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

Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults

In 1997, the US Institute of Medicine (IOM) dietary reference intakes (DRI) Committee established a magnesium (Mg) tolerable upper intake level (UL) for adults of 350 mg/d from supplemental intake alone. Diarrhea was the limiting factor. The safety of oral Mg dietary supplements exceeding the UL is currently in debate. Increasing the UL may result in more Mg supplementation, decreasing the prevalence of undernutrition for this nutrient and thus providing additional protection against numerous chronic diseases. This perspective aims to show that more recent and comprehensive evidence-based data on the occurrence of diarrhea indicate that the Mg UL for adults should be re-evaluated. To update the literature base to re-evaluate setting the Mg UL, a PubMed search was conducted to identify intervention studies published between 1997 and 2022 that used single-ingredient Mg products reporting a priori diarrhea adverse events among adults. The Food and Drug Administration Center for Food Safety and Adverse Event Reporting System (CAERS) was also searched for adverse events caused by Mg supplementation. The PubMed search identified 10 studies, including 5 meta-analyses and 5 randomized controlled trials, that met the search criteria. Seven studies (Mg intakes of 128-1200 mg/d) found no significant differences in diarrhea occurrence between the intervention and control groups. One meta-analysis found only minor differences in gastrointestinal disturbances between groups given placebo versus 520 mg Mg/d, but withdrawals were not significantly different between groups. Another meta-analysis found that 3 of 13 studies (120-973 mg/d) reported diarrhea that led to study withdrawal, but the treatment arm was not specified in 2 studies. The CAERS search, when limited to single-ingredient suspect Mg products, found only 40 attributable cases of gastrointestinal adverse events. Only one-third of these 40 cases noted a complaint of diarrhea. These updated data indicate that doses above the current UL for Mg supplements can be consumed without adverse events.

Microbiota and Metabolites as Factors Influencing Blood Pressure Regulation

The study of microbes has rapidly expanded in recent years due to a surge in our understanding that humans host a plethora of commensal microbes, which reside in their bodies and depending upon their composition, contribute to either normal physiology or pathophysiology. This article provides a general foundation for learning about host-commensal microbial interactions as an emerging area of research. The article is divided into two sections. The first section is dedicated to introducing commensal microbiota and its known effects on the host. The second section is on metabolites, which are biochemicals that the host and the microbes use for bi-directional communication with each other. Together, the sections review what is known about how microbes interact with the host to impact cardiovascular physiology, especially blood pressure regulation. © 2021 American Physiological Society. Compr Physiol 11:1731-1757, 2021.

Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease

Hypomagnesemia is commonly observed in heart failure, diabetes mellitus, hypertension, and cardiovascular diseases. Low serum magnesium (Mg) is a predictor for cardiovascular and all-cause mortality and treating Mg deficiency may help prevent cardiovascular disease. In this review, we discuss the possible mechanisms by which Mg deficiency plays detrimental roles in cardiovascular diseases and review the results of clinical trials of Mg supplementation for heart failure, arrhythmias and other cardiovascular diseases.

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.

Impact of Magnesium L-Lactate on Occurrence of Ventricular Arrhythmias in Patients with Implantable Cardioverter Defibrillators: A Randomized, Placebo-Controlled Trial

Background:

We evaluated the antiarrhythmic efficacy and quality of life (QoL) impact of oral magnesium Llactate on patients with an implantable cardioverter defibrillator (ICD).

Methods:

This prospective, double-blind, placebo-controlled trial randomized 70 patients with an ICD to receive oral magnesium L-lactate 3 tablets twice daily (504mg elemental magnesium daily) or matching placebo for 12 months. Patients were seen at baseline, 12, 24, 36, and 52 weeks. The primary endpoints were the cumulative occurrence of ICD therapy [either shock or anti-tachycardia pacing (ATP)] or QoL between the groups.

Results:

Among the 70 randomized patients with a mean ± SD follow-up of 6.4 ± 4.1 months, 10 patients in the placebo group and 8 in the magnesium group experienced either ICD shock or ATP [HR 0.84, 95% CI 0.33 to 2.12; p=0.706]. Without significant arrhythmia suppression, only minimal effects on QoL were seen. Eighty six percent of all patients had serum intracellular magnesium deficiency.

Conclusion:

In our underpowered trial, patients with ICDs had intracellular magnesium deficiency but oral magnesium Llactate only nonsignificantly reduced the occurrence of ICD therapies and had little impact on HrQoL.