Metabolic Bone Disease

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^{Metabolic Bone Disease}

^{Calcium deficiency generically represents one possible cause for Metabolic Bone Disease. Metabolic Bone Disease is generally caused by one or more of the following: Too little calcium, protein or ultraviolet light; too much phosphorus or too little or too much vitamin D3. Less common, though possible, Metabolic Bone Disease can be caused from diseases of the kidney, liver, small intestine or thyroid glands. Any of these can cause disruption of metabolic functions that affect calcium absorption.}

^{MBD is almost always caused by human error through bad diet. An animal living in the wild in their normal environment would not get MBD. It is only after being raised in captivity, where the animal is not given a proper diet that MBD occurs.}

^{Have you ever heard the words "that vegetable is a calcium blocker" or "you must give extra calcium with Vitamin D3" or "supplemental calcium must have magnesium to absorb properly"? You're about to learn just what those statements mean and the whys and the why nots.}

^Calcium^{Calcium, the most abundant mineral in the body, interacts with phosphorus to form calcium phosphate (the hard dense material which forms bone & teeth). Most of the calcium in the body is stored in this very usable form. Bone regeneration is a dynamic process and bone matter is constantly being reabsorbed & new deposits laid down. This regeneration is regulated by the serum mineral levels, PTH & Vitamin D3. The remaining calcium not used in bone regeneration is found in serum (the fluid that is left after all blood solids have been removed) & is either ionized & ready to use, or is bound to protein & not ionized.}

^{Metabolism of calcium is a complex balancing act and each of the following is vital to the process: 2Parathyroid & 3calcitonin hormones, 4Vitamin D3, the intestine, kidney, liver, thyroid gland, parathyroid gland & bone. Let's take a look at each one and what their purpose is in this process.}

^{Parathyroid Hormone (PTH)}^{The parathyroid glands are located near the thyroid glands & secrete PTH. Serum calcium levels regulate the hormone's secretion. The lower the level of serum calcium, the more PTH is excreted. If serum calcium level is high, PTH excretion is lower. As the blood filters through the parathyroid glands, they detect the amount of calcium present in the blood and react by making more or less parathyroid hormone (PTH). When the calcium level in the blood is too low, the parathyroids make more PTH. Once the PTH is released into the blood, it circulates to increase the amount of calcium in the blood (as in removing calcium from bones). When the calcium level in the blood is too high, the cells of the parathyroids make less PTH (or stop making it altogether), thereby, allowing calcium levels to decrease. Under the presence of PTH, bones will give up their calcium in an attempt to increase the blood level of calcium. Under normal conditions, this process is very highly tuned and the amount of calcium in our bones remains at a normal high level. Under the presence of too much parathyroid hormone, however, the bones will continue to release their calcium into the blood at a rate which is too high, resulting in bones which have too little calcium. Another way in the PTH acts to increase blood levels of calcium is through the intestines. Under the presence of PTH the lining of the intestine becomes more efficient at absorbing calcium.}

^Thyroid^{Calcitonin (CT) is a hormone produced by the thyroid glands. Elevated serum calcium levels stimulate its secretion, therefore acting as a counter to PTH. Calcitonin increases deposition of calcium in the bone matrix & blocks cellular uptake of calcium by the soft tissues.}^{Goitrogens (glucosinolates) are foods which blocks iodine in the thyroid and suppress thyroid function. Peaches, radishes, strawberries, broccoli, cauliflower, brussel sprouts, cabbage, mustard, kale, turnips, canola oil, millet, rutabaga contain goitrogens. The enzymes required for production of goitrogens in the plant are thought to be destroyed by cooking or leaching into cooking water. Kelp & cod are good sources of iodine.}

^Magnesium^{Magnesium suppresses PTH & stimulates CT secretion, therefore encouraging deposition of calcium in the bone & removal of calcium from the soft tissue. Magnesium enhances calcium absorption & retention, but increasing calcium intake suppresses magnesium absorption. Magnesium deficiencies are often caused by excessive calcium intake. This results in elevated PTH which prevents the utilization of the absorbed calcium for bone formation & favors soft tissue calcification. Higher magnesium intake increases the intestinal absorption of calcium & increases serum ionized calcium. Magnesium has a calcium-sparing effect & thereby decreases the need for calcium. New research has shown the proper ratio of calcium to magnesium to be close to 4:3. Diet also should not have excessive phosphate, sulfur, proteins, refined sugars or fat.}

^{Vitamin D}^{There are two forms of Vitamin D. Vitamin D2, which is synthesized by plants, and Vitamin D3, which is synthesized in the skin by ultraviolet radiation (UV B). Vitamin D2 metabolizes too quickly and is not thought to be a good source of vitamin D. Vitamin D3 is bound with serum protein & transported to the liver. This is why liver malfunction can also cause MBD. Vitamin D3 is best obtained through regular exposure to ultraviolet radiation.}^{Fusion absorption (that which is done without D3) can occur through the small intestine, but is not near as effective in maintaining proper calcium levels as calcium absorbed with the aid of D3. Calcium absorption depends on the degree to which it is soluble and thus usable. Acidic levels of the ingested food, and the presence of substances such as Oxolates, found in spinach, rhubarb, beet greens (and to a lesser extent, collards & carrots) binds calcium, rendering it unusable. Diets high in fat, can impede calcium absorption; faulty fat metabolism can adversely affect the metabolism of vitamin D. In other words, diets high in oxalates or fats, both lead to metabolic bone disease. Supplemental Vitamin D is fat soluble & can build up & become toxic.}

^Kidneys^{The kidneys function as part of the body's elimination system. Those elements that are not useful are eliminated through excretion via the kidneys. The kidneys can only handle a certain amount of input, therefore can only put out a certain amount. When there is too much calcium in the body, the kidneys can still only out put the same amount it would if the body had the normal amount and calcium build up can occur.}

^Phosphorus^{Phosphorus, when combined with calcium (in the form of calcium phosphate), forms the majority of the bone in the body. It is also used in nearly all of the body's metabolic processes. Extracted from foods, its use is controlled by Vitamin D & calcium. Calcium phosphate found in bone is retained in the body. Other phosphates are not retained & are constantly excreted, so must be replaced. Equal amounts of soluble calcium & phosphorus are required for balance. The ratio of calcium to phosphorus should be 2:1 to achieve the proper balance of soluble calcium. Too much calcium results in a phosphorus deficiency & impaired metabolic function. Too much phosphorus forms insoluble calcium phosphate which is unusable and as the body continues to absorb the phosphorus, MBD results.}

^{Herbivores & omnivores should be fed calcium rich, nutrient dense foods such as squashes, green beans, alfalfa, parsnips, mustard greens, & fruits such as figs, papaya, cantaloupe & berries.}

^{See the chart on page 2 for calcium/phosphorus ratio and identification of certain foods that are goitrogens or high in oxalates.}