More Info
									32           vitamins and minerals

MagnesiuM, HealTH
and disease PrevenTion
Magnesium is one of the major mineral nutrients in the human body. Amounting to approximately
20–28 g of magnesium, 60% is found in the bones and teeth, with the remaining 40% located in
muscle tissue. Serum levels of magnesium range from 1.5–2.1 mEq/L; it’s the second-most plentiful
positively charged ion found within the cells of the body, signifying its importance in the multitudes
of physiologic cellular functions. One of the most important metabolic processes, the synthesis and
consumption of ATP is directly linked to magnesium. Magnesium-linked ATP processes activate
approximately 300 different enzymes, which are involved in functions as diverse as DNA/RNA
synthesis, glycolysis, intracellular mineral transport, nerve impulse generation, cell membrane
electrical potential, muscle contraction, blood vessel tone and the regeneration of ATP.1

           he adult Recommended Dietary           performance athletes lose a considerable           and colon as well as triggering the release
           Allowance (RDA) for magnesium is       amount of magnesium in sweat), pregnancy           of gastrin and cholecystokinin, stimulating
           350 mg per day for men and             and lactation, diabetes, severe diarrhoea or       gastric motility. The inhibitory effect of
           280 mg for women. The typical          kidney disease. The early signs of magnesium       magnesium on preterm labour contractions
American diet provides approximately 120          deficiency include vague symptoms such as          (tocolysis) is attributed to the antagonism
mg per 1000 calories, meaning that a person       loss of appetite, stomachache and diarrhoea.       of calcium-mediated uterine contractions,
that consumes fewer than 1500 calories a          Longer-term deficiency symptoms may                whereas the anticonvulsant actions of
day is likely to be deficient in magnesium. The   manifest themselves as confusion, apathy,          magnesium in eclampsia may result from the
absorption rate of magnesium ranges from          depression, irritability, arrhythmias, weakness,   inhibition of neuromuscular transmission and
24 to nearly 85%; magnesium derived from          poor co-ordination, nausea, vomiting,              a subsequent depressant effect on smooth
metallic sources is less absorbable, whereas      electromyographic changes, muscle and              muscle contraction.3
that derived from plant sources is more easily    nerve irritability, and tremors.2
absorbed. Factors that increase the need             Magnesium has many novel uses for               Magnesium and Blood Pressure
for magnesium because of limited uptake or        common health conditions. As an antacid,           Magnesium has an important role in reducing
increased losses include excess phosphate         magnesium salts react with gastric acid            blood pressure.4 Magnesium deficiency has
consumption (soft drinks) and alcoholic           to form magnesium chloride, thereby                been found to induce elevated intracellular
beverages, high stress lifestyles, some           neutralizing hydrochloric acid. As a laxative,     concentrations of sodium and potassium,
diuretics, digitalis, strenuous exercise (high    magnesium acts osmotically in the intestine        which results in increased peripheral July/August 2010
                                                                                                  vitamins and minerals                             33
resistance and vasospasm.5 Additionally,          low intake and impaired absorption of
some research suggests that hypertensive          magnesium have also been associated with               1.    M. Shils, A. Olson and M. Shike, Modern
patients with hypomagnesemia usually              the development of osteoporosis.                             Nutrition in Health and Disease, Eighth Edition
require more antihypertensive medications                                                                      (Lea and Febiger, Philadelphia, Pennsylvania,
than hypertensive patients with normal            Magnesium and Diabetes                                       USA, 1994).
magnesium levels.6 Diets that contain plenty      Magnesium plays an important role in                   2.    E. Whitney, C.B. Cataldo and S.R. Rolfes (Eds),
                                                                                                               Understanding Normal and Clinical Nutrition
of fruits and vegetables, which are good          carbohydrate metabolism, influencing the
                                                                                                               (Wadsworth Publishing Co., Belmont, Califor
To top