The human body requires more calcium than any other mineral. At least 99% of the calcium is found in the bones and teeth, giving them strength and rigidity. Calcium has an important role in bone and teeth health , cell signaling ,protein metabolism and in case of pregnancy it is critical to fetal health.
1. General information about Calcium :
The human body requires more calcium than any other mineral. The adult human body contains about 1000 to 1200 g of calcium. At least 99% of the calcium is found in the bones and teeth, giving them strength and rigidity. The remaining 1%, which is in the blood, muscles, and nerves, plays an important role in regulating physiological functions.
Calcium is a white, malleable, metallic element. In the body it is found in various combinations such as calcium carbonate, calcium phosphate, calcium fluoride, and calcium sulphate. Large quantities of fat, oxalic acid, and phytic acid in the food can prevent proper calcium absorption.
The absorption and retention of this mineral depends on its intake as well as other factors. Normally, approximately 20 to 40 percent of this mineral is absorbed from the intestinal tract into the bloodstream. The amounts absorbed, however, may be greatly increased during periods of rapid growth when mineral needs are high. Absorption of calcium also depends on the healthy condition of the stomach and intestines and adequate supply of vitamins B12, D, C and phosphorus.
Calcium is a major structural element in bones and teeth. The mineral component of bone consists mainly of hydroxyapatite crystals, which contain large amounts of calcium and phosphate. Bone is a dynamic tissue that is remodeled throughout life. Bone cells called osteoclasts begin the process of remodeling by dissolving or resorbing bone. Bone-forming cells called osteoblasts then synthesize new bone to replace the bone that was resorbed. During normal growth, bone formation exceeds bone resorption. Osteoporosis may result when bone resorption chronically exceeds formation.
Cell signaling
Calcium plays a role in mediating the constriction and relaxation of blood vessels (vasoconstriction and vasodilation), nerve impulse transmission, muscle contraction, and the secretion of hormones like insulin. Excitable cells, such as skeletal muscle and nerve cells, contain voltage-dependent calcium channels in their cell membranes that allow for rapid changes in calcium concentrations. For example, when a muscle fiber receives a nerve impulse that stimulates it to contract, calcium channels in the cell membrane open to allow a few calcium ions into the muscle cell. These calcium ions bind to activator proteins within the cell, which release a flood of calcium ions from storage vesicles inside the cell. The binding of calcium to the protein, troponin-c, initiates a series of steps that lead to muscle contraction. The binding of calcium to the protein, calmodulin, activates enzymes that breakdown muscle glycogen to provide energy for muscle contraction
Protein metabolism
Calcium is necessary to stabilize a number of proteins and enzymes, optimizing their activities. The binding of calcium ions is required for the activation of the seven "vitamin K-dependent" clotting factors in the coagulation cascade. The term, "coagulation cascade," refers to a series of events, each dependent on the other that stops bleeding through clot formation
Pregnancy health
Calcium is required for proper foetal growth, for normal health of the mother during pregnancy and lactation, and for the secretion of breast milk.
Help in utilize other nutrients
Calcium is essential for proper utilization of phosphorus and vitamins A, C and D.
Calcium-deficient people look pale and listless, get tired, and become lazy. Deficiency of calcium causes changes in the bones and muscles. They are more sensitive to cold weather. They become nervous and suffer from mental derangements. Sweating around the head even during cold weather is the most obvious symptom of calcium deficiency in all ages. Deficiency of calcium may cause porous and fragile bones, tooth decay, heart palpitations, muscle cramps, insomnia, and irritability. Children who are born to calcium-deficient mothers generally suffer from calcium deficiency. In such children calcium deficiency becomes more prominent if there is no supply of calcium, proteins, minerals, and vitamins in the form of whole milk, fresh fruits, and vegetables.
These children fail to grow or develop healthy and strong bones. They lack appetite and if fed forcibly, may bring out all the food and milk. They suffer from late and detective teething, and are prone to having emaciated necks and enlarged heads. Deficiency of calcium lowers the body resistance and these children become an easy prey to respiratory and intestinal infections. Deficiency of calcium in young girls causes late puberty, irregular menstruation, excessive bleeding with crampy pain, anaemia, and lowered state of body resistance against infections.
In case of an inadequate supply of calcium during pregnancy, the development of the foetus continues by drawing the reserve calcium from the bones, but the mother usually suffers from a difficult labour. Bleeding, lack of breast milk, poor concentration of the mind, a prolonged lying-in period - these are all comon due to calcium deficiency after childbirth.
Many foods contain calcium, but dairy products are the most significant source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain an efficiently absorbed form of calcium.
A case-control study of 511 men found that increased calcium intake was more strongly associated with decreased colorectal cancer risk in men with higher circulating levels of IGF-1. Before conclusions can be drawn, more research is needed to clarify whether specific subgroups in the larger population have different calcium requirements with respect to decreasing the risk of colorectal cancer.
2. Osteoporosis
Osteoporosis is a skeletal disorder in which bone strength is compromised, resulting in an increased risk of fracture. Sustaining a hip fracture is one of the most serious consequences of osteoporosis. Supplemental calcium alone cannot usually restore lost bone in individuals with osteoporosis. However, optimal treatment of osteoporosis with any drug therapy also requires adequate intake of calcium (1,200 mg/day) and vitamin D (600 IU/day).
3. Kidney stones
Approximately 12% of the U.S. population will have a kidney stone at some time. Most kidney stones are composed of calcium oxalate or calcium phosphate. Although their cause is usually unknown, abnormally elevated urinary calcium (hypercalciuria) increases the risk of developing calcium stones. a recent randomized, double-blind, placebo-controlled trial in 36,282 postmenopausal women reported that a combination of supplemental calcium (1,000 mg/day) and vitamin D (400 IU/day) was associated with a significantly increased risk for kidney stones. More controlled trials are necessary to determine whether supplemental calcium affects the development of kidney stones
4. Pregnancy-induced hypertension (preeclampsia)
Pregnancy-induced hypertension (PIH) occurs in 10% of pregnancies and is a major health risk for pregnant women and their unborn children. For the general population, meeting current recommendations for calcium intake during pregnancy may help prevent PIH. Further research is required to determine whether women at high risk for PIH would benefit from calcium supplementation above the current recommendations.
5. Lead toxicity
Children who are chronically exposed to lead, even in small amounts, are more likely to develop learning disabilities, behavioral problems, and to have low IQ's. A study of over 300 children in an urban neighborhood found that 49% of children aged 1 to 8 years had blood lead levels above current guidelines, indicating excessive lead exposure. In this study, only 59% of children ages 1-3 years and 41% of children ages 4-8 years had calcium intakes meeting the recommended levels .
A recent study of blood lead levels during pregnancy found that women with inadequate calcium intake during the second half of pregnancy were more likely to have elevated blood lead levels, probably related to increased bone demineralization with the release of accumulated lead into the blood.
6. High blood pressure
The relationship between calcium intake and blood pressure has been investigated extensively over the past two decades. An analysis of 23 large observational studies found a reduction in systolic blood pressure of 0.34 millimeters of mercury (mm Hg) per 100 mg of calcium consumed daily and a reduction in diastolic blood pressure of 0.15 mm Hg per 100 mg calcium.
7. Premenstrual Syndrome (PMS)
PMS refers to a cluster of symptoms, including but not limited to fatigue, irritability, moodiness/depression, fluid retention, and breast tenderness, that begins sometime after ovulation (mid-cycle) and subsides with the onset of menstruation (the monthly period) . Low dietary calcium intakes have been linked to PMS in several studies, and supplemental calcium has been shown to decrease symptom severity
Vitamin D is commonly known as the 'Sunshine Vitamin'. The growth and maintenance of the normal bones largely depends on this. Vitamin D is a fat-soluble vitamin that is essential for maintaining normal calcium metabolism . Vitamin D3 (cholecalciferol) can be synthesized by humans in the skin upon exposure to ultraviolet-B (UVB) radiation from sunlight, or it can be obtained from the diet. When exposure to UVB radiation is insufficient for the synthesis of adequate amounts of vitamin D3 in the skin, adequate intake of vitamin D from the diet is essential for health.
Vitamin D is the most essential vitamin for preventing rickets, which is a known deficiency disease affecting children, and is characterized by defective bone formation, disturbance of calcium utilization in the body, and resulting weakness. Vitamin D assists in the assimilation of calcium, phosphorus and other minerals in the digestive tract. Also it is necessary for the healthy functioning of the parathyroid glands, which regulates the calcium level in the blood.
Vitamin D is very important during infancy and adolescence for the proper formation of teeth and bones. Good supply of Vitamin D during pregnancy benefits the mother and helps to ensure the satisfactory future development of the child.
Vitamin D deficiency May cause rickets, a disease affecting the whole body. Its most characteristic symptom is the failure of the bones to calcify properly. Vitamin D deficiency May lead to tooth decay, pyorrhoea, brittle or soft bones, retarded growth, and poor bone formation in children. Also it May cause muscular weakness, lack of vigour, deficient assimilation of minerals, and premature ageing.
The term vitamin E describes a family of eight antioxidants. Alpha-tocopherol is the only form of vitamin E that is actively maintained in the human body; therefore, it is the form of vitamin E found in the largest quantities in blood and tissues. Approximately 50 to 85 percent of vitamin E in the diet is absorbed from the gastro-intestinal tract by a mechanism similar to that of other fat-soluble vitamins. It enters the bloodstream via the lymph. The vitamin is stored in all the tissues, and the tissue stores can provide protection against the deficiency of this vitamin for long periods. About one-third of the vitamin is excreted in the bile and the balance is excreted in the urine.
The main functions of Vitamin E are to help protect the functioning of cells and the intracellular processes. Vitamin E oxygenates the tissues and reduces the need for oxygen intake markedly. It is essential for normal reproductory functions, fertility, and physical vigour. It prevents unsaturated fatty acids, sex hormones, and fat-soluble vitamins from being destroyed in the body by oxygen. Vitamin E dilates the capillaries and enables the blood to flow freely into blood-deficient muscle tissue, thus strengthening both the tissues and the nerves supplying them. It dissolves blood clots and also prevents their formation. It does not, however, interfere with the normal clotting of blood. It prevents the formation of excessive scar tissues and in some instances, even melts away unwanted scar tissue. It also promotes urine secretion. Vitamin E is said to be essential for prevention of heart disease, asthma, arthritis, and many other conditions.
When applied topically, vitamin E has been known to improve skin moisturization, softness and smoothness and also provide modest photoprotection. Deficiency of vitamin E may lead to degenerative changes in the blood capillaries which, in turn, can lead to heart and lung disease, pulmonary embolism, and a brain stroke. Deficiency of this vitamin may also lead to loss of sexual potency. A prolonged deficiency may lead to reproductive disorders, abortions, miscarriages, male or female sterility, as well as muscular disorders.
Vitamin K is a fat-soluble vitamin. It is essential for the production of protein called prothrombin and other factors involved in the blood-clotting mechanism. Hence it is known to prevent haemorrhages.
Vitamin K exists in nature in two forms. Vitamin K1, originally isolated from lucrene (alfalfa), is the only form that occurs in plants. It is a yellow oil, soluble in fat solvents, but only slightly soluble in water. Vitamin K2 has been found to be produced by many bacteria. Studies of the liver stores of vitamin K indicate that approximately 50% of the vitamin comes from the diet and 50% from bacterial production in the intestines. Vitamin K is absorbed along with fat in the diet. Bile is essential for its absorption. The absorbed vitamin passes through the lymphatic system to the general circulation. The liver stores appreciable amounts of this vitamin. There is hardly any excretion of vitamin K by the body.
Vitamin K is essential for the prevention of internal bleeding and haemorrhages. It aids in reducing excessive menstrual flow in women. This vitamin is important for the normal functioning of the liver. It is also involved in the energy producing activities of the tissues, particularly, those of the nervous system.
Primary deficiency of vitamin K in adults has not yet been clearly demonstrated, either by observation of malnourished patients or by dietetic experiments on volunteers. Hence it may be assumed that even the worst diets contain enough of this vitamin to meet normal human needs. A deficiency state would more likely be caused by a failure to absorb or utilize the vitamin. Low vitamin K intake, plus antibiotic therapy, which reduces its production by bacteria, may result in lowered levels of vitamin K in the body.
A deficiency of vitamin K which results in the blood taking longer to clot, may cause severe haemorrhages anywhere in the body. Nosebleeds and bleeding can prove to be life threatening.
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