Calcium is the most abundant mineral in the body. About 99% is deposited in the bones and teeth. The remaining 1% is involved in the soft tissues, intracellular fluids and blood.
Calcium is used in the development and maintenance of bone structure and rigidity. It functions in the:
Parathyroid hormone function
Metabolism of vitamin D
The major function of calcium is to act in cooperation with phosphorus to build and maintain bones and teeth. Another important function is the storage of the mineral in the bones for use by the body.
The calcium state of the bones is constantly fluctuating according to the diet and to the body's needs. It is essential for healthy blood and eases insomnia and its delicate messenger ions help regulate the heartbeat. Along with calcium, magnesium is needed to properly maintain the cardiovascular system.
In addition, calcium assists in the process of blood clotting and helps prevent the accumulation of too much acid or too much alkali in the blood. It also plays a part in secretion of hormones. It affects neurotransmitters, nerve transmission, muscle growth and muscle contraction.
The mineral acts as a messenger from the cell surface to the inside of the cell and helps regulate the passage of nutrients in and out of the cell walls. Calcium aids in the body's utilisation of iron and helps activate several digestive enzymes.
Calcium absorption is very inefficient
Only 20 to 30% of ingested calcium is absorbed. Women after menopause frequently absorb as little as 7%. About 100 to 200 milligrams are filtered through the blood and excreted in the urine. Another 125 to 180 mg are excreted in the faeces. Some is lost in sweat, but only when there is illness or extreme physical activity in dry, hot environments. Absorption takes place in the duodenum and ceases in the lower part of the intestinal tract, when food content becomes alkaline.
It is more efficient to take calcium in smaller doses, several times a day and at night before bedtime, which also promotes a sound sleep.
Does calcium require other nutrients for it to be properly absorbed in the body?
Yes. Absorption depends upon the presence of adequate amounts of vitamin D, which works with the parathyroid hormone to regulate the amount of calcium in the blood.
Phosphorus is needed in the same amount but should not exceed the exact amount of calcium. The body uses them together to give firmness to the bones. If an excess amount of either mineral is taken, that excess cannot be used efficiently.
A typical western diet, containing too little calcium and too much phosphorus (owing to popular food items, such as soft drinks, processed foods like meats, cheese and other convenience foods) may result in bone loss.
Fat content in moderate amounts, moving slowly through the digestive tract, helps facilitate absorption, as does bile and bile salts.
Are there different types of calcium and are some better than others?
Bone meal contains absorbable calcium but may also be contaminated with lead. We no longer recommend this form.
Calcium chloride may be irritating to the gastrointestinal tract and gluconate is available as an elixir.
Calcium phosphate interferes with the absorption of other nutrients when it is included in a multi supplement. This form may not be listed on the label.
Both calcium carbonate and magnesium carbonate - not the easiest to absorb, are found in dolomite.
Calcium gluconate, calcium lactate and calcium citrate are the best absorbed but they are lower in strength, so a tablet that uses these forms, will usually provide a lower elemental level of calcium.
MCHC - microcrystalline hydroxyapatite
The most absorbable and beneficial form of calcium for bone related health conditions (low bone density and bone breaks) is microcrystalline hydroxyapatite concentrate (MCHC) as found in the product Ethical Nutrients Ethi Cal Hi Strength Tablets and Powder. This is derived from young bovine or ovine bone by a manufacturing process designed to ensure intact micronutrients are present. Peer reviewed scientific papers have proven MCHC to restore bone, with its absorption and uptake into the bone being superior to other forms of calcium.
The main component of MCHC is a calcium phosphate complex salt, hydroxyapatite. Other highly beneficial components in MCHC are sodium, magnesium and potassium. In smaller quantities, boron, zinc, copper, manganese and silicon. MCHC contains 18% collagen and small amounts of glycoaminoglycans (growth factors). We have used this form of calcium in many situations with outstanding results. Not only have we seen improvements in bone density in older women, but we have also seen breaks in bones heal much faster than usual.
Is it easy for the body to absorb calcium?
Many other factors influence the actual amount of calcium absorbed. When in need, the body absorbs calcium more effectively; therefore the greater the need and the smaller the dietary supply, the more efficient the absorption. Absorption is also increased during rapid periods of growth.
Substances that interfere with the absorption of calcium
When excess amounts of fat, protein or sugar combine with calcium, an insoluble compound is formed, which cannot be absorbed.
Caffeine, tannin, diuretics, fluoride, mineral oil, antibiotics and thyroxine all affect the nutrient's absorption and utilisation.
Insufficient vitamin D intake or excess phosphorus hinders the absorption of calcium.
Oxalic acid found in chocolate, spinach, beet greens, Swiss chard, soybeans, almonds, cashews, kale and rhubarb, when combined with calcium make another insoluble compound, which may form into stones in the kidney or gall bladder.
Large amounts of phytic acid present in unleavened grains may also inhibit absorption by the body.
Additional factors affecting Calcium absorption
Other interfering factors include a lack of exercise, physical and emotional stress, excitement, depression and too rapid a flow of food through the intestinal tract. Even moderate exercise encourages absorption.
Remember it is vital to avoid black and green tea, herbal teas, coffee and products containing chocolate for up to 1 hour after taking your calcium supplement or eating a calcium rich meal, to ensure you get maximum absorption. Consider the Madura range of tea, which are naturally 100% tannin free and 98% caffeine free.
Parathyroid glands adjust the storage of calcium
The parathyroid glands in the neck help adjust the body's storage of calcium. If these glands are not functioning properly, accumulation may occur. The remedy for this situation is to renew the proper function of the parathyroid glands, rather than to cut down on the intake.
Calcium also needs acid for absorption
Calcium needs acid for proper assimilation. If acid in some form is not present in the body, the mineral will not be dissolved and therefore cannot be used as needed by the body. Instead, it may build up in tissues or joints as deposits, leading to a variety of disturbances. Those who take proton pump inhibitors, such as losec may need to take their calcium supplement or calcium rich foods with water, which has some Apple cider vinegar added to it. This is almost identical in composition to hydrochloric acid, needed for the absorption of these and many other minerals.
Can you have too much calcium?
When the concentration of calcium is too high, hormones and vitamin D make sure that calcium is deposited in its storage place in the bones. When it is too low, the imbalance is corrected in several ways: in the kidneys, which slow excretion; in the bones, which control the release of needed amounts; and in the intestines, which encourages absorption.
Calcium stored in the bones supplies the bloodstream, which is unaffected by dietary or food intake. However, a chronic dietary deficiency will diminish the stores in the bones after a number of years.
If the intake of calcium is too high, magnesium levels also need to be high. Too little magnesium results in calcium accumulations in the muscles, heart and kidneys.
Too much calcium can interfere with the functions of the nervous and muscular systems. An excess amount in the blood causes calcium rigour, which is characterised by muscles that contract and cannot relax. When an excess is added to blood plasma, coagulation does not take place. Too much calcium will decrease the body's absorption of zinc and iron.
How much calcium do you need?
Check our Calcium Chart for the correct amount of calcium you require. Remember that with age, it seems that the requirement for calcium increases because of a reduced rate of absorption, as well as a lessening desire to eat calcium rich foods. Supplementation of up to 2500 mg of calcium a day is considered safe.
What symptoms can you get if you have a deficiency of calcium?
Calcium deficiencies are wide spread in human society with only 1/3 to 1/2 of the necessary requirements being consumed. One of the first signs of a deficiency is a nervous affliction called tetany, which is characterised by muscle cramps, numbness and tingling in the arms and legs.
Another deficiency ailment is osteoporosis, in which the bones become porous and fragile because calcium is withdrawn from the bones and other areas faster than it is deposited in them.
All humans lose bone density starting between the ages of 30 and 40. Excessive bone loss affects over 20 million people, mostly women who are 45 and older. A good accumulation of calcium in the bones at early stages in life is the best prevention of age-related bone loss and fractures.
A deficiency may be due to a lack of vitamin D or abnormal concentrations of hormones that regulate the availability from the bones to the blood and not necessarily due to a dietary inadequacy.
Low levels of calcium increase the risk of hypertension or high blood pressure. Calcium may counteract the effects of sodium in the development of hypertension. Severe deficiency can lead to abnormal heartbeat, dementia and convulsions.
When there is not enough calcium absorbed in the body, the output of estrogen decreases. As is the case with postmenopausal women, older men are often deficient in calcium.
People who may be at risk for deficiencies
Use antacids that contain aluminium
Eat diets that are low in calories, high in protein or high in fibre
Are lactose intolerant
Take Proton pump inhibitors
Are basically inactive
Moderate cases of calcium deficiency may lead to:
Slow pulse rates
Increased cholesterol levels
Excessive irritability of nerves
Numbness of the arms and / or legs
What health problems can calcium help with?
Calcium is a natural tranquilliser and tends to calm the nerves: when taken 20-40 minutes before bedtime it promotes a deep sleep.
The production of energy and the maintenance of the immune system benefit from calcium.
By lowering cholesterol, calcium is thought to be beneficial in the treatment of cardiovascular disorders. Calcium supplements up to 1500mg have lowered blood pressure in people with or without hypertension and are thought to do so because of the condition of the smooth muscle that surrounds the blood vessels.
In addition, calcium is a recognised aid for muscle cramps in the feet or legs. It also helps "growing pains".
Arthritis, structural rigidity often caused by depletion of bone calcium, may be helped with regular supplements of calcium. Early supplementation may help prevent arthritis. Rheumatism may also be treated successfully with calcium therapy. Supplementation may help prevent bone fractures in postmenopausal women who already have osteoporosis. The hormones involved are stimulated by the concentration of calcium ions in the blood.
Problems of menopause, such as nervousness, irritability, insomnia and headaches have been overcome with administration of calcium, magnesium and vitamin D. Prevention of premenstrual tension and menstrual cramps has been shown.
Calcium supplementation can help with the following
Bone and tooth formation, tooth decay, periodontal disease
Muscle cramps, muscle contractions, menstrual cramps, tetany
High blood pressure
Psychiatric disorders, cognitive impairment
Nerve transmission, limb numbness, convulsions
Hyperactivity, heart palpitations
Lead toxicity or exposure