metabolism:
• The rate of magnesium absorption varies from as low as 24% to as high as 85%. Many factors regulate magnesium absorption. As the level of calcium intake goes down, the level of magnesium absorption goes up. A significant amount goes to the stomach for HCL production.
• Magnesium is very involved with ATP production via the Kreb's cycle.
• Glycolysis, adenyl cyclase and other reactions involving nerve impulse transmission also require high quantities of magnesium.
• High intakes of calcium, protein, vitamin D and alcohol all function to increase the magnesium requirement.
function:
• Magnesium regulates the absorption of calcium and is involved in the structural integrity of bones and teeth. If it is deficient in the bones, the bones may be dense but have poor trabecular integrity and thus be brittle. In both Finland and the Netherlands, there is a high ratio of calcium to magnesium intake (4 to 1) and the rate of osteoporosis is the highest in the world.
• Magnesium regulates the contractility of the heart muscle. It is concentrated 18x greater in the heart muscle than in the bloodstream. A decreased magnesium level in the heart muscle may predispose a person to coronary spasms. In areas where there is harder water (mainly due to magnesium), there is a much lower rate of heart disease.
• Magnesium has a relaxing effect on smooth muscle. It may be helpful in relaxing the smooth muscle of the bronchioles (improving asthma) and the arterioles (lowering blood pressure).
• It may relax uterine tissue (decreasing the cramping of dysmenorrhea), and also be useful in the treatment of angina and myocardial infarction.
• Magnesium decreases coagulation and acts as a calcium channel blocker. Thus, it helps the heart to pump more effectively.
• It is also one of the cofactors for delta 6 desaturase which is involved in the production of PGE1.
• Magnesium is necessary for the actions of PTH and 1,25 DHCC in bone calcium mobilization.
• Cofactor in many enzyme reactions (especially ATP reactions)
• Protein synthesis
• Role in neuromuscular transmitters
• Activates vitamin B-complex
dietary sources:
• High (200-400 mg/100 g food): nuts (almonds, cashews, Brazil), soybeans, brewer's yeast, buckwheat, wheat bran
• Good: Corn, peas, carrots, barley, oats, rye, wheat, rice bran, pecans, filberts, pistachios, black walnuts, green leafy vegetables (kale, endive, chard beet tops), celery, alfalfa, figs, apples, lemons, peaches, almonds, whole grains (millet, cornmeal, wheatgerm, barley, buckwheat, oats), tahini, sunflower seeds, brown rice, sesame seeds, black-eyed peas, lima beans, tofu, lentils, potato, sweet potato, peas, Brussel sprouts, broccoli, cauliflower, corn, avocado, dates, banana, blueberries, grape juice, cantaloupe, orange juice, milk
• The average intake of magnesium by so-called healthy adults in the U.S. and Western Europe ranges between 143-266 mg/day.
• High intakes of calcium, vitamin D, and protein increase the requirement for magnesium.
• Vitamin D, lactose and HCl all act to enhance absorption.
deficiency:
• Magnesium deficiency is very common in the West since magnesium is found predominantly in whole unprocessed foods.
• Deficiency symptoms include fatigue, irritability, weakness, muscle tightness or spasms, dysmenorrhea, high blood pressure, cardiomyopathy, nerve conduction problems, anorexia, insomnia, sugar cravings, poor nail growth, anxiety.
• Magnesium deficiency may be caused by any condition which increases loss or shifts the electrolyte balance, (such as renal disease) or diuretic therapy (such as antihypertensive medications).
• Malabsorption, hyperthyroidism, pancreatitis, kwashiorkor, diabetes, parathyroid gland disorders, poor intake, and diarrhea may also cause a deficiency.
• Serum magnesium is a very poor indicator of how much magnesium is actually in the tissues. For example, magnesium concentrates in the heart muscle at a 18x higher level than in the serum.
• Measuring white blood cell magnesium is a more sensitive indicator of tissue levels. An anionic magnesium measurement, recently pioneered by Drs. Burton and Bella Altura at Down-State University of New York in Brooklyn, appears to be a considerably more accurate indicator of tissue levels of magnesium than either WBC or RBC measurements.
known or potential therapeutic uses: Acute myocardial infarction, alcohol withdrawal, angina, anxiety, asthma, autism, cardiac arrhythmias, cardiomyopathy, cardiovascular disease, celiac disease, chronic fatigue syndrome (CFS), chronic obstructive pulmonary disease (COPD), congestive heart failure, constipation, diabetes mellitus, dysmenorrhea, eclampsia, eosinophilia-myalgia syndrome, fatigue, fibromyalgia, (acute) gastro-intestinal spasms or cramping, glaucoma, hearing loss, high blood pressure, high cholesterol, hyperactivity, hypoglycemia, intermittent claudication, kidney stones, lead toxicity, low HDL-cholesterol levels, migraine, mitral valve prolapse, muscle cramping, especially nocturnal, multiple sclerosis, osteoporosis, premenstrual syndrome, Raynaud’s disease, retinopathy, stroke, torticollis, toxemia of pregnancy.
maintenance dose: 500 mg per day.
• RDA:
Infants: 50-70 mg
Children: 150-300 mg
Adults: females: 280 mg per day; males: 350 mg per day
Pregnancy and lactation 350 mg per day
therapeutic dose: 500-1500 mg per day. Also used intravenously for many conditions.
side effects/toxicity:
• Hypermagnesia is rare but may result with decreased excretion, greatly increased absorption, or rarely with IM injection; toxicity results in depression of the central nervous system and possibly death
• Diarrhea is the most common adverse effect from magnesium. Excessive magnesium can actually lead to a magnesium deficiency if it causes chronic diarrhea. Magnesium also completes with calcium and can induce a calcium deficiency if calcium intake levels are already low. About 800 mg of elemental magnesium will generally cause loose stools but some people may be able to tolerate much higher doses. Different forms of magnesium, such as magnesium glycinate, may be tolerated differently as well. There is a slow release magnesium, Slo-mag, that may be helpful in elevating the intracellular levels of magnesium. Individuals with kidney failure must be cautious about magnesium supplementation since they may experience toxicity symptoms.
• Intravenous magnesium, because of its effect on smooth muscles, may cause hypotension along with dizziness and fainting. It may also cause respiratory depression or depletion of potassium.
• Intramuscular injections can often be painful and may cause a persistent lump if injection does not go deep enough to reach the muscle tissue. After the magnesium is loaded into the syringe a small amount of 2% lidocaine can be drawn into the tip of the syringe to ease the reaction. (Marz, 1997.)
