Phosphorus excretion fecal

The phosphorus balance data (Table II) show that the urinary phosphorus excretion Increased approximately two- to three-fold In all three high phosphorus studies, while the fecal phosphorus excretion Increased to a considerably lesser extent. The phosphorus balance of all three patients became more positive during the high phosphorus Intake. These studies have shown that Increasing the phosphorus Intake up to 2000 mg/day did not affect the excretions of zinc nor the zinc balance, despite the fact that there were marked changes In phosphorus metabolism, primarily a marked Increase of the urinary phosphorus excretion, while the fecal phosphorus excretion Increased to a lesser extent. 

High levels of dietary zinc were associated with marked decreases in bone calcium deposition and in the apparent retention of calcium in male weanling albino rats. Marked increases in fecal calcium levels were also observed in the zinc-fed rats. Excessive dietary zinc was associated with a shifting of phosphorus excretion from the urine to the feces. This resulted in an increase in fecal phosphorus and provided an environmental condition which would increase the possibility of the formation of insoluble calcium phosphate salts and a subsequent decrease in calcium bioavailability. The adverse effect of high dietary zinc on calcium status in young rats could be alleviated and/or reversed with calcium supplements. 

Table VI shows the effect of 0.75% dietary zinc on the phosphorus balance in young rats. A decrease in the apparent retention of phosphorus was noted in the zinc-fed rats as early as the end of the first week. Possibly a more significant observation was the apparent movement of phosphorus excretion from the urine, the normal pathway for phosphorus excretion, to the feces in rats fed the high zinc diet. Such a shifting of the phosphorus excretion to the fecal pathway in animals fed a high zinc diet should result in an increase...

Table VII shows the calcium balance of zinc-fed and non-zinc-fed rats supplemented with 0.8% calcium and/or phosphorus. Marked increases in fecal calcium and corresponding decreases in apparent calcium retentions in the zinc-fed rats could be reversed with calcium supplementation. Phosphorus supplements appeared to be associated with increases in calcium retention in the absence of zinc, but decreases in calcium retention in the presence of zinc without calcium supplementation. Decreases in fecal calcium were noted in animals fed calcium supplements in the presence of phosphorus or zinc. High levels of zinc were associated with increases in fecal calcium excretion in the absence of extra calcium or in the presence of extra phosphorus. Calcium supplementation was generally associated with a decrease in the urinary excretion of calcium, while zinc and phosphorus supplements were generally associated with an increase in urinary calcium excretion.

The excretion of body phosphorus occurs via the kidney and intestinal tract, the distribution between these pathways varying with species. For example, relatively small amounts of phosphorus are endogenously excreted into the feces of rat, pig, and human, but in the bovine, perhaps 50% or more of the fecal phosphorus may be from endogenous sources. 

The amount that fecal phosphorus levels decline with phytase supplementation will depend on the percentage of phosphorus that is available in the base ration (Yi, 1996b). With available phosphorus at 0.05% of the ration in this study, excretion of phosphorus was reduced by about 25% in pigs receiving phytase compared to the control animals. When the base diet in this study contained 0.16% available phosphorus, excretion was reduced by 50% in pigs receiving phytase but no inorganic phosphorus. 

White Phosphorus. No studies were located that specifically address white phosphorus excretion in humans after oral exposure However, two animal studies (Cameron and Patrick 1966 Lee et al. 1975) indicate rapid urinary and fecal excretion of white phosphorus, metabolites, or unabsorbed inorganic breakdown products. 

In the present study the effect of calcium and phosphorus on zinc metabolism was investigated In adult men by determining metabolic balances of zinc during different intakes of calcium and phosphorus. Three Intake levels of calcium, ranging from 200 to 2000 mg/day, and two Intake levels of phosphorus (800 and 2000 mg/day) were used during a constant dietary zinc Intake of 14.5 mg/day. Increasing the calcium Intake from 200 to 2000 mg and Increasing the phosphorus Intake from 800 to 2000 mg/day had no effect on urinary or fecal zinc excretion nor on zinc retention. absorption studies confirmed... 

Several zinc absorption studies, using oral doses of ZnCl2 were carried out. 65zq plasma levels were determined serially on the day of the oral administration of the zn tracer. Urinary and fecal 65zn excretions were determined for approximately 15 days. The subjects studied were fully ambulatory males who were In good nutritional state. They were normal according to all clinical and laboratory criteria. Including the serum levels of zinc, calcium, and phosphorus. The effect of three Intake levels of calcium on the zinc balance was studied, namely, of 200, 900,... 

Table II shows data of the effect of a high phosphorus Intake on the zinc balance. The phosphorus supplements were given to three patients during different calcium Intakes, namely, during a low calcium Intake of 200 mg per day and during higher calcium Intakes of 800 mg and 2000 mg calcium per day. The phosphorus Intake of the subjects studied was approximately 900 mg per day In the control study and was 2000 mg per day during the high phosphorus Intake. In the control study, during a low calcium Intake and a normal phosphorus Intake of 900 mg per day and a dietary zinc Intake of 17 mg per day, the urinary zinc excretion was relatively high, 1.6 mg/day, the fecal zinc excretion was In the expected range and the zinc balance was positive,...

In contrast to calcium, excretion of phosphorus occurs mainly in the urine, about two-thirds of the total amount excreted being lost by this route, almost entirely as phosphates of the various cations, the remainder being excreted in feces chiefly as calcium phosphate. Fecal phosphorus is composed of unabsorbed together with re-excreted phosphate, the latter having been estimated to average 25 to 30% of the total fecal phosphorus. ... 

Diet Phosphorus Intake Fecal Excretion Urinary Excretion Balance... 

The serum phosphate level of a worker with phossy jaw was within the normal range of values for an adult human (Hughes et al. 1962). Excretion of phosphate via urinary and fecal routes was reported qualitatively to be approximately normal. The daily output of phosphorus in the feces was about 1/4 to 1/3 of the total output in both urine and feces. 

Lee et al. (1975) measured urinary and fecal elimination of 32P in rats after oral administration of labeled white phosphorus. The total radioactivity excreted in urine and feces was assessed in three different groups of rats sacrificed at 4 hours or 1 or 5 days after dosing. Total excretion of 32P was far higher via the urinary route by 4 hours postdosing. Excretion of 32P via the fecal route increased rapidly between 4 hours and 5 days post-dosing. By 5 days post-dosing, combined urinary and fecal excretion accounted for -80% of the administered dose of 32P. 

The results obtained In zinc balance studies during different Intake levels of calcium and phosphorus were In agreement In Zn absorption studies. Figure 1 shows data of f> Zn plasma levels and of the fecal excretions following a single oral... 

Fecal excretion of the macro elements was, on average, 3% for sodium, 19% for potassium, 28% for ash, 36% for phosphorus, 69% for magnesium, and 84% for calcium. The apparent absorption rate is negatively correlated with fecal excretion of the macro elements. The real absorption rate of all these elements is higher than the apparent absorption rate, mainly due to the salivary, biliary and pancreatic excretion of absorbed macro elements into the intestine. 

It has been generally established that thyroid dysfunction leads to a disturbance of mineral metabolism. In hyperthyroidism an increased excretion of calcium and phosphorus is constantly found which is diminished by iodine medication and is still further diminished after subtotal thyroidectomy. The high urinary calcium excretion also returns to normal after about 14 days treatment with the antithyroid drug thiouracil. A high fecal excretion of calcium has also been reported but is not a clearly established feature of hyperthyroidism. Long-standing untreated hyperthyroidism is accompanied by an osteoporosis, the cause of which is still a matter of differing opinion. 

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