Calcium/phosphorus ratio

Single Haversian systems differ significantly in calcium-phosphorus ratio. 

Dietary phosphorus also affects calcium metabolism. Polyphosphate decreases calcium absorption in young men while orthophosphate supplement does not (26J. However, in the rat all forms of phosphate decrease calcium absorption about equally (31). However, widely divergent dietary calcium phosphorus ratios do not seem to affect calcium utilization by people as long as there is adequate phosphorus intake (32). In general phosphorus stimulates calcium retention in man (3277... 

There arc several unique features exhibited by the D vitamins. First, they are not required nutritionally al all if the organism has access to ultraviolet light (which is present in sunlight). Some animals, kept away from ultraviolet light, require so little D vitamins that the need cannot be demonstrated using ordinary diets. Rats, for example, exhibit a need for D vitamins when the calcium/phosphorus ratio in the diet is about 5 1 but not when it is the more usual 1 1. Chickens, on the other hand, exhibit a need even when the calcium/phosphorus ratio is normal (1.5 1). 

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,... 

The dietary calcium/phosphorus ratio is important for the maintenance of kidney health. Where there is too much phosphate, mineral deposits may develop in the kidneys, in a process called nephiocalcinasis. Female rats are especially prone to nephiocalcinosis, which occurs when the calcium/phosphorus ratio is under 1/0.. For this reason, a recommended Ca/P ratio is 1.66 (the same as 1/0.6) Reeves, 1997). 

Hypocalcemia commonly occurs during the first I or 2 days of life in premature, low-birth-weight infants. The exact mccKaiusm is not clear. Hypocalcemia can also present in newborns fed cow milk, because cow milk contains calcium and phosphorus in a ratio of about 1.34/1.0, by weight. Mother s milk contains relatively less phosphate the calcium/phosphorus ratio is 2.25/1,0. The excess phosphate in cow milk promotes hyperphosphatemia in the newborn. It is thought that plasma phosphate, in elevated concentrations, fonns a complex with plasma calcium. Formation of this complex reduces the levels of free calcium, resulting in symptoms of hypocalcemia. The newborn is not as able to make hormonal adjustments to maintain plasma calcium levels as is the older infant (Mizrachi et al., 1968). 

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. 

Stoerk, H.C., Carnes, W.H. Relation of dietary calcium-phosphorus ratio to serum calcium and to parathyroid volume. J. Nutr. 29, 43-50 (1945)... 

Mellanby in 1918 first described experimental rickets, using the puppy as his experimental animal, and shortly afterwards McCollum et aZ. described the same disease in the rat. It is of interest that Mellanby later found that confinement of his dogs predisposed them toward development of rickets. Also, it is of interest that the rat is normally resistant to vitamin D deficiency and for such a condition to express itself in this animal there must be concomitant unbalance of the calcium-phosphorus ratio or else a deficiency of these elements (Shohl and Wolbach ). McCollum and his co-workers showed that cod-liver oil added to the diet of vitamin D-deficient rats induced calcification to take place. 

In an adequate, well-balanced diet the ratio of calcium to phosphorus is of little significance from the nutritional viewpoint, but in less-balanced diets this ratio assumes some importance. At the pH of the intestine calcium phosphate is difficultly soluble, and excessive amounts of calcium will render most of the phosphate insoluble and thus not available for absorption a high ratio of phosphate to calcium has a similar effect upon the calcium. This effect is enhanced when there is a deficiency of vitamin D, the incidence of rickets being directly related both to the actual amount ingested and to the calcium-phosphorus ratio. 

In infants the ideal calcium-phosphorus ratio is 2 1, which represents the proportion of these minerals in mother s milk. With increasing age this ratio is not so important and may fall below 1. 

Calcium Related Diseases Calcium-Phosphorus Ratio and Vitamin D Calcium Losses During Processing, Cooking,... 

CALCIUM-PHOSPHORUS RATIO AND VITAMIN D, When considering the calcium and phosphorus requirements, it is important to realize that the proper utilization of these minerals of the body is dependent upon three factors (1) an adequate supply of calcium and phosphorus in an available form, (2) a suitable ratio between them, and (3) sufficient vitamin Dto make possible the assimilation and utilization of the calcium and phosphorus. 

Generally speaking, nutritionists recommend a calcium-phosphorus ratio of 1.5 1 in infancy, decreasing to 1 1 at 1 year of age, and remaining at 1 1 throughout the rest of life although they consider ratios between 2 1 and 1 2 as satisfactory. However, if plenty of vitamin D is present (provided either in the diet or by sunlight), the ratio of calcium to phosphorus becomes less critical. Likewise, less vitamin D is needed when there is a desirable calcium-phosphorus ratio. 

The calcium-phosphorus ratio is determined by the total intake of each of the minerals. For the most part, this means foods, for few people take calcium and/or phosphorus mineral supplements. 

Also see CALCIUM, section headed "Calcium-Phosphorus Ratio and Vitamin D " and PHOSPHORUS, section headed "Calcium-Phosphorus Ratio and Vitamin D.")... 

The calcium-phosphorus ratio is important to the proper utilization of these minerals, as is adequate vitamin D. 

Generaly, nutritionists recommend a calcium-phosphorus ratio of 1.5 1 in Infancy, decreasing to 1 1 at 1 year of age and remaining at 1 1 througbaul ihe rest of life although they consider ratios between 2 1 and 1 2 as satis-facioiy. 

Phosphorus is absorbed chiefly in the upper small intestine, the duodenum. The amount absorbed is dependent on several factors, such as source, calcium phosphorus ratio, intestinal pH, lactose intake, and dietary levels of calcium, phosphorus, vitamin D, iron, aluminum, manganese, potassium, and fat. As is the case for most nutrients, the greater the need, the more efficient the absorption. Absorption increases, although not proportionally, with increased intake. 

---