Effects of magnesium supplementation in hypertensive patients: assessment by office, home, and ambulatory blood pressures

Effect of Magnesium on Ventricular Extrasystoles in Children

Magnesium (Mg) is a crucial element for cardiovascular system and its deficiency results in a variety of cardiac arrhythmias. The aim of this study is to determine the effect of oral Mg supplementation on the frequency of ventricular extrasystoles (VES) in children. Magnesium supplementation was given to 42 children who had VES without structural heart disease. Clinical, electrocardiographic, and Holter monitoring studies were reviewed. The mean baseline 24 h VES burden on Holter monitoring was 10.26% ± 4.13% and it was decreased to 6.62% ± 3.88% after. There was no significant difference between the pre-treatment serum Mg levels and the decrease in the frequency of VES. In conclusion, oral Mg therapy was found to be effective at suppressing VES in children regardless of serum Mg levels. Large and randomized studies are needed to demonstrate the effect of magnesium on VES suppression.

Magnesium and Hypertension: Decoding Novel Anti-hypertensives

Hypertension (HTN) is a complex multifactorial disease that is one of the most prevalent disorders in our modern world. It can lead to fatal complications like coronary artery disease (CAD) and congestive heart failure (CHF) in high-risk individuals. The silent nature of HTN also contributes to its immense caseload and, today, with a number of combinations and various antihypertensive agents, patient compliance is becoming increasingly difficult. This article has reviewed the role and mechanisms of magnesium (Mg) in reducing HTN in the human body so as to provide more information that may help include it as a mainstream antihypertensive regimen. This review has also shed light on the cardioprotective nature of Mg against pathologies like CHF with special mention to patient groups who are at high risk for low Mg levels. Many studies included in this article solidify the former link, but some also provide contradicting data.

Calcium, Magnesium, and Zinc Supplementation during Pregnancy: The Additive Value of Micronutrients on Maternal Immune Response after SARS-CoV-2 Infection

Magnesium may contribute to the immune response during and after SARS-CoV-2 infection by acting as a cofactor for immunoglobulin production and other processes required for T and B cell activity. Considering magnesium as a recommended dietary supplement during pregnancy and the possible role of magnesium deficiency in COVID-19 and its complications, the current study sought to determine the effect of magnesium and magnesium-containing nutritional supplements on the immune response following SARS-CoV-2 infection in pregnant women, as well as to observe differences in pregnancy outcomes based on the supplements taken during pregnancy. The study followed a cross-sectional design, where patients with a history of SARS-CoV-2 infection during their pregnancy were surveyed for their preferences in nutritional supplementation and their profile compared with existing records from the institutional database. A cohort of 448 pregnant women with COVID-19 during 22 months of the pandemic was assembled, out of which 13.6% took a magnesium-only supplement, and 16.5% supplemented their diet with a combination of calcium, magnesium, and zinc. Around 60% of patients in the no-supplementation group had the SARS-CoV-2 anti-RBD lower than 500 U/mL, compared with 50% in those who took magnesium-based supplements. A quantity of magnesium >450 mg in the taken supplements determined higher levels of antibody titers after COVID-19. Low magnesium dosage (<450 mg) was an independent risk factor for a weak immune response (OR-1.25, p-value = 0.003). The observed findings suggest supplementing the nutritional intake of pregnant women with magnesium-based supplements to determine higher levels of SARS-CoV-2 anti-RBD antibodies, although causality remains unclear.

Association of Serum Magnesium with Blood Pressure in Patients with Hypertensive Crises: A Retrospective Cross-Sectional Study

The role of magnesium in blood pressure has been studied among hypertensive patients; however, there is a dearth of studies exploring the role of magnesium in hypertensive crises. The primary objective of this study was to evaluate the relationship between serum magnesium and blood pressure in patients with hypertensive crises. This was a single-center, retrospective, chart review, cross-sectional study of patients with hypertensive crises. Patients were included if they were eighteen years of age or older, with an international classification disease ninth revision (ICD-9) code of 401.9 (hypertensive crises: emergency or urgency) and a documented magnesium level on their electronic medical record. The primary outcome of the study was the correlation between serum magnesium and blood pressure (systolic blood pressure and diastolic blood pressure) in patients with hypertensive crises. Two hundred and ninety-three patients were included in the study. The primary outcome result showed that serum magnesium was positively correlated with systolic blood pressure (r = 0.143, p = 0.014), but not diastolic blood pressure. Conclusion: This study found a significant positive association between magnesium and systolic blood pressure, but not diastolic blood pressure, among patients with hypertensive crises. This positive association of serum magnesium with systolic blood pressure was maintained after adjusting for covariates. This study’s findings suggest a potential role of magnesium in blood pressure among patients with hypertensive crises.

Evaluation of serum magnesium differences in hypertensive crises and control patients: A randomly matched case-control study

Although the role of magnesium in blood pressure has been well studied among hypertensive patients, no study has explored the role of magnesium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum magnesium levels between hypertensive crises patients and matched controls (age‐, sex‐, race‐, and diabetes‐matched) in a 1:1 random match. This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented magnesium level. The control group patients were required to be 18 years of age or older, have no diagnosis of hypertensive crises, and have a documented magnesium level. The primary outcome of the study was to compare the mean serum magnesium in patients with hypertensive crises versus patients without hypertensive crises. Three hundred and fifty‐eight patients were included in the study: 179 patients in both the case group and control group. The primary outcome results showed that serum magnesium concentration was not significantly different between the case group (1.89 ± 0.29 mg/dl) and control group (1.90 ± 0.31 mg/dl) (p = .787). This study found no significant difference in serum magnesium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of magnesium on blood pressure in hypertensive crises.

Impact of Micronutrients on Hypertension: Evidence from Clinical Trials with a Special Focus on Meta-Analysis

Hypertension (HT) is one of the pivotal risk factors for various detrimental diseases like cardiovascular diseases (CVDs), cerebrovascular disease, and renal dysfunction. Currently, many researchers are paying immense attention to various diet formula (dietary approach) with a special focus on micro and macronutrients along with modified lifestyle and standard anti-hypertensive drugs. Micronutrients (minerals/vitamins) play a central role in the regulation of blood pressure (BP) as they aid the function of macronutrients and also improve the anti-hypertensive functions of some anti-hypertensive agents. Even though several studies have demonstrated the beneficial effects of micronutrients on controlling BP, still some ambiguity exists among the nutritionists/doctors, which combination or individual mineral (dietary approach) contributes to better BP regulation. Therefore, this critical review article was attempted to delineate the underlying role of micronutrients (minerals and vitamins) for the management and prevention or delaying of HT and their related complications with strong affirmation from clinical trials as well as its mechanism of controlling BP. Moreover, the major source and recommended daily allowance (RDA) of various micronutrients are included in this review for guiding common readers (especially HT subjects) and dieticians to choose/recommend a better micronutrient and their combinations (other nutrients and standard anti-hypertensive drugs) for lowering the risk of HT and its related co-morbid conditions like CVDs.

Magnesium, Little Known But Possibly Relevant: A Link between NASH and Related Comorbidities

Non-alcoholic steatohepatitis (NASH) is characterized by an abnormal hepatic lipid accumulation accompanied by a necro-inflammatory process and a fibrotic response. It comprises from 10% to 30% of cases of patients with non-alcoholic liver disease, which is a global health problem affecting around a quarter of the worldwide population. Nevertheless, the development of NASH is often surrounded by a pathological context with other comorbidities, such as cardiovascular diseases, obesity, insulin resistance or type 2 diabetes mellitus. Dietary imbalances are increasingly recognized as the root cause of these NASH-related comorbidities. In this context, a growing concern exists about whether magnesium consumption in the general population is sufficient. Hypomagnesemia is a hallmark of the aforementioned NASH comorbidities, and deficiencies in magnesium are also widely related to the triggering of complications that aggravate NASH or derived pathologies. Moreover, the supplementation of this cation has proved to reduce mortality from hepatic complications. In the present review, the role of magnesium in NASH and related comorbidities has been characterized, unraveling the relevance of maintaining the homeostasis of this cation for the correct functioning of the organism.

Effectively Prescribing Oral Magnesium Therapy for Hypertension: A Categorized Systematic Review of 49 Clinical Trials

Trials and meta-analyses of oral magnesium for hypertension show promising but conflicting results. An inclusive collection of 49 oral magnesium for blood pressure (BP) trials were categorized into four groups: (1) Untreated Hypertensives; (2) Uncontrolled Hypertensives; (3) Controlled Hypertensives; (4) Normotensive subjects. Each group was tabulated by ascending magnesium dose. Studies reporting statistically significant (p < 0.05) decreases in both systolic BP (SBP) and diastolic BP (DBP) from both baseline and placebo (if reported) were labeled "Decrease"; all others were deemed "No Change." Results: Studies of Untreated Hypertensives (20 studies) showed BP "Decrease" only when Mg dose was >600 mg/day; <50% of the studies at 120-486 mg Mg/day showed SBP or DBP decreases but not both while others at this Mg dosage showed no change in either BP measure. In contrast, all magnesium doses (240-607 mg/day) showed "Decrease" in 10 studies on Uncontrolled Hypertensives. Controlled Hypertensives, Normotensives and "magnesium-replete" studies showed "No Change" even at high magnesium doses (>600 mg/day). Where magnesium did not lower BP, other cardiovascular risk factors showed improvement. Conclusion: Controlled Hypertensives and Normotensives do not show a BP-lowering effect with oral Mg therapy, but oral magnesium (≥240 mg/day) safely lowers BP in Uncontrolled Hypertensive patients taking antihypertensive medications, while >600 mg/day magnesium is required to safely lower BP in Untreated Hypertensives; <600 mg/day for non-medicated hypertensives may not lower both SBP and DBP but may safely achieve other risk factor improvements without antihypertensive medication side effects.

Clinical and Metabolic Responses to Magnesium Supplementation in Women with Polycystic Ovary Syndrome

We hypothesized that magnesium supplementation might help improve metabolic profiles and clinical symptoms of polycystic ovary syndrome (PCOS) through its role in insulin action. The present study aimed to investigate the effect of magnesium supplementation on metabolic profiles and levels of sex hormones in women with PCOS. In this parallel randomized, double-blind, placebo-controlled clinical trial, 60 women with PCOS aged 20-45 years were recruited. After stratification for body mass index (BMI), age, and types of medications, participants were randomly assigned to consume magnesium supplements (containing 250 mg magnesium oxide) or placebo for 8 weeks. To assess biochemical indicators, a venous blood sample was taken after an overnight fasting. The mean age of study participants was 26.4 years. We found that magnesium supplementation for 8 weeks among women with PCOS had favorable effects on BMI compared with the placebo group (changes from baseline in intervention group: - 0.31 ± 0.07 vs. 0.07 ± 0.09 kg/m² in control group). In addition, the supplementation lead to preventing the increase in waist circumference in intervention group compared with the control group (0.02 vs. 1.15 cm). No significant effects on glycemic variables and lipid profile were seen following the magnesium supplementation. A significant increase in serum LH levels in intervention group and a decrease in placebo group were observed (P = 0.01). Although we found a significant decrease in serum testosterone levels in intervention and placebo groups, comparing the changes between the two groups, a marginally significant difference in serum testosterone levels was found (51.65 vs. 47.80 in intervention, 43.41 vs. 39.46 in placebo, P = 0.08). A significant increase in serum dehydroepiandrogens (DHEA) (136.32 vs. 172.37 intervention, 102.74 vs. 120.15 placebo, P = 0.01) was seen in two groups. Magnesium supplementation had no significant effects on FSH, 17OH-progesteron, sex hormone-binding globulin (SHBG), and free androgen index (FAI) levels. We found evidence indicating that magnesium supplementation did not influence serum lipid profiles and glycemic indicators among women with PCOS. Magnesium supplementation resulted in reduced BMI and testosterone levels as well as increased DHEA concentrations in women with PCOS. Also, magnesium supplementation may increase serum LH levels. ClinicalTrials.gov IRCT registration no. NCT02178150.

Effect of magnesium sulfate on baroreflex during acute hypoxemia in chronically instrumented fetal sheep

AIM

To investigate the effects of magnesium sulfate on fetal baroreflex in normoxemia or acute fetal hypoxemia.

METHODS

Fetal baroreflex response was elicited using phenylephrine (30 μg) in saline and magnesium sulfate in 8 chronically treated and instrumented fetal sheep. Hypoxemia was induced using nitrogen gas inflow for 30 min. Baroreflex, calculated as the ratio of the fetal heart rate change to the mean arterial pressure, was monitored after magnesium sulfate administration and in rapid and nonrapid eye movement (NREM) sleep states. Baroreflex was assessed in response to hypoxemia in control groups in both the rapid and NREM sleep states.

RESULTS

Baroreflex was not significantly affected by saline, magnesium sulfate and rapid or NREM sleep states in normoxemic sheep. Hypoxemia increased the baroreflex in the saline-treated group (hypoxemic vs normoxemic rapid eye movement sleep: 4.37 ± 2.48 vs 2.72 ± 0.83; P < 0.05; hypoxemic vs normoxemic NREM sleep: 4.30 ± 1.47 vs 3.15 ± 0.83; P < 0.001). Magnesium sulfate decreased the baroreflex in the hypoxemic fetuses (magnesium sulfate hypoxemic vs. control normoxemic fetuses: 1.42 ± 0.92 vs 3.15 ± 0.83, P < 0.05).

CONCLUSION

The hypoxemic fetal sheep, from the ewes that were receiving magnesium sulfate, showed a significantly reduced in the baroreflex response. In clinical practice, baroreflex-related decelerations in hypoxemic fetuses of mothers receiving magnesium sulfate should be carefully interpreted.

Low Serum Magnesium Levels and Its Association with High Blood Pressure in Children

OBJECTIVE

To evaluate the association of hypomagnesemia with prehypertension (preHTN) and hypertension in children.

STUDY DESIGN

A total of 3954 apparently healthy Mexican children were enrolled in a cross-sectional study. Exclusion criteria were type 2 diabetes; hepatic, renal, or endocrine disease; impaired fasting glucose; chronic diarrhea; and intake of vitamins or magnesium supplements in the previous 6 months. preHTN was defined by systolic and/or diastolic blood pressure ≥90th to <95th percentile and hypertension by systolic and/or diastolic blood pressure ≥95th percentile, according to age, sex, and height percentile. Hypomagnesemia was defined by serum magnesium concentration <1.8 mg/dL (<0.74 mmol/L). To control for potential sources of bias related to age, participants were allocated into 2 groups, aged 6-10 years and 11-15 years.

RESULTS

The prevalence of preHTN and hypertension was 12.2% and 6.4%, respectively, in children aged 6-10 years and 13.9% and 10.6% in those aged 11-15 years. Hypomagnesemia was identified in 59 children with preHTN (27.3%) and 52 (45.6%) with hypertension in the 6-10 year age group, and in 115 children with preHTN (36.0%) and 109 (49.6%) with hypertension in the 11-15 year age group. Adjusted multiple logistic regression analysis showed that in children in both age groups, hypomagnesemia was associated with both preHTN (6-10 years: OR, 2.18, P < .0005; 11-15 years: OR, 1.38, P = .018) and hypertension (6-10 years: OR, 4.87, P < .0005; 11-15 years: OR, 1.83, P = .0002).

CONCLUSION

Our results indicate that serum magnesium level <1.8 mg/dL is significantly associated with preHTN and hypertension in apparently healthy children.

Magnesium in disease

Although the following text will focus on magnesium in disease, its role in healthy subjects during physical exercise when used as a supplement to enhance performance is also noteworthy. Low serum magnesium levels are associated with metabolic syndrome, Type 2 diabetes mellitus (T2DM) and hypertension; consequently, some individuals benefit from magnesium supplementation: increasing magnesium consumption appears to prevent high blood pressure, and higher serum magnesium levels are associated with a lower risk of developing a metabolic syndrome. There are, however, conflicting study results regarding magnesium administration with myocardial infarction with and without reperfusion therapy. There was a long controversy as to whether or not magnesium should be given as a first-line medication. As the most recent trials have not shown any difference in outcome, intravenous magnesium cannot be recommended in patients with myocardial infarction today. However, magnesium has its indication in patients with torsade de pointes and has been given successfully to patients with digoxin-induced arrhythmia or life-threatening ventricular arrhythmias. Magnesium sulphate as an intravenous infusion also has an important established therapeutic role in pregnant women with pre-eclampsia as it decreases the risk of eclamptic seizures by half compared with placebo.

The relationship between dietary magnesium intake, stroke and its major risk factors, blood pressure and cholesterol, in the EPIC-Norfolk cohort

BACKGROUND

Dietary magnesium could modify the major stroke risk factors, high blood pressure (BP) and cholesterol, but has been understudied in both sexes in a single population. This study aimed to investigate if dietary magnesium intake was associated with BP, total cholesterol (TC) and incident stroke risk in an adult population.

METHODS

We conducted cross-sectional analyses in a case-cohort study of 4443, men and women aged 40-75, representative of 25,639 participants years of the EPIC (European Prospective Investigation into Cancer)-Norfolk cohort. The cohort included 928 stroke cases (42,556.5 person years). Dietary data from 7 day food diaries were analysed using multivariate regression to assess associations between quintiles or data-derived categories of dietary magnesium intake and BP, TC and stroke risk, adjusted for relevant confounders.

RESULTS

We observed differences of -7 mmHg systolic BP (P trend ≤ 0.01) and -3.8 mmHg diastolic BP (P trend=0.01) between extreme intakes of magnesium in men, a significant inverse association with TC was observed (P trend=0.02 men and 0.04 women). Compared to the bottom 10%, the top 30% of magnesium intake was associated with a 41% relative reduction in stroke risk (HR 0.59; 95% CI 0.38-0.93) in men.

CONCLUSIONS

Lower dietary magnesium intake was associated with higher BP and stroke risk, which may have implications for primary prevention.

Effects of daily walking on office, home and 24-h blood pressure in hypertensive patients

Aerobic exercise has been recommended in the management of hypertension. However, few studies have examined the effect of walking on ambulatory blood pressure (BP), and no studies have employed home BP monitoring. We investigated the effects of daily walking on office, home, and 24-h ambulatory BP in hypertensive patients. Sixty-five treated or untreated patients with essential hypertension (39 women and 26 men, 60 ± 9 years) were examined in a randomized cross-over design. The patients were asked to take a daily walk of 30-60 min to achieve 10 000 steps/d for 4 weeks, and to maintain usual activities for another 4 weeks. The number of steps taken and home BP were recorded everyday. Measurement of office and ambulatory BP, and sampling of blood and urine were performed at the end of each period. The average number of steps were 5349 ± 2267/d and 10 049 ± 3403/d in the control and walking period, respectively. Body weight and urinary sodium excretion did not change. Office, home, and 24-h BP in the walking period were lower compared to the control period by 2.6 ± 9.4/1.3 ± 4.9 mmHg (p < 0.05), 1.6 ± 6.8/1.5 ± 3.7 mmHg (p < 0.01), and 2.4 ± 7.6/1.8 ± 5.3 mmHg (p < 0.01), respectively. Average 24-h heart rate and serum triglyceride also decreased significantly. The changes in 24-h BP with walking significantly correlated with the average 24-h BP in the control period. In conclusion, daily walking lowered office, home, and 24-h BP, and improved 24-h heart rate and lipid metabolism in hypertensive patients. However, the small changes in BP may limit the value of walking as a non-pharmacologic therapy for hypertension.

Association between dietary whole grain intake and risk of mortality: two large prospective studies in US men and women

IMPORTANCE

Higher intake of whole grains has been associated with a lower risk of major chronic diseases, such as type 2 diabetes mellitus and cardiovascular disease (CVD), although limited prospective evidence exists regarding whole grains' association with mortality.

OBJECTIVE

To examine the association between dietary whole grain consumption and risk of mortality.

DESIGN, SETTING, AND PARTICIPANTS

We investigated 74 341 women from the Nurses' Health Study (1984-2010) and 43 744 men from the Health Professionals Follow-Up Study (1986-2010), 2 large prospective cohort studies. All patients were free of CVD and cancer at baseline.

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) for total mortality and mortality due to CVD and cancer according to quintiles of whole grain consumption, which was updated every 2 or 4 years by using validated food frequency questionnaires.

RESULTS

We documented 26 920 deaths during 2 727 006 person-years of follow-up. After multivariate adjustment for potential confounders, including age, smoking, body mass index, physical activity, and modified Alternate Healthy Eating Index score, higher whole grain intake was associated with lower total and CVD mortality but not cancer mortality: the pooled HRs for quintiles 1 through 5, respectively, of whole grain intake were 1 (reference), 0.99 (95% CI, 0.95-1.02), 0.98 (95% CI, 0.95-1.02), 0.97 (95% CI, 0.93-1.01), and 0.91 (95% CI, 0.88-0.95) for total mortality (P fortrend < .001); 1 (reference), 0.94 (95% CI, 0.88-1.01), 0.94 (95% CI, 0.87-1.01), 0.87 (95% CI, 0.80-0.94), and 0.85 (95% CI, 0.78-0.92) for CVD mortality (P fortrend < .001); and 1 (reference), 1.02 (95% CI, 0.96-1.08), 1.05 (95% CI, 0.99-1.12), 1.04 (95% CI, 0.98-1.11), and 0.97 (95% CI, 0.91-1.04) for cancer mortality (P fortrend = .43). We further estimated that every serving (28 g/d) of whole grain consumption was associated with a 5% (95% CI, 2%-7%) lower total morality or a 9% (95% CI, 4%-13%) lower CVD mortality, whereas the same intake level was nonsignificantly associated with lower cancer mortality (HR, 0.98; 95% CI, 0.94-1.02). Similar inverse associations were observed between bran intake and CVD mortality, with a pooled HR of 0.80 (95% CI, 0.73-0.87; P fortrend < .001), whereas germ intake was not associated with CVD mortality after adjustment for bran intake.

CONCLUSIONS AND RELEVANCE

These data indicate that higher whole grain consumption is associated with lower total and CVD mortality in US men and women, independent of other dietary and lifestyle factors. These results are in line with recommendations that promote increased whole grain consumption to facilitate disease prevention.

Late outcome of a randomized study on oral magnesium for premature complexes

Background

Ventricular and supraventricular premature complexes (PC) are frequent and usually symptomatic. According to a previous study, magnesium pidolate (MgP) administration to symptomatic patients can improve the PC density and symptoms.

Objective

To assess the late follow-up of that clinical intervention in patients treated with MgP or placebo.

Methods

In the first phase of the study, 90 symptomatic and consecutive patients with PC were randomized (double-blind) to receive either MgP or placebo for 30 days. Monthly follow-up visits were conducted for 15 months to assess symptoms and control electrolytes. 24-hour Holter was performed twice, regardless of symptoms, or whenever symptoms were present. In the second phase of the study, relapsing patients, who had received MgP or placebo (crossing-over) in the first phase, were treated with MgP according to the same protocol.

Results

Of the 45 patients initially treated with MgP, 17 (37.8%) relapsed during the 15-month follow-up, and the relapse time varied. Relapsing patients treated again had a statistically significant reduction in the PC density of 138.25/hour (p < 0.001). The crossing-over patients reduced it by 247/hour (p < 0.001). Patients who did not relapse, had a low PC frequency (3 PC/hour). Retreated patients had a 76.5% improvement in symptom, and crossing-over patients, 71.4%.

Conclusion

Some patients on MgP had relapse of symptoms and PC, indicating that MgP is neither a definitive nor a curative treatment for late follow-up. However, improvement in the PC frequency and symptoms was observed in the second phase of treatment, similar to the response in the first phase of treatment.

The BRAzil MAGnesium (BRAMAG) trial: a randomized clinical trial of oral magnesium supplementation in pregnancy for the prevention of preterm birth and perinatal and maternal morbidity

BACKGROUND

Preterm birth is the leading cause of infant mortality globally, including Brazil. We will evaluate whether oral magnesium citrate reduces the risk of placental dysfunction and its negative consequences for both the fetus and mother, which, in turn, should reduce the need for indicated preterm delivery.

METHODS/DESIGN

We will complete a multicenter, randomized double-blind clinical trial comparing oral magnesium citrate 150 mg twice daily (n = 2000 women) to matched placebo (n = 1000 women), starting at 121/7 to 206/7 weeks gestation and continued until delivery. We will include women at higher risk for placental dysfunction, based on clinical factors from a prior pregnancy (e.g., prior preterm delivery, stillbirth or preeclampsia) or the current pregnancy (e.g., chronic hypertension, pre-pregnancy diabetes mellitus, maternal age > 35 years or pre-pregnancy maternal body mass index > 30 kg/m2). The primary perinatal outcome is a composite of preterm birth < 37 weeks gestation, stillbirth > 20 weeks gestation, neonatal death < 28 days, or SGA birthweight < 3rd percentile. The primary composite maternal outcome is preeclampsia arising < 37 weeks gestation, severe non-proteinuric hypertension arising < 37 weeks gestation, placental abruption, maternal stroke during pregnancy or ≤ 7 days after delivery, or maternal death during pregnancy or ≤ 7 days after delivery.

DISCUSSION

The results of this randomized clinical trial may be especially relevant in low and middle income countries that have high rates of prematurity and limited resources for acute newborn and maternal care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02032186, registered December 19, 2013.

Additional benefit in CVD risk indices derived from the consumption of fortified milk when combined with a lifestyle intervention

OBJECTIVE

The current study aimed to evaluate the effect of fortified milk combined with a lifestyle and counselling programme on several CVD risk factors after a 3-month dietary intervention.

DESIGN

Hypercholesterolaemic adults were randomized to a group supplemented with low-fat milk that was enriched with phytosterols, α-linolenic and linoleic fatty acids, vitamins and antioxidants (enriched milk group, EMG: n 40), a placebo milk group (PMG: n 36) or a control group (CG: n 25). The EMG and PMG consumed respectively 500 ml of enriched milk or placebo milk daily and attended biweekly counselling sessions over a 3-month period.

SETTING

Harokopio University, Athens, Greece.

SUBJECTS

A sample of 101 hypercholesterolemic adults aged 40-60 years.

RESULTS

Regarding lifestyle changes, total and saturated fat intakes decreased significantly in both intervention groups compared with the CG (P < 0·005). Furthermore, total steps were increased (P = 0·029) and BMI was decreased (P = 0·017) significantly in both intervention groups compared with the CG. Regarding biochemical indices, EPA content in erythrocyte membranes increased (P < 0·001) while serum C-reactive protein decreased (P = 0·003) significantly in both intervention groups compared with the CG. Finally, significant increases in plasma folic acid and vitamin B12 levels and a significant decrease in homocysteine levels were observed in the EMG compared with the PMG and CG (all P < 0·001). A favourable change in LDL cholesterol:HDL cholesterol was also observed in the EMG and tended to be significant compared with the PMG and CG (P = 0·066).

CONCLUSIONS

The present study showed that consumption of fortified milk accompanied with lifestyle counselling induces extra benefits in terms of LDL cholesterol:HDL cholesterol and serum homocysteine levels.

Hypomagnesemia and prehypertension in otherwise healthy individuals

BACKGROUND

Given the potential implications in the policies focused on the prevention of hypertension, we evaluate the relationship between low serum magnesium levels and prehypertension in otherwise healthy subjects.

METHODS

A cross-sectional study that enrolled 175 healthy men and non-pregnant women, 20 to 65 years of age was carried out. Type 2 diabetes, impaired fasting glucose, hypertension, chronic diarrhea, cancer, impaired renal function, as well as the intake of magnesium supplements in the previous six months, were the exclusion criteria. Hypomagnesemia was defined by serum magnesium concentration of <0.7 mmol/L and prehypertension by Systolic (S) and Diastolic (D) blood pressure (BP) of 120 to 139 and 80 to 89 mmHg. A multivariate logistic conditional forward analysis, adjusted by sex, age, alcohol consumption waist circumference, body mass index, fasting glucose and triglyceride levels was conducted to evaluate the association between hypomagnesemia and prehypertension.

RESULTS

Prehypertension was identified in 68 (13.2%) subjects who were compared with 107 (20.8%) control individuals without prehypertension. Individuals with prehypertension showed lower magnesium (0.73±0.20 vs. 0.77±0.21, p<0.001) and higher triglyceride levels (2.8±3.5 vs. 1.8±1.2, p=0.04) as compared with non-prehypertensive individuals. There were no other significant differences between the groups. The adjusted multivariate logistic conditional forward analysis showed a significant association between hypomagnesemia and prehypertension (OR 1.98; 95% CI 1.11-4.20, p=0.04).

CONCLUSIONS

Our finding suggests that low serum magnesium levels could play an important role in the pathophysiology of prehypertension in otherwise healthy subjects.

Relationship between dietary magnesium, manganese, and copper and metabolic syndrome risk in Korean adults: the Korea National Health and Nutrition Examination Survey (2007-2008)

Recent studies have reported correlations between mineral intake and metabolic syndrome (MS), but accurate relationships and consistency in the results are difficult to confirm. Accordingly, this study aims to assess the dietary intakes of magnesium (Mg), manganese (Mn), and copper (Cu) to determine their relationship with MS. Data from a total of 5,136 adults (2,084 men, 3,052 women) was collected from the 2007-2008 Korea National Health and Nutrition Examination Survey (KNHANES), and the intakes of Mg, Mn, and Cu of the MS patients were compared with those of healthy adults. The relationship between the intakes of these minerals and the MS risks was analyzed. Diagnosis of MS was evaluated by the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) standards. Among all study subjects, 25.9 % (540 subjects) of the men and 24.5 % (748 subjects) of the women met diagnostic criteria for inclusion in the MS group. In the men, daily intakes of Mg and Cu in the MS group were significantly lower than those in control group, and in the women, daily intakes of energy, Mg, Mn, and Cu in the MS group were significantly lower than those of the control group. The women subjects with high blood pressure showed significantly lower intakes of Mg, Mn, and Cu than control subjects. In addition, in the women, the highest quartile of Mg and Cu was inversely associated with MS, but with adjustment were not maintained. However, in the postmenopausal women, MS was significant and inversely associated with the highest quartiles of Cu intake and the association remained significant after adjustments. Considering that MS incidence increases and dietary intake and nutrient density decrease with increasing age, and mineral intake is reduced accordingly, these results suggest that meal management with adequate mineral intake is advisable to control MS.

Magnesium: novel applications in cardiovascular disease--a review of the literature

Magnesium is an ubiquitous element and its formulation determines its efficacy and administration. It is used for gastrointestinal and obstetric disease and recently cardiovascular and neurological indications have also been explored. The role of serum/dietary magnesium intake on cardiovascular disease, carotid intima-media thickness (CIMT), hypertension (HTN) and cholesterol synthesis has been investigated. Despite differences in patient populations, some observational and interventional studies have suggested that low serum/dietary magnesium is associated with higher CIMT and more cardiovascular risk factors. A few clinical and basic science interventional studies have also shown the benefits of magnesium administration in cardiovascular disease prevention and as a neuroprotective agent. Low magnesium levels have been implicated in inflammation and endothelial dysfunction. Hypomagnesemia results in increased C-reactive protein and cytokine exaggeration, increased nuclear factor kappa B and platelet dysfunction, which can lead to thrombosis. Magnesium appears to play a vital function in cardiovascular stability and health, but an optimal dose and formulation has not been defined. Potentially promising avenues include the combination of magnesium with a statin to reduce cholesterol, C-reactive protein and CIMT, and its early use to reduce stroke morbidity and mortality. Understanding the role of magnesium in inflammation and mineralization and how it has the potential for playing a role in modulating cardiovascular and neurological disease can be a new frontier in medicine.

Additional antihypertensive effect of magnesium supplementation with an angiotensin II receptor blocker in hypomagnesemic rats

BACKGROUND/AIMS

Magnesium (Mg) is an essential element for vascular function and blood pressure regulation. Several studies have demonstrated that Mg concentration is inversely associated with blood pressure, and that Mg supplementation attenuates hypertension. The purpose of this study was to evaluate the effect of dietary Mg supplementation on the blood pressure effects of an angiotensin II receptor blocker (ARB) in hypomagnesemic rats.

METHODS

Fifty male Sprague-Dawley rats were randomly divided into Mg-deficient (n = 30), normal diet plus Mg (n = 10), and control groups (n = 10). Mg-free, high-Mg, and normal-Mg diets were respectively fed to the rats. After 14 weeks, 10 of the 30 Mg-deficient rats were treated with Mg, 10 Mg-deficient rats received an ARB, and 10 Mg-deficient rats received an ARB plus Mg for 4 weeks.

RESULTS

Systolic blood pressure was significantly higher in the Mg-deficient rats than in the control rats at week 14. Hypomagnesemic rats exhibited decreased systolic blood pressure after treatment with Mg, and systolic blood pressure showed a greater decrease after ARB treatment. Treatment with the ARB/Mg combination resulted in the greatest decrease in systolic blood pressure. Mg deficiency did not affect the serum angiotensin II level, but did increase the serum aldosterone concentration. Concomitant Mg/ARB supplementation significantly decreased the elevated serum aldosterone level in hypomagnesemic rats. Kidney tissues of the hypomagnesemic rats revealed mild to moderate inflammatory infiltrates. Mg and/or ARB treatment did not reverse the inflammatory reaction in the kidneys of hypomagnesemic rats.

CONCLUSIONS

Concurrent dietary Mg supplementation can enhance ARB-induced blood pressure reduction in rats with hypomagnesemic hypertension.

Effect of bezafibrate on office, home and ambulatory blood pressure in hypertensive patients with dyslipidemia

It has been suggested that fibrates, lipid-lowering agents with a peroxisome proliferator-activated receptor-α agonistic property, lower blood pressure (BP) in some experimental models of hypertension. However, the effect of fibrates on BP in humans has been inconsistent, and there are few studies using home or ambulatory BP monitoring. We investigated the effects of bezafibrate on office, home and ambulatory BP in hypertensive patients with dyslipidemia. Thirty-two essential hypertensive patients with dyslipidemia (6 men and 26 women, mean age 65±8 years old) were assigned to a control period and a bezafibrate period (200 mg twice daily) for 8 weeks each in a randomized crossover manner. Bezafibrate significantly reduced serum triglyceride, total and low-density lipoprotein-cholesterol, blood glucose, plasma insulin, the homeostasis model assessment ratio and increased high-density lipoprotein-cholesterol. Compared with the control period, changes in office, home and 24-h BP with bezafibrate were -0.7±2.1/-1.6±1.2 mm Hg, +0.9±1.0/-0.5±0.6 and +0.8±1.4/-0.6±0.9 mm Hg, respectively. None of these differences in BP was significant. In conclusion, bezafibrate improved lipid metabolism and insulin sensitivity but did not affect office, home or ambulatory BP in hypertensive patients with dyslipidemia. Fibrates do not appear to lower BP in patients with essential hypertension.

Magnesium and vascular changes in hypertension

Many factors have been implicated in the pathogenesis of hypertension, including changes in intracellular concentrations of calcium, sodium, potassium, and magnesium. There is a significant inverse correlation between serum magnesium and incidence of cardiovascular diseases. Magnesium is a mineral with important functions in the body such as antiarrhythmic effect, actions in vascular tone, contractility, glucose metabolism, and insulin homeostasis. In addition, lower concentrations of magnesium are associated with oxidative stress, proinflammatory state, endothelial dysfunction, platelet aggregation, insulin resistance, and hyperglycemia. The conflicting results of studies evaluating the effects of magnesium supplements on blood pressure and other cardiovascular outcomes indicate that the action of magnesium in the vascular system is present but not yet established. Therefore, this mineral supplementation is not indicated as part of antihypertensive treatment, and further studies are needed to better clarify the role of magnesium in the prevention and treatment of cardiovascular diseases.

Effect of magnesium supplementation on blood pressure: a meta-analysis

To date, there has been inconclusive evidence regarding the effect of magnesium supplements on blood pressure (BP). This meta-analysis was conducted to assess the effect of magnesium supplementation on BP and to establish the characteristics of trials showing the largest effect size. Primary outcome measures were systolic blood pressure (SBP) and diastolic blood pressure (DBP) at the end of the follow-up period. One hundred and forty-one papers were identified, of which 22 trials with 23 sets of data (n=1173), with 3 to 24 weeks of follow-up met the inclusion criteria, with a supplemented elemental magnesium range of 120-973 mg (mean dose 410 mg). 95% confidence intervals (CI) were calculated using DerSimonian and Laird's random-effects model, with effect size calculated using Hedges G. Combining all data, an overall effect of 0.36 and 0.32 for DBP and SBP, respectively, was observed (95% CI 0.27-0.44 for DBP and 0.23-0.41 for SBP), with a greater effect being seen for the intervention in crossover trials (DBP 0.47, SBP 0.51). Effect size increased in line with increased dosage. Although not all individual trials showed significance in BP reduction, combining all trials did show a decrease in SBP of 3-4 mm Hg and DBP of 2-3 mm Hg, which further increased with crossover designed trials and intake >370 mg/day. To conclude, magnesium supplementation appears to achieve a small but clinically significant reduction in BP, an effect worthy of future prospective large randomised trials using solid methodology.

The role of magnesium in hypertension and cardiovascular disease

Magnesium intake of 500 mg/d to 1000 mg/d may reduce blood pressure (BP) as much as 5.6/2.8 mm Hg. However, clinical studies have a wide range of BP reduction, with some showing no change in BP. The combination of increased intake of magnesium and potassium coupled with reduced sodium intake is more effective in reducing BP than single mineral intake and is often as effective as one antihypertensive drug in treating hypertension. Reducing intracellular sodium and calcium while increasing intracellular magnesium and potassium improves BP response. Magnesium also increases the effectiveness of all antihypertensive drug classes. It remains to be conclusively proven that cardiovascular disease such as coronary heart disease, ischemic stroke, and cardiac arrhythmias can be prevented or treated with magnesium intake. Preliminary evidence suggests that insulin sensitivity, hyperglycemia, diabetes mellitus, left ventricular hypertrophy, and dyslipidemia may be improved with increased magnesium intake. Various genetic defects in magnesium transport are associated with hypertension and possibly with cardiovascular disease. Oral magnesium acts as a natural calcium channel blocker, increases nitric oxide, improves endothelial dysfunction, and induces direct and indirect vasodilation.

Feasibility and antihypertensive effect of replacing regular salt with mineral salt -rich in magnesium and potassium- in subjects with mildly elevated blood pressure

Background

High salt intake is linked to hypertension whereas a restriction of dietary salt lowers blood pressure (BP). Substituting potassium and/or magnesium salts for sodium chloride (NaCl) may enhance the feasibility of salt restriction and lower blood pressure beyond the sodium reduction alone. The aim of this study was to determine the feasibility and effect on blood pressure of replacing NaCl (Regular salt) with a novel mineral salt [50% sodium chloride and rich in potassium chloride (25%), magnesium ammonium potassium chloride, hydrate (25%)] (Smart Salt).

Methods

A randomized, double-blind, placebo-controlled study was conducted with an intervention period of 8-weeks in subjects (n = 45) with systolic (S)BP 130-159 mmHg and/or diastolic (D)BP 85-99 mmHg. During the intervention period, subjects consumed processed foods salted with either NaCl or Smart Salt. The primary endpoint was the change in SBP. Secondary endpoints were changes in DBP, daily urine excretion of sodium (24-h dU-Na), potassium (dU-K) and magnesium (dU-Mg).

Results

24-h dU-Na decreased significantly in the Smart Salt group (-29.8 mmol; p = 0.012) and remained unchanged in the control group: resulting in a 3.3 g difference in NaCl intake between the groups. Replacement of NaCl with Smart Salt resulted in a significant reduction in SBP over 8 weeks (-7.5 mmHg; p = 0.016). SBP increased (+3.8 mmHg, p = 0.072) slightly in the Regular salt group. The difference in the change of SBP between study groups was significant (p < 0.002).

Conclusions

The substitution of Smart Salt for Regular salt in subjects with high normal or mildly elevated BP resulted in a significant reduction in their daily sodium intake as well as a reduction in SBP.

Trial Registration

ISRCTN: ISRCTN01739816

Magnesium improves the beta-cell function to compensate variation of insulin sensitivity: double-blind, randomized clinical trial

BACKGROUND

Given that role of magnesium in insulin secretion is uncertain, our objective was to determine whether oral supplementation with magnesium chloride (MgCl(2)) improves the ability of beta-cells to compensate for variations in insulin sensitivity in non-diabetic individuals with significant hypomagnesaemia.

MATERIALS AND METHODS

Eligible individuals were non-diabetic, normo-tensive men and non-diabetic, normo-tensive, non-pregnant women with serum magnesium levels ≤0·70 mM/L; they were enrolled in a randomized double-blind clinical trial to receive either 50 mL of 5% MgCl(2) solution or 50 mL of inactive solution daily for 3 months. The primary trial end point was a change in the AUC of the hyperbolic model of beta-cell function (HMbCF) derived from the fasting state. Individuals, caregivers and personnel who assessed the outcomes were all blinded to the group assignments.

RESULTS

A total of 54 and 52 individuals were assigned to the MgCl(2) and placebo groups, respectively; five individuals in the MgCl(2) group and four in the placebo group dropped out. There were no serious adverse events or side effects because of MgCl(2) or placebo. At the beginning of the study, the AUC of the HMbCF was similar in both groups (AUC = 7·591 and 7·895 cm(2)); at the end of follow-up, the curve of the MgCl(2) group showed a hyperbolic distribution (AUC = 18·855 cm(2)), whereas in the placebo group, there were no changes (AUC = 7·631 cm(2)).

CONCLUSIONS

MgCl(2) 2·5 g daily improves the ability of beta-cells to compensate for variations in insulin sensitivity in non-diabetic individuals with significant hypomagnesaemia.

Non-pharmacological aspects of blood pressure management: what are the data?

Hypertension affects 29% of US adults and is a significant risk factor for cardiovascular morbidity and mortality. Epidemiological data support contribution of several dietary and other lifestyle-related factors to the development of high blood pressure (BP). Several clinical trials investigated the efficacy of non-pharmacological interventions and lifestyle modifications to reduce BP. Best evidence from randomized controlled trials supports BP-lowering effects of weight loss, the Dietary Approaches to Stop Hypertension (DASH) diet, and dietary sodium (Na(+)) reduction in those with prehypertension, with more pronounced effects in those with hypertension. In hypertensive participants, the effects on BP of DASH combined with low Na(+) alone or with the addition of weight loss were greater than or equal to those of single-drug therapy. Trials where food was provided to participants were more successful in showing a BP-lowering effect. However, clinical studies with long-term follow-up revealed that lifestyle modifications were difficult to maintain. Findings from controlled trials of increased potassium, calcium, or magnesium intake, or reduction in alcohol intake revealed modest BP-lowering effects and are less conclusive. The reported effects of exercise independent of weight loss on BP are inconsistent.

Diurnal blood pressure variation and related behavioral factors

Blood pressure (BP) varies according to many internal and external factors, and behavioral factors have an important role in diurnal BP variation. BP rises sharply on waking in the morning and falls during sleep at night, although it varies throughout the day and night. These changes in BP are closely related to mental and physical activities, and the sympathetic nervous system mainly contributes to the diurnal variation in BP. Other behavioral factors, such as food consumption and obesity, dietary intake of sodium, drinking and smoking habits, consumption of coffee and tea, and bathing, also affect the diurnal variation in BP. Alterations in diurnal BP variation due to behavioral factors are frequently seen in patients with hypertension and can be classified as morning hypertension, daytime hypertension and nighttime hypertension. Appropriate lifestyle modifications may normalize or improve both the level and rhythm of BP in these patients.

Antihypertensive effect of Cu and Mg enriched modified poultry eggPsi on Zn-induced hypertension in Wistar rat

PROJECT

Excessive bioavailability of Zn either due to genetic predisposition or its high concentration in diet has been linked to increase in the prevalence of hypertension (HT) implicating the resultant deficiencies of Cu and Mg as its cause in some populations. To combat their nutritional deficiencies, a modified poultry egg (ME(Psi)) was designed containing higher amounts of Cu, Mg and other antioxidants (vitamin E and linolenic acid) in their optimized concentrations. Prior to its human clinical trials, its efficacy was tested in Zn induced HT Wistar rat model in the present study.

PROCEDURE

In one set, the rats were fed on equicaloric semi-synthetic basal diet containing 20 mg Zn/kg diet (control diet-I, control group-I), Zn-induced-hypertensive-diets-II and III (Zn-HT-diet-II and Zn-HT-diet-III) containing 40 and 80 mg Zn/kg diet (groups-II and III) for 180 days. In another set, the rats were initially fed Zn-HT-diet-II and Zn-HT-diet-III for 90 days and then shifted to ME(Psi) mixed Zn-HT-diet-II and III designated as groups-IIME and IIIME fed for another 90 days completing 180 days of feeding.

RESULTS

The results revealed that increase in systolic pressure (SP) and heart rates (HR) were Zn concentration dependent and coincided well with higher serum Zn, Cu, Mg, aldosterone, cortisol, dyslipidemia and higher Zn, and low Cu and Mg concentrations in liver of groups-II and III rats. On feeding ME(Psi) mixed diets, a significant reduction in SP and HR were linked with decrease in serum Zn, Cu, Mg, aldosterone, cortisol and blood lipid profile along with fall in Zn and rise in Cu and Mg concentrations in liver of groups-IIME and IIIME approaching closer to control group-I.

CONCLUSION

This study makes the basis for human clinical trials of ME(Psi) on HT patients who exhibit high Zn, Cu and Mg in their blood serum.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Effects of oral magnesium supplementation on insulin sensitivity and blood pressure in normo-magnesemic nondiabetic overweight Korean adults

BACKGROUND AND AIM

Little is known about the effect of magnesium on insulin sensitivity and BP in healthy individuals. Therefore, we investigated whether magnesium could improve insulin sensitivity and blood pressure (BP) in normo-magnesemic nondiabetic overweight adults.

METHODS AND RESULTS

In a double-blinded, placebo-controlled, randomized trial, a total of 155 participants (BMI > or = 23 kg/m(2)) received either 12.3 mmol (300 mg) of elemental magnesium in the form of magnesium oxide (n=75) or placebo (n=80) each day for 12 weeks, constituting the intent-to-treat population. A repeated-measures ANOVA was used to evaluate the between-group changes in variables during the study. The baseline characteristics between the intervention and control groups were similar. There were no significant differences between the groups in the pattern of change of the homeostasis model assessment insulin resistance index, BP over time during the 12-week study. In subgroup analysis, magnesium supplementation (n=8, 27, and 24, respectively) lowered BP much more than placebo (n=16, 29, and 25, respectively) in those subjects whose systolic BP > or = 140 mmHg, diastolic BP 80-90 mmHg, and diastolic BP > or = 90 mmHg at the start of the study (P=0.016, 0.043, and 0.023, respectively); in comparison, those subjects whose initial BP reading was low at baseline did not show a change in BP. No significant adverse events related to magnesium supplementation were recorded.

CONCLUSIONS

These results suggested that magnesium supplementation does not reduce BP and enhance insulin sensitivity in normo-magnesemic nondiabetic overweight people. However, it appears that magnesium supplementation may lower BP in healthy adults with higher BP.

Oral magnesium supplementation reduces ambulatory blood pressure in patients with mild hypertension

BACKGROUND

Accumulating evidence implicates a role of Mg(2+) in the pathophysiology of essential hypertension. Previous studies evaluating the antihypertensive efficacy of Mg(2+) supplementation gave contradictory results. This study aimed to investigate the effect of oral Mg(2+) supplementation on 24-h blood pressure (BP) and intracellular ion status in patients with mild hypertension.

METHODS

A total of 48 patients with mild uncomplicated hypertension participated in the study. Among them, 24 subjects were assigned to 600 mg of pidolate Mg(2+) daily in addition to lifestyle recommendations for a 12-week period and another 24 age- and sex-matched controls were only given lifestyle recommendations. At baseline and study-end (12 weeks) ambulatory BP monitoring, determination of serum and intracellular ion levels, and 24-h urinary collections for determination of urinary Mg(2+) were performed in all study subjects.

RESULTS

In the Mg(2+) supplementation group, small but significant reductions in mean 24-h systolic and diastolic BP levels were observed, in contrast to control group (-5.6 +/- 2.7 vs. -1.3 +/- 2.4 mm Hg, P < 0.001 and -2.8 +/- 1.8 vs. -1 +/- 1.2 mm Hg, P = 0.002, respectively). These effects of Mg(2+) supplementation were consistent in both daytime and night-time periods. Serum Mg(2+) levels and urinary Mg(2+) excretion were significantly increased in the intervention group. Intracellular Mg(2+) and K(+) levels were also increased, while intracellular Ca(2+) and Na(+) levels were decreased in the intervention group. None of the intracellular ions were significantly changed in the control group.

CONCLUSION

This study suggests that oral Mg(2+) supplementation is associated with small but consistent ambulatory BP reduction in patients with mild hypertension.

Potassium Magnesium Supplementation for Four Weeks Improves Small Distal Artery Compliance and Reduces Blood Pressure in Patients with Essential Hypertension

It has been postulated that the loss of arterial compliance may precede cardiovascular diseases, and that arterial compliance is an important parameter to consider when evaluating arterial diseases such as essential hypertension (EH) and the effects of antihypertensive treatment. In all, 133 EH patients and 147 healthy subjects were enrolled in this study. Large arterial compliance (C1) and small arterial compliance (C2) were measured by the CVProfilor DO-2020 CardioVascular Profiling System. Thirty-five patients randomly received magnesium potassium supplementation (magnesium, 70.8 mg/d; potassium, 217.2 mg/d) for four weeks, and 32 patients received lacidipin (4 mg/d) as a control. Before and after the four weeks, blood pressure, C1, and C2 were measured. It was found that arterial compliance was significantly lower in EH patients compared with healthy subjects (C1: 12.53 +/- 0.33 vs. 15.63 +/- 0.30 ml/mmHg x 10, p < 0.01;C2: 3.79 +/- 0.17 vs. 5.69 +/- 0.25 ml/mmHg x 100, p < 0.01). On lacidipine, systolic and diastolic BP decreased 13.27 +/- 1.76 mm Hg and 6.33 +/- 1.55 mm Hg, and C1 and C2 compliance values increased 25.05% +/- 4.49% and 34.50% +/- 7.40%, respectively. On K+ and Mg2+ supplementation, systolic and diastolic BP decreased 7.83 +/- 1.87 mm Hg and 3.67 +/- 1.03 mm Hg, and C1 and C2 compliance values increased 12.44% +/- 4.43% and 45.25% +/- 6.67%, respectively. Decreases in systemic vascular resistance (mean arterial pressure divided by cardiac output) by 11.9% and 16.6 % (p < 0.01) were seen between the drug-induced changes, respectively. Both large arterial compliance and small arterial compliance were decreased in essential hypertension patients. In essential hypertension patients, magnesium and potassium supplementation could improve small arterial compliance, while lacidipine improved large arterial compliance significantly.

AZT-induced oxidative cardiovascular toxicity: attenuation by Mg-supplementation

Cardiovascular effects of chronic AZT treatment on SD male rats (185 g) fed either a normal Mg diet (0.1% MgO) or a high Mg diet (0.6% MgO) were examined. AZT treatment (1 mg/ml drinking water) for 3 weeks led to a 5.5-fold (0.88 +/- 0.11 nmol/min/10(6) cells, P < 0.05) elevation in neutrophil basal activity of O2(-) production versus controls (0.16 +/- 0.03 nmol/min, assayed ex vivo as SOD-inhibitable cytochrome c reduction). Concomitantly, plasma 8-isoprostane and PGE(2) levels rose 2.1-fold and 3-fold (both P < 0.05), respectively, compared to control; however, RBC GSH decreased 28% (P < 0.02) with GSSG content increased 3-fold, indicative of systemic oxidative stress. High Mg diet substantially attenuated the AZT-induced neutrophil activation by 70% (0.26 +/- 0.05 nmol/min, P < 0.05); reduced plasma 8-isoprostane and PGE(2) to levels comparable to normal; and RBC GSH was restored back to 92% of control. AZT alone caused moderate, but significant vascular inflammatory lesions in the heart (assessed by H&E staining). Immunohistochemical staining revealed significantly higher (about 4-fold) infiltration of CD11b positive cells (WBC surface marker) in the atria and ventricles of AZT-treated rats. However, these inflammatory pathological markers were minimal in samples of rats treated with AZT plus high Mg diet. Moreover, AZT alone significantly (P < 0.02) decreased rat weight gain by 21% at 3 weeks; Mg-supplementation completely prevented (P < 0.05) the weight gain loss due to AZT intake. It is concluded that high dietary Mg may provide beneficial effects against AZT toxicity due to its systemic antioxidative/anti-inflammatory properties.

Magnesium sulfate in emergency department patients with hypertension

To compare the effect of IV magnesium with other antihypertensives in emergency department (ED) patients with hypertension. ED patients with a systolic BP > 135 mmHg or diastolic BP > 85 were approached for entry into the study. Those granting consent were randomly placed into one of three treatment groups: (1) 1.5 gm IV MgSO(4) (n = 42), (2) a parenteral or oral antihypertensive agent (n = 41), (3) both IV MgSO(4) and an antihypertensive agent (n = 44). Systolic and diastolic blood pressures were measured at entry into the study and at 15, 30, 45, and 60 min after magnesium or other antihypertensive medications were given. The main outcome measure was blood pressure at 60 min, and results were compared using one-way analysis of variance with the post hoc Tukey HSD test. Compared to systolic and diastolic blood pressures at time 0, both were lower at 15, 30, 45, and 60 min in all groups (p < 0.05). No significant difference in systolic or diastolic BP at any time point was observed when response to treatment was compared between the three groups. Intravenous MgSO(4) is as effective as antihypertensives at lowering BP in emergency department patients.

Effect of magnesium L-lactate on blood pressure in patients with an implantable cardioverter defibrillator

BACKGROUND

Previous studies have evaluated the impact of oral magnesium on blood pressure; however, they used magnesium salts with low bioavailability, had methodological issues, and showed differing results.

OBJECTIVE

To evaluate the long-term blood pressure-lowering ability of oral magnesium L-lactate versus placebo in patients with implanted cardioverter defibrillators (ICDs).

METHODS

In this double-blind, 24-week trial, 50 patients with ICDs were randomized to receive magnesium L-lactate (6 tablets daily, supplying a total of 504 mg of elemental magnesium daily) or matching placebo for at least 12 weeks. Baseline intracellular and serum magnesium concentrations were determined. The primary efficacy endpoint was the mean sitting systolic blood pressure at 24 weeks.

RESULTS

In 50 patients who completed at least 12 weeks of follow-up, 86% of patients, regardless of randomization, had a baseline intracellular magnesium deficiency, but no patients had a serum magnesium deficiency. At 12 weeks, magnesium L-lactate significantly reduced systolic blood pressure compared with placebo (117.7 +/- 11.8 vs 126.3 +/- 16.7 mm Hg, respectively; p = 0.04). In the 45 patients who continued in the study through the 24-week time period, the systolic blood pressure reduction was maintained, but statistical significance was lost (118.1 +/- 14.1 vs 125.5 +/- 17.2 mm Hg, respectively; p = 0.13). Magnesium L-lactate did not impact diastolic blood pressure at either time period (p > or = 0.75 for both). Patients with a documented history of hypertension at baseline showed similar qualitative results to the primary analysis.

CONCLUSIONS

A large number of subjects with ICDs have an intracellular magnesium deficiency not captured through serum magnesium determination. The use of magnesium L-lactate in patients with an ICD results in significant improvement in systolic blood pressure at 12 weeks, which may be maintained through 24 weeks.

An inverse relationship between cumulating components of the metabolic syndrome and serum magnesium levels

Metabolic syndrome has been defined as the presence of abdominal obesity combined with 2 of the following factors: hypertension, dyslipidemia, and impaired glucose tolerance, or diabetes mellitus. Magnesium is an essential cofactor for more than 300 enzymes involved in carbohydrate and lipid metabolism. In this study, we enrolled 117 consecutive overweight and obese patients and we measured serum magnesium levels together with fasting serum glucose, high-density lipoprotein cholesterol, and triacylglycerols. A strong inverse relationship between magnesium levels in serum and the presence of metabolic syndrome was noticed. Moreover, magnesium levels decreased as the number of components of metabolic syndrome increased. Also, there is an inverse relationship between serum magnesium levels and high-sensitivity C-reactive protein. We concluded that decreased levels of serum magnesium are associated with increased risk for metabolic syndrome, perhaps by a low-grade inflammation process.

Magnesium metabolism in hypertension and type 2 diabetes mellitus

The increasing evidence for the clinical relevance of altered magnesium metabolism to states of altered insulin resistance confirms the role of magnesium deficit as a possible underlying common mechanism of the "insulin resistance" of hypertension and altered glucose tolerance. The pioneer work of Lawrence M. Resnick and his group using the cellular ion-based approach that we are only partially presenting here has consistently contributed to the progress of the field, demonstrating (a) the critical importance of magnesium metabolism in regulating insulin sensitivity as well as vascular tone, and blood-pressure homeostasis; (b) that magnesium deficiency, defined on the basis of intracellular free magnesium levels, and or serum ionized magnesium is a common feature of both diabetic and hypertensive states as well as various other cardiovascular and metabolic processes and aging; (c) the ability of environmental factors such as dietary nutrient-sugar and mineral content to alter the set point of steady-state cell ion activity; and (d) that magnesium supplementation is indicated in conditions associated with magnesium deficit although well-designed therapeutic trials of magnesium in essential hypertension and type 2 diabetes mellitus are needed in the near future.