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| The topic of bone density and calcium is one of the most common subjects that come up at Vitamin Connection. Opinions vary widely, yet the facts behind calcium and magnesium absorption are are not always understood.
The American diet is horrible in the damage it does to our skeletal system. First, the long string proteins in our meats and dairy products require large amounts of digestive acids (calcium bicarbonate) to break them down. The body replaces the calcium needed for digestion by severely depleting our bone "reserves." Second, phosphoric acid, deliberately added to soft drinks to "sharpen" the flavor, reacts with both the calcium in our digestive system and the calcium in our food to form calcium phosphate. Calcium phosphate cannot be absorbed by the body and is passed out in the urine. More calcium must be pulled from the bones to replace the loss. Studies show that teenage girls who drink soda get only 60% of the calcium of girls who don't drink soda. Finally, magnesium, which is critically important for calcium uptake into the bones, is virtually depleted from our soils and is not replaced in fertilizer because it does nothing to help crops grow.
Myth #1: I get a lot of my calcium from milk and cheese fortified with vitamin D.
While it is true that a constituent analysis of milk shows it to be rich in calcium, and TV commercials, doctors and many nutritionists tout its virtues, the body has to secrete a lot of calcium bicarbonate to digest milk. What is most important here is the ratio between calcium absorption and calcium depletion. Urinalysis shows a net calcium loss when people consume dairy products. This net loss is greater in people who have developed allergies to milk and have difficulty with milk digestion.
Myth #2: I take a lot of Tums. I get plenty of calcium.
Tums, Tums Ultra, and Rolaids have between 250-400 mg of calcium carbonate. But these figures do not tell the story. Calcium needs an acidic environment for absorption, and these anti-acids reduce the acidity, thereby reducing absorption. But it gets worse. Using antacids over a long period of time may be harmful and may lead to osteomalacia (a softening of the bones). Antacids containing aluminum and magnesium hydroxide tend to bind phosphates in the gut, resulting in severe phosphate depletion and toxic accumulation of aluminum.
Myth #3: Calcium citrate is the best form of calcium.
It may be--for you. A series of studies showed that calcium citrate was absorbed 22-27% more than calcium carbonate. Once again, it is more complicated than that. In general, there are two types of calcium: soluble and insoluble. The soluble forms are calcium citrate, calcium gluconate, and calcium lactate. The insoluble forms are bone meal, calcium carbonate, dolomite, and calcium phosphate. While "soluble" calcium sounds easier to absorb, it is really a function of body types. "Insoluble" calcium dissolves in an acid environment. If your body is naturally acidic, you may absorb calcium carbonate well. Or you can boost its absorption by taking it with meals and a glass of unsweetened orange, grapefruit, or cranberry juice. Calcium carbonate is 40% elemental calcium while calcium citrate is only 22% elemental calcium--but statistically, most people absorb more calcium with calcium citrate. Not sure of your body acidity? Consider the advice of Drs. Balch in Prescription for Nutritional Healing and take a supplement that combines soluble and insoluble calcium.
There is a third type of calcium supplement made from cattle bones. Microcrystalline hydroxyapatite (MCHC) typically contains 25% calcium as well as many other trace elements and collagen. Research conducted in Britain over a ten-year period showed hydroxyapatite to be an extremely bioavailable form of calcium. Other clinical studies indicate that MCHC is utilized more effectively than "synthetic" calcium supplements. In fact, hydroxyapatite absorbed 100% more than calcium gluconate, a soluble calcium. MCHC was uniquely found to not only prevent further loss of bone, but to restore its mineral content as well. Some supplements contain all three types of calcium.
Myth #4: I take calcium for my bones. The magnesium just helps it absorb better.
Both calcium and magnesium are stored in the bone "reserves," and both are vital for bone density. While calcium gives bones their strength, magnesium helps them maintain their elasticity, therefore helping to prevent injury. Magnesium is also crucial for calcium absorption, as we will discuss in Part 2.
Myth #5: I'm approaching menopause. I should start taking calcium so I don't get osteoporosis.
You should have started sooner. Studies show a direct relationship between osteoporosis and the amount of calcium women absorb between the ages of 16 and 25. The amount of calcium absorbed in youth affects not only the propensity for the disease, but a woman's ability to absorb calcium as she ages. This is a double whammy for girls who consume a lot of soda pop. The fact of the matter is, it is never too early to regulate calcium absorption.
Next month we will look at the important role of magnesium and other factors involved with calcium absorption.
For more Information:
Bone Resorption Assessment, Great Smokies Diagnostic Laboratory
http://www.gsdl.com/assessments/boneresorption/appguide/index.html
Osteoporosis: Prevention and Natural Treatment
http://ourworld.compuserve.com/homepages/Dr_John/calcium.htm
Microcrystalline Hydroxyapatite, Villa Park Technical Library
http://www.villaparkpharmacy.com/abs04.htm
Calcium Hydroxyapatite: A Superior Bone Support Supplement
http://www.amni.com/reprints/osteoguard.html
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