The human body utilizes the mineral calcium as one of the main structural building compound to form various hard organic systems. Calcium imparts hardness and strength to the skeletal system and the teeth and almost ninety nine percent of the human body's total three pounds of calcium is in the skeleton and the dentition - calcium also functions in synapse communication in the neurons of the brain. The bones and the teeth can be said to be reservoirs of the mineral calcium, and the mineral in the bones and teeth is not permanently entrenched - it can be transported to other areas or lost in the urine during a disorder or with increasing age. Calcium is almost constantly being exchanged between the bones and the body fluids or even the soft tissues - where the remaining calcium is stored and utilized in various biochemical processes. As a relatively constant blood level of calcium is maintained and regulated by homeostatic processes in the body, there is a distinct danger in the event of insufficient dietary intake of calcium, the amount lost through excretion and loss from the bones may not be replenished - this will inevitably give rise to a deficiency in the mineral. The importance of the remaining one percent of calcium outside the skeletal system cannot be ignored. Calcium is very important to maintain the strength and integrity of all the intracellular membranes and its presence is vital to many important enzyme reactions such as those involved in clotting of blood and many other physiological reactions. Calcium takes part in all neuron to neuron communication through he synapses in the nervous system, it also actively regulates the level of the excitability of the peripheral nerves and muscles so that low calcium levels will inevitably increase the irritability felt in the nerves. Calcium is also vital for normal muscular contraction and relaxation, and is important in regulating the rhythm of the heart and other muscular systems. Due to its great importance both in forming organic structures and its role in physiological reactions calcium is naturally of vital importance for the growth and development of an individual. The importance of calcium is underlined by the fact that during the final trimester of pregnancy, about 200 and 300 mg of calcium is deposited daily in the skeleton of a developing human fetus - all of this calcium is sourced from the mother. As a child is nursed, calcium is again sourced from the mother via the breast milk - which has a calcium content from about 250 to 500 mg of calcium - the growing child receives about this much calcium from his or her mother though breast feeding. Pregnant or lactating women will suffer from a loss of calcium if the amount of calcium lost in the milk or in supplying the fetus is not equaled by the amount supplied through the diet - most of the calcium going to the milk of to the developing child will then be coming out of her bones, the health of both the mother and child will be affected and skeletal system of both mother and child will be weakened. Therefore, it is vitally essential that pregnant or lactating women consume sufficient calcium in the daily diet. Low levels of calcium in the body can come about only in cases of severe deficiencies, as the human body tends to maintain a fairly constant blood level of the mineral calcium. Convulsions and muscle spasms might start to affect the person if the deficiency is really bad. The term calcium "balance" is used by researchers to measure any person's calcium status. Calcium intake in its totality is computed against the total amount of calcium excreted or lost through the urine, the feces and perspiration. The calcium balance in the body of a person will be zero if the total amount of the mineral excreted is equal or even to the amount ingested via dietary sources. The calcium balance will be negative if more calcium is excreted in the urine than is consumed in the diet and so on. The calcium balance is positive if more calcium is consumed in total than is excreted in total. Needless to say, there are a lot of errors inherent in the balance method of measuring calcium levels in the body. This is particularly so, as varied factors can directly affect the retention and excretion of calcium in the human body. However, the balance method of measuring calcium in the diet can be very accurate if the clinical researchers are extremely careful in eliminating all causes of errors or if they account for as many of these extraneous factors as possible during the tests - which must also be conducted over a fairly long testing period for the greatest accuracy of the tests. Calcium in the body can also be measured by another method which compares the density difference of all the different bones in the person over different lengths of time - this measure is very accurate in showing low or gain of calcium deposits in the skeletal system. The measurement of bone density is by far the most accurate method of measuring if sufficient calcium is present in the diet of the person - human bones tend to lose calcium and become less dense over time if there is insufficient calcium in the diet. The onset of disorders like rickets in children, osteomalacia and osteoporosis in adults is directly attributable to the lack of the mineral calcium in the diet. Calcium deficiencies have also other serious effects besides their well known effects on bone mineralization and faulty nerve and muscle irritability. Lack of calcium in the body could also play a role in the inhibited rising blood and tissue levels of two well known poisonous metals - lead and cadmium. The human body tends to retain more lead whenever the levels of dietary calcium are low. These connections between the mineral calcium and related bio-chemical events in the body have been directly demonstrated in many experiments conducted on humans and animal test subjects. It is now known that very low levels of calcium in the diet can induce high blood and tissue levels of the metal lead. Animals may actually consume more lead if the levels of dietary calcium are very low. Animals tests conducted rats and monkeys supplied with a diet deficient in calcium voluntarily consumed nearly forty four times the amount of lead from drinking water rich in lead - this consumption of lead containing water exceeding lead intake under normal circumstances, and the animals tended to prefer the lead rich water even when lead free pure water was made available for drinking. This preference for lead that animals with deficient levels of calcium did not diminish even when they were injected with toxic levels of lead - the preference for the lead was based solely on the amount of calcium in the body. As children deficient in calcium has been demonstrated in human studies to have higher blood levels of lead, it can be said that there is a real connection between cases of accumulated lead poisoning and calcium deficiency in humans as well. Thus, a diet deficient in calcium may actually be the real villain in cases of lead poisoning in humans and such problems may not be caused by lead present in paint at all. When levels of calcium are low in the body, the metal cadmium, a toxic pollutant, also tends to be retained by the body at higher concentrations - this can have drastic implications for the health of the concerned person. In humans the average RDA for the mineral calcium can range from a low of 360 mg in the body of infants to a high of 1200 mg in pregnant and lactating women. In adults, RDA for both men and women (who are not pregnant or lactating), is about 800 mg on average. The RDA for women tends to change after menopause in middle age. Mother's milk is the best source of calcium for a new born baby; human milk has calcium to phosphorus ratio of about 2.4:1 and is the ultimate source of nutrition for a growing child. A good natural source of calcium for everyone else is of course, cow's milk, this has a calcium to phosphorous ratio of 1.2:1, it is not necessary the best or the only natural source of the mineral calcium - many other animals posses milk far more nutritious in mineral content, we just do not use them. Calcium is also abundant in egg yolk and fish when consumed whole, vegetable sources such as soybeans, green leafy vegetables like turnip greens and mustard greens, broccoli and kale, various roots and tubers and all plant seeds are rich in calcium content. Significant amounts of calcium can also be obtained by consuming all types of stews and soups made from bones. The absorption of calcium in the body is also positively affected by the presence of lactose - the sugar found in milk and all dairy products. Many other compounds containing calcium can be used as supplements - thus calcium can be consumed in the form of calcium carbonate, in the form of calcium gluconate, calcium lactate and many other compounds of calcium. There is no "best" supplement as scientist have not been able to come up with a general agreement on the best supplemental form of calcium. Using more than one supplemental form of calcium at the same time is probably wise in treating any deficiency. Supplements of the vitamin D also need to be taken along with the supplemental calcium as this vitamin is essential for the proper absorption and utilization of calcium in the body. A wide array of dosage levels are intended with supplemental use of calcium, supplemental tablet at less than 100 mg to several hundred milligrams each are available in the market. Dairy products of all kinds and milk are the main source of most dietary calcium. Scientific research has not conclusively proved the belief that calcium sourced from dairy products is absorbed optimally in the body. Good natural sources for the mineral calcium include also foods like sardines and canned salmon, as well as tofu from soybeans. Since there are so many supplemental forms of calcium, it can be difficult to make a choice about the best form of calcium supplement to use during the process of supplementation. The absorption rate of supplemental calcium carbonate is not as good as the other supplemental forms of calcium, however, less pills of this form are needed during the period of supplementation - therefore, and this form of calcium is considered ideal as a supplement. The result of the majority of scientific studies but by no means all clinical studies, suggests that absorption rate of calcium citrate is better than the absorption of the calcium carbonate supplemental form. At the same time, almost all the comparative studies done on the absorption rate of calcium citrate-malate - CCM - supplements suggests that it is absorbed a lot better than the supplemental calcium carbonate in human beings. Nutritionally oriented doctors tend to recommend the supplements of CCM and increasingly prefer this form of supplement to all other supplemental forms of calcium. Bone mass in humans is also improved by the microcrystalline hydroxyapatite - MCHC - form of supplemental calcium, this is a chemical variation of the bone meal form of the mineral calcium. However, the absorption rate of MCHC appears to be poor compared to other forms of calcium normally used in supplemental regimes. Conclusions cannot be drawn at this present time as far as the use of amino acid chelates of calcium as supplements is concerned - this is because only preliminary research exists as far as their use in humans is concerned. Further studies need to be conducted before these compounds can be considered safe for use in supplements. When both calcium and vitamin D deficiency exists in the body, the physical symptoms exhibited by the person are called rickets when it affects children and osteomalacia when it affects adults. A deficiency of the vitamin D is much more likely to affect vegans - pure vegetarians who avoid dairy products and eggs, people with dark skin, and populations of the far northern climates, as well as people staying indoors most of the time. When compared to other people, vegans typically consume far lesser calcium and vitamin D in the diet - since, their diet is so restricted to plant matter. At any rate, the majority of people are provided with calcium at levels far below the recommended amounts in the diet. The greater risk of osteoporosis that many white and Asian women face is believed to be this lack of dietary calcium in the normal diets of such women.
The dietary guidelines for calcium set up under the aegis of the National Academy of Sciences is that calcium must be consumed at levels 25-50% higher than what was previously recommended by most dieticians. The recommended calcium supplemental level for ages 19 to 51 years, is at least 1,000 mg a day, preferably as part of the diet - mostly from natural sources of the mineral. The recommended dosage of calcium for supplemental needs of all adults who have crossed age 51 is 1,200 mg of the mineral on a daily basis. For most adults, the most common dosage used in supplements is about 800mg - 1,000 mg of the mineral daily. If doctors recommend general increase in the intake of calcium - usually at 1,200mg - 1,500 mg daily - they normally include the several hundred milligrams of calcium receive from the typical diet.
Supplemental use of calcium has been linked to specific physical symptoms such as persistent constipation, abdominal bloating and excessive gas. The consumption of calcium carbonate supplements along with large amounts of calcium received by consuming large amounts of dairy products was the cause of a condition formerly known as "milk alkali syndrome" - a toxic effect of accumulated calcium in the body. Medical doctors used to recommend people affected by ulcers to take this supplemental combination as a treatment, but they no longer do so these days and hence, such toxic symptoms are no longer common in the general population. Supplements of calcium must not be used by individuals affected by disorders like hyperparathyroidism or diseases like chronic kidney disease as it can worsen things. Such patients must always consult with a nutritionally oriented physician on the possibility of supplementing with calcium before they go ahead. Supplementation using calcium for those individuals with kidney stones must also be done only after consulting with a doctor - they should supplement only after receiving an okay from the doctor. As far as supplemental use of calcium for healthy adults is concerned, the best may be the highest amount normally recommended by nutritionally oriented doctors, this is a dose of 1,200 mg daily. Such dosages are quite safe and are not linked to any adverse side effects.