The Two Forms of Calcium in the Human Body

Calcium is an essential mineral in the human body, found in two primary forms: bound calcium in bone tissue and free, ionized calcium in the blood and soft tissues. About 99% of the body’s calcium is stored in bones as hydroxyapatite, a solid, crystalline combination of calcium and phosphate. This structure provides strength, stability, and resilience to the skeleton, enabling bones to bear weight and endure physical forces. Additionally, this stored calcium acts as a reservoir, releasing calcium into the bloodstream when dietary intake is inadequate, helping to maintain calcium balance and support bone health.

The remaining 1% of calcium exists in its ionized form, circulating in the body’s fluids and playing a crucial role in various biological functions. Ionized calcium is essential for nerve transmission, facilitating the efficient transfer of electrical signals between neurons. This process supports brain function, reflexes, and communication between the nervous system and muscles. In muscle contraction, calcium enables the interaction between actin and myosin filaments within muscle cells, powering both voluntary movements, like those involved in locomotion, and involuntary actions such as the rhythmic beating of the heart and the contraction of digestive muscles.
The Two Forms of Calcium in the Human Body

Bone Health Essentials

Osteoporosis is a debilitating condition characterized by weakened, hollow, and brittle bones that are prone to fracturing even from minor trauma. It affects approximately 30 million Americans, predominantly older adults, and its consequences extend far beyond mere physical discomfort, significantly diminishing independence and overall quality of life. Sadly, many individuals succumb to complications arising from osteoporosis, making it imperative to address this condition proactively.

Both women and men are susceptible to osteoporosis, with statistics indicating that one out of every two women and one out of eight men will develop the condition at some point in their lives. However, it is never too early nor too late to start taking measures to improve bone health. Understanding that bones are living tissues constantly undergoing a process of removal and replacement underscores the importance of lifestyle choices in maintaining skeletal integrity throughout life.

A crucial aspect of bone health is adequate nutrition, particularly the intake of calcium, vitamin D, phosphorus, zinc, vitamins K and C, copper, and manganese. These nutrients play essential roles in bone formation and maintenance, with calcium serving as a primary component of bone structure. Insufficient dietary intake of these nutrients can lead to the body drawing from its "calcium reservoir," resulting in bone demineralization and increased susceptibility to osteoporosis.

Moreover, various factors can predispose individuals to osteoporosis, including genetic predisposition, ethnicity, hormonal factors, lifestyle choices, and medication use. For instance, individuals with a family history of osteoporosis or fractures, non-Hispanic whites or Asians, post-menopausal women not receiving estrogen replacement therapy, and those with low calcium or vitamin D intake are at elevated risk. Additionally, factors such as inadequate weight-bearing exercise, smoking, low body weight, estrogen deficiency, excessive dieting, and certain medication use further exacerbate the likelihood of developing osteoporosis.

Fortunately, preventive measures can mitigate the risk of osteoporosis and its associated complications. Adopting a balanced diet rich in essential nutrients, engaging in regular weight-bearing exercise, avoiding smoking, and ensuring adequate sunlight exposure are fundamental steps in promoting bone health. Furthermore, healthcare providers may recommend hormone replacement therapy or prescribe medications to manage osteoporosis risk factors effectively.

In conclusion, osteoporosis is a significant public health concern with far-reaching implications for affected individuals and society as a whole. By fostering awareness, implementing preventive strategies, and addressing modifiable risk factors, we can strive to reduce the incidence and impact of osteoporosis, thereby enhancing the well-being and longevity of individuals worldwide.
Bone Health Essentials

Bones: Reservoir for calcium

The name calcium is derived from Latin word calas meaning lime was known as early as the first centuries when the ancient Romans prepared lime as CaO.

There are two types of calcium. One type of calcium is tightly bound within the bone and the other more accessible type of calcium is found on the bone. The body contains about 2% of Ca and 98% of this is in the bones.

The skeleton serves as a bank of minerals for the body. It is a major reservoir for providing calcium for both the extracellular and intracellular pools. The body can borrow from the skeletal stores when blood calcium levels drop and return calcium to bones as needed.

The medication of parathyroid also is necessary for the withdrawal of calcium from the skeleton.

Generally sufficient calcium gets ingested through the normal through the normal diet. It gets from upper intestinal tract and is excrete through urine and faeces. As the upper portion of intestine, the condition is acidic, it tends to favor absorption of calcium. As calcium salts have better solubility.

Bone is constantly remodeled throughout life in response to mechanical stress and a need for calcium in extracellular fluids. Calcium and phosphate are released to blood during bone resorption and deposited into bone during bone formation.

A high protein diet especially derived from animal foods causes calcium loss in the body. The higher sulphur to calcium ratio of metal increases calcium excretion and a diet rich in meal can cause bone demineralization.
Bones: Reservoir for calcium

Hormone of calcitonin

Calcitonin was discovered more than 45 years ago as a hormone that lowers circulating calcium levels.

The discovery of calcitonin established the presence of a new regulatory system for calcium homeostasis. Calcitonin, a hormone isolated from the human thyroid gland, is a single-chain, 32 amino acid polypeptide with a molecular weight of 3600.

Calcitonin is produced by the mitochondria-rich parafollicular or C-cells of the thyroid and is secreted in response to elevations in plasma calcium  concentration and in response to a numb her of gut hormones, including gastrin and glucoagon.

Other tissue sources of calcitonin include the pituitary, a variety of neuroendocrine cells, and carcinomatus lesions such as medullary thyroid carcinoma and small cell lung cancer.

Bone and kidney are the two primary targets of calcitonin and both are important for the activity of calcitonin to acutely decrease circulating levels of calcium.

In bone, calcitonin acts directly on osteoblasts, reducing calcium release into the plasma through inhibition of bone resorption, whereas in the kidneys calcitonin reduces reabsorption of both calcium and phosphorus, producing a modest increase in excretion of both ions. The former may contribute to the hypocalcaemic effect of pharmacologic effect of pharmacologic doses of calcitonin.
Hormone of calcitonin

Etiology of osteoporosis

Osteoporosis is the thinning of bone tissue and loss of bone density over time. Osteoporosis results when too much bone resorption occurs, too little formation exists, or a combination of both co-exists.

A major cause of osteoporoses is less than optimal bone growth during childhood and adolescence, resulting in failure to reach optimal peak bone mass.

Thus, peak bone mass attained early in life is one of the major important factors affecting the risk of osteoporosis.

Other common causes of osteoporosis include aging, menopause, endocrine disorders, metabolic disorders, malnutrition, malabsorption, and malignancy. Menopause and ageing are the most common causes of osteoporosis.

Endocrine, metabolic and nutritional disorders are more likely to cause osteomalacia, which radiographically resembles osteoporosis but is metabolically and clinically different from osteoporosis.

Increased bone resorption results from estrogen deficiency associated the menopause in normal women also one of the major cause of osteoporosis.

Males with low levels of testosterone are also more prone. The use of tobacco and a family history of osteoporosis also increase the risk.
Etiology of osteoporosis

Osteoporosis

Food Nutrition
Osteoporosis is a preventable, treatable condition of weak, hollow, brittle bones that break easily. In its advanced stages, it is a painful condition affecting approximately 30 million Americans, causing fractures, typically of the hip, wrist, and spine.

Osteoporosis greatly reduces independence and the quality of life of its victims; many die from complications of osteoporosis. In the U.S., one out of every two women, and one out of eight men, develop osteoporosis.

It is never too early or too late to improve bone health. Bones are living tissues. Throughout life, old bone is removed and replaced by new bone.

Many factors affect the rate of bone addition and loss. Our bodies need calcium for proper heart, muscle and nerve function, to maintain blood pressure, and for blood clotting. If the diet doesn't provide enough calcium, we take it from our "calcium reservoir" (otherwise known as our bones).

If old bone is removed at a rate that is too fast, or if the rate of new bone replacement occurs too slowly, then gradually bones become porous and fragile. For example, 40% of the bone's density can be lost during advanced osteoporosis.

A lifelong adequate intake of calcium and vitamin D, as well as phosphorus, zinc, vitamins K and C, copper and manganese, helps bone health by increasing (as much as is genetically possible) the amount of bone formed during youth and early adulthood.

Adequate diet and hormone levels also slow down the rate of overall bone loss that occurs later in life. When recommended amounts of calcium are consumed during the bone-building years, maximum bone mass "reserves" with a consequent reduction in osteoporosis, and 50% fewer hip fractures later in life.

Many factors increase one's chance of developing osteoporosis. People at greatest risk for osteoporosis are older adults, especially women, who:

*have a family history of osteoporosis or of an adult family member breaking a bone (heredity influences peak bone mass in part because of vitamin D receptor- gene levels);

*are non-Hispanic white or Asian;

*are post-menopausal women not on hormone (estrogen) replacement therapy;

*have had low calcium intake after age 35;

*have had consistently low vitamin D intake or low sunlight exposure;

*do little weight-bearing exercise;

*smoke cigarettes;

*have a small, thin frame (adult body weight less than 125#);

*have never been pregnant;

*have a history of estrogendeficiency as a result of amenorrhea, late menarche, or an early menopause, either naturally or surgically;

*have or had excessive dieting;

*have a history of taking thyroid medication, cortisone-like medications, anti-seizure drugs, or certain other medications.

To find out more about preventing your risk for osteoporosis and bone fractures, or for treatment options, ask your health care provider. Having a bone mineral density scan is a painless test for osteoporosis especially important for women age 50 and over.
Food Nutrition