The american journal of human genetics

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Studies have shown that a decline in urinary magnesium excretion during protein-energy malnutrition (PEM) is accompanied by a reduced intestinal absorption of magnesium. The catch-up growth associated with recovery from PEM is achieved only if magnesium supply is increased substantially (6, 14).

Most of the early pathologic consequences of magnesium depletion are neurologic or neuromuscular defects (12, 15), some of which probably reflect the influence of the element on potassium flux within tissues. Thus, a decline in magnesium status produces anorexia, nausea, muscular weakness, lethargy, staggering, and, if deficiency is prolonged, weight loss. Progressively increasing with the severity and duration of depletion are manifestations of hyperirritability, hyperexcitability, muscular spasms, and tetany, leading ultimately to convulsions.

An increased susceptibility to audiogenic shock is common in experimental animals. Cardiac arrhythmia and pulmonary oedema frequently have fatal consequences (12). It has been suggested that losec sub-optimal magnesium status may be a factor in the aetiology of coronary heart disease and hypertension but additional evidence is needed (16).

Dietary sources, absorption, and emotions of magnesiumDietary deficiency of magnesium of a severity sufficient to provoke pathologic changes is rare.

Magnesium is widely distributed in plant and animal foods, and geochemical and other environmental variables rarely have a major influence on its content in foods.

Although most unrefined cereal grains are reasonable sources, many highly refined flours, tubers, fruits, and fungi and most oils and fats contribute little dietary magnesium (17-19).

Corn flour, cassava and sago flour, and polished rice flour have an extremely low magnesium content. Table 45 presents representative data for the dietary magnesium intakes the american journal of human genetics infants and adults.

Stable isotope studies with 25Mg and 26Mg indicate that between 50 percent and 90 percent of the labelled magnesium from maternal milk and infant formula can be absorbed by infants (11, 20). Studies with adults consuming conventional diets show that the efficiency of magnesium absorption can vary greatly depending on magnesium intake (31, 32). In one study 25 percent of magnesium was absorbed when magnesium intake was high compared with 75 percent when intake was low the american journal of human genetics. This provided one of the american journal of human genetics sets of data illustrating the homeostatic capacity of the body to adapt to a wide variety of ranges in magnesium intake (35, 36).

Magnesium absorption appears to be greatest within the duodenum and ileum and occurs by both passive and active processes (37). This is probably attributable to the magnesium-binding action of phytate phosphorus associated with the fibre (38-40). However, consumption of phytate- and cellulose-rich products (usually containing high concentrations of magnesium) increases magnesium intake, which often compensates for the decrease in absorption.

The effects of dietary components such as phytate on magnesium absorption are probably critically important only at low magnesium intake.

Fresno is no consistent evidence that modest increases in the intake of calcium (34-36), iron, or manganese (22) affect magnesium balance.

The kidney has a very significant role in magnesium homeostasis. Active reabsorption of magnesium takes place in the loop of Henle in the proximal convoluted tubule and is influenced by both the urinary concentration of sodium and probably by acid-base balance (42). The latter relationship may well account for the observation from Chinese studies that dietary changes which result in increased urinary pH and decreased titratable acidity the american journal of human genetics reduce the american journal of human genetics magnesium output by 35 percent despite marked increases in dietary magnesium input for vegetable protein diets (30).

Criteria for assessing magnesium requirements and allowancesIn 1996 Shils and Rude (44) published a constructive review of past procedures used to derive estimates of magnesium the american journal of human genetics. They questioned the arguments of many authors that metabolic balance studies are probably the only practicable, non-invasive techniques for assessing the relationships of magnesium intake to magnesium status.

At the same time, they emphasised the the american journal of human genetics scarcity of data on variations in urinary magnesium output and on magnesium levels in serum, erythrocytes, lymphocytes, bone, sky johnson soft tissues.

Such data are needed to verify current assumptions that pathologic responses to a decline in magnesium supply are not likely occur biosystems engineering if magnesium balance remains relatively constant. Estimated allowances of magnesiumThe scarcity of studies from which to derive estimates of dietary allowances for magnesium has been emphasised by virtually all the agencies faced with this task.

One United Kingdom agency commented particularly on the scarcity of studies with young subjects, and circumvented the problem of discordant data from work with adolescents and adults by restricting the range of studies considered emergency medical service. Using experimental data virtually identical to those used for a detailed critique of the basis for US estimates (27), the Scientific Committee for Food of the European Communities (46) did not propose magnesium allowances (or population reference intakes, PRIs) because of inadequate Acitretin (Soriatane)- Multum. Statements of acceptable intakes leave uncertainty as to the extent of overestimation of derived recommended intakes.



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