Feces calcium

Calcium in the feces—Calcium is excreted mainly in the feces, most of which is dietary intake that is not absorbed (see Fig. C-4). The remainder, called endogenous fecal calcium (which ranges between 125 and 180 mg per day) comes from shed epithelial cells and the digestive juices (bile and pancreatic juice). As shown in Fig. C-4, approximately 70 to 80% of food calcium is unabsorbed and excreted in the feces. 

Adults require 1-2 mg of copper per day, and eliminate excess copper in bile and feces. Most plasma copper is present in ceruloplasmin. In Wilson s disease, the diminished availability of ceruloplasmin interferes with the function of enzymes that rely on ceruloplasmin as a copper donor (e.g. cytochrome oxidase, tyrosinase and superoxide dismutase). In addition, loss of copper-binding capacity in the serum leads to copper deposition in liver, brain and other organs, resulting in tissue damage. The mechanisms of toxicity are not fully understood, but may involve the formation of hydroxyl radicals via the Fenton reaction, which, in turn initiates a cascade of cellular cytotoxic events, including mitochondrial dysfunction, lipid peroxidation, disruption of calcium ion homeostasis, and cell death. 

Apparent absorption (intake minus fecal excretion) of calcium decreased when the diet contained muffins with added sodium phytate to increase the molar ratio of phytate/calcium from 0.04 to 0.14 and 0.24. One-half of the men excreted more calcium in feces than was consumed when the high phytate diet was consumed. People consuming diets with molar ratios of phytate/calcium exceeding 0.2 may be at risk of calcium deficiency because of low bioavailability of dietary calcium unless physiological adjustments can be accomplished that maintain homeostasis. 

For HS-I, with calcium intakes of about 1100 mg/day, no difference was observed in either apparent absorption or balance of calcium over the last 10 of 15 days when the phytate intake was 0.2 or 2.0 g/day. The molar ratio of phytate/calcium was either 0.01 or 0.1 in HS-I. In HS-II the calcium intake was lower, about 740 mg/day, but the same across three levels of phytic acid, 0.5, 1.7 and 2.9 g/day. The phytate/calcium molar ratios were 0.04, 0.14 and 0.24. Apparent absorption of calcium for the 15-day diet treatment period became progressively less as the molar ratio of phytate/calcium increased, to the extent that 6 of 12 individuals excreted more calcium in the feces than they consumed when the mean ratio was 0.24. About 200 mg of calcium was excreted daily in the urine by... 

Significantly more phosphorus was excreted in the feces when 1.2% calcium and 1.2% phosphorus diets were fed with either egg white (317 mg) or soy (303 mg), than when any of the other rations were fed. Orthogonal contrast analysis indicated that statistically significant sources of these differences included ration phosphorus level (P <0.001), calcium level (P< 0.0001), and calcium level x protein source (P< 0.0461). The degree of effectiveness of increasing phosphorus excretion with increased ration level of calcium was greater in egg white fed animals than in soy fed animals. 

Bloom (12J reported that in both older rats (63 days of age) and younger rats (33 days of age) the amount of calcium retained was less when 5% dried spinach, either raw or cooked, was included in the diet in 1-week balance studies (Figure 1). The experimental diets contained about 0.4% calcium, and one drop of cod liver oil was given each rat every day. Most of the calcium excretion on the spinach diet was in the feces. Retentions of calcium on the basal low fiber diet and on diets containing filter paper in amounts to equal the crude fiber in spinach or 12 times the crude fiber in spinach were high. There was no significant difference in calcium retentions between raw and cooked spinach. The low retention of calcium from spinach could not be attributed to the presence of crude fiber in the diet. 

Schultz et al. (26) found that feeding spinach to four infants for 3-6 days did not affect calcium balance, with the possible exception of a slight lowering when dried spinach was fed. Infants 5 weeks-6 months of age were fed only milk formula for a 6-day control period. The spinach was added to the formula diet in the following amounts 6 g dried spinach, 60 g pureed spinach, or 70 g raw spinach per day. The infants were also given cellulose in amounts of 6 or 9 g/day. There was generally a larger output of feces when the diet contained spinach. 

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. 

The data presented in this paper indicate that excess levels (0.75%) of dietary zinc result in decreases in the bioavailability of calcium and phosphorus in rats and interfere with normal bone mineralization. High dietary levels of calcium or zinc appeared to cause a shift in the excretion of phosphorus from the urine to the feces, while the presence of extra phosphorus tended to keep the pathway of phosphorus excretion via the urine. The presence of large amounts of phosphorus in the Intestinal tract due to high intakes of zinc would increase the possibility of the formation of insoluble phosphate salts with various cations, including calcium, which may be present. A shift in phosphorus excretion from the feces to the urine, however, could result in an environmental condition within the system which would tend to increase the bioavailability of cations to the animal. The adverse effect of zinc toxicity on calcium and phosphorus status of young rats could be alleviated with calcium and/or phosphorus supplements. 

Most of the forementioned studies which examined the influence of various dietary fiber on the bioavailability of calcium by human subjects have depended upon the comparative measurements of calcium content of diets and calcium contents of stools and urine. As reviewed by Allen (3), calcium balance studies have distinct limitations relative to accuracy and precision. However, their ease of application and cost, laboratory equipment requirements, and real (or perceived) safety in comparison to available radioactive or stable isotope methods continue to make their use popular. In calcium balance studies, calcium absorption is assumed to be the difference between calcium excretion in the feces and calcium intake. Usually this is expressed as a percent of the calcium intake. This method assumes that all fecal calcium loss is unabsorbed dietary calcium which is, of course, untrue since appreciable amounts of calcium from the body are lost via the intestinal route through the biliary tract. Hence, calcium absorption by this method may underestimate absorption of dietary calcium but is useful for comparative purposes. It has been estimated that bile salts may contribute about 100 g calcium/day to the intestinal calcium contents. Bile salt calcium has been found to be more efficiently absorbed through the intestinal mucosa than is dietary calcium (20) but less so by other investigators (21). 

Urine, feces and food were analyzed for calcium content by atomic absorption spectrophotometry. Data were subjected to statistical analysis by analysis of variance and Duncan s Multiple Range Test. 

Addition of bran from hard red and soft white wheat bran, psyllium fiber, and cellulose resulted in increased losses of calcium in feces in comparison to losses when no fiber supplements were used (P<0.05). Urinary calcium losses were not significantly affected however, calcium balances were lowered when these four fiber sources were added to the laboratory controlled diet (P < 0.05). 

Bile acids and salts have been found to enhance the absorption of both calcium and vitamin D hence, to increase calcium absorption both directly and indirectly (3,37). However, the ability of some dietary fibers such as lignin and pectin to absorb conjugated and deconjugated bile salts onto their surfaces to be excreted in the feces (a mechanism credited to the hypocholesterolemic effect of some dietary fibers) may result in an overall decrease in calcium absorption from the gastrointestinal tract (7,33,38-40). 

The main inorganic components of the urine are the cations Na"", C, Ca "", Mg and NH4 and the anions Cl , S04 , and HP04 , as well as traces of other ions. In total, Na"" and Cl represent about two-thirds of all the electrolytes in the final urine. Calcium and magnesium occur in the feces in even larger quantities. The amounts of the various inorganic components of the urine also depend on the composition of the diet. For example, in acidosis there can be a marked increase in the excretion of ammonia (see p. 326). Excretion of Na C, and phosphate via the kidneys is subject to hormonal regulation (see p. 330). 

Patients with advanced renal insufficiency (Ccr less than 30 mL/min) exhibit phosphate retention and some degree of hyperphosphatemia. The retention of phosphate plays a role in causing secondary hyperparathyroidism associated with osteodystrophy and soft-tissue calcification. Calcium acetate, when taken with meals, combines with dietary phosphate to form insoluble calcium phosphate, which is excreted in the feces. 

Excretion - Calcium is mainly excreted in the feces. Urinary excretion does not exceed 150 mg/day in patients on low calcium diets. Urinary excretion decreases with age, in early renal failure, and during pregnancy. Calcium also is excreted by the sweat glands. 

Calcium acetate, when taken with meals, combines with dietary phosphate to form insoluble calcium phosphate which is excreted in the feces. 

Factorial = calcium needs for growth + calcium losses (urine, feces, sweat) adjusted for absorption. 

The bulk-forming laxative group includes the hydrophilic substances described previously calcium polycarbophil FiberCon, Equalactin), methylcellulose Citrucel), and various psyllium seed derivatives Metamucil). All act by increasing the bulk of the feces, part of this action being due to their capacity to attract water and form a hydrogel. The increased volume of feces stretches the walls of the GI tract and stimulates peristalsis. Their action may not be evident for 2 to 3 days after starting treatment. Because their use results... 

Mechanism of Action An antacid that reduces gastric acid by binding with phosphate in the intestine, and then is excreted as aluminum carbonate in feces. Aluminum carbonate may increase the absorption of calcium due to decreased serum phosphate levels. The drug also has astringent and adsorbent properties. Therapeutic Effect Neutralizes or increases gastric pH reduces phosphates in urine, preventing formation of phosphate urinary stones reduces serum phosphate levels decreases fluidity of stools. 

Mecfianism of Action A cinchona alkaloid that relaxes skeletal muscle by increasing the refractory period, decreasing excitability of motor end plates (curare-like), and affecting distribution of calcium with muscle fiber. Antimalaria Depresses oxygen uptake, carbohydrate metabolism, elevates pH in intracellular organelles of parasites. Therapeutic Effect Relaxes skeletal muscle produces parasite death. Pharmacokinetics Rapidly absorbed mainly from upper small intestine. Protein binding 70%-95%. Metabolized in liver. Excreted in feces, saliva, and urine. Half-life 8-14 hr (adults), 6-12 hr (children). 

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. 

Absorption of dietary calcium is linked not only to the amount but also to the kind fatty acids in the diet of infants. In a controlled study, the fatty acid composition in one experimental formula was adjusted to simulate human milk, but the structure was dissimilar because the Ci6 o in the formula was mostly at the sn-3 rather than the sn-2 position. The greatest loss of calcium in the feces occurred when formulae with the wrong proportions of Ci6 0 and Ci8 o were fed. Fat absorption and calcium retention were highest in infants fed human milk, followed by infants fed formulae containing a high level of Ci2 o (Nelson et al., 1996, 1998). 

The principal physiological role of vitamin D is in the maintenance of the plasma concentration of calcium. Calcitriol acts to increase intestinal absorption of calcium, to reduce its excretion by increasing reabsorption in the distal renal tubule, and to mobilize the mineral from bone - of the 25 mol of calcium in the adult body, 99% is in bone. The daily intake of calcium is around 25 mmol, and intestinal secretions add an additional 7 mmol to the intestinal contents 10 to 14 mmol of this is normally absorbed, with 18 to 22 mmol excreted in feces. Bone turnover accounts for exchange of 10 mmol of calcium between bone and plasma daily. The kidneys filter some 240 mmol of calcium daily, almost all of which is reabsorbed urinary excretion of calcium is about 3 to 7 mmol per day. 

The SAAM (Simulation, Analysis And Modeling) computer program developed by Berman and Weiss (8) was used to analyze the isotope dilution and balance data. The observed time dependent dilution of both calcium tracers in plasma, as reflected in urine at longer times, coupled with their cumulative appearance in urine and feces is used to calculate kinetic parameters of the model. The balance data are then used to calculate the steady state... 

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