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Calcium: What is it?

Calcium, the most abundant mineral in the human body, has several important
functions. More than ninety-nine percent of total body calcium is stored in the bones
and teeth where it functions to support their structure. The remaining one percent is
found throughout the body in blood, muscle, and the fluid between cells. Calcium is needed for muscle contraction –including the heart, blood vessel contraction and expansion, the secretion of hormones and enzymes, and sending messages [in the form of electrical impulses] through the nervous system. A constant level of calcium is maintained in body fluid and tissues so that these vital body processes function efficiently. [Continued]
What is the recommended intake for calcium?
The Recommended Daily Allowance or ‘RDA’ recommends the average daily intake that is sufficient to meet the nutrient requirements of nearly all healthy individuals in each age and gender group. For calcium, the recommended intake is listed as an Adequate Intake or ‘AI,’ which is a recommended average intake level based on observed or experimentally determined levels. The current recommendations for calcium for infants, children and adults is about 270 mg/day up to one year of age, increasing gradually to about 1,200 mg/day at age fifty and older. . [Continued]
What foods provide calcium?

In the U.S. milk, yogurt and cheese are the major sources of calcium in a typical
diet. The inadequate intake of dairy foods may explain why many Americans are deficient in calcium since dairy foods are the best source of calcium in the diet. A variety of non-fat and reduced fat dairy products that contain the same amount of calcium as regular dairy products are available today for individuals concerned about saturated fat content from regular dairy products. Although dairy products are the main source of calcium, other foods also contribute to overall calcium intake. Individuals with lactose intolerance --individuals who experience symptoms such as bloating and diarrhea because they cannot completely digest the milk sugar [lactose] and those who follow a ‘vegan’diet. [Continued]
Helping hints for meeting our calcium needs
The following are strategies and tips to help you meet our calcium needs each day:
use low fat or fat free milk instead of water in recipes such as pancakes, mashed potatoes, pudding and instant, hot breakfast cereals. Blend a fruit smoothie made with low fat or fat free yogurt for a great breakfast. Sprinkle grated low fat or fat free cheese on salad, soup or pasta. Choose low fat or fat free milk instead of carbonated soft drinks. Serve raw fruits and vegetables with a low fat or fat free yogurt based dip. Create a vegetable stir-fry and toss in diced calcium-set tofu. Enjoy a parfait with fruit and low fat or fat free yogurt. Complement our diet with calcium-fortified foods such as certain cereals, orange juice and soy beverages. [Continued]
What affects calcium absorption and excretion?

Calcium absorption refers to the amount of calcium that is absorbed from the digestive tract into our body's circulation; it can be affected by the calcium status of the body, vitamin D status, age, pregnancy and plant substances in the diet. The amount of calcium consumed at one time such as in a meal can also affect absorption. For example, the efficiency of calcium absorption decreases as the amount of calcium consumed at a meal increases. Net calcium absorption can be as high as sixty percent in infants and young children and it slowly decreases to fifteen or twenty percent in adulthood and even more as we age. . [Continued]
The role of calcium on disease prevention
Our bones are living tissues and continue to change throughout life. During childhood and adolescence, bones increase in size and mass. Bones continue to add more mass until around age thirty, when peak bone mass is reached. This is the point when the maximum amount of bone is achieved. Because bone loss, like bone growth, is a gradual process, the stronger our bones are at this age, the more our bone loss will be delayed as we age. Therefore, it is particularly important to consume adequate calcium and vitamin D throughout infancy, childhood, and adolescence. It is also important to engage in weight-bearing exercise to maximize bone strength and bone density to help prevent osteoporosis later in life. [Continued]
Calcium and high blood pressure

Some studies indicate that individuals who eat a vegetarian diet high in minerals
(including calcium, magnesium and potassium) and fiber, and low in fat, tend to
have reduced blood pressure. Findings from clinical trials indicate that an increased calcium intake lowers blood pressure and the risk of hypertension. However, the results of some of these studies produced small and inconsistent reductions in blood pressure; one reason for these results is because these studies tended to test the effect of single nutrients rather than foods on blood pressure. [Continued]
Calcium and cancer: Colorectal cancer

The relationship between calcium intake and the risk of colon cancer has not been
conclusively determined. Research studies investigating the role calcium plays in the
prevention of colon cancer show mixed results. Some studies suggest that increased intakes of dietary and supplemental calcium are associated with a decreased risk of colon cancer. Supplementation with calcium carbonate is reported to lead to reduced risk of adenomas [nonmalignant tumors] in the colon, a precursor to colon cancer, but it is not known if this will ultimately translate into reduced cancer risk. [Continued]

When can a calcium deficiency occur?
Inadequate calcium intake, decreased calcium absorption and increased calcium loss in urine can decrease total calcium in the body, with the potential of producing osteoporosis and other consequences of chronically low calcium intake. If an individual does not consume enough dietary calcium or experiences rapid losses of calcium from the body, it is withdrawn from their bones in order to maintain
normal levels in the blood. [Continued]
Signs of calcium deficiency

Because circulating blood calcium levels are tightly regulated in the bloodstream, hypocalcemia or low blood calcium does not usually occur due to low calcium intake, but rather results from a medical problem or treatment such as renal failure, surgical removal of the stomach, which significantly decreases calcium absorption, and use of certain types of diuretics, resulting in increased loss of calcium and fluid through urine. Simple dietary calcium deficiency produces no signs at all. Hypocalcemia can cause numbness and tingling in fingers, muscle cramps, convulsions, lethargy, poor appetite, and mental confusion. It can also result in abnormal heart rhythms and even death. [Continued]
Who may need extra calcium to prevent a deficiency?

Menopause often leads to increases in bone loss with the most rapid rates
occurring during the first five years after menopause. Drops in estrogen production after menopause result in increased bone resorption, and decreased calcium absorption. Annual decreases in bone mass of up to five percent are often seen during the years immediately following menopause, with decreases less than one percent per year seen after age sixty-five. Some studies suggest that increased calcium intakes during menopause will not completely offset bone loss –So, it is very important to consume enough calcium before menopause appears. Hormone therapy or ‘HT,’ previously known as hormone replacement therapy or HRT, with sex hormones such as estrogen and progesterone, helps to prevent osteoporosis and fractures. However, some medical groups and professional medical societies recommend that postmenopausal women consider using other agents such as biphosphonates, medications used to slow or stop bone-resorption, because of potential health risks of HT if combination HT [estrogen and progestin] is solely being administered to prevent or treat osteoporosis. [Continued]

Is there a health risk of too much calcium?
The Tolerable Upper Limit [UL] is the highest level of daily intake of calcium from food, water and supplements that is likely to pose no risks of adverse health effects to almost all individuals in the general population. The UL for children and adults ages one year and older including pregnant and lactating women is 2500 mg/day. It is not possible to establish a UL for infants under the age of one year. While low intakes of calcium can result in deficiency and undesirable health conditions, excessively high intakes of calcium can also have adverse effects. Adverse conditions associated with high calcium intakes are hypercalcemia or elevated levels of calcium in the blood, impaired kidney function and decreased absorption of other minerals. Hypercalcemia can also result from excess intake of vitamin D, such as from supplement overuse at levels of 50,000 IU or higher. However, hypercalcemia from diet and supplements is very rare. Most cases of hypercalcemia occur as a result of malignancy, especially in the advanced stages. Another concern with high calcium intakes is the potential for calcium to interfere with the absorption of other minerals, iron, zinc, magnesium and phosphorus. Most Americans should consider their intake of calcium from all foods including fortified ones before adding supplements to their diet to help avoid the risk of reaching levels at or near the UL for calcium --2500 mg. For additional assistance regarding calcium needs, consider checking with a physician. [Continued]

Calcium and Medication Interactions

Calcium supplements may decrease levels of the drug digoxin, a medication given
to heart patients. The interaction between calcium and vitamin D supplements and
digoxin may also increase the risk of hypercalcemia. Calcium supplements also interact with fluoroquinolones, a class of antibiotics including ciprofloxacin, levothyroxine [thyroid hormone] used to treat thyroid deficiency, antibiotics in the tetracycline family, tiludronate disodium. a drug used to treat Paget's disease and phenytoin, an anti-convulsant drug. In all of these cases, calcium supplements decrease the absorption of these drugs when the two are taken at the same time. [Continued]
Supplemental sources of calcium

General dietary guidelines for Americans recommend that individuals consume a
variety of foods to meet their nutrient needs since no single food can supply all the nutrients in the amounts we need. However, for some people it may be necessary to take supplements in order to meet the recommended intakes for calcium. The two main forms of calcium found in supplements are carbonate and citrate. Calcium carbonate is the most common because it is inexpensive and convenient. The absorption of calcium citrate is similar to calcium carbonate. For instance, a calcium carbonate supplement contains forty percent of calcium while a calcium citrate supplement only contains about twenty percent. However, we would have to take more pills of calcium citrate to get the same amount of calcium as we would get from a calcium carbonate pill since citrate is a larger molecule than carbonate. One advantage of calcium citrate over calcium carbonate is better absorption in those individuals who have decreased stomach acid. [Continued] Health & Life® MedixNet®
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