Phosphorus daily requirement

The elements essential for life can be divided into macroelements (daily requirement > 100 mg) and microelements (daily requirement < 100 mg). The macroelements include the electrolytes sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg), and the nonmetals chlorine (Cl), phosphorus (P), sulfur (S), and iodine (I). 

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). 

Calcium has long been suspected as adversely affecting the bioavailability of manganese. Excessive intakes of calcium or phosphorus have been shown to increase the daily requirements for manganese in swine (3-5) probably due to decreased absorption of this mineral. However, comparatively little information is available on the comparative effects of different sources of calcium on manganese utilization in humans. 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Despite the negative balances that occurred over considerable periods early in lactation, there was a net positive balance over the lactation and dry period as a whole. It has therefore become normal practice to consider the complete lactation in assessing calcium and phosphorus requirements early negative balances are regarded as normal, since no ill effects are evident as long as subsequent replenishment of body reserves takes place, and daily requirements are formulated on the basis of total production over the lactation. However, although the lactation approach is... 

A study of the phosphorus maintenance requirement of adults made by Sherman showed that balance was achieved with an intake of 0.88 g. daily, so that the safe daily allowance is computed to be 1.32 g. Children should be allowed about half as much again as adults, and in pregnancy and lactation the intake should be twice the ordinary figure. 

In summary, lOOg of fish affords low levels of sodium and medium-to-high levels of all the remaining dietary minerals. In fact, it can contribute 50-100% of the total daily requirements of magnesium, phosphorus, iron, copper, selenium, and iodine. A Mediterranean diet, rich in fatty fish and all kinds of shellfish, can lead to an overall balanced mineral supply, which may well reach over 20% of daily requirements of phosphorus, iron, selenium, and iodine. 

Electrolytes that are included routinely in PN admixtures include sodium, potassium, phosphorus (as phosphate), calcium, magnesium, chloride, and acetate. When determining electrolytes in PN admixtures, the patient s renal function always must be taken into account. Typical daily electrolyte maintenance requirements for adults with normal renal function are listed in Table 97-3. 

Note 1 Total phosphorus as P shall be limited to the extent necessary to prevent nuisance growth of algae, weeds, and slimes that result in a violation of the water quality criteria. Phosphorus discharges shall not exceed a daily average of one milligram per liter as total P, or stricter requirements imposed by Ohio Environmental Protection Agency. 

The human organism contains 1-1.4 kg calcium, and about 1% of this is in the extracellular fluid. The rest is largely in bone. The serum calcium concentration is 9-11.5 mg/dL, of which 4.5-5.0 mg/dL is in the free, ionized, biologically active form. The rest is protein bound or complexed with a variety of chelators, such as citrate. The daily dietary calcium requirement is 400-500 mg, and each day, 300-400 mg calcium is lost in the urine and an additional 150 mg in the feces. Inorganic phosphorus (largely as HP042 ) amounts to 2.7-4.5 mg/dL in adult serum. 

Sufficient dietary calcium arid phosphate must be absorbed to support growth (including pregnancy) and replace mineral lost from the body. Phosphates are present in adequate quantities in a wide variety of foods, and it is very unlikely that hypophosphatemia results from inadequate dietary phosphorus. Phosphate is absorbed from the small intestine with Ca + as a counterion and by an independent process that requires vitamin D metabolites. Normal daily intake of phosphate is about 800-1500 mg. Phosphate is highly conserved by the body, and obligatory losses are minimal. 

The phosphorus memory (phosphorus retained in soils and sediments and potential release from these sources) can extend the time required for a wetland or an aquatic system to reach an alternate stable condition to meet enviromnental regulation such as TMDLs (total daily maximum daily loads). 

The net daily maintenance requirement for calcium, phosphorus and magnesium may be calculated as follows ... 

Administration of 5.7 mEq of phosphate per kg body weight per day to test group 2 resulted in a positive phosphate balance with a serum value of 4.5 mEq per kg body weight per day. If calcium was not provided simultaneously, the daily calcium losses amounted to 0,1 mEq per kg body weight per day in this test series. During long term parenteral nutrition, administration of phosphorus, calcium, trace elements and vitamins is an absolute requirement (Dudricic t al,., 1970 Schmidt, 1966). 

During pregnancy and lactation supplemental vitamin D would seem desirable in view of the increase in requirement of calcium and phosphorus and the effect of vitamin D on utilization of these elements. Approximately 400 units daily appears to be adequate. 

REQUIRED INTAKE. There is no required level of intake of nucleic acids per se. A nutritious, well-balanced diet provides the precursors necessary for the synthesis of the purines, pyrimidines, and ribose sugar in the body. The only direct requirement is for the mineral phosphorus. Since it is a component of DNA and RNA, it is in every cell of the body. Children and adults require 800 to 1,200 mg daily. 

Sodium trimethylphosphate solutions (phosphorus standards) of 5.00-20.00 mg/L are required to be prepared daily for the calibration curve. 

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