Bone calcium-phosphorus ratio

Bone mainly consists of HA, but during the various development stages of bone other calcium phosphates are also found. They occur in the following series, the chemical formula of the calcium -phosphorus ratio Ca/P of which varies from 1.00 to 1.67 not all values between the extremeties are mentioned ... 

A special relationship betv een calcium and phosphate is suggested by the fact that the calcium/phosphorus ratio in bone is about 2.2/1.0, by weight. As almost all of the body s calcium and most of the body s phosphate occurs in bone, one might expect that the ratio of calcium/phosphorus in the diet that supports maximal growth would be similar to the ratio of these elements in bone. This ratio would be expected to be influenced by the fact that dietary F is more readily absorbed than Ca and by the use of P for soft tissues,... 

There is increased sensitivity to vitamin D in patients who are undergoing renal dialysis and who have an abnormal calcium/phosphorus ratio. Patients on continuous ambulatory peritoneal dialysis (CAPD) who develop secondary hyperparathyroidism may already have low bone turnover or adynamic bone lesions, and if treated indiscriminately with calcitriol their low bone turnover can get worse (62). 

Wykshak, G., and R.E. Frisch. Carbonated Beverages, Dietary Calcium, the Dietary Calcium/Phosphorus Ratio, and Bone Fractures in Girls and Boys. Journal of Adolescent Health 15, no. 3 (May 1994) 210-15. 

Studies with dogs nevealed that high dietary phosphate results in bone loss and a decline in bone mass. The diets contained calcium/phosphorus mg/mg) at a 1/10 ratio, and resulted in a loss of trabecular bone at a greater rate than cortical bone (Calvo and Park, 1996). 

Hydroxyapatite A calcium phosphate ceramic with a calcium to phosphorus ratio of 5/3 and nominal composition Cai0(PO4)6(OH)2. It has good mechanical properties and excellent biocompatibility. Hydroxyapatite is the mineral constituent of bone. 

Phosphorus. Eighty-five percent of the phosphoms, the second most abundant element in the human body, is located in bones and teeth (24,35). Whereas there is constant exchange of calcium and phosphoms between bones and blood, there is very Httle turnover in teeth (25). The Ca P ratio in bones is constant at about 2 1. Every tissue and cell contains phosphoms, generally as a salt or ester of mono-, di-, or tribasic phosphoric acid, as phosphoHpids, or as phosphorylated sugars (24). Phosphoms is involved in a large number and wide variety of metaboHc functions. Examples are carbohydrate metaboHsm (36,37), adenosine triphosphate (ATP) from fatty acid metaboHsm (38), and oxidative phosphorylation (36,39). Common food sources rich in phosphoms are Hsted in Table 5 (see also Phosphorus compounds). 

Although much attention has been directed toward the relationship between calcium intake and osteoporosis, little consideration has been given to the possible influence of dietary phosphorus on the development of this disease in either man or animals. In a study designed to determine the optimal concentration of calcium and phosphorus in the diet of adult mice, aging animals were found to undergo a greater loss of bone when the Ca/P ratio was 1 1 than... 

A potential concern has been the dietary ratio of calcium to phosphorus (Ca P) in relation to bone health. Based on data from animal studies and on the relative calcium content in bone, a dietary Ca P ratio of 1 1 to 2 1 is recommended as beneficial for bone mineralization in humans (NAS 1980A Chinn 1981 Linkswiler and Zemel 1979). The Ca P ratio in cow s milk (1.3 1) closely approximates that found in bones. The average American diet is estimated to contain a Ca P ratio of 1 1.6 (Chinn 1981 Greger and Krystofiak 1982) to 1 3 (Linkswiler and Zemel 1979), and if no dairy foods are consumed, it may be as low as 1 4. 

There is some evidence, mostly from animal studies, to suggest that high dietary levels of phosphorus, especially if dietary levels of calcium are low, may adversely affect bone mass and calcium metabolism (Greger and Krystofiak 1982). However, in humans there is little direct evidence to indicate that large variations in dietary phosphorus or in the Ca P ratio have any significant influence on calcium utilization or balance (Heaney et al. 1982). Some preliminary findings, however, suggest that the form of phosphorus may influence calcium absorption (Zemel et al. 1982). Hexametaphosphate, as compared with orthophos-... 

The recommended ratio of phosphorus to calcium is 1 1, except in infants it is 2 1. For older infants, the recommended intake of phosphorus is increased to 80% of the calcium requirement, so that the ratio is similar to cow s milk (Harper 1969). Both phosphorus and calcium are distributed similarly in foods, hence a sufficient intake of calcium ensures a sufficient intake of phosphorus. The exception is cows milk, which contains more phosphorus than calcium (Harper 1969). The adult daily requirement for phosphorus is about 700 mg. A balanced diet provides sufficient amounts of phosphorus because it is commonly found in foods (phosphoproteins and phospholipids, inorganic phosphate), especially milk and milk products, wheat, meats and fish (Latner 1975). In the body, normal serum (inorganic) phosphorus levels are 4-7 mg/100 mL in children and 3-4.5 mg/100 mL in adults and the elderly. In body fluids and tissues, normal serum phosphorus levels found are 40, 170-250, 360, and 22,600 mg/100 mL in blood, muscle, nerve, and both bones and teeth, respectively (Harper 1969 Tietz 1970). 

Phosphates are important because they affect the absorption of calcium and other elements. The absorption of inorganic phosphorus depends on the amount of calcium, iron, strontium, and aluminum present in the diet. Chapman and Pugsley (1971) have suggested that a diet containing more phosphorus than calcium is as detrimental as a simple calcium deficiency. The ratio of calcium to phosphorus in bone is 2 to 1. It has been recommended that in early infancy, the ratio should be 1.5 to 1 in older infants, 1.2 to 1 and for adults, 1 to 1. The estimated annual per capita intake in the United States is 1 g Ca and 2.9 g P, thus giving a ratio of 0.35. The danger in raising phosphorus levels is that calcium may become unavailable. 

The crystalline mineral in bones and teeth is generally regarded as an imperfect calcium hydroxyapatite. Apatite minerals, principally calcium fluorapatite, are both abundant and ubiquitous and are the principal source of phosphate for fertilizers. Their abundance is probably an expression of the very high affinity which calcium and phosphate ions have for each other so that it is perhaps not surprising that, on account of its stability, calcium hydroxyapatite has been selected to play an important part, both structurally and physiologically, in many living things. Ions other than calcium, phosphate and hydroxyl are present in the crystallites in which the atomic ratio of calcium to phosphorus departs considerably from the theoretical value of 1-67 (Table 35.1). 

The recommended daily dietary intake of phosphorus is 300-500 mg for children under 1 year, 800 mg for children under 10 years and 1200 mg for adults. These amounts are easily achieved in a normal diet. It is more important to maintain an appropriate ratio of calcium to phosphorus in the diet than the actual realised amount of phosphorus. Meat, poultry and fish (without bones) contain about 15-20 times more phosphorus than calcium eggs, cereals and legumes contain about 2-4 times more phosphorus than calcium. Only milk, cheese, leafy vegetables and bones contain more calcium than phosphorus. 

Osteomalacia is an adult form of rickets caused by lack of vitamin D, inadequate intake of calcium or phosphorus, or an incorrect dietary ratio of calcium and phosphorus. It is characterized by a softening and deformity of bones, bone tenderness and pain, muscular weakness, and tetany. 

Diets in the United States are believed to contain disproportionately high ratios of phosphorus to calcium (about 5 to 1), which have been shown in animal studies to result in significant loss of bone minerals." ... 

Rickets—Lack of vitamin D will cause rickets in infants and children, even though the diet is adequate in calcium and phosphorus. (Rickets may also be caused by lack of either calcium or phosphorus, or an incorrect ratio of the two minerals.) This disease is caused from failure of the bones to calcify normally (meaning that the deposition of calcium and phosphorus salts is not normal). As a result, they are soft and pliable and become deformed. The weight of the body causes the ends of the long bones of the legs to... 

Dietary fat does not affect calcium absorption except in individuals with diseases that impair fat malabsorption (e.g., short bowel syndrome, ceUac disease, and pancreatitis). In these conditions, the calcium forms an insoluble and unabsorbable soap with the unabsorbed fat in the alkaline lumen of the small intestine, potentially resulting in impaired bone mineralization. In addition, the luminal calcium is not available to precipitate the oxalates, meaning that the free oxalates will be hyperabsorbed leading to increased risk for renal oxalate stones. Neither dietary phosphorus nor a wide range of phosphorus-to-calcium ratios affect intestinal calcium absorption in very low-birth-weight infants and adults. 

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