| ||Magnesium and carbohydrate metabolism|
| ||Disorders of magnesium metabolism|
| ||Magnesium deficiency produces insulin resistance and increased thromboxane synthesis|
| ||Magnesium and glucose homeostasis|
| ||Magnesium content of erythrocytes in patients with vasospastic angina|
| ||Variant angina due to deficiency of intracellular magnesium|
| ||Magnesium and sudden death|
| ||Magnesium deficiency produces spasms of coronary arteries: Relationship to etiology of sudden death ischemic heart disease |
| ||Magnesium and potassium in diabetes and carbohydrate metabolism. Review of the present status and recent results.|
| ||Hypocalcemia associated with estrogen therapy for metastatic adenocarcinoma of the prostate|
| ||[Overview--suppression effect of essential trace elements on arteriosclerotic development and it's mechanism]|
| ||Magnesium hormonal regulation and metabolic interrelations|
| ||Magnesium deficiency: Possible role in osteoporosis associated with gluten-sensitive enteropathy|
| ||Energy and nutrient intake in patients with CF|
| ||Kidney stone clinic: Ten years of experience|
| ||Plasma copper, zinc and magnesium levels in patients with premenstrual tension syndrome|
| ||Oral magnesium successfully relieves premenstrual mood changes|
| ||Magnesium and the premenstrual syndrome|
| ||Magnesium concentration in brains from multiple sclerosis patients |
| ||Zinc, copper and magnesium concentration in serum and CSF of patients with neurological disorders |
| ||The susceptibility of the centrocecal scotoma to electrolytes, especially in multiple sclerosis |
| ||Experimental and clinical studies on dysregulation of magnesium metabolism and the aetiopathogenesis of multiple sclerosis. |
| ||Magnesium concentration in plasma and erythrocytes in MS|
| ||Comparative findings on serum IMg2+ of normal and diseased human subjects with the NOVA and KONE ISE's for Mg2+|
| ||Migraine--diagnosis, differential diagnosis and therapy]|
| ||Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study.|
| ||Electromyographical ischemic test and intracellular and extracellular magnesium concentration in migraine and tension-type headache patients.|
| ||Magnesium supplementation and osteoporosis|
| ||Calcium, phosphorus and magnesium intakes correlate with bone mineral content in postmenopausal women |
| ||Magnesium in the physiopathology and treatment of renal calcium stones|
| ||Urinary factors of kidney stone formation in patients with Crohn's disease|
| ||Renal stone formation in patients with inflammatory bowel disease|
| ||Magnesium metabolism in health and disease|
| ||Prophylaxis of recurring urinary stones: hard or soft mineral water|
| ||Urothelial injury to the rabbit bladder from various alkaline and acidic solutions used to dissolve kidney stones|
| ||Cellular and humoral immunity in rats after gestational zinc or magnesium deficiency|
| ||Prospective study of nutritional factors, blood pressure, and hypertension among US women.|
| ||Association of macronutrients and energy intake with hypertension.|
| ||Relations between magnesium, calcium, and plasma renin activity in black and white hypertensive patients|
| ||Effect of renal perfusion pressure on excretion of calcium, magnesium, and phosphate in the rat.|
| ||Concentration of free intracellular magnesium in the myocardium of spontaneously hypertensive rats treated chronically with calcium antagonist or angiotensin converting enzyme inhibitor|
| ||Nonpharmacologic treatment of hypertension.|
| ||Micronutrient effects on blood pressure regulation.|
| ||Role of magnesium and calcium in alcohol-induced hypertension and strokes as probed by in vivo television microscopy, digital image microscopy, optical spectroscopy, 31P-NMR, spectroscopy and a unique magnesium ion-selective electrode.|
| ||Consequences of magnesium deficiency on the enhancement of stress reactions; preventive and therapeutic implications (a review).|
| ||Effect of dietary magnesium supplementation on intralymphocytic free calcium and magnesium in stroke-prone spontaneously hypertensive rats.|
| ||Electrolytes and hypertension: results from recent studies.|
| ||Calcium antagonists in pregnancy as an antihypertensive and tocolytic agent|
| ||The pathogenesis of eclampsia: the 'magnesium ischaemia' hypothesis.|
| ||Intracellular Mg2+, Ca2+, Na2+ and K+ in platelets and erythrocytes of essential hypertension patients: relation to blood pressure.|
| ||A prospective study of nutritional factors and hypertension among US men|
| ||Electrolytes in the epidemiology, pathophysiology, and treatment of hypertension.|
| ||Minerals and blood pressure.|
| ||The effect of Ca and Mg supplementation and the role of the opioidergic system on the development of DOCA-salt hypertension.|
| ||Attenuated vasodilator responses to Mg2+ in young patients with borderline hypertension.|
| ||Dietary modulators of blood pressure in hypertension|
| ||Daily intake of macro and trace elements in the diet. 4. Sodium, potassium, calcium, and magnesium|
| ||Effects of a combination of evening primrose oil (gamma linolenic acid) and fish oil (eicosapentaenoic + docahexaenoic acid) versus magnesium, and versus placebo in preventing pre-eclampsia.|
| ||Relationship of magnesium intake and other dietary factors to blood pressure: the Honolulu heart study.|
| ||Serum calcium, magnesium, copper and zinc and risk of cardiovascular death.|
| ||Hypertension, diabetes mellitus, and insulin resistance: the role of intracellular magnesium|
| ||[Guidelines on treatment of hypertension in the elderly, 1995--a tentative plan for comprehensive research projects on aging and health-- Members of the Research Group for "Guidelines on Treatment of Hypertension in the Elderly", Comprehensive Research Projects on Aging and Health, the Ministry of Health and Welfare of Japan]|
| ||Micronutrient profiles in HIV-1-infected heterosexual adults|
| ||Fish oil and other nutritional adjuvants for treatment of congestive heart failure|
| ||The use of oral magnesium in mild-to-moderate congestive heart failure|
| ||Magnesium supplementation in patients with congestive heart failure|
| ||Magnesium: A critical appreciation|
| ||Significance of magnesium in congestive heart failure|
| ||The rationale of magnesium as alternative therapy for patients with acute myocardial infarction without thrombolytic therapy|
| ||Mortality risk and patterns of practice in 4606 acute care patients with congestive heart failure: The relative importance of age, sex, and medical therapy|
| ||The study of renal magnesium handling in chronic congestive heart failure|
| ||Management of acute myocardial infarction in the elderly|
| ||Supraventricular tachycardia after coronary artery bypass grafting surgery and fluid and electrolyte variables|
| ||[Magnesium: current studies--critical evaluation--consequences]|
| ||Magnesium deficiency-related changes in lipid peroxidation and collagen metabolism in vivo in rat heart.|
| ||[Value of magnesium in acute myocardial infarct]|
| ||Concentrations of magnesium, calcium, potassium, and sodium in human heart muscle after acute myocardial infarction.|
| ||[MAGNESIUM in cardiology]|
| ||MAGNESIUM therapy in acute myocardial infarction when patients are not candidates for thrombolytic therapy |
| ||[Oral MAGNESIUM supplementation to patients receivingdiuretics -- normalization of MAGNESIUM, POTASSIUM and sodium, and POTASSIUM pumps in the skeletal muscles].|
| ||Effects of intravenous MAGNESIUM sulfate on arrhythmias in patients with congestive heart failure.|
| ||MAGNESIUM-POTASSIUM interactions in cardiac arrhythmia. Examples of ionic medicine.|
| ||Clinical clues to MAGNESIUM deficiency.|
| ||Muscle and serum magnesium in pulmonary intensive care unit patients.|
| ||Unrecognized pandemic subclinical diabetes of the affluent nations: Causes, cost and prevention|
| ||Vitamin and mineral deficiencies which may predispose to glucose intolerance of pregnancy|
| ||Different effects of Mg2+ on endothelin-1- and 5-hydroxytryptamine- elicited responses in goat cerebrovascular bed|
| ||Ethanol-induced contraction of cerebral arteries in diverse mammals and its mechanism of action|
| ||Mgsup 2sup +-Casup 2sup + interaction in contractility of vascular smooth muscle: Mgsup 2sup + versus organic calcium channel blockers on myogenic tone and agonist-induced responsiveness of blood vessels|
| ||The case for intravenous magnesium treatment of arterial disease in general practice: Review of 34 years of experience|
| ||Acute hypermagnesemia after laxative use|
| ||Antacids drugs: Multiple but too often unknown pharmacological properties|
| ||[Magnesium: current concepts of its physiopathology, clinical aspects and therapy]|
| ||Bronchial reactivity and dietary antioxidants|
| ||Studies of the effects of inhaled magnesium on airway reactivity to histamine and adenosine monophosphate in asthmatic subjects|
| ||Magnesium attenuates the neutrophil respiratory burst in adult asthmatic patients|
| ||Physicochemical characterization of nedocromil bivalent metal salt hydrates. 1. Nedocromil magnesium|
| ||Skeletal muscle magnesium and potassium in asthmatics treated with oral beta2-agonists|
| ||Nutrient intake of patients with rheumatoid arthritis is deficient in pyridoxine, zinc, copper, and magnesium|
| ||Magnesium in supraventricular and ventricular arrhythmias|
| ||Ionic mechanisms of ischemia-related ventricular arrhythmias|
| ||Trace elements in prognosis of myocardial infarction and sudden coronary death|
| ||Magnesium flux during and after open heart operations in children.|
| ||An expanded concept of "insurance" supplementation--broad-spectrum protection from cardiovascular disease.|
| ||Intakes of vitamins and minerals by pregnant women with selected clinical symptoms.|
| ||[Amyotrophic lateral sclerosis--causative role of trace elements]|
| ||Aluminum Deposition in Central Nervous System of Patients with Amyotrophic Lateral Sclerosis From the Kii Peninsula of Japan|
| ||[Deficiency of certain trace elements in children with hyperactivity]|
| ||[Level of magnesium in blood serum in children from the province of Rzesz'ow]|
| ||Frequently nebulized beta-agonists for asthma: effects on serum electrolytes.|
| ||Effect of nebulized albuterol on serum potassium and cardiac rhythm in patients with asthma or chronic obstructive pulmonary disease.|
| ||Calcium, phosphate, vitamin D, and the parathyroid|
| ||Clinical and biochemical effects of nutritional supplementation on the premenstrual syndrome|
| ||Rationales for micronutrient supplementation in diabetes. |
| ||Comparison of the effects of magnesium hydroxide and a bulk laxative on lipids, carbohydrates, vitamins A and E, and minerals in geriatric hospital patients in the treatment of constipation.|
| ||Small bowel obstruction caused by a medication bezoar: report of a case.|
| ||Nonsustained polymorphous ventricular tachycardia during amiodarone therapy for atrial fibrillation complicating cardiomyopathy. Management with intravenous magnesium sulfate.|
| ||The osmotic and intrinsic mechanisms of the pharmacological laxative action of oral high doses of magnesium sulphate. Importance of the release of digestive polypeptides and nitric oxide.|
| ||Intravenous magnesium sulfate in acute severe asthma not responding to conventional therapy|
| ||Effect of inhaled magnesium sulfate on sodium metabisulfite-induced Bronchoconstriction in asthma|
| ||Magnesium sulfate therapy in certain emergency conditions|
| ||Effect of intravenous magnesium sulphate on airway calibre and airway reactivity to histamine in asthmatic subjects|
| ||Inhalation therapy with magnesium sulfate and salbutamol sulfate in bronchial asthma|
| ||MgSO4 relaxes porcine airway smooth muscle by reducing Ca2+ entry|
| ||Effect of intravenous magnesium sulfate on cardiac arrhythmias in critically III patients with low serum ionized magnesium|
| ||The antiarrhythmic effects of taurine alone and in combination with magnesium sulfate on ischemia/reperfusion arrhythmia|
| ||Magnesium taurate and fish oil for prevention of migraine.|
Magnesium metabolism in health and disease
DIS. MON. (USA), 1988, 34/4 (166-218)
Magnesium is an important element for health and disease. Magnesium, the second most abundant intracellular cation, has been identified as a cofactor in over 300 enzymatic reactions involving energy metabolism and protein and nucleic acid synthesis. Approximately half of the total magnesium in the body is present in soft tissue, and the other half in bone. Less than 1% of the total body magnesium is present in blood. Nonetheless, the majority of our experimental information comes from determination of magnesium in serum and red blood cells. At present, we have little information about equilibrium among and state of magnesium within body pools. Magnesium is absorbed uniformly from the small intestine and the serum concentration controlled by excretion from the kidney. The clinical laboratory evaluation of magnesium status is primarily limited to the serum magnesium concentration, 24-hour urinary excretion, and percent retention following parenteral magnesium. However, results for these tests do not necessarily correlate with intracellular magnesium. Thus, there is no readily available test to determine intracellular/total body magnesium status. Magnesium deficiency may cause weakness, tremors, seizures, cardiac arrhythmias, hypokalemia, and hypocalcemia. The causes of hypomagnesemia are reduced intake (poor nutrition or IV fluids without magnesium), reduced absorption (chronic diarrhea, malabsorption, or bypass/resection of bowel), redistribution (exchange transfusion or acute pancreatitis), and increased excretion (medication, alcoholism, diabetes mellitus, renal tubular disorders, hypercalcemia, hyperthyroidism, aldosteronism, stress, or excessive lactation). A large segment of the U.S. population may have an inadequate intake of magnesium and may have a chronic latent magnesium deficiency that has been linked to atherosclerosis, myocardial infarction, hypertension, cancer, kidney stones, premenstrual syndrome, and psychiatric disorders. Hypermagnesemia is primarily seen in acute and chronic renal failure, and is treated effectively by dialysis.
Prophylaxis of recurring urinary stones: hard or soft mineral water
MINERVA MED. (Italy), 1987, 78/24 (1823-1829)
The influence of a calcium-rich mineral water on urine crystallisation in patients with recurring kidney stones was investigated. A calcium and magnesium rich water like the one tested increases the calcium and magnesium content of the urine but decreases oxaluria even after a dietary oxalate load.
Urothelial injury to the rabbit bladder from various alkaline and acidic solutions used to dissolve kidney stones
J. UROL. (BALTIMORE) (USA), 1986, 136/1 (181-183)
Different irrigating solutions are used clinically to dissolve uric acid, cystine and struvite stones. These studies were undertaken to assess the toxicity to the rabbit bladder epithelium of several commonly used formulations. Test solutions were infused antegrade through a left ureterotomy overnight. Bladders were removed and routine histological sections made. A pH 7.6 solution of NaHCOsub 3 appeared harmless. The same solution with two percent acetylcysteine produced slight injury. All pH solutions caused significant damage to the urothelium. Hemiacidrin, which contains magnesium, produced less danger than did other pH 4 solutions without that cation. Our data tend to support Suby's conclusions that addition of magnesium reduces urothelial injury even though the presence of magnesium will slow dissolution of struvite.
Cellular and humoral immunity in rats after gestational zinc or magnesium deficiency
Journal of Nutritional Biochemistry (USA), 1996, 7/6 (327-332)
The effects of gestational Mg or Zn deficiency on the humoral or cellular immunity of newborn rats were investigated. Mg deficiency was induced by feeding a diet containing 180 ppm Mg from day 0 to day 21 of gestation and Zn deficiency was induced by feeding a diet containing 1.5 ppm Zn from day 0 to day 19. Controls were fed a diet with 1,000 ppm Mg and 100 ppm Zn from day 0 to day 21. Thereafter, all maternal rats and newborns were fed diets with normal amounts of Mg or Zn. Three and six weeks after birth, T-cell subpopulations in blood and thymus and B-cells in blood of the newborns were detected by flow cytometry. Plasma contents of IgG, IgM, and IgA were determined by radial immunodiffusion. Mg deficiency reduced litter size and pup weight. Three weeks after birth, the total number of leukocytes and lymphocytes in blood was significantly decreased, due to a reduction of T-helper and cytotoxic T-cells. Activated T-cells and B-cells were unchanged. Six weeks after birth, T-cell subpopulations approached controls values, whereas IgG content in plasma was slightly reduced. Gestational Zn deficiency reduced litter size and induced malformations. Three and six weeks after birth, body weight, number of leukocytes, lymphocyte, and T-cell subpopulations were not significantly changed. Plasma IgM was decreased 3 weeks after birth in correlation to the number of B-cells, which represented only 4% of total lymphocytes. These effects were repaired by the sixth week. Plasma IgG was reduced at 6 weeks. No effects on T-cell subpopulations in isolated thymocytes were detected after gestational Mg or Zn deficiency.
Prospective study of nutritional factors, blood pressure, and hypertension among US women.
Hypertension (UNITED STATES) May 1996, 27 (5) p1065-72
We examined prospectively the relation of nutritional factors with hypertension and blood pressure levels among 41,541 predominantly white US female nurses, aged 38 to 63 years, who completed a detailed semiquantitative food frequency questionnaire in 1984 and were without diagnosed hypertension, cancer, or cardiovascular disease. During 4 years of follow-up, from 1984 to 1988, 2,526 women reported a diagnosis of hypertension. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary calcium, magnesium, potassium, and fiber were not significantly associated with risk of hypertension, after adjusting for age, body mass index, alcohol, and energy intake. Among women who did not report hypertension during the follow-up period, calcium, magnesium, potassium, and fiber were each significantly inversely associated with self-reported systolic and diastolic pressures, after adjusting for age, body mass index, alcohol consumption, and energy intake. When the four nutrients were added simultaneously to the regression model, only fiber and magnesium intakes retained significant inverse associations with systolic and diastolic pressures. In analyses of food groups, intakes of fruit and vegetables were inversely associated with systolic and diastolic pressures, and intakes of cereals and meat were directly associated with systolic pressure. These results support hypotheses that age, body weight, and alcohol consumption are strong determinants of risk of hypertension in middle-aged women. They are compatible with the possibilities that magnesium and fiber as well as a diet richer in fruits and vegetables may reduce blood pressure levels.
Association of macronutrients and energy intake with hypertension.
J Am Coll Nutr (UNITED STATES) Feb 1996, 15 (1) p21-35
Hypertension, a major public health problem, becomes more prevalent during aging. Epidemiological studies suggest that environmental factors such as nutrition may play a major role in blood pressure (BP) regulation. It is generally accepted that obesity and sodium/alcohol consumption are important factors, and many believe that calcium, magnesium and potassium consumption are regulatory as well. Less emphasis has been placed on whether macronutrients influence blood pressure significantly. This review focused on the ability of excess calories and consumption of carbohydrates, fats, and proteins to regulate blood pressure. (207 Refs.)
Relations between magnesium, calcium, and plasma renin activity in black and white hypertensive patients
Miner Electrolyte Metab (SWITZERLAND) 1995, 21 (6) p417-22
The heterogeneous status of magnesium and calcium metabolism in the hypertensive population may be related to the plasma renin activity (PRA). This study investigates the relationships between serum and erythrocyte magnesium (Mg2+) and calcium (Ca2+) concentrations and PRA in black and white essential hypertensive patients. Thirty-nine normotensive (20 black, 19 white) and 47 hypertensive (25 black, 22 white) subjects were studied. The PRA was measured by radioimmunoassay, Mg2+ and Ca2+ by atomic absorption spectroscopy, and serum ionized Ca2+ by a specific electrode. PRA and ionized Ca2+ were significantly lower in the black hypertensive as compared with the white hypertensive group (1.99 +/- 0.33 vs. 5.96 +/- 1.02 ng/ml/h for PRA; 1.28 +/- 0.07 vs. 1.42 +/- 0.01 mmol/l for ionized Ca2+: black hypertensives vs. white hypertensives p < 0.05). Ionized Ca2+ was significantly increased (p < 0.05) in the white hypertensive patients as compared with the normotensive controls (1.42 +/- 0.01 vs. 1.29 +/- 0.04 mmol/l). In the black hypertensive group, serum and erythrocyte Mg2+ were significantly (p < 0.05) decreased as compared with the other groups. The erythrocyte Ca2+ concentration was significantly elevated in both black and white hypertensive patients. In the group as a whole, serum Mg2+ and PRA were negatively correlated and ionized Ca2+ and PRA and ionized Ca2+ and erythrocyte Ca2+ positively correlated. However, in the subgroups, these correlations were only significant in the white group: r = -0.67 and p < 0.05 serum Mg2+ vs. PRA; r = 0.64, and p < 0.05 ionized Ca2+ vs. PRA; r = 0.82 and p < 0.01 ionized [Ca2+]i vs. erythrocyte Ca2+. These data suggest a relationship between PRA, Mg2+, and Ca2+ which may be more important in white than in black hypertensive patients.
Effect of renal perfusion pressure on excretion of calcium, magnesium, and phosphate in the rat.
Clin Exp Hypertens (UNITED STATES) Nov 1995, 17 (8) p1269-85
Abnormalities in renal handling of calcium, magnesium, or phosphate have been implicated in the development and/or maintenance of human hypertension. We have shown recently that renal excretion of these ions is correlated to blood pressure in Dahl salt-sensitive as well as salt-resistant rats. The present study was designed to determine whether renal perfusion pressure per se could affect excretion of these ions. Urinary excretion of calcium, magnesium, and phosphate was studied in anaesthetized Sprague-Dawley rats under basal conditions and during an intravenous infusion of angiotensin II (ANG II), vasopressin (AVP) or phenylephrine (PE). A cuff, placed around the aorta between the two renal arteries, allowed maintenance of normal perfusion pressure in the left kidney, while that in the right kidney was allowed to rise. Infusion of pressor agents raised mean arterial blood pressure to comparable levels (means +/- SE): ANG II (n = 7), before = 102 +/- 4, during = 133 +/- 3 mmHg, AVP (n = 8), before = 110 +/- 7, during = 136 +/- 5 mmHg, PE (n = 6), before = 111 +/- 6, during = 141 +/- 6 mmHg. Although there was no difference in excretion of calcium, magnesium and phosphate between the two kidneys under basal conditions, infusion of ANG II or PE induced hypercalciuria, hypermagnesiuria and hyperphosphaturia in the right kidney which was exposed to the increased arterial pressure. Such effects did not appear in the pressure-controlled left kidney. Infusion of AVP was associated with reduced excretion of calcium and magnesium, and increased excretion of phosphate, in the normotensive kidney. The response to the similarly increased renal perfusion pressure in this group was also reduced for calcium and magnesium, and enhanced for phosphate. The results indicate (1) renal excretion of calcium, magnesium and phosphate is renal perfusion pressure-dependent; the higher the renal perfusion pressure, the greater the excretion of these ions. (2) Independently of perfusion pressure, AVP can inhibit phosphate reabsorption and stimulate divalent cation reabsorption.
Concentration of free intracellular magnesium in the myocardium of spontaneously hypertensive rats treated chronically with calcium antagonist or angiotensin converting enzyme inhibitor
Arch Mal Coeur Vaiss (FRANCE) Aug 1994, 87 (8) p1041-5
In this study, we determined a) whether chronic antihypertensive treatment could alter myocardial free intracellular magnesium concentrations, b) whether changes in magnesium concentration would correlate with resistance to anoxia of hypertensive rat hearts. Six-month old male spontaneously hypertensive (HT) rats (n = 11) were compared to rats from the same strain treated with a calcium channel antagonist, nitrendipine (60 mg/kg/j; n = 11) or with a converting-enzyme inhibitor, perindopril (2 mg/kg/j; n = 9) during three months. The hearts were perfused in retrograde isovolumic mode and submitted to a standardized anoxia-recovery protocol. Aortic perfusion pressure and left ventricular pressure were constantly monitored. P-31 NMR spectra were simultaneously recorded and allowed to quantify the changes in myocardial inorganic phosphate, phosphocreatine and ATP. The pH was derived from the chemical shifts of inorganic phosphate and phosphocreatine, and the free intracellular magnesium concentration from the alpha-beta chemical shifts of ATP. Both treatments lowered systolic blood pressure and reversed left ventricular hypertrophy, perindopril being slightly more efficient at the dose administered. Intracellular magnesium concentration, calculated from the P-31 NMR spectra, was 277 +/- 17 microM in the untreated hypertensive group, 311 +/- 15 microM in the nitrendipine group and 401 +/- 17 microM in the perindopril group (p < 0.001 versus untreated and nitrendipine). There was a significant correlation between intracellular magnesium concentration and left ventricular developed pressure at the early stage of post-anoxic recovery (r = 0.61; p < 0.01). P-31 NMR spectroscopy demonstrates an increase in myocardial free intracellular magnesium concentration following chronic administration of an angiotensin-converting enzyme inhibitor, perindopril, spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Nonpharmacologic treatment of hypertension.
Curr Opin Nephrol Hypertens (UNITED STATES) Oct 1992, 1 (1) p85-90
A variety of lifestyle modifications will lower both the blood pressure and various other cardiovascular risk factors that are frequently present in patients with hypertension. Numerous recent studies document the overall efficacy of some (weight reduction, sodium restriction, physical activity, moderation of alcohol) and the relative lack of effect of others (stress management and calcium, magnesium, and fish oil supplements). In particular, the Trials of Hypertension Prevention, Phase I (a control trial funded by the National Heart, Lung, and Blood Institute) provides important new data on the ability of these various modalities to prevent the development of hypertension, an equally or even more important goal than the reduction of already-established disease. (32 Refs.)
Micronutrient effects on blood pressure regulation.
Nutr Rev (UNITED STATES) Nov 1994, 52 (11) p367-75
Five micronutrients have been shown to directly influence blood pressure: sodium, calcium, potassium, magnesium, and chloride. The data presented here are based on accumulated findings from epidemiologic, laboratory, and clinical investigations, many of which focused primarily on a single nutrient. However, as also discussed here, nutrients are not consumed in isolation, and their physiologic interactions and combined effects on blood pressure are the subjects of much of the current research in the area of diet and hypertension. (71 Refs.)
Role of magnesium and calcium in alcohol-induced hypertension and strokes as probed by in vivo television microscopy, digital image microscopy, optical spectroscopy, 31P-NMR, spectroscopy and a unique magnesium ion-selective electrode.
Alcohol Clin Exp Res (UNITED STATES) Oct 1994, 18 (5) p1057-68
It is not known why alcohol ingestion poses a risk for development of hypertension, stroke and sudden death. Of all drugs, which result in body depletion of magnesium (Mg), alcohol is now known to be the most notorious cause of Mg-wasting. Recent data obtained through the use of biophysical (and noninvasive) technology suggest that alcohol may induce hypertension, stroke, and sudden death via its effects on intracellular free Mg2+ ([Mg2+]i), which in turn alter cellular and subcellular bioenergetics and promote calcium ion (Ca2+) overload. Evidence is reviewed that demonstrates that the dietary intake of Mg modulates the hypertensive actions of alcohol. Experiments with intact rats indicates that chronic ethanol ingestion results in both structural and hemodynamic alterations in the microcirculation, which, in themselves, could account for increased vascular resistance. Chronic ethanol increases the reactivity of intact microvessels to vasoconstrictors and results in decreased reactivity to vasodilators. Chronic ethanol ingestion clearly results in vascular smooth muscle cells that exhibit a progressive increase in exchangeable and cellular Ca2+ concomitant with a progressive reduction in Mg content. Use of 31P-NMR spectroscopy coupled with optical-backscatter reflectance spectroscopy revealed that acute ethanol administration to rats results in dose-dependent deficits in phosphocreatine (PCr), the [PCr]/[ATP] ratio, intracellular pH (pHi), oxyhemoglobin, and the mitochondrial level of oxidized cytochrome oxidase aa3 concomitant with a rise in brain-blood volume and inorganic phosphate. Temporal studies performed in vivo, on the intact brain, indicate that [Mg2+]i is depleted before any of the bioenergetic changes. Pretreatment of animals with Mg2+ prevents ethanol from inducing stroke and prevents all of the adverse bioenergetic changes from taking place. Use of quantitative digital imaging microscopy, and mag-fura-2, on single-cultured canine cerebral vascular smooth muscle, human endothelial, and rat astrocyte cells reveals that alcohol induces rapid concentration-dependent depletion of [Mg2+]i. These cellular deficits in [Mg2+]i seem to precipitate cellular and subcellular disturbances in cytoplasmic and mitochondrial bioenergetic pathways leading to Ca2+ overload and ischemia. A role for ethanol-induced alterations in [Mg2+]i should also be considered in the well-known behavioral actions of alcohol. (90 Refs.)
Consequences of magnesium deficiency on the enhancement of stress reactions; preventive and therapeutic implications (a review).
J Am Coll Nutr (UNITED STATES) Oct 1994, 13 (5) p429-46
Stress intensifies release of catecholamines and corticosteroids that increase survival of normal animals when their lives are threatened. When magnesium (Mg) deficiency exists, stress paradoxically increases risk of cardiovascular damage including hypertension, cerebrovascular and coronary constriction and occlusion, arrhythmias and sudden cardiac death (SCD). In affluent societies, severe dietary Mg deficiency is uncommon, but dietary imbalances such as high intakes of fat and/or calcium (Ca) can intensify Mg inadequacy, especially under conditions of stress. Adrenergic stimulation of lipolysis can intensify its deficiency by complexing Mg with liberated fatty acids (FA), A low Mg/Ca ratio increases release of catecholamines, which lowers tissue (i.e. myocardial) Mg levels. It also favors excess release or formation of factors (derived both from FA metabolism and the endothelium), that are vasoconstrictive and platelet aggregating; a high Ca/Mg ratio also directly favors blood coagulation, which is also favored by excess fat and its mobilization during adrenergic lipolysis. Auto-oxidation of catecholamines yields free radicals, which explains the enhancement of the protective effect of Mg by anti-oxidant nutrients against cardiac damage caused by beta-catecholamines. Thus, stress, whether physical (i.e. exertion, heat, cold, trauma--accidental or surgical, burns), or emotional (i.e. pain, anxiety, excitement or depression) and dyspnea as in asthma increases need for Mg. Genetic differences in Mg utilization may account for differences in vulnerability to Mg deficiency and differences in body responses to stress. (259 Refs.)
Effect of dietary magnesium supplementation on intralymphocytic free calcium and magnesium in stroke-prone spontaneously hypertensive rats.
Clin Exp Hypertens (UNITED STATES) May 1994, 16 (3) p317-26
The effects of dietary magnesium (Mg) supplementation on intralymphocytic free Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) were examined in the stroke-prone spontaneously hypertensive rats (SHRSP) at the age of 10 weeks. After 40 day Mg supplementation (0.8% Mg in the diet), systolic blood pressure (SBP) was significantly lower in Mg supplemented group (Mg group) than the control group (0.2% Mg). [Ca2+]i was significantly lower and [Mg2+]i was significantly higher in Mg group than in the control group. Further, [Ca2+]i was positively and [Mg2+]i was negatively correlated with SBP. These results suggest that dietary Mg supplementation modifies [Ca2+]i and [Mg2+]i, and modulates the development of hypertension.
Electrolytes and hypertension: results from recent studies.
Am J Med Sci (UNITED STATES) Feb 1994, 307 Suppl 1 pS17-20
The effects of dietary electrolytes on blood pressure may start as early as the prenatal period as there is evidence to suggest that a high maternal calcium, magnesium, and potassium intake is reflected in lower infant blood pressure levels. One randomized trial in newborn infants suggested that, in this early phase, high sodium intake is associated with an increased blood pressure change. Such a sodium effect is not present when children grow older, and between 6 and 16 years a high potassium intake appears to limit the increase in blood pressure. Recent observational population studies have shown that the association between dietary sodium intake and blood pressure level in adults is less than initially reported. In randomized trials, the average fall in blood pressure from moderate sodium restriction is small, although benefits may be larger in the elderly. A high potassium intake has consistently been shown to reduce blood pressure levels in treated and untreated hypertensive subjects, although the overall effects are modest. The available data on calcium are difficult to interpret. From observational studies an inverse association between dietary calcium intake and blood pressure levels has repeatedly been reported. Also, several disturbances in calcium metabolism in hypertensive subjects have been demonstrated. Findings in randomized trials are less consistent and indicate a marked heterogeneity in response. (36 Refs.)
Calcium antagonists in pregnancy as an antihypertensive and tocolytic agent
Wien Med Wochenschr (AUSTRIA) 1993, 143 (19-20) p519-21
In pregnancy calcium antagonism is of great importance. The uterus-relaxing properties of verapamil are well known, diltiazem shows an excellent tokolytic efficacy and is also effective as hypotensive in pregnancy-induced hypotension. In contrast to verapamil and diltiazem the dihydropyridines were not clinically successful as tokolytic or hypotensive in pregnancy. Magnesium is a therapy of first choice in the EPH-gestosis. (44 Refs.)
The pathogenesis of eclampsia: the 'magnesium ischaemia' hypothesis.
Med Hypotheses (ENGLAND) Apr 1993, 40 (4) p250-6
'Magnesium ischaemia' is a term used to denote the functional impairment of the ATP-dependent sodium/potassium and calcium pumps in the cell membranes and within the cell itself. The production of ATP and the functioning of these pumps is magnesium-dependent and is critically sensitive to acidosis. Zinc and iron deficiencies may secondarily impair these pumps and thus contribute to 'magnesium ischaemia' (as does acidosis). This term is two-dimensional at its simplest; it refers to a functional magnesium deficiency, whether actual or induced. It is argued that chronic acidosis is the most common inducing factor. This simple hypothesis can begin to unify diverse pathophysiologies: some spontaneous abortions, aspects of Type II and gestational diabetes and the curious observation that heroin addicts become diabetic. It can also unify clinical thinking about pregnancy-induced hypertension, pre-eclampsia/eclampsia and acute fatty liver of pregnancy, as well as the coagulopathy of pregnancy. It makes important predictions about perinatal morbidity and suggests that early supplementation might prevent much pregnancy-induced disease.
Intracellular Mg2+, Ca2+, Na2+ and K+ in platelets and erythrocytes of essential hypertension patients: relation to blood pressure.
Clin Exp Hypertens [A] (UNITED STATES) 1992, 14 (6) p1189-209
Alterations in intracellular cation metabolism have been implicated in the pathophysiology of essential hypertension. Total magnesium, calcium, sodium and potassium levels were studied in serum erythrocytes and platelets, from 154 subjects (76 hypertensive and 78 normotensives; 104 blacks and 50 whites). In the combined black and white hypertensive group, platelet sodium and calcium and erythrocyte calcium were elevated and serum potassium, serum magnesium and platelet magnesium decreased. In the black hypertensive patients, platelet sodium and calcium and erythrocyte calcium were increased, whereas serum magnesium, serum potassium, platelet magnesium and erythrocyte magnesium were decreased. In the white hypertensive group, platelet sodium and erythrocyte calcium were raised and platelet magnesium was decreased. In the black hypertensive patients, serum and platelet magnesium and serum calcium were negatively and erythrocyte and platelet calcium positively correlated with mean arterial pressure. In the white hypertensive patients platelet sodium was directly related to mean arterial pressure. These results suggest that intracellular sodium and calcium overload and magnesium depletion may be important in the pathophysiology of hypertension. Magnesium disturbances are more consistent and widespread in black hypertensive patients than in white hypertensive patients.
A prospective study of nutritional factors and hypertension among US men
Circulation (UNITED STATES) Nov 1992, 86 (5) p1475-84
BACKGROUND. An effect of diet in determining blood pressure is suggested by epidemiological studies, but the role of specific nutrients is still unsettled. METHODS AND RESULTS. The relation of various nutritional factors with hypertension was examined prospectively among 30,681 predominantly white US male health professionals, 40-75 years old, without diagnosed hypertension. During 4 years of follow-up, 1,248 men reported a diagnosis of hypertension. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary fiber, potassium, and magnesium were each significantly associated with lower risk of hypertension when considered individually and after adjustment for age, relative weight, alcohol consumption, and energy intake. When these nutrients were considered simultaneously, only dietary fiber had an independent inverse association with hypertension. For men with a fiber intake of < 12 g/day, the relative risk of hypertension was 1.57 (95% confidence interval, 1.20-2.05) compared with an intake of > 24 g/day. Calcium was significantly associated with lower risk of hypertension only in lean men. Dietary fiber, potassium, and magnesium were also inversely related to baseline systolic and diastolic blood pressure and to change in blood pressure during the follow-up among men who did not develop hypertension. Calcium was inversely associated with baseline blood pressure but not with change in blood pressure. No significant associations with hypertension were observed for sodium, total fat, or saturated, transunsaturated, and polyunsaturated fatty acids. Fruit fiber but not vegetable or cereal fiber was inversely associated with incidence of hypertension. CONCLUSIONS. These results support hypotheses that an increased intake of fiber and magnesium may contribute to the prevention of hypertension.
Electrolytes in the epidemiology, pathophysiology, and treatment of hypertension.
Prim Care (UNITED STATES) Sep 1991, 18 (3) p545-57
The data regarding the value of manipulating electrolytes in hypertension are controversial. It appears there are subsets of hypertensive patients who respond with lowering of blood pressure in conjunction with changes in intake of sodium, potassium, and calcium. The information regarding phosphorus and magnesium is less convincing. This paper examines current reports regarding these electrolytes and their role in the pathophysiology and treatment of essential hypertension. (52 Refs.)
Minerals and blood pressure.
Ann Med (FINLAND) Aug 1991, 23 (3) p299-305
The mineral elements sodium, potassium, calcium and magnesium play a central role in the normal regulation of blood pressure. In particular, these mineral elements have important interrelationships in the control of arterial resistance. These elements, especially sodium and potassium, also regulate the fluid balance of the body and, hence, influence the cardiac output. Evidence shows that the present levels of intake of mineral elements are not optimum for maintaining normal blood pressure but predispose to the development of arterial hypertension. Research results suggest that without sodium chloride (common salt) and other sodium compounds being added to the diet arterial hypertension would be virtually non existent. Moreover, blood pressure would not rise with age. In communities with a high consumption of added sodium, a high intake of potassium and, possibly, magnesium seem to protect against the development of arterial hypertension and the rise of blood pressure with age. A marked reduction of sodium intake is effective in treating even severe hypertension. A moderate restriction of sodium intake or an increase in potassium intake exert remarkable antihypertensive effects, at least in some hypertensive patients. Magnesium and possibly also calcium supplements may be effective in reducing blood pressure in some hypertensives. In hypertensive patients treated with drugs sodium restriction and potassium and magnesium supplementation enhance the therapeutic effect, reduce the number and dosage, and lessen the adverse effects of prescribed antihypertensive drugs. Hence, a fall in sodium consumption and increases in potassium and magnesium consumption are useful in preventing and treating arterial hypertension. (62 Refs.)
The effect of Ca and Mg supplementation and the role of the opioidergic system on the development of DOCA-salt hypertension.
Am J Hypertens (UNITED STATES) Jan 1991, 4 (1 Pt 1) p72-5
The effect of calcium and magnesium supplementation and the role of opioidergic system was examined in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The rats were divided into four groups receiving standard laboratory rat diet (control group; n = 9); a calcium-rich diet with 2% CaCl2 added (Ca-group; n = 12); a magnesium-rich diet with 0.5% MgO added (Mg-group; n = 11); and a calcium and magnesium-rich diet with 2% CaCl2 and 0.5% MgO added (Ca/Mg-group; n = 11); each diet contained 7% NaCl. After four weeks on these diets, the rats were decapitated and blood was obtained for the measurement of plasma electrolytes, intraerythrocyte sodium, potassium and magnesium content (RBC-Na, -K, in mEq/L cells and RBC-Mg, in mg/dL cells) and plasma beta-endorphin concentration (beta-END, in pg/mL). In the control group, systolic blood pressure and RBC-Na were obviously higher than in the other groups. Plasma beta-endorphin concentration was 45.1 +/- 13.4 in the control group, 70.7 +/- 17.4 in the Ca-group (P less than .05 v control group), 58.0 +/- 20.1 in the Mg-group and 83.8 +/- 24.8 in the Ca/Mg-group (P less than .01 v control group). The blood pressure correlated significantly with both RBC-Na (r = 0.416, P less than .01) and beta-END (r = 0.436, P less than .005). A negative correlation was also observed between RBC-Na and beta-END (r = 0.437, P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)
Attenuated vasodilator responses to Mg2+ in young patients with borderline hypertension.
Circulation (UNITED STATES) Aug 1990, 82 (2) p384-93
Limb vascular responses to magnesium (Mg2+) and potassium (K+) ions were studied in 19 young patients with borderline hypertension (BHT) and compared with those of 22 age-matched normotensive subjects (NT) by measuring the forearm blood flow response to intra-arterial infusion of magnesium sulfate and potassium chloride using venous occlusion plethysmography. Percent decrements of forearm vascular resistance with Mg2+ infusions were significantly less in BHT subjects than in NT (-37.2 +/- 4.2% versus -53.0 +/- 2.0%, p less than 0.05, during the infusion of 0.1 meq Mg2+/min, and -52.2 +/- 4.3% versus -65.6 +/- 1.5%, p less than 0.05, during the infusion of 0.2 meq Mg2+/min). Moreover, the relation of the magnitude of Mg2+ response to initial vascular resistance in six of 10 BHT subjects lies above the 95% confidence interval for predicted values calculated for response points in 11 NT subjects, suggesting attenuated vasodilator responses of Mg2+ in a significant proportion of BHT subjects. In contrast, the response points to K+ in eight of nine BHT subjects fall within the 95% confidence interval, suggesting normal vasodilator responses to K+ in the majority of BHT subjects. Furthermore, the effect of small increments in local serum calcium concentrations on Mg2(+)- and K(+)-induced vasodilation was studied in normal volunteers. Isosmolar CaCl2 solution infused into the same brachial artery at a rate of 0.09 meq/min severely blunted the vasodilating actions of Mg2+ (-30.1 +/- 6.5% versus -65.8 +/- 3.2%, p less than 0.01, during the infusion of 0.2 meq Mg2+/min) but did not affect those of K+ (-63.1 +/- 3.1% versus -55.9 +/- 3.8%, NS, during the infusion of 0.154 meq K+/min). It appears that Mg2(+)-induced vasodilation should be due to the antagonistic action of Mg2+ to calcium, but K(+)-induced vasodilation might not be directly related to calcium movement. Thus, these attenuated responses to Mg2+ but normal responses to K+ in BHT subjects may indicate an underlying defect in vascular Mg2+ metabolism, which ultimately may be related to the alterations in calcium handling by plasma membranes rather than to the abnormalities of membrane Na(+)-K+ pump activity.
Dietary modulators of blood pressure in hypertension
Eur J Clin Nutr (ENGLAND) Apr 1990, 44 (4) p319-27
To study the role of diet, 197 patients of essential hypertension were randomized to either experimental diet (group A, 97 cases) or normal diet (group B, 100 cases) with diuretics given to both the groups. The age varied between 25 and 65 years and 154 were males. The study diet included a significantly higher content of potassium (K), magnesium (Mg), calcium (Ca), polyunsaturated fat, and complex carbohydrates compared to the normal diet. At entry to the study, age, sex, risk factors, mean blood pressures, mean serum Mg, K, Ca, and Na, and drug therapy were comparable in both groups. After 1 year of follow-up, there were significantly fewer patients with resistant hypertension in group A (5) than in group B (17). Mean systolic (148.22 +/- 10.1 mm Hg) and diastolic (90.2 +/- 4.84 mm Hg) pressures in group A were lowered compared to mean systolic (160 +/- 12.0 mm Hg) and diastolic (103.3 +/- 5.8 mm Hg) pressures in group B and initial mean systolic (152.2 +/- 12.8 mm Hg) and diastolic (99.8 +/- 7.2 mm Hg) pressures. Mean serum magnesium (1.86 +/- 9.22 mEq/l) and potassium (4.86 +/- 0.39 mEq/l) levels in group A were significantly higher compared to mean levels of 1.56 +/- 0.11 and 4.0 +/- 0.29 mEq/l, respectively, in group B. However compared to initial levels, K and Mg showed no significant changes in groups A and B. There was a significantly lower incidence of complications in group A (58) compared to group B (100). It is possible that a diet low in Na/K ratio and rich in complex carbohydrates, polyunsaturates, K and Mg may cause a significant reduction in blood pressure and its complications.
Daily intake of macro and trace elements in the diet. 4. Sodium, potassium, calcium, and magnesium
Ann Ig (ITALY) Sep-Oct 1989, 1 (5) p923-42
To complete the picture of the daily dietary intake of minerals, sodium, potassium, calcium and magnesium have now been considered. The study has been carried out in the Italian Marches Region after carefully evaluating the food consumption habits of the population. The foodstuffs comprising the 70 diets examined were collected in institutional canteens and private homes immediately prior to meals. The food was sampled ready for consumption as it had thus undergone the various preparation and cooking procedures, during which considerable changes in mineral content occur. In comparison with the various food consumption standards, the amount of sodium found appears excessively high (4.8 g/d) whereas that of magnesium is insufficient (0.24 g/d). A high sodium intake, and more recently a high Na/K ratio, have been associated with hypertension. Also a lack of magnesium and a high Ca/Mg ratio have repeatedly been associated with hypertension risk. The data to emerge from our study: a high sodium intake, an insufficiency of magnesium, and thus high Na/K and Ca/Mg ratios, would appear likely to enhance cardiovascular disease risk. Even though not all Authors agree on the existence of such correlations, a more correct diet as regards mineral intake is undoubtedly something to encourage.
Effects of a combination of evening primrose oil (gamma linolenic acid) and fish oil (eicosapentaenoic + docahexaenoic acid) versus magnesium, and versus placebo in preventing pre-eclampsia.
Women Health (UNITED STATES) 1992, 19 (2-3) p117-31
In a placebo controlled, partially double-blinded, clinical trial, a combination of evening primrose oil and fish oil was compared to Magnesium Oxide, and to a Placebo in preventing Pre-Eclampsia of Pregnancy. All were given as nutritional supplements for six months to a group of primiparous and multiparous pregnant women. Some of these women had personal or family histories of hypertension (21%). Only those patients who received prenatal care at the Central Maternity Hospital for Luanda were included in the study. Compared to the Placebo group (29%), the group receiving the mixture of evening primrose oil and fish oil containing Gamma-linolenic acid (GLA), Eicosapentaenoic acid (EPA), and Docosahexaenoic acid (DHA) had a significantly lower incidence of edema (13%, p = 0.004). The group receiving Magnesium Oxide had statistically significant fewer subjects who developed hypertension of pregnancy. There were 3 cases of eclampsia, all in the Placebo group.
Relationship of magnesium intake and other dietary factors to blood pressure: the Honolulu heart study.
Am J Clin Nutr (UNITED STATES) Feb 1987, 45 (2) p469-75
Associations between blood pressure and intakes of 61 dietary variables assessed by 24-h recall method were investigated in 615 men of Japanese ancestry living in Hawaii who had no history of cardiovascular disease or treated hypertension. Magnesium, calcium, phosphorus, potassium, fiber, vegetable protein, starch, vitamin C, and vitamin D intakes were significant variables that showed inverse associations with blood pressure in univariate and a multivariate analyses. Magnesium had the strongest association with blood pressure, which supports recent interest in its relation to blood pressure. Nevertheless, it was not possible to separate the effect of magnesium from that of other variables because of the problem of high intercorrelation among many nutrients. While recommendations based upon cross-sectional studies must be viewed cautiously, these results suggest that foods such as vegetables, fruits, whole grains, and low-fat dairy items are major sources of nutrients that may be protective against hypertension.
Serum calcium, magnesium, copper and zinc and risk of cardiovascular death.
Eur J Clin Nutr (ENGLAND) Jul 1996, 50 (7) p431-7
OBJECTIVE: To study the association of serum calcium, magnesium, copper and zinc concentrations with cardiovascular mortality. DESIGN: A nested case-control study within a prospective population study. SUBJECTS AND METHODS: 230 men dying from cardiovascular diseases and 298 controls matched for age, place of residence, smoking and follow-up time. Mean follow-up time was 10 years. Serum calcium, magnesium, copper and zinc concentrations were determined from samples kept frozen at -20 degrees C. RESULTS: High serum copper and low serum zinc concentrations were significantly associated with an increased mortality from all cardiovascular diseases and from coronary heart disease in particular. The relative risk of coronary heart disease mortality between the highest and lowest tertiles of serum copper and zinc were 2.86 (P = 0.03) and 0.69 (P = 0.04), respectively. Adjustment for social class, serum cholesterol, body mass index, hypertension and known heart disease at baseline examination did not materially alter the results. No significant differences were observed in concentrations of serum calcium and magnesium between cases and controls. CONCLUSIONS: High serum copper and low serum zinc are associated with increased cardiovascular mortality whereas no association was found with serum calcium and magnesium and mortality risk.
Hypertension, diabetes mellitus, and insulin resistance: the role of intracellular magnesium
Am J Hypertens (UNITED STATES) Mar 1997, 10 (3) p346-55
Magnesium is one of the most abundant ions present in living cells and its plasma concentration is remarkably constant in healthy subjects. Plasma and intracellular magnesium concentrations are tightly regulated by several factors. Among them, insulin seems to be one of the most important. In fact, in vitro and in vivo studies have demonstrated that insulin may modulate the shift of magnesium from extracellular to intracellular space. Intracellular magnesium concentration has also been shown to be effective on modulating insulin action (mainly oxidative glucose metabolism), offset calcium-related excitation-contraction coupling, and decrease smooth cell responsiveness to depolarizing stimuli, by stimulating Ca2+-dependent K+ channels. A poor intracellular magnesium concentration, as found in non-insulin-dependent diabetes mellitus (NIDDM) and in hypertensive (HP) patients, may result in a defective tyrosine-kinase activity at the insulin receptor level and exaggerated intracellular calcium concentration. Both events are responsible for the impairment in insulin action and a worsening of insulin resistance in non-insulin-dependent diabetic and hypertensive patients. By contrast, in NIDDM patients daily magnesium administration, restoring a more appropriate intracellular magnesium concentration, contributes to improve insulin-mediated glucose uptake. Similarly, in HP patients magnesium administration may be useful in decreasing arterial blood pressure and improving insulin-mediated glucose uptake. The benefits deriving from daily magnesium supplementation in NIDDM and HP patients are further supported by epidemiological studies showing that high daily magnesium intake to be predictive of a lower incidence of NIDDM and HP. In conclusion, a growing body of studies suggest that intracellular magnesium may play a key role on modulating insulin-mediated glucose uptake and vascular tone. We further suggest that a reduced intracellular magnesium concentration might be the missing link helping to explain the epidemiological association between NIDDM and hypertension. (74 Refs.)
[Guidelines on treatment of hypertension in the elderly, 1995--a tentative plan for comprehensive research projects on aging and health-- Members of the Research Group for "Guidelines on Treatment of Hypertension in the Elderly", Comprehensive Research Projects on Aging and Health, the Ministry of Health and Welfare of Japan]
Nippon Ronen Igakkai Zasshi (JAPAN) Dec 1996, 33 (12) p945-75
We propose the following guidelines for treatment of hypertension in the elderly. 1. Indications for Treatment. 1) Age: Lifestyle modification is recommended for patients aged 85 years and older. Antihypertensive therapy should be limited to patients in whom the merit of the treatment is obvious. 2) Blood pressure: Systolic BP > 160 mmHg, diastolic BP > 90 approximately 10 mmHg. Systolic BP < age + 100 mmHg for those aged 70 years and older. Patients with mild hypertension (140-160/ 90-95 mmHg) associated with cardiovascular disease should be considered for antihypertensive drug therapy. 2. Goal of Therapy for BP: The goal BP in elderly patients is higher than that in younger patients (BP reduction of 10-20 mmHg for systolic BP and 5-10 mmHg for diastolic BP). In general, 140-160/< 90 mmHg is recommended as the goal. However, lowering the BP below 150/85 should be done with caution. 3. Rate of Lowering BP: Start with half the usual dose, observe at the same dose for at least four weeks, and reach the target BP over two months. Increasing the dose of antihypertensive drugs should be done very slowly. 4. Lifestyle Modification: 1) Dietary modification: (1) Reduction of sodium intake is highly effective in elderly patients due to their high salt-sensitivity. NaCl intake of less than 10 g/day is recommended. Serum Na+ should be occasionally measured. (2) Potassium supplementation is recommended, but with caution in patients with renal insufficiency. (3) Sufficient intake of calcium and magnesium is recommended. (4) Reduce saturated fatty acids. Intake of fish is recommended. (2) Regular physical activity: Recommended exercise for patients aged 60 years and older: peak heart rate 110/minute, for 30-40 minutes a day, 3-5 days a week. (3) Weight reduction. (4) Moderation of alcohol intake, smoking cessation. 5. Pharmacologic Treatment: 1) Initial drug therapy. First choice: Long-acting (once or twice a day) Ca antagonists or ACE inhibitors. Second choice: Thiazide diuretics (combined with potassium-sparing diuretic). 2) Combination therapy. (1) For patients without complications, either of the following is recommended. i) Ca antagoinst + ACE inhibitor, ii) ACE inhibitor + Ca antagonist (or low-dose diuretics), iii) diuretic + Ca antagonist (or ACE inhibitor), iv) beta-blockers, alpha 1-blockers, alpha + beta blockers can be used according to the patho-physiological state of the patient. (2) For patients with complications. Drug(s) should be selected according to each complication. 3) Relatively contraindicated drugs. beta-Blockers and alpha 1-blockers are relatively contraindicated in elderly patients with hypertension in Japan. Centrally acting agents such as reserpine, methyldopa and clonidine are also relatively contraindicated beta-Blockers are contraindicated in patients with congestive heart failure, arteriosclerosis obliterans, chronic obstructive pulmonary disease, diabetes mellitus (or glucose intolerance), or bradycardia. These conditions are often present in elderly subjects. Elderly subjects are susceptible to alpha 1-blocker-induced orthostatic hypotension, since their baroreceptor reflex is diminished. Orthostatic hypotension may cause falls and bone fractures in the elderly.
Micronutrient profiles in HIV-1-infected heterosexual adults
Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology ( USA), 1996, 12/1 (75-83)
There is compelling evidence that micronutrients can profoundly affect immunity. We surveyed vitamin supplement use and circulating concentrations of 22 nutrients and glutathione in 64 HIV-1 seropositive men and women and 33 seronegative controls participating in a study of heterosexual HIV-1 transmission. We assayed antioxidants (vitamins A, C, and E; total carotenes), vitamins B6 and B12, folate, thiamin, niacin, biotin, riboflavin, pantothenic acid, free and total choline and carnitine, biopterin, inositol, copper, zinc, selenium, and magnesium, HIV-infected patients had lower mean circulating concentrations of magnesium (p < 0.0001), total carotenes (p = 0.009), total choline (p = 0.002), and glutathione (p = 0.045), and higher concentrations of niacin (p < 0.0001) than controls. Fifty-nine percent of HIV+ patients had low concentrations of magnesium, compared with 9% of controls (p < 0.0001). These abnormal concentrations were unrelated to stage of disease. Participants who took vitamin supplements had consistently fewer low concentrations of antioxidants, across HIV infection status and disease stage strata (p = 0.0006). Nevertheless, 29% of the HIV+ patients taking supplemental vitamins had subnormal levels of one or more antioxidants. The frequent occurrence of abnormal micronutrient nutriture, as found in these HIV+ subjects, may contribute to disease pathogenesis. The low magnesium concentrations may be particularly relevant to HIV-related symptoms of fatigue, lethargy, and impaired mentation.
Fish oil and other nutritional adjuvants for treatment of congestive heart failure
Medical Hypotheses (United Kingdom), 1996, 46/4 (400-406)
Published clinical research, as well as various theoretical considerations, suggest that supplemental intakes of the 'metavitamins' taurine, coenzyme Q10, and L-carnitine, as well as of the minerals magnesium, potassium, and chromium, may be of therapeutic benefit in congestive heart failure. High intakes of fish oil may likewise be beneficial in this syndrome. Fish oil may decrease cardiac afterload by an antivasopressor action and by reducing blood viscosity, may reduce arrhythmic risk despite supporting the heart's beta-adrenergic responsiveness, may decrease fibrotic cardiac remodeling by impeding the action of angiotensin II and, in patients with coronary disease, may reduce the risk of atherothrombotic ischemic complications. Since the measures recommended here are nutritional and carry little if any toxic risk, there is no reason why their joint application should not be studied as a comprehensive nutritional therapy for congestive heart failure.
The use of oral magnesium in mild-to-moderate congestive heart failure
Congestive Heart Failure (USA), 1997, 3/2 (21-24)
Magnesium has been shown to increase cardiac output and low serum magnesium concentrations are associated with frequent arrhythmias and higher mortality in patients with HF. We investigated the use of oral magnesium oxide in decreasing the morbidity and mortality in patients with mild-to- moderate HF. Oral magnesium oxide or placebo was given to 10 patients with NYHA Class II and III HF in a double-blind manner. In monthly follow-up visits, we measured magnesium levels, Euroquol quality of life values, mean arterial pressures, heart rates, and feet walked in 6 minutes. The mean arterial pressure increased an average of 5.3 mm Hg in the magnesium oxide group and decreased an average of 0.67 mm Hg in the placebo group (p = 0.0174). In addition, the heart rate decreased in the patients receiving magnesium oxide, and increased in the patients receiving placebo (p=0.0994). In each group, the NYHA Class decreased, while the Euroquol scale values and feet walked in 6 minutes increased. Due to the small number of patients enrolled, studies with greater numbers of patients that analyze additional oral formulations of magnesium would be beneficial. In addition enrolling HF patients in outpatient programs would be helpful.