Magnesium supplementation, metabolic and inflammatory markers, and global genomic and proteomic profiling: a randomized, double-blind, controlled, crossover trial in overweight individuals

Association of serum magnesium with metabolic syndrome and the role of chronic kidney disease: A population-based cohort study with Mendelian randomization

OBJECTIVES

To assess the association of serum magnesium with prevalent and incident metabolic syndrome (MetS) and its individual components in the general population and to examine any effect modification by chronic kidney disease (CKD) status.

METHODS

We analysed longitudinal data from the population-based KORA F4/FF4 study, including 2996 participants (387 with CKD) for cross-sectional analysis and 1446 participants (88 with CKD) for longitudinal analysis. Associations with MetS, as well as single components of MetS, were assessed by adjusted regression models. Nonlinearity was tested by restricted cubic splines and analyses were stratified by CKD. Causality was evaluated by two-sample Mendelian randomization (MR).

RESULTS

Serum magnesium (1 SD) was inversely associated with prevalent MetS (odds ratio [OR] 0.90, 95% confidence interval [CI] 0.83, 0.98). The association was more pronounced in individuals with CKD (OR 0.75, 95% CI 0.59, 0.94). Among MetS components, serum magnesium was negatively associated with elevated fasting glucose (OR 0.78, 95% CI 0.71, 0.88) and, again, this association was more pronounced in individuals with CKD (OR 0.67, 95% CI 0.53, 0.84). Serum magnesium was not associated with incident MetS or its components. Restricted cubic spline analysis revealed a significant nonlinear inverse relationship of serum magnesium with MetS and elevated fasting glucose. MR analysis suggested an inverse causal effect of serum magnesium on MetS (OR 0.91, 95% CI 0.85, 0.97).

CONCLUSION

Serum magnesium is associated with prevalent, but not incident MetS, and this effect is stronger in individuals with CKD. MR analysis implies a potential, albeit weak, causal role of magnesium in MetS.

Magnesium and the Hallmarks of Aging

Magnesium is an essential ion in the human body that regulates numerous physiological and pathological processes. Magnesium deficiency is very common in old age. Age-related chronic diseases and the aging process itself are frequently associated with low-grade chronic inflammation, called 'inflammaging'. Because chronic magnesium insufficiency has been linked to excessive generation of inflammatory markers and free radicals, inducing a chronic inflammatory state, we formerly hypothesized that magnesium inadequacy may be considered among the intermediaries helping us explain the link between inflammaging and aging-associated diseases. We show in this review evidence of the relationship of magnesium with all the hallmarks of aging (genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, disabled autophagy, dysbiosis, and chronic inflammation), which may positively affect the human healthspan. It is feasible to hypothesize that maintaining an optimal balance of magnesium during one's life course may turn out to be a safe and economical strategy contributing to the promotion of healthy aging. Future well-designed studies are necessary to further explore this hypothesis.

Dietary magnesium, C-reactive protein and interleukin-6: The Strong Heart Family Study

OBJECTIVES

To examine the associations of dietary Mg intake with inflammatory biomarkers (C-reactive protein (CRP) and interleukin 6 (IL-6)), and the interaction of dietary Mg intake with single nucleotide polymorphism (SNP) rs3740393, a SNP related to Mg metabolism and transport, on CRP and IL-6 among American Indians (AIs).

METHODS

This cross-sectional study included AI participants (n = 1,924) from the Strong Heart Family Study (SHFS). Mg intake from foods and dietary supplements was ascertained using a 119-item Block food frequency questionnaire, CRP and IL-6 were measured from blood, and SNP rs3740393 was genotyped using MetaboChip. Generalized estimating equations were used to examine associations of Mg intake, and the interaction between rs3740393 and dietary Mg, with CRP and IL-6.

RESULTS

Reported Mg intake was not associated with CRP or IL-6, irrespective of genotype. A significant interaction (p-interaction = 0.018) was observed between Mg intake and rs3740393 on IL-6. Among participants with the C/C genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.04 (95% CI: -0.10 to 0.17) pg/mL higher. Among participants with the C/G genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.08 (95% CI: -0.21 to 0.05) pg/mL lower, and among participants with the G/G genotype, for every 1 SD higher in log-Mg, log-IL-6 was 0.19 (95% CI: -0.38 to -0.01) pg/mL lower.

CONCLUSIONS

Mg intake may be associated with lower IL-6 with increasing dosage of the G allele at rs3740393. Future research is necessary to replicate this finding and examine other Mg-related genes that influence associations of Mg intake with inflammation.

Candidate SNP Markers Significantly Altering the Affinity of TATA-Binding Protein for the Promoters of Human Hub Genes for Atherogenesis, Atherosclerosis and Atheroprotection

Atherosclerosis is a systemic disease in which focal lesions in arteries promote the build-up of lipoproteins and cholesterol they are transporting. The development of atheroma (atherogenesis) narrows blood vessels, reduces the blood supply and leads to cardiovascular diseases. According to the World Health Organization (WHO), cardiovascular diseases are the leading cause of death, which has been especially boosted since the COVID-19 pandemic. There is a variety of contributors to atherosclerosis, including lifestyle factors and genetic predisposition. Antioxidant diets and recreational exercises act as atheroprotectors and can retard atherogenesis. The search for molecular markers of atherogenesis and atheroprotection for predictive, preventive and personalized medicine appears to be the most promising direction for the study of atherosclerosis. In this work, we have analyzed 1068 human genes associated with atherogenesis, atherosclerosis and atheroprotection. The hub genes regulating these processes have been found to be the most ancient. In silico analysis of all 5112 SNPs in their promoters has revealed 330 candidate SNP markers, which statistically significantly change the affinity of the TATA-binding protein (TBP) for these promoters. These molecular markers have made us confident that natural selection acts against underexpression of the hub genes for atherogenesis, atherosclerosis and atheroprotection. At the same time, upregulation of the one for atheroprotection promotes human health.

Comparative effects of vitamin and mineral supplements in the management of type 2 diabetes in primary care: A systematic review and network meta-analysis of randomized controlled trials

Medical nutrition treatment can manage diabetes and slow or prevent its complications. The comparative effects of micronutrient supplements, however, have not yet been well established. We aimed at evaluating the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM) to inform clinical practice. Electronic and hand searches for randomized controlled trials (RCTs) were performed until June 1, 2022. We selected RCTs enrolling patients with T2DM who were treated with vitamin supplements, mineral supplements, or placebo/no treatment. Data were pooled via frequentist random-effects network meta-analyses. A total of 170 eligible trials and 14223 participants were included. Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively). Vitamin K supplements ranked best in reducing glycated hemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence. Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%). Niacin supplements ranked best in triglyceride reductions and increasing high-density lipoprotein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively). Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%). Our analyses indicated that micronutrient supplements, especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more efficacious in managing T2DM than other micronutrients. Considering the clinical importance of these findings, new research is needed to get better insight into this issue.

Nutritional supplements improve cardiovascular risk factors in overweight and obese patients: A Bayesian network meta-analysis

Background

Overweight and obesity are considered as one of the major risk factors for cardiovascular diseases (CVD). At present, many studies have proved that multiple nutritional supplements play an active role in metabolic diseases. However, the comparative efficacy of different nutritional supplements in improving indicators of cardiometabolic risk in obese and overweight patients is uncertain.

Methods

Cochrane Library, PubMed, Embase, and Web of Science were searched for the period from January 1990 to March 2022. A random-effect model was built in the Bayesian network meta-analysis. The surface under the cumulative ranking analysis (SUCRA) and clustering rank analysis was performed for ranking the effects.

Results

The study included 65 RCTs with 4,241 patients. In terms of glucose control, probiotic was more conductive to improve FBG (MD: -0.90; 95%CrI: -1.41 to -0.38), FINS (MD: -2.05; 95%CrI: -4.27 to -0.02), HOMA-IR (MD: -2.59; 95%CI -3.42 to -1.76). Probiotic (MD: -11.15, 95%CrI -22.16 to -1.26), omega-3 (MD: -9.45; 95%CrI: -20.69 to -0.93), VD (MD: -17.86; 95%CrI: -35.53 to -0.27), and probiotic +omega-3 (MD: 5.24; 95%CrI: 0.78 to 9.63) were beneficial to the improvement of TGs, TC and HDL-C, respectively. The SUCRA revealed that probiotic might be the best intervention to reduce FBG, FINS, HOMA-IR; Simultaneously, α-lipoic acid, VD, and probiotic + omega-3 might be the best intervention to improve TGs, TC, and HDL-C, respectively. Cluster-rank results revealed probiotic had the best comprehensive improvement effect on glucose metabolism, and probiotic + omega-3 may have a better comprehensive improvement effect on lipid metabolism (cluster-rank value for FBG and FINS: 3290.50 and for TGs and HDL-C: 2117.61).

Conclusion

Nutritional supplementation is effective on CVD risk factors in overweight and obese patients. Probiotic supplementation might be the best intervention for blood glucose control; VD, probiotic + omega-3 have a better impact on improving lipid metabolism. Further studies are required to verify the current findings.

Higher magnesium levels are associated with better glycaemic control and diabetes remission post-bariatric surgery

BACKGROUND

Low Magnesium (Mg) dietary intake has been associated with increased risk of type 2 diabetes mellitus (T2DM). Furthermore, in patients with T2DM, hypomagnesemia is associated with worst glycaemic control. Bariatric surgery (BS) remains the most effective treatment in severe obesity and also provides resolution/improvement of T2DM. Our aim is to evaluate the association between Mg supplementation post-BS and Mg serum levels with diabetes status after BS.

METHODS

We performed an observational study on patients with obesity and T2DM who underwent BS. Data was assessed pre-BS and one-year post-BS.

RESULTS

We included a total of 403 patients with T2DM. At baseline, 43.4% of the patients had Mg deficiency. Pre-BS, patients with Mg deficiency had poorer glycaemic control - HbA1c 7.2 ± 1.6% vs 6.4 ± 1.0% (p < 0.001), fasting plasma glucose 146.2 ± 58.8 mg/dL vs 117.5 ± 36.6 mg/dL (p < 0.001) and were under a greater number of anti-diabetic drugs 1.0 (IQR 0-2.0) vs 1.0 (IQR 0-1.0) (p = 0.002). These findings persisted at one-year post-BS. At the first-year post-BS, 58.4% of the patients had total remission of T2DM and 4.1% had partial remission. Patients without Mg deficiency at one-year post-BS had higher rates of total and partial remission. Higher serum Mg levels at baseline is an independent predictor of total T2DM remission (p < 0.0001). The optimal cut-off of baseline Mg to predict total T2DM remission was 1.50 mg/dL with a sensitivity of 73% and a specificity of 58% (area under ROC = 0.65). Patients that were under Mg supplementation post-BS had serum Mg values, glycaemic control and total remission of T2DM similar to patients non-supplemented.

CONCLUSION

In patients with T2DM submitted to BS, higher Mg serum levels at baseline and 1-year after BS were associated with better glycaemic control and higher rates of total T2DM remission at the first year post-BS.

The Role of Nutrition on Meta-inflammation: Insights and Potential Targets in Communicable and Chronic Disease Management

PURPOSE OF REVIEW

Chronic low-grade inflammation may contribute to the onset and progression of communicable and chronic diseases. This review examined the effects and eventual mediation roles of different nutritional factors on inflammation.

RECENT FINDINGS

Potential nutritional compounds influencing inflammation processes include macro and micronutrients, bioactive molecules (polyphenols), specific food components, and culinary ingredients as well as standardized dietary patterns, eating habits, and chrononutrition features. Therefore, research in this field is still required, taking into account critical aspects of heterogeneity including type of population, minimum and maximum intakes and adverse effects, cooking methods, physiopathological status, and times of intervention. Moreover, the integrative analysis of traditional variables (age, sex, metabolic profile, clinical history, body phenotype, habitual dietary intake, physical activity levels, and lifestyle) together with individualized issues (genetic background, epigenetic signatures, microbiota composition, gene expression profiles, and metabolomic fingerprints) may contribute to the knowledge and prescription of more personalized treatments aimed to improving the precision medical management of inflammation as well as the design of anti-inflammatory diets in chronic and communicable diseases.

Nutrigenomic Interventions to Address Metabolic Stress and Related Disorders in Transition Cows

For dairy cattle, the period involving a shift from late pregnancy to early lactation termed transition or periparturient is an excruciating phase. Health-related disorders are likely to happen in this time frame. Timely postpartum and metabolic adjustments to this new physical state demands correct management strategies to fulfill the cow's needs for a successful transition to this phase. Among the management strategies, one of the most researched methods for managing transition-related stress is nutritional supplementation. Dietary components directly or indirectly affect the expression of various genes that are believed to be involved in various stress-related responses during this phase. Nutrigenomics, an interdisciplinary approach that combines nutritional science with omics technologies, opens new avenues for studying the genome's complicated interactions with food. This revolutionary technique emphasizes the importance of food-gene interactions on various physiological and metabolic mechanisms. In animal sciences, nutrigenomics aims to promote the welfare of livestock animals and enhance their commercially important qualities through nutritional interventions. To this end, an increasing volume of research shows that nutritional supplementation can be effectively used to manage the metabolic stress dairy cows undergo during the transition period. These nutritional supplements, including polyunsaturated fatty acids, vitamins, dietary amino acids, and phytochemicals, have been shown to modulate energy homeostasis through different pathways, leading to addressing metabolic issues in transition cows.

The Effect of Oral Magnesium Supplementation on Inflammatory Biomarkers in Adults: A Comprehensive Systematic Review and Dose-response Meta-analysis of Randomized Clinical Trials

This is a comprehensive systematic review and dose-response meta-analysis evaluating the effects of oral magnesium supplementation on inflammatory biomarkers including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) among adults. The major databases including PubMed, Web of Science, Embase, and Google Scholar were searched for relevant publications until December 14, 2020, using appropriate keywords. The Cochrane Collaboration tool was used to assess the quality of each study. We also performed a subgroup analysis to identify probable sources of heterogeneity. A total of 18 studies with 927 participants fulfilled the eligibility criteria and included in this meta-analysis. Our results indicate that the supplementation with magnesium had no statistically significant effect on serum concentrations of CRP (WMD, - 0.49; 95% CI, - 1.72 to 0.75 mg/L; P = 0.44), IL-6 (WMD, - 0.03; 95% CI, - 0.40 to 0.33 pg/mL; P = 0.86), and TNF-α (WMD, 0.12; 95% CI, - 0.08 to 0.31 pg/mL; P = 0.24) compared with controls. In addition, based on dose-response assessment, no significant non-linear association was found between magnesium supplementation dosage or duration on serum CRP and IL-6 concentrations. The findings of the present systematic review and meta-analysis did not support the notion that oral magnesium supplementation could have favorable effects on CRP, IL-6, and TNF-α in the adult population.

Effect of Magnesium Supplementation on Inflammatory Parameters: A Meta-Analysis of Randomized Controlled Trials

Magnesium (Mg) may have several beneficial effects on human health outcomes. One hypothesized mechanism eliciting such effects is the action of Mg on serum inflammatory parameters. However, studies on this topic to date have several important limitations. Therefore, the present systematic review and meta-analysis aimed to summarize the current state of the art of all randomized control trials (RCTs) investigating the effects of Mg supplementation versus placebo on serum parameters of inflammation. We searched several databases until 23 November 2021 for RCTs. Eligible studies were RCTs investigating the effect of oral Mg supplementation vs. placebo and having serum inflammatory markers as an outcome. Among 2484 papers initially screened, 17 randomized controlled trials (889 participants; mean age: 46 years; females: 62.5%) were included. Generally, a low risk of bias was present. In meta-analysis, Mg supplementation significantly decreased serum C reactive protein (CRP) and increased nitric oxide (NO) levels. In descriptive findings, Mg supplementation significantly reduced plasma fibrinogen, tartrate-resistant acid phosphatase type 5, tumor necrosis factor-ligand superfamily member 13B, ST2 protein, and IL-1. In conclusion, Mg supplementation may significantly reduce different human inflammatory markers, in particular serum CRP and NO levels.

Oral Magnesium Supplementation for Treating Glucose Metabolism Parameters in People with or at Risk of Diabetes: A Systematic Review and Meta-Analysis of Double-Blind Randomized Controlled Trials

There is a large and growing body of literature focusing on the use of oral magnesium (Mg) supplementation for improving glucose metabolism in people with or at risk of diabetes. We therefore aimed to investigate the effect of oral Mg supplementation on glucose and insulin-sensitivity parameters in participants with diabetes or at high risk of diabetes, compared with a placebo. Several databases were searched investigating the effect of oral Mg supplementation vs placebo in patients with diabetes or conditions at high risk of diabetes. Data were reported as standardized mean differences (SMDs) with their 95% confidence intervals (CIs) using follow-up data of glucose and insulin-sensitivity parameters. Compared with placebo, Mg supplementation reduced fasting plasma glucose in people with diabetes. In people at high risk of diabetes, Mg supplementation significantly improved plasma glucose per se, and after a 2 h oral glucose tolerance test. Furthermore, Mg supplementation demonstrated an improvement in insulin sensitivity markers. In conclusion, Mg supplementation appears to have a beneficial role and improves glucose parameters in people with diabetes. Moreover, our work indicates that Mg supplementation may improve insulin-sensitivity parameters in those at high risk of diabetes.

What Can We Change in Diet and Behaviour in Order to Decrease Carotid Intima-Media Thickness in Patients with Obesity?

Atherosclerosis-considered the major cause of cardiovascular diseases (CVDs)-is strongly associated with obesity, to which it strongly contributes. Moreover, atherosclerosis is characterised by a long asymptomatic phase, and its progression can lead to serious cardiovascular (CV) events. The carotid intima-media thickness (cIMT) has been determined as a predictor of CV events, as well as a marker of subclinical atherosclerosis, and has been used in clinical trials as an alternative assessment method or a surrogate endpoint. It should be noted that several behavioural approaches can directly influence the cIMT values, and decrease or increase the CV risk. In our paper, we aimed to summarize the current knowledge regarding IMT measurement among patients with obesity as a risk group-also in terms of the obesity paradox where the diagnosis of subclinical atherosclerosis is especially essential and implements the early therapeutic approach. We also summarized behavioural, modifiable factors, such as the Mediterranean diet, the Dietary Approach to Stop Hypertension Diets, body weight reduction or the intake of micro- and macronutrients, with a particular focus on the studies where the cIMT values were one of the outcomes. In order to collect the literature data related to the presented topic, the PubMed database was explored.

Blunted PTH response to vitamin D insufficiency/deficiency and colorectal neoplasia risk

BACKGROUND & AIMS

In contrast to many observational studies, large-scale randomized trials do not support the protective role of vitamin D for the prevention of colorectal neoplasia. However, in previous studies, individuals with blunted parathyroid hormone (PTH) response to vitamin D insufficiency/deficiency (BPRVID), were not differentiated from those with high PTH response to vitamin D insufficiency/deficiency (HPRVID). Individuals with BPRVID are responsive to magnesium treatment, particularly treatment of magnesium plus vitamin D while those with HPRVID are responsive to vitamin D treatment. We prospectively compared these two distinct groups (i.e. BPRVID and HPRVID) for risk of incident adenoma, metachronous adenoma, and incident colorectal cancer (CRC) METHODS: Three nested case-control studies in the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) Screening Trial.

RESULTS

We found optimal 25(OH)D levels were associated with a significantly reduced risk of CRC, primarily among women. The associations between 25(OH)D and CRC risk significantly differed by PTH levels, particularly among women. Compared to individuals with optimal levels for both 25(OH)D and PTH, all others were at an elevated risk of incident CRC, primarily in women. We found those with BPRVID had 2.56-fold significantly increased risk of CRC compared to 1.65-fold non-significantly increased risk for those with HPRVID. Among women, we observed those with BPRVID had 4.79-6.25-fold significantly increased risks of incident CRC and adenoma whereas those with HPRVID had 3.65-fold significantly increased risk of CRC.

CONCLUSIONS

Individuals with BPRVID are at higher risks of incident adenoma and CRC compared to those with HPRVID, particularly among women.

Magnesium in Obesity, Metabolic Syndrome, and Type 2 Diabetes

Magnesium (Mg²⁺) deficiency is probably the most underestimated electrolyte imbalance in Western countries. It is frequent in obese patients, subjects with type-2 diabetes and metabolic syndrome, both in adulthood and in childhood. This narrative review aims to offer insights into the pathophysiological mechanisms linking Mg²⁺ deficiency with obesity and the risk of developing metabolic syndrome and type 2 diabetes. Literature highlights critical issues about the treatment of Mg²⁺ deficiency, such as the lack of a clear definition of Mg²⁺ nutritional status, the use of different Mg²⁺ salts and dosage and the different duration of the Mg²⁺ supplementation. Despite the lack of agreement, an appropriate dietary pattern, including the right intake of Mg²⁺, improves metabolic syndrome by reducing blood pressure, hyperglycemia, and hypertriglyceridemia. This occurs through the modulation of gene expression and proteomic profile as well as through a positive influence on the composition of the intestinal microbiota and the metabolism of vitamins B1 and D.

Effect of Magnesium Supplementation on Circulating Biomarkers of Cardiovascular Disease

(1) Background: Magnesium supplementation may be effective for the prevention of cardiometabolic diseases, but the mechanisms are unclear. Proteomic approaches can assist in identifying the underlying mechanisms. (2) Methods: We collected repeated blood samples from 52 individuals enrolled in a double-blind trial which randomized participants 1:1 to oral magnesium supplementation (400 mg magnesium/day in the form of magnesium oxide) or a matching placebo for 10 weeks. Plasma levels of 91 proteins were measured at baseline with follow-up samples using the Olink Cardiovascular Disease III proximity extension assay panel and were modeled as arbitrary units in a log₂ scale. We evaluated the effect of oral magnesium supplementation for changes in protein levels and the baseline association between serum magnesium and protein levels. The Holm procedure was used to adjust for multiple comparisons. (3) Results: Participants were 73% women, 94% white, and had a mean age of 62. Changes in proteins did not significantly differ between the two intervention groups after correction for multiple comparisons. The most statistically significant effects were on myoglobin [difference −0.319 log₂ units, 95% confidence interval (CI) (−0.550, −0.088), p = 0.008], tartrate-resistant acid phosphatase type 5 (−0.187, (−0.328, −0.045), p = 0.011), tumor necrosis factor ligand superfamily member 13B (−0.181, (−0.332, −0.031), p = 0.019), ST2 protein (−0.198, (−0.363, −0.032), p = 0.020), and interleukin-1 receptor type 1 (−0.144, (−0.273, −0.015), p = 0.029). Similarly, none of the associations of baseline serum magnesium with protein levels were significant after correction for multiple comparisons. (4) Conclusions: Although we did not identify statistically significant effects of oral magnesium supplementation in this relatively small study, this study demonstrates the value of proteomic approaches for the investigation of mechanisms underlying the beneficial effects of magnesium supplementation. Clinical Trials Registration: ClinicalTrials.gov NCT02837328.

Association of magnesium consumption with type 2 diabetes and glucose metabolism: A systematic review and pooled study with trial sequential analysis

Prevention of type 2 diabetes (T2D) with diet or diet supplementation is challenging. This article aims to draw conclusive associations between magnesium intake and T2D incidence and evaluate the effect of magnesium supplementation on glucose metabolism. Databases were searched for related articles from inception to May 15, 2019. Prospective cohort studies investigating the relevant relationship as well as randomized controlled trials (RCTs) assessing the effect of magnesium supplementation were eligible. We conducted trial sequential analysis (TSA) to prove the sufficiency of the current evidence. Twenty-six publications involving 35 cohorts were included in the analysis. Compared to the lowest magnesium intake, the highest level was associated with a 22% lower risk for T2D; the risk was reduced by 6% for each 100 mg increment in daily magnesium intake. Additional analysis of 26 RCTs (1168 participants) was performed, revealing that magnesium supplementation significantly reduced the fasting plasma glucose (FPG) level (SMD, -0.32 [95% CI, -0.59 to -0.05], 2-hour oral glucose tolerance test (2-h OGTT) result (SMD, -0.30 [-0.58 to -0.02]), fasting insulin level (SMD, -0.17 [-0.30 to -0.04]), homeostatic model assessment-insulin resistance (HOMA-IR) score (SMD, -0.41 [-0.71 to -0.11]), triglyceride (TG) level, systolic blood pressure (SBP) and diastolic blood pressure (DBP). TSA showed an inverse association, with most benefits of magnesium supplementation on glucose metabolism being stable. In conclusion, magnesium intake has an inverse dose-response association with T2D incidence, and supplementation appears to be advisable in terms of glucose parameters in T2D/high-risk individuals.

The Association between Serum Magnesium Levels and Depression in an Adult Primary Care Population

Depression is common, places a large burden on the patient, their family and community, and is often difficult to treat. Magnesium supplementation is associated with improved depressive symptoms, but because the mechanism is unknown, it is unclear whether serum magnesium levels act as a biological predictor of the treatment outcome. Therefore, we sought to describe the relationship between serum magnesium and the Patient Health Questionnaire (PHQ, a measure of depression) scores. A cross-sectional analysis of medical records from 3604 adults (mean age 62 years; 42% men) seen in primary care clinics between 2015 and 2018, with at least one completed PHQ were included. The relationship between serum magnesium and depression using univariate analyses showed a significant effect when measured by the PHQ-2 (−0.19 points/mg/dL; 95% CI −0.31, −0.07; P = 0.001) and the PHQ-9 (−0.93 points/mg/dL; 95% CI −1.81, −0.06; P = 0.037). This relationship was strengthened after adjusting for covariates (age, gender, race, time between serum magnesium and PHQ tests, and presence of diabetes and chronic kidney disease) (PHQ-2: −0.25 points/mg/dL; 95% CI −3.33, −0.09; P < 0.001 and PHQ-9: −1.09 95% CI −1.96 −0.21; P = 0.015). For adults seen in primary care, lower serum magnesium levels are associated with depressive symptoms, supporting the use of supplemental magnesium as therapy. Serum magnesium may help identify the biological mechanism of depressive symptoms and identify patients likely to respond to magnesium supplementation.

Effects of magnesium citrate, magnesium oxide and magnesium sulfate supplementation on arterial stiffness in healthy overweight individuals: a study protocol for a randomized controlled trial

Background

Arterial stiffness is closely related to the process of atherosclerosis, an independent cardiovascular risk factor, and predictive of future cardiovascular events and mortality. Recently, we showed that magnesium citrate supplementation results in a clinically relevant improvement of arterial stiffness. It remained unclear whether the observed effect was due to magnesium or citrate, and whether other magnesium compounds may have similar effects. Therefore, we aim to study the long-term effects of magnesium citrate, magnesium oxide and magnesium sulfate on arterial stiffness. In addition, we aim to investigate possible underlying mechanisms, including changes in blood pressure and changes in gut microbiota diversity.

Methods

In this randomized, double-blind, placebo-controlled trial, a total of 162 healthy overweight and slightly obese men and women will be recruited. During a 24-week intervention, individuals will be randomized to receive: magnesium citrate; magnesium oxide; magnesium sulfate (total daily dose of magnesium for each active treatment 450 mg); or placebo. The primary outcome of the study is arterial stiffness measured by the carotid–femoral pulse wave velocity (PWV_c–f), which is the gold standard for quantifying arterial stiffness. Secondary outcomes are office blood pressure, measured by a continuous blood pressure monitoring device, and gut microbiota, measured in fecal samples. Measurements will be performed at baseline and at weeks 2, 12 and 24.

Discussion

The present study is expected to provide evidence for the effects of different available magnesium formulations (organic and inorganic) on well-established cardiovascular risk markers, including arterial stiffness and blood pressure, as well as on the human gut microbiota. As such, the study may contribute to the primary prevention of cardiovascular disease in slightly obese, but otherwise healthy, individuals.

Trial registration

ClinicalTrials.gov, NCT03632590. Retrospectively registered on 15 August 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3414-4) contains supplementary material, which is available to authorized users.

The Effects of Choline and Magnesium Co-Supplementation on Metabolic Parameters, Inflammation, and Endothelial Dysfunction in Patients With Type 2 Diabetes Mellitus: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective: To our knowledge, no study has investigated the effects of choline and magnesium co-supplementation on metabolic parameters, inflammation, and endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM). The aim of this study was investigation of the effects of the choline and magnesium co-supplementation on metabolic parameters, inflammation, and endothelial dysfunction in patients with T2DM.Methods: A randomized double-blind placebo-controlled parallel clinical trial was carried out among 96 diabetic patients. Ninety-six patients were randomly assigned to either choline, magnesium, choline-magnesium, or placebo for 2 months. Anthropometric measurement; metabolic, inflammatory, and endothelial markers; dietary intake; and physical activity were assessed at baseline and after treatment.Results: There was a significant change in serum magnesium in both magnesium and choline-magnesium groups (p < 0.05). Also, significant changes were observed in interleukin (IL)-6 levels in magnesium and choline-magnesium groups (p < 0.05). Moreover, vascular cell adhesion molecule-1 (VCAM-1) levels decreased in choline and choline-magnesium groups (p < 0.05). When adjusted for potential confounders, inflammation and endothelial factors (IL-6 and VCAM-1) decreased significantly in the choline-magnesium group as compared to other groups (p < 0.05). Compared to baseline values there were no significant differences in all anthropometric measurements and metabolic factors among four groups (p > 0.05).Conclusions: Choline and magnesium co-supplementation was more effective in improving inflammation and endothelial dysfunction than supplementation with choline or magnesium alone.

Effects of Magnesium Deficiency on Mechanisms of Insulin Resistance in Type 2 Diabetes: Focusing on the Processes of Insulin Secretion and Signaling

Magnesium (Mg²⁺) is an essential mineral for human health and plays an important role in the regulation of glucose homeostasis and insulin actions. Despite the widespread clinical evidences for the association of Mg²⁺ deficiency (MgD) and type 2 diabetes mellitus (T2D), molecular mechanisms by which Mg²⁺ contributes to insulin resistance (IR) are still under discussion. Mg²⁺ regulates electrical activity and insulin secretion in pancreatic beta-cells. Intracellular Mg²⁺ concentrations are critical for the phosphorylation of the insulin receptor and other downstream signal kinases of the target cells. Low Mg²⁺ levels result in a defective tyrosine kinase activity, post-receptor impairment in insulin action, altered cellular glucose transport, and decreased cellular glucose utilization, which promotes peripheral IR in T2D. MgD triggers chronic systemic inflammation that also potentiates IR. People with T2D may end up in a vicious circle in which MgD increases IR and IR causes MgD, that requires periodic monitoring of serum Mg²⁺ levels.

Heart Failure With Preserved Ejection Fraction: Prevention and Management

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome that constitutes nearly half of all heart failure cases. Because of lack of effective pharmacological targets to improve outcomes, the emphasis of the management and prevention of HFpEF should be through control of risk factors. This review will use the framework proposed by the American Heart Association on 7 simple measures ("Life's Simple 7") that involves diet and lifestyle changes to achieve ideal cardiovascular health. These 7 measures include (1) smoking, (2) obesity, (3) exercise, (4) diet, (5) blood pressure, (6) cholesterol, and (7) glucose control, which can help control the most common comorbidities and risk factors associated with HFpEF, such as hypertension, diabetes, and obesity. Therefore, application of these 7 simple measures would be a patient-centered and cost-effective way of prevention and management of HFpEF.

Blood and dietary magnesium levels are not linked with lower prostate cancer risk in black or white men

Recent studies suggest a diet low in dietary magnesium intake or lower blood magnesium levels is linked with increased prostate cancer risk. This study investigates the race-specific link between blood magnesium and calcium levels, or dietary magnesium intake, and the diagnosis of low-grade and high-grade prostate cancer. The study included 637 prostate cancer cases and 715 biopsy-negative controls (50% black) recruited from Nashville, TN or Durham, NC. Blood was collected at the time of recruitment, and dietary intake was assessed by food frequency questionnaire. Percent genetic African ancestry was determined as a compliment to self-reported race. Blood magnesium levels and dietary magnesium intake were significantly lower in black compared to white men. However, magnesium levels or intake were not associated with risk of total prostate cancer or aggressive prostate cancer. Indeed, a higher calcium-to-magnesium diet intake was significantly protective for high-grade prostate cancer in black (OR = 0.66 (0.45, 0.96), p = 0.03) but not white (OR = 1.00 (0.79, 1.26), p = 0.99) men. In summary, there was a statistically significant difference in magnesium intake between black and white men, but the biological impact was unclear, and we did not confirm a lower prostate cancer risk associated with magnesium levels.

Effects of magnesium supplementation on carotid intima-media thickness and metabolic profiles in diabetic haemodialysis patients: a randomised, double-blind, placebo-controlled trial

This study evaluated the effects of Mg administration on carotid intima-media thickness (CIMT), glycaemic control and markers of cardio-metabolic risk in diabetic haemodialysis (HD) patients. This randomised, double-blind, placebo-controlled clinical trial was conducted in fifty-four diabetic HD patients. Participants were randomly divided into two groups to take either 250 mg/d Mg as magnesium oxide (n 27) or placebo (n 27) for 24 weeks. Mg supplementation resulted in a significant reduction in mean (P&lt;0·001) and maximum levels of left CIMT (P=0·02) and mean levels of right CIMT (P=0·004) compared with the placebo. In addition, taking Mg supplements significantly reduced serum insulin levels (β=-9·42 pmol/l; 95% CI -14·94, -3·90; P=0·001), homoeostasis model of assessment-insulin resistance (β=-0·56; 95 % CI -0·89, -0·24; P=0·001) and HbA1c (β=-0·74 %; 95 % CI -1·10, -0·39; P&lt;0·001) and significantly increased the quantitative insulin sensitivity check index (β=0·008; 95 % CI 0·002, 0·01; P=0·002) compared with the placebo. In addition, Mg administration led to a significant reduction in serum total cholesterol (β=-0·30 mmol/l; 95% CI -0·56, -0·04; P=0·02), LDL-cholesterol (β=-0·29 mmol/l; 95% CI -0·52, -0·05; P=0·01), high-sensitivity C-reactive protein (hs-CRP) (P&lt;0·001) and plasma malondialdehyde (MDA) (P=0·04) and a significant rise in plasma total antioxidant capacity (TAC) levels (P&lt;0·001) compared with the placebo. Overall, we found that taking Mg for 24 weeks by diabetic HD patients significantly improved mean and maximum levels of left and mean levels of right CIMT, insulin metabolism, HbA1c, total cholesterol and LDL-cholesterol, hs-CRP, TAC and MDA levels.

The Effects of Oral Magnesium Supplementation on Glycemic Response among Type 2 Diabetes Patients

Background: Magnesium (Mg) supplementation may help control glycemic response among type 2 diabetes (T2D) patients. Objective: This study means to determine whether Mg supplementation improves glycemic control indicators in patients with T2D. Methods: After one week of the dietary stabilization phase, 42 T2D patients were stratified according to sex, age, fasting blood sugar (FBS) and Mg levels and then randomly allocated into two groups. The intervention group was on 250 mg/day of elemental Mg for three months while the control group did not receive any type of supplements throughout the intervention period. Results: The daily administration of 250 mg of elemental Mg indicated a significant improvement in HbA1C (8.32 to 7.96%, p < 0.001), insulin levels (IL) (15.56 to 12.18 μIU/mL, p < 0.001), C-peptide (2.28 to 1.90 ng/mL, p = 0.001), HOMA.IR (6.16 to 4.44, p < 0.001) and HOMA.β% (59.99 to 52.37, p = 0.036) of the intervention group when compared with the control group after three months of intervention. Conclusion: The results of this study revealed that oral Mg supplementation reduces insulin resistance and improves the glycemic control indicators among T2D patients. Trial registration: current controlled trials PHRC/HC/32/15. Registered 5 October 2015.

Challenges in the Diagnosis of Magnesium Status

Magnesium is a critical mineral in the human body and is involved in ~80% of known metabolic functions. It is currently estimated that 60% of adults do not achieve the average dietary intake (ADI) and 45% of Americans are magnesium deficient, a condition associated with disease states like hypertension, diabetes, and neurological disorders, to name a few. Magnesium deficiency can be attributed to common dietary practices, medications, and farming techniques, along with estimates that the mineral content of vegetables has declined by as much as 80⁻90% in the last 100 years. However, despite this mineral's importance, it is poorly understood from several standpoints, not the least of which is its unique mechanism of absorption and sensitive compartmental handling in the body, making the determination of magnesium status difficult. The reliance on several popular sample assays has contributed to a great deal of confusion in the literature. This review will discuss causes of magnesium deficiency, absorption, handling, and compartmentalization in the body, highlighting the challenges this creates in determining magnesium status in both clinical and research settings.

Severely low serum magnesium is associated with increased risks of positive anti-thyroglobulin antibody and hypothyroidism: A cross-sectional study

Trace elements, such as iodine and selenium, are closely related to autoimmune thyroiditis and thyroid function. Low serum magnesium is associated with several chronic diseases; however, its associations with autoimmune thyroiditis and thyroid function are unclear. We investigated the relationships between low serum magnesium, autoimmune thyroiditis, and thyroid function in 1,257 Chinese participants. Demographic data were collected via questionnaires, and levels of serum thyroid stimulating hormone, anti-thyroid peroxidase antibody, anti-thyroglobulin antibody (TGAb), free thyroxine, serum magnesium, serum iodine, and urinary iodine concentration were measured. Participants were divided into serum magnesium level quartiles (≤0.55, 0.551-0.85, 0.851-1.15, and >1.15 mmol/L). The median serum magnesium level was 0.89 (0.73-1.06) mmol/L; levels ≤0.55 mmol/L were considered severely low (5.9% of participants). The risks of TGAb positivity and Hashimoto thyroiditis (HT) diagnosed using ultrasonography in the lowest quartile group were higher than those in the adequate magnesium group (0.851-1.15 mmol/L) (p < 0.01, odds ratios [ORs] = 2.748-3.236). The risks of total and subclinical-only hypothyroidism in the lowest quartile group were higher than those in the adequate magnesium group (0.851-1.15 mmol/L) (p < 0.01, ORs = 4.482-4.971). Severely low serum magnesium levels are associated with an increased rate of TGAb positivity, HT, and hypothyroidism.

Effect of magnesium supplements on serum C-reactive protein: a systematic review and meta-analysis

INTRODUCTION

The aim of the study was to undertake a systematic review and meta-analysis of prospective studies to determine the effect of magnesium (Mg) supplementation on C-reactive protein (CRP). Design: Systematic review and meta-analysis of randomised controlled trials (RCTs).

MATERIAL AND METHODS

Data sources: PubMed-Medline, Web of Science, Cochrane Database, and Google Scholar databases were searched (up until December 2016). Eligibility criteria: Randomized controlled trials evaluating the impact of Mg supplementation on CRP. We used random effects models meta-analysis for quantitative data synthesis. For sensitivity analysis was used the leave-one-out method. Heterogeneity was quantitatively assessed using the I² index. Main outcome: Level of CRP after Mg supplementation.

RESULTS

From a total of 96 entries identified via searches, eight studies were included in the final selection. The meta-analysis indicated a significant reduction in serum CRP concentrations following Mg supplementation (weighted mean difference (WMD) -1.33 mg/l; 95% CI: -2.63 to -0.02, heterogeneity p < 0.123; I² = 29.1%). The WMD for interleukin 6 was -0.16 pg/dl (95% CI: -3.52 to 3.26, heterogeneity p = 0.802; I² = 2.3%), and 0.61 mg/dl (95% CI: -2.72 to 1.48, p = 0.182, heterogeneity p = 0.742; I² = 6.1%) for fasting blood glucose. These findings were robust in sensitivity analyses. Random-effects meta-regression revealed that changes in serum CRP levels were independent of the dosage of Mg supplementation (slope: -0.004; 95% CI: -0.03, 0.02; p = 0.720) or duration of follow-up (slope: -0.06; 95% CI: -0.37, 0.24; p = 0.681).

CONCLUSIONS

This meta-analysis suggests that Mg supplementation significantly reduces serum CRP level. RCTs with a larger sample size and a longer follow-up period should be considered for future investigations to give an unequivocal answer.

Magnesium Replacement Improves the Metabolic Profile in Obese and Pre-Diabetic Patients with Mild-to-Moderate Chronic Kidney Disease: A 3-Month, Randomised, Double-Blind, Placebo-Controlled Study

BACKGROUND/AIMS

Magnesium is an essential mineral for many metabolic functions. There is very little information on the effect of magnesium supplementation on metabolic profiles of chronic kidney disease (CKD) patients. The aim of this study was to assess the influence of magnesium supplementation on metabolic profiles of pre-diabetic, obese and mild-to-moderate CKD patients with hypomagnesemia.

METHODS

A total of 128 hypomagnesemic, pre-diabetic and obese patients with an estimated glomerular filtration rate between 90 and 30 ml/min/1.73m2 were enrolled in a randomised, double-blind, placebo-controlled trial. Patients in the magnesium group received 365 mg of oral magnesium (n = 57) once daily for 3 months, while patients in the control group received a placebo (n = 61), also once daily for 3 months. Hypomagnesemia is defined by a serum magnesium level <1.8 mg/dl in males and <1.9 mg/dl in females; obesity is defined as a body mass index ≥30 kg/m2; and pre-diabetes is defined as fasting plasma glucose ≥100 but <126 mg/dl. The primary end point of the study was the change in insulin resistance measured by the homeostastic model assessment for insulin resistance (HOMA-IR).

RESULTS

At the end of follow-up, insulin resistance (-24.5 vs. -8.2%, P = 0.007), HOMA-IR index (-31.9 vs. -3.3%, P < 0.001), hemoglobin A1c (-6.6 vs. -0.16%, P < 0.001), insulin (-29.6 vs. -2.66%, P < 0.001), waist circumference (-4.8 vs. 0.55%, P < 0.001) and uric acid (-0.8 vs. 2.2%, P = 0.004) were significantly decreased in terms of mean changes; albumin (0.91 vs. -2.91%, P = 0.007) and magnesium (0.21 ± 0.18 vs. -0.04 ± 0.05 mg/dl, P < 0.001) were significantly increased in those taking magnesium compared with a placebo. The decrease in metabolic syndrome (-10.5 vs. -4.9%, P = 0.183), obesity (-15.7 vs. -8.2%, P = 0.131), pre-diabetes (-17.5 vs. -9.8%, P = 0.140), and systolic (-5.0 ± 14.8 vs. 0.22 ± 14.9 mm Hg, P = 0.053) and diastolic (-3.07 ± 9.7 vs. 0.07 ± 9.6 mm Hg, P = 0.071) blood pressure did not achieve to a significant level after study.

CONCLUSION

Our data support the argument that magnesium supplementation improves the metabolic status in hypomagnesemic CKD patients with pre-diabetes and obesity.

Magnesium deficiency and increased inflammation: current perspectives

Animal studies have shown that magnesium deficiency induces an inflammatory response that results in leukocyte and macrophage activation, release of inflammatory cytokines and acute-phase proteins, and excessive production of free radicals. Animal and in vitro studies indicate that the primary mechanism through which magnesium deficiency has this effect is through increasing cellular Ca²⁺, which is the signal that results in the priming of cells to give the inflammatory response. Primary pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-1; the messenger cytokine IL-6; cytokine responders E-selectin, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1; and acute-phase reactants C-reactive protein and fibrinogen have been determined to associate magnesium deficiency with chronic low-grade inflammation (inflammatory stress). When magnesium dietary intake, supplementation, and/or serum concentration suggest/s the presence of magnesium deficiency, it often is associated with low-grade inflammation and/or with pathological conditions for which inflammatory stress is considered a risk factor. When magnesium intake, supplementation, and/or serum concentration suggest/s an adequate status, magnesium generally has not been found to significantly affect markers of chronic low-grade inflammation or chronic disease. The consistency of these findings can be modified by other nutritional and metabolic factors that affect inflammatory and oxidative stress. In spite of this, findings to date provide convincing evidence that magnesium deficiency is a significant contributor to chronic low-grade inflammation that is a risk factor for a variety of pathological conditions such as cardiovascular disease, hypertension, and diabetes. Because magnesium deficiency commonly occurs in countries where foods rich in magnesium are not consumed in recommended amounts, magnesium should be considered an element of significant nutritional concern for health and well-being in these countries.

Genome-Wide Meta-Analysis Unravels Interactions between Magnesium Homeostasis and Metabolic Phenotypes

Magnesium (Mg²⁺) homeostasis is critical for metabolism. However, the genetic determinants of the renal handling of Mg²⁺, which is crucial for Mg²⁺ homeostasis, and the potential influence on metabolic traits in the general population are unknown. We obtained plasma and urine parameters from 9099 individuals from seven cohorts, and conducted a genome-wide meta-analysis of Mg²⁺ homeostasis. We identified two loci associated with urinary magnesium (uMg), rs3824347 (P=4.4×10^-13) near TRPM6, which encodes an epithelial Mg²⁺ channel, and rs35929 (P=2.1×10^-11), a variant of ARL15, which encodes a GTP-binding protein. Together, these loci account for 2.3% of the variation in 24-hour uMg excretion. In human kidney cells, ARL15 regulated TRPM6-mediated currents. In zebrafish, dietary Mg²⁺ regulated the expression of the highly conserved ARL15 ortholog arl15b, and arl15b knockdown resulted in renal Mg²⁺ wasting and metabolic disturbances. Finally, ARL15 rs35929 modified the association of uMg with fasting insulin and fat mass in a general population. In conclusion, this combined observational and experimental approach uncovered a gene-environment interaction linking Mg²⁺ deficiency to insulin resistance and obesity.

Association of Plasma Magnesium with Prediabetes and Type 2 Diabetes Mellitus in Adults

Our study aimed to assess the associations of plasma magnesium with prediabetes and type 2 diabetes (T2D) among Chinese adults. We conducted a case-control analysis of 4447 participants: 867 newly diagnosed prediabetes patients, 1475 newly diagnosed T2D patients and 2105 normal glucose tolerance (NGT) individuals. In a subsample of 599 apparently healthy individuals, we measured plasma hs-CRP levels to examine their relation to plasma magnesium. Plasma magnesium and hs-CRP were measured by inductively coupled plasma mass spectrometry and an enzyme-linked immunosorbent assay, respectively. Plasma magnesium decreased from NGT to prediabetes to T2D, and was inversely associated with prediabetes and T2D. After adjustment for potential confounding factors, the ORs from the lowest to highest quartiles of plasma magnesium were 1, 0.57 (95%CI, 0.44–0.74), 0.49 (0.37–0.65) and 0.51 (0.37–0.70) for prediabetes, and 1, 0.26 (0.20–0.33), 0.15 (0.12–0.20) and 0.15 (0.11–0.20) for T2D. Consistently, plasma magnesium was inversely correlated with plasma hs-CRP in our subsample analysis; the geometric mean hs-CRP concentration for ascending quartiles of plasma magnesium were 1.29 (1.06–1.57), 1.16 (0.95–1.41), 1.00 (0.81–1.22), and 0.71 (0.58–0.88) mg/l. Plasma magnesium was independently and inversely associated with prediabetes and T2D in Chinese adults.

Oral magnesium supplementation improves endothelial function and attenuates subclinical atherosclerosis in thiazide-treated hypertensive women

BACKGROUND

Epidemiological studies demonstrate an inverse association between serum magnesium and incidence of cardiovascular disease. Diuretics commonly cause hypomagneseamia.

METHOD

We evaluated effects of magnesium supplementation on blood pressure (BP) and vascular function in thiazide-treated hypertensive women in a randomized, double-blind, clinical trial. Hypertensive women (40-65 years) on hydrochlorothiazide and mean 24-h BP at least 130/80 mmHg were divided into placebo and supplementation (magnesium chelate 600 mg/day) groups. Patients were evaluated for nutritional and biochemical parameters, office and ambulatory blood pressure monitoring, brachial flow-mediated dilatation (FMD), peripheral arterial tonometry, assessment of carotid intima-media thickness, central hemodynamic parameters and pulse wave velocity at inclusion and after 6-month follow-up.

RESULTS

The magnesium group had a significant reduction in SBP (144 ± 17 vs. 134 ± 14 mmHg, P = 0.036) and DBP (88 ± 9 vs. 81 ± 8 mmHg, P = 0.005) at 6 months, without effect on plasma glucose, lipids, or arterial stiffness parameters. The placebo group showed a significant increase in carotid intima-media thickness (0.78 ± 0.13 vs. 0.89 ± 0.14 mm, P = 0.033) without change in the magnesium group (0.79 ± 0.16 vs. 0.79 ± 0.19 mm, P = 0.716) after 6 months. The magnesium group demonstrated a significant increase in variation of FMD vs. the placebo group (+3.7 ± 2.1 vs. 2.4 ± 1.2%, P = 0.015). There was a significant correlation between the intracellular magnesium variation and FMD (r = 0.44, P = 0.011).

CONCLUSION

Magnesium supplementation was associated with better BP control, improved endothelial function and amelioration of subclinical atherosclerosis in these thiazide-treated hypertensive women.

Effect of magnesium supplementation on type 2 diabetes associated cardiovascular risk factors: a systematic review and meta-analysis

BACKGROUND

Cardiovascular disorders remain the leading cause of death in type 2 diabetic patients. In the present study, a systematic review and a meta-analysis of randomised controlled trials (RCTs) were conducted aiming to evaluate the effect of magnesium supplementation on type 2 diabetes (T2D) associated cardiovascular risk factors in both diabetic and nondiabetic individuals.

METHODS

PubMed, Scopus, Cochrane, Web of Science and Google Scholar databases were searched from inception to 30 June 2016 aiming to identify RCTs evaluating the effect of magnesium supplementation on T2D associated cardiovascular risk factors. The data were analysed using a random effect model with inverse variance methodology. Sensitivity analysis, risk of bias analysis, subgroup analysis, meta-regression and publication bias analysis were also conducted for the included studies using standard methods.

RESULTS

Following magnesium supplementation, a significant improvement was observed in fasting plasma glucose (FPG) [weighted mean difference (WMD) = -4.641 mg dL-1 , 95% confidence interval (CI) = -7.602, -1.680, P = 0.002], high-density lipoprotein (HDL) (WMD = 3.197 mg dL-1 , 95% CI = 1.455, 4.938, P < 0.001), low-density lipoprotein (LDL) (WMD = -10.668 mg dL-1 , 95% CI = -19.108, -2.228, P = 0.013), plasma triglycerides (TG) (WMD = -15.323 mg dL-1 , 95% CI = -28.821, -1.826, P = 0.026) and systolic blood pressure (SBP) (WMD = -3.056 mmHg, 95% CI = -5.509, -0.603, P = 0.015). During subgroup analysis, a more beneficial effect of magnesium supplementation was observed in diabetic subjects with hypomagnesaemia.

CONCLUSIONS

Magnesium supplementation can produce a favourable effect on FPG, HDL, LDL, TG and SBP. Therefore, magnesium supplementation may decrease the risk T2D associated cardiovascular diseases, although future large RCTs are needed for making robust guidelines for clinical practice.

Dietary magnesium intake and risk of incident coronary heart disease in men: A prospective cohort study

BACKGROUND & AIMS

The associations between dietary magnesium intake and stroke and coronary heart disease (CHD) incidences are inconsistent and not established in Asian. We aimed to determine the association between dietary magnesium intake and the risk of stroke and CHD in a Japanese population.

SUBJECTS/METHODS

We studied 85,293 Japanese subjects by questionnaire at baseline (age 45-74 years, without cardiovascular disease or cancer in 1995 and 1998 for Cohorts I and II, respectively). The participants were followed until the end of 2009 and 2010 in Cohorts I and II, respectively. Dietary magnesium intake was estimated from a self-administered 138-item food-frequency questionnaire.

RESULTS

After 1,305,738 person-years of follow-up, 4110 strokes and 1283 cases of CHD were documented. The multivariable-adjusted hazard ratios (HRs, 95% confidence intervals, 95%CIs) of CHD for the fourth and fifth quintiles of dietary magnesium intake were 0.70 (0.50-0.99) and 0.66 (0.44-0.97) in men (P for trend = 0.036), respectively, and third quintile of dietary magnesium intake was 0.61 (0.39-0.96) in women (P for trend = 0.241), compared with the lowest quintile in men and women. We observed no decreased risks of incident stroke in men or women with higher dietary magnesium intakes.

CONCLUSIONS

Higher dietary magnesium intake was associated with a reduced risk of CHD in Japanese men.

Role of magnesium supplementation in the treatment of depression: A randomized clinical trial

Current treatment options for depression are limited by efficacy, cost, availability, side effects, and acceptability to patients. Several studies have looked at the association between magnesium and depression, yet its role in symptom management is unclear. The objective of this trial was to test whether supplementation with over-the-counter magnesium chloride improves symptoms of depression. An open-label, blocked, randomized, cross-over trial was carried out in outpatient primary care clinics on 126 adults (mean age 52; 38% male) diagnosed with and currently experiencing mild-to-moderate symptoms with Patient Health Questionnaire-9 (PHQ-9) scores of 5–19. The intervention was 6 weeks of active treatment (248 mg of elemental magnesium per day) compared to 6 weeks of control (no treatment). Assessments of depression symptoms were completed at bi-weekly phone calls. The primary outcome was the net difference in the change in depression symptoms from baseline to the end of each treatment period. Secondary outcomes included changes in anxiety symptoms as well as adherence to the supplement regimen, appearance of adverse effects, and intention to use magnesium supplements in the future. Between June 2015 and May 2016, 112 participants provided analyzable data. Consumption of magnesium chloride for 6 weeks resulted in a clinically significant net improvement in PHQ-9 scores of -6.0 points (CI -7.9, -4.2; P<0.001) and net improvement in Generalized Anxiety Disorders-7 scores of -4.5 points (CI -6.6, -2.4; P<0.001). Average adherence was 83% by pill count. The supplements were well tolerated and 61% of participants reported they would use magnesium in the future. Similar effects were observed regardless of age, gender, baseline severity of depression, baseline magnesium level, or use of antidepressant treatments. Effects were observed within two weeks. Magnesium is effective for mild-to-moderate depression in adults. It works quickly and is well tolerated without the need for close monitoring for toxicity.

Effects of long-term magnesium supplementation on endothelial function and cardiometabolic risk markers: A randomized controlled trial in overweight/obese adults

Long-term magnesium supplementation improves arterial stiffness, a cardiovascular disease risk marker. Effects on endothelial function may be another mechanism whereby increased magnesium intakes affect cardiovascular risk. Therefore, a 24-week, randomized, double-blind, placebo-controlled trial was performed to examine effects of magnesium supplementation on endothelial function and cardiometabolic risk markers. Fifty-two overweight and obese subjects (30 men and 22 women, age 62 ± 6 years) were randomized to receive either three times daily magnesium (total dose: 350 mg) or placebo capsules. Endothelial function was assessed at the start and at the end of the study. Cardiometabolic risk markers were measured at baseline, after 12 weeks, and at week 24. Brachial artery flow-mediated vasodilation did not change following long-term magnesium supplementation (0.49 pp; 95% CI: −0.38 to 1.36 pp; P = 0.26). Changes in reactive hyperemia index, retinal microvascular caliber and plasma markers for microvascular endothelial function (sVCAM-1, sICAM-1 and sE-selectin) were also not different. In addition, no effects on serum lipids, plasma glucose, insulin sensitivity, and low-grade systemic inflammation were observed. In conclusion, a daily magnesium supplement of 350 mg for 24 weeks does not improve endothelial function and cardiometabolic risk markers in overweight and obese middle-aged and elderly adults.

Perspective: The Case for an Evidence-Based Reference Interval for Serum Magnesium: The Time Has Come

The 2015 Dietary Guidelines Advisory Committee indicated that magnesium was a shortfall nutrient that was underconsumed relative to the Estimated Average Requirement (EAR) for many Americans. Approximately 50% of Americans consume less than the EAR for magnesium, and some age groups consume substantially less. A growing body of literature from animal, epidemiologic, and clinical studies has demonstrated a varied pathologic role for magnesium deficiency that includes electrolyte, neurologic, musculoskeletal, and inflammatory disorders; osteoporosis; hypertension; cardiovascular diseases; metabolic syndrome; and diabetes. Studies have also demonstrated that magnesium deficiency is associated with several chronic diseases and that a reduced risk of these diseases is observed with higher magnesium intake or supplementation. Subclinical magnesium deficiency can exist despite the presentation of a normal status as defined within the current serum magnesium reference interval of 0.75-0.95 mmol/L. This reference interval was derived from data from NHANES I (1974), which was based on the distribution of serum magnesium in a normal population rather than clinical outcomes. What is needed is an evidenced-based serum magnesium reference interval that reflects optimal health and the current food environment and population. We present herein data from an array of scientific studies to support the perspective that subclinical deficiencies in magnesium exist, that they contribute to several chronic diseases, and that adopting a revised serum magnesium reference interval would improve clinical care and public health.

Obesity and hypomagnesemia

BACKGROUND

Whether low serum magnesium is an epiphenomenon related with obesity or, whether obesity per se is cause of hypomagnesemia, remains to be clarified.

OBJECTIVE

To examine the relationship between body weight status and hypomagnesemia in apparently healthy subjects.

METHODS

A total of 681 healthy individuals aged 30 to 65years were enrolled in A cross-sectional study. Extreme exercise, chronic diarrhea, alcohol intake, use of diuretics, smoking, oral magnesium supplementation, diabetes, malnutrition, hypertension, liver disease, thyroid disorders, and renal damage were exclusion criteria. Based in the Body Mass Index (BMI), body weight status was defined as follows: normal weight (BMI <25kg/m²); overweight (BMI ≥25<30 BMIkg/m²); and obesity (BMI ≥30kg/m²). Hypomagnesemia was defined by serum magnesium concentration ≤0.74mmol/L. A multiple logistic regression analysis was used to compute the odds ratio (OR) between body weight status (independent variables) and hypomagnesemia (dependent variable).

RESULTS

The multivariate logistic regression analysis showed that dietary magnesium intake (OR 2.11; 95%CI 1.4-5.7) but no obesity (OR 1.53; 95%CI 0.9-2.5), overweight (OR 1.40; 95%CI 0.8-2.4), and normal weight (OR 0.78; 95%CI 0.6-2.09) were associated with hypomagnesemia. A subsequent logistic regression analysis adjusted by body mass index, waist circumference, total body fat, systolic and diastolic blood pressure, and triglycerides levels showed that hyperglycemia (2.19; 95%CI 1.1-7.0) and dietary magnesium intake (2.21; 95%CI 1.1-8.9) remained associated with hypomagnesemia.

CONCLUSIONS

Our results show that body weight status is not associated with hypomagnesemia and that, irrespective of obesity, hyperglycemia is cause of hypomagnesemia in non-diabetic individuals.

Effect of magnesium supplementation on glucose metabolism in people with or at risk of diabetes: a systematic review and meta-analysis of double-blind randomized controlled trials

Although higher dietary intakes of magnesium (Mg) seem to correspond to lower diabetes incidence, research concerning Mg supplementation in people with or at risk of diabetes is limited. Thus, we aimed to investigate the effect of oral Mg supplementation on glucose and insulin-sensitivity parameters in participants with diabetes or at high risk of diabetes compared with placebo. A literature search in PubMed, EMBASE, SCOPUS, Cochrane Central Register of Controlled Trials and Clinicaltrials.gov without language restriction, was undertaken. Eligible studies were randomized controlled trials (RCTs) investigating the effect of oral Mg supplementation vs placebo in patients with diabetes or at high risk of diabetes. Standardized mean differences (SMD) and 95% confidence intervals (CIs) were used for summarizing outcomes with at least two studies; other outcomes were summarized descriptively. Eighteen RCTs (12 in people with diabetes and 6 in people at high risk of diabetes) were included. Compared with placebo (n=334), Mg treatment (n=336) reduced fasting plasma glucose (studies=9; SMD=-0.40; 95% CI: -0.80 to -0.00; I²=77%) in people with diabetes. In conditions in people at high risk of diabetes (Mg: 226; placebo=227 participants), Mg supplementation significantly improved plasma glucose levels after a 2 h oral glucose tolerance test (three studies; SMD=-0.35; 95% CI: -0.62 to -0.07; I²=0%) and demonstrated trend level reductions in HOMA-IR (homeostatic model assessment-insulin resistance; five studies; SMD=-0.57; 95% CI: -1.17 to 0.03; I²=88%). Mg supplementation appears to have a beneficial role and improves glucose parameters in people with diabetes and also improves insulin-sensitivity parameters in those at high risk of diabetes.

Oral Magnesium Treatment Reduces Anemia and Levels of Inflammatory Markers in Experimental Diabetes

Magnesium has been reported to improve glucose utilization in diabetes mellitus. However, information on its effects on anemic and inflammatory markers in diabetes mellitus is limited. This study investigated the effect of oral magnesium (Mg) treatment on some markers of anemia and inflammation in 25 male Wistar rats. Rats (200 ± 15 g) were randomly divided into five groups (n = 5). Group 1 was control (received orally 0.2 mL distilled water daily), group 2 (Diabetic Untreated), group 3 (Diabetic Mg treated-100 mg/kg bw), group 4 (Diabetic Mg treated-250 mg/kg bw), group 5 (Diabetic Insulin treated-1 IU/kg bw). Diabetes was induced with a single dose of alloxan (100 mg/kg intraperitoneal (i.p.)). All treatments were done for 14 days. Anemic and inflammatory markers were investigated on blood samples obtained from each animal using standard laboratory methods. Significant increase (p < 0.05) in total white blood cell (WBC) count was observed in diabetic untreated rats (7.67 ± 0.397 × 10⁹/L) compared to control (5.88 ± 0.25 × 10⁹/L), DMg 100 (5.86 ± 0.74 × 10⁹/L) and DMg 250 (5.06 ± 0.78 × 10⁹/L). Hemoglobin concentration, packed cell volume (PCV) and red blood cell (RBC) count was decreased (p < 0.05) in DU compared to control, DMg 100, and DI rats. Erythrocyte sedimentation rate (ESR) was significantly increased (p < 0.05) in DU compared to control, DMg 100, DMg 250, and DI groups. Fibrinogen level was increased (p < 0.05) in DU rats (0.44 ± 0.02 g/dL) compared to control(0.26 ± 0.02 g/dL). Values obtained in DMg 100 (0.30 ± 0.03 g/dL), DMg 250 (0.22 ± 0.04 g/dL), and DI (0.36 ± 0.02 g/dL) rats were comparable to control (0.26 ± 0.02 g/dL). Total protein, albumin, and globulin levels were decreased in DU rats compared to normal control, DMg 100, DMg 250, and DI rats. In conclusion, anemia and increased hematologic and metabolic inflammatory markers may be associated with untreated diabetes mellitus. Treatment of alloxan-induced diabetic rats with magnesium improved the anemic state and reduced hematologic and metabolic inflammatory markers.

A systematic review and meta-analysis of randomized controlled trials on the effects of magnesium supplementation on insulin sensitivity and glucose control

A systematic review and meta-analysis was conducted to evaluate the effect of oral magnesium supplementation on insulin sensitivity and glucose control in both diabetic and non-diabetic individuals. PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from inception to November 25, 2015) to identify RCTs evaluating the effect of magnesium on insulin sensitivity and glucose control. A random-effects model and generic inverse variance method were used to compensate for the heterogeneity of studies. Publication bias, sensitivity analysis, and meta-regression assessments were conducted using standard methods. The impact of magnesium supplementation on plasma concentrations of glucose, glycated hemoglobin (HbA1c), insulin, and HOMA-IR index was assessed in 22, 14, 12 and 10 treatment arms, respectively. A significant effect of magnesium supplementation was observed on HOMA-IR index (WMD: -0.67, 95% CI: -1.20, -0.14, p=0.013) but not on plasma glucose (WMD: -0.20mmol/L, 95% CI: -0.45, 0.05, p=0.119), HbA1c (WMD: 0.018mmol/L, 95% CI: -0.10, 0.13, p=0.756), and insulin (WMD: -2.22mmol/L, 95% CI: -9.62, 5.17, p=0.556). A subgroup analysis comparing magnesium supplementation durations of <4 months versus ≥4 months, exhibited a significant difference for fasting glucose concentrations (p<0.001) and HOMA-IR (p=0.001) in favor of the latter subgroup. Magnesium supplementation for ≥4 months significantly improves the HOMA-IR index and fasting glucose, in both diabetic and non-diabetic subjects. The present findings suggest that magnesium may be a beneficial supplement in glucose metabolic disorders.

Long-term magnesium supplementation improves arterial stiffness in overweight and obese adults: results of a randomized, double-blind, placebo-controlled intervention trial

BACKGROUND

Epidemiologic studies have suggested a protective effect of magnesium intake on cardiovascular disease risk. However, intervention trials of magnesium supplementation on blood pressure and conventional cardiometabolic risk markers are inconsistent. Effects on vascular function markers related to cardiovascular disease risk have rarely been studied.

OBJECTIVE

The objective was to evaluate the effects of long-term magnesium supplementation on arterial stiffness.

DESIGN

We performed a 24-wk, randomized, double-blind, placebo-controlled intervention study. Fifty-two overweight and slightly obese individuals (30 men and 22 postmenopausal women, mean ± SD age: 62 ± 6 y) were randomly allocated to receive either 3 times daily magnesium (3 × 117 mg or 350 mg/d) or placebo capsules. Twenty-four-hour urine collections and 24-h ambulatory blood pressure assessments were performed at the start and end of the study. Carotid-to-femoral pulse wave velocity (PWVc-f) was assessed at baseline, after 12 wk, and at week 24.

RESULTS

Serum magnesium concentrations did not differ after 12 wk but tended to increase after 24-wk magnesium supplementation compared with placebo by 0.02 mmol/L (95% CI: 0.00, 0.04 mmol/L; P = 0.09). Twenty-four-hour urinary magnesium excretion increased by 2.01 mmol (95% CI: 1.22, 2.93 mmol; P < 0.001) at week 24. PWVc-f was not changed after 12 wk (0.0 m/s; 95% CI: -0.6, 0.5 m/s; P = 0.90) but was improved in the magnesium compared with the placebo group by 1.0 m/s (95% CI: 0.4, 1.6 m/s; P = 0.001) after 24 wk. Office and 24-h ambulatory blood pressure levels were not changed. No adverse events were observed.

CONCLUSION

Our data indicate that a daily magnesium supplement of 350 mg for 24 wk in overweight and obese adults reduces arterial stiffness, as estimated by a decrease in PWVc-f, suggesting a potential mechanism by which an increased dietary magnesium intake beneficially affects cardiovascular health. This trial was registered at clinicaltrials.gov as NCT02235805.

An in vivo study on the metabolism and osteogenic activity of bioabsorbable Mg-1Sr alloy

Previous studies indicated that local delivery of strontium effectively increased bone quality and formation around osseointegrating implants. Therefore, implant materials with long-lasting and controllable strontium release are avidly pursued. The central objective of the present study was to investigate the in vivo biocompatibility, metabolism and osteogenic activity of the bioabsorbable Mg-1Sr (wt.%, nominal composition) alloy for bone regeneration. The general corrosion rate of the alloy implant as a femoral fracture fixation device was 0.55±0.03mm·y(-1) (mean value±standard deviation) in New Zealand White rabbits which meet the bone implantation requirements and can be adjusted by material processing methods. All rabbits survived and the histological evaluation showed no abnormal physiology or diseases 16 weeks post-implantation. The degradation process of the alloy did not significantly alter 16 primary indexes of hematology, cardiac damage, inflammation, hepatic functions and metabolic process. Significant increases in peri-implant bone volume and direct bone-to-implant contact (48.3%±15.3% and 15.9%±5.6%, respectively) as well as the expressions of four osteogenesis related genes (runt-related transcription factor 2, alkaline phosphatase, osteocalcin, and collagen, type I, alpha 1) were observed after 16 weeks implantation for the Mg-1Sr group when compared to the pure Mg group. The sound osteogenic properties of the Mg-1Sr alloy by long-lasting and controllable Sr release suggesting a very attractive clinical potential.

STATEMENT OF SIGNIFICANCE

Sr (strontium) has exhibited pronounced effects to reduce the bone fracture risk in osteoporotic patients. Nonetheless, long-lasting local Sr release is hardly achieved by traditional methods like surface treatment. Therefore, a more efficient Sr local delivery platform is in high clinical demand. The stable and adjustable degradation process of Mg alloy makes it an ideal Sr delivery platform. We combine the well-known osteogenic properties of strontium with magnesium to manufacture bioabsorbable Mg-1Sr alloy with stable Sr release based on our previous studies. The in vitro and in vivo results both showed the alloy's suitable degradation rate and biocompatibility, and the sound osteogenic properties and stimulation effect on bone formation suggest its very attractive clinical potential.

Magnesium and disturbances in carbohydrate metabolism

Magnesium is actively involved in a number of metabolic reactions as an important co-factor, with special emphasis on carbohydrate metabolism. After a brief overview of the regulation of intra- and extracellular magnesium, the present review first describes the regulatory role of magnesium in important metabolic pathways involved in energy metabolism and glycaemic control. Next the clinical significance of hypomagnesaemic conditions with regard to the management of glucose in prediabetic stages, such as insulin resistance/impaired glucose tolerance and in type 2 diabetes mellitus are characterized. Cross-sectional as well as longitudinal studies suggest that a reduced dietary magnesium intake serves as a risk factor for the incidence of both impaired glucose regulation and type 2 diabetes. Mechanisms that might be responsible for diabetes-associated hypomagnesaemia are discussed. Furthermore, the role of hypomagnesaemia in the development and progression of chronic diabetic complications are addressed. Finally, the available literature on the effects of magnesium supplementation on glycaemic control parameters during prediabetic conditions (preventive approach) as well as type 2 diabetes mellitus (therapeutic approach) are reviewed systematically. There is considerable evidence that chronic magnesium supplementation may delay the progression from impaired glucose regulation to type 2 diabetes; however, the effects of oral magnesium supplementation as an adjunct therapy for type 2 diabetes are quite heterogeneous with respect to the various measures of glycaemic control. The results of this review suggest a requirement for critical consideration of the pros and cons of magnesium replacement therapy, based on variables such as magnesium status, stage of disease and glycaemic control.

Non-soya legume-based therapeutic lifestyle change diet reduces inflammatory status in diabetic patients: a randomised cross-over clinical trial

The present randomised cross-over clinical trial investigated the effects of two intervention diets (non-soya legume-based therapeutic lifestyle change (TLC) diet v. isoenergetic legume-free TLC diet) on inflammatory biomarkers among type 2 diabetic patients. A group of thirty-one participants (twenty-four women and seven men; weight 74.5 (SD 7.0) kg; age 58.1 (SD 6.0) years) were randomly assigned to one of the two following intervention diets for 8 weeks: legume-free TLC diet or non-soya legume-based TLC diet. The latter diet was the same as the legume-free TLC diet, except that two servings of red meat were replaced with different types of cooked non-soya legumes such as lentils, chickpeas, peas and beans over a period of 3 d per week. The intervention period was followed by a washout period of 4 weeks, after which the groups followed the alternate treatment for 8 weeks. Concentrations of inflammatory markers were measured at baseline and after the intervention periods. Compared with the legume-free TLC diet, the non-soya legume-based TLC diet significantly decreased high-sensitivity C-reactive protein, IL-6 and TNF-α in overweight diabetic patients. The replacement of two servings of red meat by non-soya legumes in the isoenergetic TLC diet for a period of 3 d per week reduced the plasma concentrations of inflammatory markers among overweight diabetic patients, independent of weight change.