2 percent of overall body weight. An overwhelming 99 percent of this calcium resides in bones and teeth. The remaining calcium, present in its free form, assumes a central role in various physiological processes within and between the body's cells. Calcium emerges as a fundamental necessity for mobility, regulation of nerve impulses, muscle contractions, heartbeat regulation, and blood coagulation. Moreover, it substantiates the normal operations of digestive enzymes and contributes to energy metabolism, while also participating in the intricate process of cell division.
Absorption Dynamics and Calcium Regulation
The primary absorption of calcium occurs in the small intestine, with absorption rates varying between 10-50 percent. The intricate control of free calcium concentrations is maintained through a meticulously orchestrated interplay between the intestine, kidneys, skeleton, vitamin D, and parathyroid hormone. In cases of low blood calcium levels (hypocalcemia), the skeleton releases calcium to reinstate equilibrium. Conversely, when blood calcium levels rise (hypercalcemia), excess calcium is either stored in bones or eliminated through urine and faeces.
Optimising Calcium Intake: Dietary Factors
To secure an adequate calcium intake, it is imperative to incorporate calcium-rich foods into the diet. Several dietary and lifestyle factors affect the assimilation and absorption of calcium.
Physical exercise performed at a moderate intensity stimulates calcium absorption. Adequate stomach acid and dietary fibre further enhance absorption. An ample supply of protein is also essential for optimal absorption, although excessive protein intake heightens the demand for calcium due to increased excretion.
The dietary intake of vitamin C facilitates the absorption of calcium from food sources. Similarly, vitamin D stands as a prerequisite for ensuring satisfactory calcium absorption. Furthermore, vitamin D aids the body in appropriate calcium utilisation, while promoting calcium reabsorption from the kidneys to prevent urinary losses.
Certain dietary components can impede calcium absorption, including oxalates found in certain vegetables and phytic acid present in legumes, nuts, and seeds. An elevated consumption of alcohol, caffeine, sugar, and salt heightens calcium excretion.
However, overconsumption of calcium can negatively impact zinc absorption and disrupt the balance between calcium and magnesium.
Identifying Calcium Deficiency: Signs and Symptoms
Long-term calcium deficiency is well-established for its capacity to result in osteoporosis in adults and stunted growth in children. Additionally, calcium deficiency may manifest through various symptoms, including:
- Facial, arm, and leg numbness and tingling
- Sleep disturbances
- Hypertension
- Deterioration of dental health
- Bleeding gums
- Brittle and weak nails
- Hair loss
- Muscle tension and cramps
- PMS and menstrual cramps
Dietary Sources of Calcium
Calcium-rich foods are prevalent, encompassing various sources. While dairy products represent the primary source, an abundance of plant-based foods also contains substantial calcium. Notable dietary sources include green leafy vegetables and nuts.
Choosing Calcium Supplements Wisely
In the event that calcium supplementation is considered, it is advisable to monitor magnesium intake to preserve the balance between these two essential minerals. Calcium citrate and calcium citrate malate represent two calcium supplement forms known for their high absorbability. Furthermore, calcium pyruvate serves as another commendable option, primarily favoured by endurance athletes.