September 25, 2009 RENU

  1. Calcium accounts for approximately 1.5% of total body weight.
  2. Bones & teeth house 99% of the calcium in the body, while the remaining 1% is distributed in other areas.
  3. In a process known as bone mineralization, calcium & phosphorus join to form calcium phosphate, which gives structure & strength to bones.
  4. Calcium may prevent/treat cataracts, colon cancer, high BP, kidney stones, osteoporosis, premenstrual syndrome, pregnancy induced hypertension & preeclampsia.
  5. Calcium in food and supplements decreases the absorption of heme and nonheme iron.
  6. Magnesium & calcium compete with each other for intestinal absorption. Consequently, calcium supplements shdn’t be taken at the same time as magnesium supplements.
  7. Excessive intakes of calcium (more than 3,000 mg per day) may result in elevated blood calcium levels, a condition known as hypercalcemia. If blood levels of phosphorus are low at the same time, it can lead to soft tissue calcification(unwanted accumulation of calcium in cells other than bone).
  8. The amount of calcium in foods is not adversely impacted by cooking or long-term storage.
  9. Hypochlorhydria, a condition characterized by insufficient secretion of stomach acid, affects many people, especially in the elderly. Lack of stomach acid impairs the absorption of calcium.
  10. Vitamin D accelerates the absorption of calcium from the gastrointestinal tract.   Adequate intake of vitamin D is necessary for the absorption & utilization of calcium. As a result, vitamin D deficiency, or impaired conversion of the inactive to the active form of vitamin D (which takes place in the liver & kidneys), may also lead to a poor calcium status.
  11. High consumption of potassium reduces the urinary excretion of calcium while high intakes of sodium, caffeine, or protein cause an increase in the urinary excretion of calcium.
  12. Certain types of fiber, like the one found in wheat & oat bran, may interfere with calcium absorption by decreasing transit time, limiting the amount of time during digestion for calcium to be absorbed. Dietary fiber also stimulates the proliferation of “friendly” bacteria in the gut, which bind calcium and make it less available for absorption.
  13. Oxalic acid, found in spinach, beets, celery, pecans, peanuts, tea and cocoa, can bind to calcium and form an insoluble complex that is excreted in the feces. While research studies confirm the ability of phytic acid and oxalic acid in foods to lower availability of calcium, the decrease in available calcium is relatively small.
  14. Phytic acid, found in whole grains, nuts, and legumes, can bind to calcium to form and insoluble complex, thereby decreasing the absorption of calcium.
  15. Insufficient calcium intake, poor calcium absorption, and/or excessive calcium losses through the urine & feces can cause calcium deficiency.
  16. In children, calcium deficiency can cause improper bone mineralization, which leads to rickets, a condition characterized by bone deformities & growth retardation.
  17. In adults, calcium deficiency may result in osteomalacia, or “softening of the bone”.
  18. Calcium deficiency, along with other contributing factors, can also result in osteoporosis.
  19. Low levels of calcium in the blood (especially one particular form of calcium, called free ionized calcium) may cause a condition called tetany, in which nerve activity becomes excessive. Symptoms of tetany include muscle pain and spasms, as well as tingling and/or numbness in the hands and feet.
  20. The corticosteroids (like hydrocortisone, prednisone) are a family of anti-inflammatory drugs that reduce the body’s ability to activate vitamin D, resulting in decreased calcium absorption & increased calcium excretion in the urine.
  21. Aluminum-containing antacids, may increase the urinary & stool loss of calcium.
  22. Thyroid hormones may increase urinary excretion of calcium.
  23. Anticonvulsant medications used to control seizure activity in people with epilepsy & brain cancer, decrease the activity of vitamin D, resulting in decreased calcium absorption.
  24. Certain antibiotics may interfere with calcium absorption.
  25. Hormone replacement therapy may decrease calcium excretion & increase calcium absorption in postmenopausal women.
  26. Alendronate (Fosamax (TM)) is used in the treatment & prevention of osteoporosis. Calcium supplements may interfere with alendronate absorption. Since most people who take alendronate also take calcium supplements, it is advisable to take the alendronate at least 2hrs before or after taking the calcium supplement.
  27. Calcium from antacids, dairy products, & supplements can decrease the absorption of tetracycline antibiotics, thereby reducing the effectiveness of these drugs.
  28. Calcium supplements fall into 3categories. 1) naturally derived i.e unrefined calcium carbonate that appears as bone meal, oyster shell, limestone & dolomite(clay) are less expensive but may contain toxic material called lead, 2) refined calcium carbonate, which is most commonly used, is inexpensive but less well absorbed than other forms, 3) chelated is calcium bound to an organic acid(like citrate, malate, lactate, or gluconate) or to an amino acid, such as aspartate.
  29. To improve absorption, calcium carbonate should be taken with meals, as the presence of food in the stomach causes the secretion of hydrochloric (stomach) acid, a compound that breaks down calcium carbonate.
  30. Calcium recommendations are as follows:
  • 0-6 months: 210 mg
  • 6-12 months: 270 mg
  • 1-3 years: 500 mg
  • 4-8 years: 800 mg
  • 9-13 years: 1300 mg
  • 14-18 years: 1300 mg
  • 19-30 years: 1000 mg
  • 31-50 years: 1000 mg
  • 51+ years: 1200 mg
  • Postmenopausal women not taking hormone replacement therapy: 1500 mg
  • Pregnant and lactating women (younger than 18 years): 1300 mg
  • Pregnant and lactating women (older than 18 years): 1000 mg

Entry Filed under: Nutrition

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