Читать книгу The Vitamin Cure - Monte Lai - Страница 38
ОглавлениеMagnesium is an essential element that exists in an ionic form in biological systems. The magnesium ion is the fourth most abundant cation in the body and the second most abundant cation inside the cell. The human body contains about 25 g of magnesium, of which 60% is stored in the bones and the rest in various organs and tissues. Genetic DNA material is negatively charged, so the binding of cationic magnesium ions stabilizes the structural stability of the anionic DNA. Magnesium ions are also required to support the involvement of 300 different enzymes in various important physiological functions in the body.
What Are the Major Functions of Magnesium?
• Cellular energy. Magnesium ions are required to support enzymatic reactions during the conversion of glucose to high-energy ATP in cells. The ATPase enzymes that catalyze ATP to release energy and thus maintain all normal physiological functions—such as reading, writing, walking, talking, and thinking—require magnesium ions as contributing constituents. Therefore, magnesium ions are needed for the activation and activities of ATP and ATPase that are related to cellular energy production.
• Bone health. Magnesium ions participate in maintaining the strength and hardness of the bones. They are present in a crystalline form inside bones as well as in a cationic form on the surface of bones. Magnesium ions present on the surface of bones are in dynamic equilibrium with magnesium ions in the bloodstream. When more blood magnesium ions are needed, the bones release magnesium ions into the bloodstream. When too many magnesium ions are present in the bloodstream, the bones absorb excessive magnesium ions from the bloodstream. Magnesium ions are required for the functions of both osteoblasts and osteoclasts in bone tissue.
• Blood glucose. Magnesium ions can enhance cellular insulin sensitivity and lower blood glucose levels. Insulin helps magnesium ions enter the pancreatic cells and enhance insulin production. The interplay between magnesium and insulin regulates the blood level of glucose. Insulin resistance blocks magnesium ions from entering into the cells and furthermore increases urine excretion, leading to magnesium deficiency.
• Blood pressure. Magnesium ions prevent calcium ions from entering into endothelial cells in the blood vessels. They act like natural calcium channel blockers. In addition, magnesium ions induce the dilatation of the blood vessels and decrease intracellular sodium concentrations, hence lowering blood pressure.
What Are the Symptoms of Magnesium Deficiency?
• The major symptoms of magnesium deficiency are muscle spasms, atrial fibrillation, and seizure. Although magnesium deficiency is rare, magnesium insufficiency is rather common. In the US, 65% of people have an insufficient dietary intake of magnesium, and 81% of people aged 71 years and older are magnesium insufficient.
• Certain acute and chronic diseases can give rise to magnesium deficiency. These diseases include digestive disorders and kidney and endocrine malfunctions. Digestive disorders include malnutrition, severe vomiting, acute and chronic diarrhea, and acute pancreatitis. Antacid medications can also lead to magnesium deficiency. Diuretics, hypercalcemia, acute renal failure, alcoholism, and renal toxins, such as cisplatin and amphotericin B, contribute to renal malfunctions. Endocrine malfunctions include type 2 diabetes, phosphate deficiency, hypoparathyroidism, and hyperparathyroidism.
Prevention and Treatment of Diseases
• Prevention. Meta-analysis confirms that magnesium supplements can help prevent cardiovascular disease (48), metabolic syndrome (87), colorectal cancer (56), heart disease (73), stroke (108), type 2 diabetes (60), and migraines (88).
• Treatment. Meta-analysis confirms that magnesium supplements can help treat hypertension (78).
Which Food Items Are Magnesium Rich?
Many foods contain magnesium. For example, fish, lobsters, legumes, dark-green leafy vegetables, nuts, oats, and tofu are excellent sources of magnesium. Other foods containing magnesium are avocados, bananas, chocolate, and whole wheat.
This list of magnesium-rich food items is adapted from information provided by the USDA.
| FOOD | PORTION | MAGNESIUM CONTENT, MG | % DAILY REFERENCE VALUE |
|---|---|---|---|
| Oatmeal | ½ cup | 96 | 24 |
| Brown rice (cooked) | 1 cup | 86 | 22 |
| Mackerel (cooked) | 3 ounces | 82 | 21 |
| Spinach (cooked) | ½ cup | 78 | 20 |
| Almonds | 1 ounce | 77 | 19 |
| Beets | ½ cup | 75 | 19 |
| Peanuts | 1 ounce | 48 | 12 |
| Okra | ½ cup | 37 | 9 |
| Milk | 8 ounces | 34 | 9 |
| Banana | 1 | 32 | 8 |
Daily reference value of magnesium is 400 mg according to the 2013 FDA food-labeling guidelines.
What Are the Recommended Dietary Allowances for Magnesium?
| 1–3 years | 80 mg |
| 4–8 years | 130 mg |
| 9–13 years | 240 mg |
| 14–18 years | 410 mg (boys); 360 mg (girls) |
| 19 years and older | 420 mg |
The upper daily intake limit of magnesium is 350 mg.
Magnesium Supplements
• Dosage. The most common dosages of magnesium supplements in the marketplace are 50–500 mg. Read the product labeling carefully when purchasing magnesium to determine the amount of magnesium in each tablet, not just its total weight.
• Types. Popular magnesium supplements are magnesium oxide, magnesium chloride, and magnesium malate. Magnesium oxide is the least expensive, but less of it is absorbed by the intestines, and it may cause diarrhea. Magnesium chloride is a good choice if a high daily dose of magnesium supplement is required. In high doses, all magnesium supplements are laxatives, but among them, magnesium hydroxide in particular is most commonly used as a laxative.
• Type 2 diabetes. Supplementation with magnesium may decrease the risk of type 2 diabetes. Magnesium ions increase cellular insulin sensitivity. The suggested daily dose is 350 mg for four months.
• Stroke. Sufficient dietary intake of magnesium lowers the risk of stroke. Studies have shown that daily consumption of 300 mg of magnesium from foods reduced the risk of stroke by 8%.
• Heart failure. Magnesium supplements improve some of the symptoms associated with heart failure. Heart failure patients who took magnesium supplements at a dose of 300 mg for one year had fewer incidences of atrial fibrillation and better survival rates.
• Lack of exercise. Magnesium supplements may augment physical strength and activity. Studies from the US have shown that supplementation with magnesium at a dose of 350 mg daily improved walking and shortened the time required to transition from a seated position to standing in elderly people.
• Migraine. Magnesium supplements prevent migraines. A randomized controlled trial has shown that supplementation with magnesium diminished the risk of migraines by 40% in migraine patients who took magnesium supplements at a dose of 600 mg daily for 12 weeks.
• Hearing loss. Magnesium supplements prevent hearing loss induced by noise. One randomized controlled trial has shown that magnesium supplementation decreases noise-induced hearing loss in participants who take daily magnesium supplements at a dose of 200 mg.
• Angina. Magnesium supplements may mitigate certain symptoms associated with angina. The consumption of magnesium supplements at a daily dose of 350 mg for six months made it easier for angina patients to perform daily tasks.
• Menstruation. Magnesium supplements prevent menstrual migraines, premenstrual syndrome, and menstrual pain. The recommended daily dose is 400 mg of magnesium chloride taken every day starting three days before the beginning of menstruation.
• Antacid activity. Magnesium can be used as an antacid agent. The recommended daily dose is 100 mg of magnesium chloride for patients with stomach hyperacidity.
• Other diseases. Magnesium supplements can help treat hypertension, kidney stones, and throbbing pain in the feet during pregnancy. The recommended daily dose is 200 mg of magnesium chloride.
• Intravenous injections. Intravenous injections of magnesium ions under a physician’s supervision can be used to treat acute asthma, atrial fibrillation, drug overdose, diabetic ketoacidosis, pancreatitis, hyperthyroidism, and hepatitis.
Safety Issues
• Side effects. People who take high doses of magnesium supplements may experience side effects that include stomach discomfort, nausea, vomiting, or diarrhea. Avoid taking magnesium supplements above the daily upper limit of 350 mg.
• Overdose. High doses of magnesium supplements may lead to exceedingly high blood levels of magnesium, particularly in patients with kidney disease, causing hypotension, fatigue, and atrial fibrillation.
• Zinc supplement. High doses of zinc supplements may interfere with the absorption of magnesium by the intestines.
What Types of Drugs May Interact with Magnesium?
• Antacid drugs. Antacid drugs, such as proton pump inhibitors, reduce the blood level of magnesium. Long-term antacid drug users should consider taking magnesium supplements. Studies have shown that in spite of taking magnesium supplements, about 25% of long-term antacid users still had a problem with low blood levels of magnesium and needed to discontinue taking proton pump inhibitors.
• Other drugs. Digoxin (a heart disease drug), antibiotic tetracycline, oral anticoagulants, and diuretics interfere with the absorption of magnesium by the intestines.
