Calcium for bone health

Calcium for Bone Health
 Special importance of Calcium Orotate

 Calcium is an important mineral required for vascular function, muscle tone, nerve transmission, bone and dental health. As we age, bone breakdown starts and it exceeds bone formation, resulting in increased bone loss, which later on becomes one of the important reasons for bone related issues. It is thus recommended to daily consume calcium and other nutrients for proper bone functioning. Calcium is an essential element that makes up between 1.5-2% of body weight accounting for 1200-1600 g of the typical adult male body. In the blood most of the calcium exists in the form of free dissolved calcium ions that act as electrolyte and constitute almost 99% of the hard tissues of body namely the bones and teeth. The rest is distributed in blood and soft tissues, such as muscles, liver and heart. 

• Calcium orotate is calcium salt of orotic acid, that is now-a-days considered as most effective calcium supplement. As researched by Mr. Hans Nieper, Orotate penetrates deep inside the cell membrane and enables calcium ions to reach the energy power house of the cells (mitochondria) and the nucleus (which is an abode of genetic material such as DNA and RNA). It is known that Calcium Orotate is much more efficient than Calcium Carbonate, in reaching osteo cells, thereby strengthening bones. Orotate is an important raw material for building the backbone of DNA and RNA. Calcium Orotate is known to absorb very well in the gut. Further its absorption can be facilitated by Vitamin D

Benefits of Calcium Orotate*:

o    Maintains bone and teeth health
o    Prevention of bone disorders (osteoporosis; osteoarthritis etc)
o    Aids in weight loss
o    Improves cognition
o    Enhances athletic performance
Bone formation

Bone formation is also known as ossification, a process by which new bone is produced. Important minerals within bone are calcium, phosphate and magnesium. There is about 1 kg of calcium in the adult skeleton as a complex crystalline material with phosphate in the form of hydroxyapatite, Ca₁₀ (PO₄)₆(OH) _2, which is laid down on an organic matrix such as sialoprotein and phosphor proteins including osteo nectin and bone proteoglycans. The turnover of the bone is controlled by the activities of bone cells: osteoblasts, osteoclasts, osteocytes.

Osteoblasts are specialized connective tissues, arising from mesenchymal stem cells that give rise to osteoblasts, adipocytes and myocytes. Osteoblasts are also known as structural cells. They together with osteoclasts, appear to act in remodelling units, whose activities are closely coupled by locally acting cell messengers known as cytokines.

Osteoclasts are large cells derived from haemopoietic cells and are responsible for the resorption or dissolving of bones. Osteoclasts arise from bone marrow are linked to WBCs. Osteoclasts have more than one nucleus.

Osteocytes are derived from osteoblasts and they lie within the mineralised bone matrix, they produce new bone that is known as osteoid. These cells can sense cracks, pressures and help to direct where osteoclasts dissolve.

Bone remodeling:

Bone remodeling can be divided into five stages:

1. Bone resorption phase: It is a phase wherein the osteoclasts breakdown the tissue in bones, and release calcium into the bloodstream.

2. Reversal phase: It couples bone resorption to bone formation. In this phase osteoblasts are involved. As discussed earlier, osteoblasts along with osteoclasts appear to act as remodelling cells.

3. Bone formation: It is a process by which new bone is synthesized, osteoid cells are involved in this process

4. Mineralisation Phase: Bone mineralisation is involved in providing hardness and strength to the bones. It involves laying down of minerals on the bone. The bone shaft which is the main and most rigid part of the bone contains hydroxy apatite, calcium phosphate and ions of magnesium, zinc, sodium, carbonate and fluoride. It involves production of crystals of calcium phosphate by osteoblasts. The bone is reshaped throughout life as per the stresses that act on bones. Bone mineralisation takes place throughout life and is mainly dependent on calcium ions and inorganic phosphate. At the end of a long bone is epiphysis (a hyaline cartilage), a region that regulates bone growth.A more porous region of bone known as the trabaculae, is present beneath the epiphysis. The porosity of trabaculae permits access to the blood supply, allowing this part of a bone to act as a reservoir of calcium, ready to supply calcium to the blood if plasma calcium levels begin to fall. 

5. Rest Phase: It is also known as quiescent phase. It is a state of bone when at rest.

Growth and Nutrition

As a most abundant mineral in your body, calcium is required for growth and nutrition of your body, because it forms such an important part of skeleton: bones and teeth. 

Cofactor and regulator of biochemical reaction

• Blood clotting: When there is tissue injury, the enzyme thromboplastin is released from affected cell or blood platelets. Thromboplastin catalyses the conversion of protein prothrombin into thrombin, in presence of calcium ions. Thrombin is an enzyme that further converts fibrinogen into fibrin, which forms web of fibrous proteins to form a blood clot.

• Role of calcium in Contraction of muscle: Calcium triggers muscle contraction, by acting with regulatory proteins such as actin and myosin. When the level of calcium ions increases, calcium ions bind to troponin, causing conformation changes, leading to release of tropomyosin. This in turn exposes binding sites. And cross bridges and contraction occurs. 

ABSORPTION

Calcium is absorbed by two distinct mechanisms, passive diffusion and active transport. The active transport requires the expenditure of energy adenosine triphosphate (ATP), mediated through a saturable protein called calbindin and sunshine vitamin i.e. Vitamin D. In normal adults, about 95% of calcium is absorbed through active transport. The passive process involves non saturable diffusion of calcium down its concentration gradient. However this process does not require any energy expenditure 

Active absorption is more efficient in the duodenum and proximal jejunum where the PH is more acidic, where calbindin is present. However absorption is greater in the ileum where the residue time is greatest. 
Transport/Absorption of Calcium Orotate:
Orotate or orotic acid is a mineral transporter, which very efficiently assists the transport of calcium through cellular membranes. This facilitates uptake of calcium in the bone. It has been reported that orotate is known to facilitate highest absorption of calcium up to 95%, making it an only calcium that gets deposited in bone tissue. 

Factors favouring absorption:

Vitamin D: The active form of vitamin D, 1-25 dihydroxy cholecalciferols, regulate the synthesis of a calcium binding protein that serves as a calcium carrier in the intestinal cell, transporting calcium across the intestinal cells for it to be released into the bloodstream. The presence of active form of vitamin D can result in 10-30% increase in calcium absorption.

Acidity of the digestive mass: Calcium is more soluble and absorbed in acidic conditions. Most calcium absorption occurs in small intestine, in which the acidity of the digestive mass released from the stomach is soon neutralised. Anything that increases the acidity of the digestive mass released from stomach is neutralised. Anything that increases the acidity of the digestive mass before it enters the small intestine prolongs the time taken for this neutralisation to occur and so increases the efficiency of calcium absorption.

Lactose: Lactose favours absorption of calcium in infants. This is due to the effect of lactose on intestinal flora and the consequent lowering of PH or on calcium per se that maintained it in the form available for transport. The lactose in breast milk and formula improves calcium absorption from 33-48%. A relatively high ratio of lactose to calcium is required to promote calcium absorption. Lactose increases the diffusional component of calcium and phosphorus, especially in the ileum and probably acts osmotically to alter the junctions between epithelial cells.

Protein and phosphorus: The extent to which protein intake affects calcium absorption may depend on amount of calcium in the diet. Increased protein is reported increase the excretion of calcium in urine. Increase in protein intake could lead to 50% increase in urinary calcium excretion. An increase in the amount of phosphate in the diet has the opposite effect on calcium excretion, causing a reduction in the amount excreted. Fortunately, foods with high protein content are also rich in phosphate, so the net effect of increased protein intake on calcium losses via urine is considerably less than is expected from the effect of the protein alone. Protein supplements composed of purified protein practically devoid of phosphate, however may have an adverse effect on calcium balance if consumed in large amounts.

There is an inverse relationship between the dietary phosphorus intake and urinary calcium. Neither dietary phosphorus level nor calcium/phosphorus ratio affects calcium absorption in adults or low birth weight infants.

Need for calcium: The efficiency with which calcium is absorbed may be influenced by the body’s need for calcium. During pregnancy, lactation and adolescence when calcium needs are greatest, absorption efficiency is as high as 50%. Also, when calcium intakes are low the body adapts, by absorbing a greater proportion of dietary calcium available and excreting less.