Gastrointestinal tract aluminum

Less than 1% of that taken into the body orally is absorbed from the gastrointestinal tract. Aluminum can increase the absorption of other chemicals such as fluoride, calcium, iron, and phosphates. Most of the aluminum absorbed into the body will eventually end up in the bones or lungs. Aluminum that is not absorbed by the bones or lungs is excreted by the kidneys. 

Sucralfate [54182-58-0] an aluminum salt of sucrose octasulfate, is used as an antacid and antiulcer medication (59). Bis- and tris-platinum complexes of sucrose show promise as antitumor agents (60). Sucrose monoesters are used in some pharmaceutical preparations (21). A sucrose polyester is under evaluation as a contrast agent for magnetic resonance imaging (mri) (61). Oral adrninistration of this substance opacifies the gastrointestinal tract and eliminates the need for purging prior to mri. 

Absorption from the gastrointestinal tract can be affected by other drugs and by food. Aluminum, calcium, and magnesium ions in antacids or dairy products form insoluble chelates with all tetracyclines and inhibit their absorption. Food inhibits tetracycline absorption but enhances doxycycline absorption food delays but does not diminish metronidazole absorption fatty food enhances griseofulvin absorption. 

These antibiotics are partially absorbed from the stomach and upper gastrointestinal tract. Food impairs absorption of all tetracyclines except doxycycline and minocycline. Absorption of doxycycline and minocy-cbne is improved with food. Since the tetracyclines form insoluble chelates with calcium (such as are found in many antacids), magnesium, and other metal ions, their simultaneous administration with milk (calcium), magnesium hydroxide, aluminum hydroxide, or iron will interfere with absorption. Because some of the tetracyclines are not completely absorbed, any drug remaining in the intestine may inhibit sensitive intestinal microorganisms and alter the normal intestinal flora. 

Tetracyclines, as broad-spectrum antibiotics, are the drugs of choice in treating Mycoplasma pneumoniae infections. Most tetracyclines are absorbed to various degrees (30 to 100%) from the gastrointestinal tract, primarily from the stomach and upper small intestine. The absorption of tetracyclines is hindered by milk and milk products, by numerous antacids such as aluminum hydroxide, sodium bicarbonate, and calcium carbonate, and by iron preparations such as ferrous sulfate. Therefore, these and similar substances should not be administered orally together with tetracycline (Figure 3.4). 

No aluminum-related deaths in healthy humans have been reported after oral exposure. One aluminum compound that can be life threatening to humans is aluminum phosphide, a grain fumigant. Accidental or volitional ingestion (to commit suicide) of large amounts has caused death (Chopra et al. 1986 Khosla et al. 1988). The toxicity from this compound is due to the exposure to phosphine gas which is produced in the gastrointestinal tract after the aluminum phosphide is ingested. 

It is possible that systemic absorption of airborne aluminum occurs via the lungs, gastrointestinal tract after mucociliary clearance from the respiratory tract (ICRP 1994), or via the olfactory tract. Gitelman et al. (1995) found a better correlation between respirable aluminum air concentrations and urinary... 

Aluminum is also found in human skin (Alfrey 1980 Tipton and Cook 1963), lower gastrointestinal tract (Tipton and Cook 1963), lymph nodes (Hamilton et al. 1972/73), adrenals (Stitch 1957 Tipton and Cook 1963), and parathyroid glands (Cann et al. 1979). There is evidence that with increasing age of humans, aluminum concentrations may increase in the lungs and brain tissue (Allfey 1980 Crapper and DeBoni 1978 Markesbery et al. 1981 McDermott et al. 1979 Stitch 1957 Tipton and Shafer 1964). 

Becker RR, Blotcky AJ, Leffler JA, et al. 1977. Evidence for aluminum absorption from the gastrointestinal tract and bone deposition by aluminum carbonate ingestion with normal renal function. J Lab Clin Med 90 810-815. 

Monobasic sodium phosphate should not he administered concomitantly with aluminum, calcium, or magnesium salts since they bind phosphate and could impair its ahsorption from the gastrointestinal tract. Interaction between calcium and phosphate, leading to the formation of insoluble calcium phosphate precipitates, is possible in parenteral admix-tures.< >... 

No one paid much attention to Libman (geniuses have that problem) because it was assumed that the mammalian gastrointestinal tract does not absorb particles such as the aluminum and silicon found in toothpaste. But doctors at the University of London have found, in experiments on rats, that polystyrene particles are indeed absorbed into the veins of the intestinal tract and reach the liver. Polystyrene is a completely insoluble substance if it can be absorbed by the intestine, there are probably few, if any, substances that cannot enter the venous or lymphatic circulations to some degree—including aluminum and silicon. 

Clearly, in the presence of the high level of silicon, aluminum was prevented from binding at gill epithelial surfaces and systemic absorption. This exclusion occurred at the interface between creature and the external environment, and a fundamental question is, Is this a general effect, not only at the fish gill, but also at plant root membranes and in the gastrointestinal tract of mammals and humans ... 

An indirect preventive role for silicon has been suggested in senile dementia of the Alzheimer type. This notion was deduced from the silicon s ability to reduce the absorption of aluminum through formation of insoluble hydroxyaluminosilicates in the gastrointestinal tract (Birchall and Chappell 1989, Edwardson et al. 1993). 

Absorption-precipitation. Many agents may form a larger complex - precipitates with other particles such as metallic ions (aluminum, bismuth, calcium, iron)-while passing via the gastrointestinal tract. 

Historically, aluminum has not been considered an important toxicant. With the total body burden of aluminum less than 30 mg, it was thought that the skin, gastrointestinal tract, emd lungs were effective barriers in excluding environmentfil aluminum from interned entry. ... 

The amount of aluminum absorbed from the gastrointestinal tract may be dependent on certain factors. For example. Mayor et ai 56,57 report that increased parathyroid hormone treatment causes increased intestinal aluminum absorption and higher brain aluminum concentrations in rats given oral aluminum. They also observed that parathyroid hormone withdrawal in rats resulted in a rapid decrease of brain aluminum concentration independent of dietary aluminum. Those authors suggest that reduced parathyroid hormone aids in reducing brain aluminum accumulation, and that both Alzheimers disease and dialysis encephalopa-... 

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