Absorption of minerals

Proteins and Meals. Nutritional properties of the oilseed protein meals and their derived products are deterrnined by the amino acid compositions, content of biologically active proteins, and various nonprotein constituents found in the defatted meals. Phytic acid (3), present as salts in all four meals, is beheved to interfere with dietary absorption of minerals such as 2inc, calcium, and iron (67) (see Food toxicants, naturally occurring Mineral nutrients). ... 

Allelopathic inhibition of mineral uptake results from alteration of cellular membrane functions in plant roots. Evidence that allelochemicals alter mineral absorption comes from studies showing changes in mineral concentration in plants that were grown in association with other plants, with debris from other plants, with leachates from other plants, or with specific allelochemicals. More conclusive experiments have shown that specific allelochemicals (phenolic acids and flavonoids) inhibit mineral absorption by excised plant roots. The physiological mechanism of action of these allelochemicals involves the disruption of normal membrane functions in plant cells. These allelochemicals can depolarize the electrical potential difference across membranes, a primary driving force for active absorption of mineral ions. Allelochemicals can also decrease the ATP content of cells by inhibiting electron transport and oxidative phosphorylation, which are two functions of mitochondrial membranes. In addition, allelochemicals can alter the permeability of membranes to mineral ions. Thus, lipophilic allelochemicals can alter mineral absorption by several mechanisms as the chemicals partition into or move through cellular membranes. Which mechanism predominates may depend upon the particular allelochemical, its concentration, and environmental conditions (especially pH). 

Although many physiological and biochemical processes In plants are affected by various allelochemicals, In most Instances the details of the mechanism of action of a particular allelochemical have not been elucidated. Because soil mediates the transfer of most allelochemicals (except perhaps volatile compounds) from a donor to a receiver, plant roots are often the first tissues to contact an allelochemical. Thus, It Is not surprising that root growth and development are Inhibited In many Instances of allelopathy (1.-3) One of the primary physiological functions of plant roots Is the absorption of mineral nutrients. Therefore, It Is logical that the Influence of allelopathic Interactions on mineral absorption by plant roots has been Investigated. 

One of the primary bases for the hypothesis that allelochemicals affect mineral uptake rests with the fact that the concentration of minerals In receiver plants can be altered by donor plants by a mechanism other than competition for minerals. In general, studies In support of this hypothesis have Involved measuring the amount of mineral present per weight of a particular plant part following absorption of minerals by the roots of the Intact receiver. 

There is no available information on absorption of mineral oil hydraulic fluids following inhalation or dermal absorption. There are data suggesting that mineral oil aerosols are cleared from the lungs via alveolar macrophages. No specific methods to reduce absorption of dermally applied or inhaled mineral oil hydraulic fluids were located, but it is expected that removal of contaminated clothing and multiple washings of contaminated skin would reduce the dermal absorption of these materials. 

Dietary Reference Intake (DRI) of Cu, 17-18% of the DRI of K, P, and Fe, and between 5 and 13% of the DRI of Zn, Mg, and Mn (Table 5.1). Potatoes are generally not rich in Ca, but can be a valuable source of trace elements, such as Se and I, if fertilized appropriately (Eurola et al., 1989 Poggi et al., 2000 Turakainen et al., 2004 Broadley et al., 2006). Moreover, since potato tubers have relatively high concentrations of organic compounds that stimulate the absorption of mineral micronutrients by humans, such as ascorbate (vitamin C), protein cysteine and various organic and amino acids (USDA, 2006), and low concentrations of compounds that limit their absorption, such as phytate (0.11-0.27% dry matter Frossard et al., 2000 Phillippy et al., 2004) and oxalate (0.03% dry matter Bushway et al., 1984), the bioavailability of mineral elements in potatoes is potentially high. 

Docusate Calcium (Surfak)/Docusate Potassium (Dialose)/ Docusate Sodium (DOSS, Colace) [Emollient Laxative/Fecal Softener] Uses Constipation adjunct to painful anorectal conditions (hemorrhoids) Action Stool softener Dose Adults. 50-500 mg PO + daily qid Peds. Infants-3 y 10-40 mg/24 h daily qid 3-6 y 20-60 mg/24 h + daily qid 6-12 y 40-120 mg/24 h + daily qid Caution [C, ] Contra Use w/ mineral oil intestinal obst, acute abd pain, N/V Disp Caps, syrup, Liq, soln SE Rare abd cramping, D Interactions T Absorption of mineral oil EMS Monitor for Sxs of electrolyte disturbances and hypovolemia d/t D OD May cause N/V/D and abd pain symptomatic and supportive... 

Modulation of the gastrointestinal absorption of minerals including iron (3,15-18,22-24)... 

Growth regulators can influence a plant s absorption of minerals from the soil. The uptake of potassium by wheat, for example, is accelerated by treating the plant with gibberellic acid. The uptake of both nitrogen and phosphorus by wheat and soybean plants is enhanced by treatment with 2,4-D. 

Prebiotics and synbiotics containing fructooligosaccharides enhance mineral bioavailability by improving the absorption of minerals in the colon, especially calcium, iron, and magnesium (Caers, 2004 Coudray, 2004 Hidaka et al., 2001 Ohta et al., 1994 Roberfroid, 2005). The mechanism... 

The behavior of minerals is often influenced by the presence of other food constituents. The recent interest in the beneficial effect of dietary fiber has led to studies of the role fiber plays in the absorption of minerals. It has been shown (Toma and Curtis 1986) that mineral absorption is decreased by fiber. A study of the behavior of iron, zinc, and calcium showed that interactions occur with phytate, which is present in fiber. Phytates can form insoluble complexes with iron and zinc and may interfere with the... 

A series of experiments were initiated to examine the effects of dietary fibers on the plasma uptake of an oral dose of manganese in humans. Stable isotope techniques are the ideal methods for measuring the intestinal absorption of minerals however this technique is impossible for manganese because of its monoisotopic nature (14). Also, ethical considerations prohibit the use of radioactive forms of manganese. Thus, a technique which was both relatively easy to conduct and safe to administer repeatedly to the same subject was developed. 

In discussing the absorption of minerals, especially In the context of their biological availability. It Is Important to clarify three terms for the subdivisions of the absorptive process uptake refers to the entrance of the nutrient Into the mucosal cell from the intestinal lumen transfer refers to the passage of the nutrient out of the mucosal cell and transport refers to the removal of the nutrient from the vicinity of the Intestine to other parts of the organism. All three processes are essential for a dietary component, such as zinc, to achieve a nutritional role for the the organism. From the array of mechanisms thought... 

One approach which has been used to improve diet homogeneity, which is important for balance and absorption studies, is to use regular foods and then homogenized them in a blender. However, it is not known if absorption of minerals is the same when foods are homogenized as when they are not. 

Saturated fatty acids are better absorbed as MAGs than as FFA, as the latter can form less-absorbable hydrated acid soaps and complexes with calcium and other divalent ions (41). The effect is more pronounced when the amount of calcium in the diet is high (42). In the presence of insoluble soaps, cholesterol absorption may be reduced (43). Thus, the stereospecific position of fatty acids in the TAGs can have an effect on their absorption and on the absorption of minerals and other lipid constituents. 

Hypha (plural, hyphae)—Cellular unit of a fungus, typically a branched and tubular filament. Many strands (hyphae) together are called mycelium. Root hair—These are tiny, tubular outgrowths of the root epidermis, mostly occurring behind the actively growing root tip, and used to increase surface area of the root to enhance the absorption of minerals and water from the soil. 

Nowadays saponins have been studied because different beneficial properties to health have been described. Saponins possess a broad variety of biological effects analgesic, antiinflammatory, antimicrobial, antioxidant, antiviral, and cytotoxic activity, effect on the absorption of minerals and vitamins and on animal growth, hemolytic and immunosti-mulatory effects, increased permeability of the intestinal mucosa neuro-protective action, and reduction of fat absorption (Gu lii-Ustundag and Mazza, 2007). However, the biological properties of quinoa saponins require further study. 

Increased nutritional value (better digestibility and increased absorption of minerals and vitamins)... 

Docusate (e.g.. Colace) Improves penetration of water and fat into feces. Diarrhea, abdominal cramps. Increases absorption of mineral oil (do not use with mineral oil). PO/PR. 

In 1923, Hevesy applied his radioactive tracer studies to the absorption of minerals by plants. It had long been assumed that plants, in contrast to animals, do not excrete the minerals they absorb. Hevesy demonstrated that solutions containing the lead isotope then termed thorium-B were absorbed by plants and caused them to retain some radioactivity. When unlabelled lead solution was subsequently used as nutrient, Hevesy found that the radioactive isotope gradually returned to the nutrient solution. Clearly, there was active metal exchange occurring at all times. 

Considerable investigation has been reported on the effects of increasing dietary fiber on utilization of various minerals. Fiber supplementation may dilute the concentration of minerals by increasing fecal bulk, may lessen the absorption by decreasing fecal transit time, may encourage absorption of minerals upon fiber residues or trap minerals within residues, and/or may complex with phytate and other Inhibitors of mineral utilization. However, results of studies investigating utilization of different minerals under conditions of additions of different levels and sources of fiber have in no way been conclusive (26-29). 

Organic acids may improve the absorption of minerals, such as Ca, P, Mg and Zn, in the small intestine (Kirchgessner and Roth, 1988). The presence of anions appears to facilitate cation mineral absorption, and formic, fumaric and n-butyric acid have all been shown to improve apparent total tract digestibility of Ca and total P, as well... 

Absorption of mineral elements is either by simple diffusion or by carrier-mediated transport. The exact mechanisms for aU minerals have not been estabhshed, but the absorption of calcimn, for example, is regulated by 1,25-dehydroxycholecalciferol (see p. 80). Low alimentary pH favoiu caldinn absorption, but absorption is inhibited by a number of dietary factors such as the presence of oxalates and phytates. An excess of either calcium or phosphorus interferes with the absorption of the other. The absorption of calcium is also influenced by the requirements of the animal. For example, the absorption of calcium from the digestive tract of laying hens is much greater when shell formation is in progress than when the shell gland is inactive. 

The refining of cereals leads to an appreciable fall in their mineral content but, on the other hand, dietary fibre decreases the absorption of minerals such as calcium and iron. It has been suggested that in Britain the consumption of wholemeal chapattis may be a factor in causing rickets and osteomalacia in immigrants from the Indian subcontinent. These subjects tend to be deficient in vitamin D (page 156) and therefore to absorb and metabolize the available calcium less efficiently. 

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