Dietary magnesium deficiency affects gut microbiota and anxiety-like behaviour in C57BL/6N mice

Progress and trends of research on mineral elements for depression

Objective

To explore the research progress and trends on mineral elements and depression.

Methods

After querying the MeSH database and referring to the search rules, the search terms were selected and optimized to obtain the target literature collection. We analyzed the general characteristics of the literature, conducted network clustering and co-occurrence analysis, and carried out a narrative review of crucial literature.

Results

Bipolar disorder was a dominant topic in the retrieved literature, which saw a significant increase in 2010 and 2019-2020. Most studies focused on mineral elements, including lithium, calcium, magnesium, zinc, and copper. The majority of journals and disciplines were in the fields of psychiatry, neuropsychology, neuropharmacology, nutrition, medical informatics, chemistry, and public health. The United States had the highest proportion in terms of paper sources, most-cited articles, high-frequency citations, frontier citations, and high centrality citation. Regarding the influence of academic institutions, the top five were King's College London, the Chinese Academy of Sciences, University of Barcelona, INSERM, and Heidelberg University. Frontier keywords included bipolar disorder, drinking water, (neuro)inflammation, gut microbiota, and systematic analysis. Research on lithium response, magnesium supplementation, and treatment-resistant unipolar depression increased significantly after 2013.

Conclusion

Global adverse events may have indirectly driven the progress in related research. Although the literature from the United States represents an absolute majority, its influence on academic institutions is relatively weaker. Multiple pieces of evidence support the efficacy of lithium in treating bipolar disorder (BD). A series of key discoveries have led to a paradigm shift in research, leading to increasingly detailed studies on the role of magnesium, calcium, zinc, and copper in the treatment of depression. Most studies on mineral elements remain diverse and inconclusive. The potential toxicity and side effects of some elements warrant careful attention.

Feeding gut microbes to nourish the brain: unravelling the diet-microbiota-gut-brain axis

The prevalence of brain disorders, including stress-related neuropsychiatric disorders and conditions with cognitive dysfunction, is rising. Poor dietary habits contribute substantially to this accelerating trend. Conversely, healthy dietary intake supports mood and cognitive performance. Recently, the communication between the microorganisms within the gastrointestinal tract and the brain along the gut-brain axis has gained prominence as a potential tractable target to modulate brain health. The composition and function of the gut microbiota is robustly influenced by dietary factors to alter gut-brain signalling. To reflect this interconnection between diet, gut microbiota and brain functioning, we propose that a diet-microbiota-gut-brain axis exists that underpins health and well-being. In this Review, we provide a comprehensive overview of the interplay between diet and gut microbiota composition and function and the implications for cognition and emotional functioning. Important diet-induced effects on the gut microbiota for the development, prevention and maintenance of neuropsychiatric disorders are described. The diet-microbiota-gut-brain axis represents an uncharted frontier for brain health diagnostics and therapeutics across the lifespan.

Probiotic-driven advancement: Exploring the intricacies of mineral absorption in the human body

The interplay between probiotics and mineral absorption is a topic of growing interest due to its great potential for human well-being. Minerals are vital in various physiological processes, and deficiencies can lead to significant health problems. Probiotics, beneficial microorganisms residing in the gut, have recently gained attention for their ability to modulate mineral absorption and mitigate deficiencies. The aim of the present review is to investigate the intricate connection between probiotics and the absorption of key minerals such as calcium, selenium, zinc, magnesium, and potassium. However, variability in probiotic strains, and dosages, alongside the unique composition of individuals in gut microbiota, pose challenges in establishing universal guidelines. An improved understanding of these mechanisms will enable the development of targeted probiotic interventions to optimize mineral absorption and promote human health.

Host-microbiota interaction in intestinal stem cell homeostasis

Intestinal stem cells (ISCs) play a pivotal role in gut physiology by governing intestinal epithelium renewal through the precise regulation of proliferation and differentiation. The gut microbiota interacts closely with the epithelium through myriad of actions, including immune and metabolic interactions, which translate into tight connections between microbial activity and ISC function. Given the diverse functions of the gut microbiota in affecting the metabolism of macronutrients and micronutrients, dietary nutrients exert pronounced effects on host-microbiota interactions and, consequently, the ISC fate. Therefore, understanding the intricate host-microbiota interaction in regulating ISC homeostasis is imperative for improving gut health. Here, we review recent advances in understanding host-microbiota immune and metabolic interactions that shape ISC function, such as the role of pattern-recognition receptors and microbial metabolites, including lactate and indole metabolites. Additionally, the diverse regulatory effects of the microbiota on dietary nutrients, including proteins, carbohydrates, vitamins, and minerals (e.g. iron and zinc), are thoroughly explored in relation to their impact on ISCs. Thus, we highlight the multifaceted mechanisms governing host-microbiota interactions in ISC homeostasis. Insights gained from this review provide strategies for the development of dietary or microbiota-based interventions to foster gut health.

Magnesium (Mg2+): Essential Mineral for Neuronal Health: From Cellular Biochemistry to Cognitive Health and Behavior Regulation

Magnesium (Mg2+) is a crucial mineral involved in numerous cellular processes critical for neuronal health and function. This review explores the multifaceted roles of Mg2+, from its biochemical interactions at the cellular level to its impact on cognitive health and behavioral regulation. Mg2+ acts as a cofactor for over 300 enzymatic reactions, including those involved in ATP synthesis, nucleic acid stability, and neurotransmitter release. It regulates ion channels, modulates synaptic plasticity, and maintains the structural integrity of cell membranes, which are essential for proper neuronal signaling and synaptic transmission. Recent studies have highlighted the significance of Mg2+ in neuroprotection, showing its ability to attenuate oxidative stress, reduce inflammation, and mitigate excitotoxicity, thereby safeguarding neuronal health. Furthermore, Mg2+ deficiency has been linked to a range of neuropsychiatric disorders, including depression, anxiety, and cognitive decline. Supplementation with Mg2+, particularly in the form of bioavailable compounds such as Magnesium-L-Threonate (MgLT), Magnesium-Acetyl-Taurate (MgAT), and other Magnesium salts, has shown some promising results in enhancing synaptic density, improving memory function, and alleviating symptoms of mental health disorders. This review highlights significant current findings on the cellular mechanisms by which Mg2+ exerts its neuroprotective effects and evaluates clinical and preclinical evidence supporting its therapeutic potential. By elucidating the comprehensive role of Mg2+ in neuronal health, this review aims to underscore the importance of maintaining optimal Mg2+ levels for cognitive function and behavioral regulation, advocating for further research into Mg2+ supplementation as a viable intervention for neuropsychiatric and neurodegenerative conditions.

Dietary Magnesium Intake Is Inversely Associated With Ulcerative Colitis: A Case-Control Study

Background

Ulcerative colitis (UC) causes long-lasting inflammation and ulcers in the gut. Limited observational data are available linking dietary magnesium intake and UC. In the present study, we aimed to investigate the association between dietary magnesium intake and UC in adults.

Methods

The current population-based case-control study was performed on 109 UC patients and 218 age (±2 years) and sex-matched controls. The diagnosis of UC was made according to the standard criteria by a gastroenterology specialist. Dietary intakes were assessed using a validated self-administrated 106-item dish-based Food Frequency Questionnaire (FFQ). We also used a pretested questionnaire to collect data on potential confounders.

Results

Individuals in the top tertile of magnesium intake were less likely to have UC compared with those in the bottom tertile. A significant inverse relationship was found between dietary magnesium intake and UC (odds ratio [OR]: 0.32, 95% confidence interval [CI]: 0.18-0.59) in the crude model. This relationship was also observed when we took several potential confounding into account (OR: 0.30, 95% CI: 0.14-0.68).

Conclusions

Adherence to a magnesium-rich diet may have a role in preventing UC. However, further studies are needed to confirm our findings.

Combined resistant dextrin and low-dose Mg oxide administration increases short-chain fatty acid and lactic acid production by gut microbiota

The consumption of resistant dextrin improves constipation, while its fermentation and degradation by the intestinal microbiota produce short-chain fatty acids (SCFA) and lactic acid, which have beneficial effects on host metabolism and immunity. Mg oxide (MgO) is an important mineral that is used to treat constipation. Therefore, resistant dextrin and MgO are often administered together to improve constipation. However, limited information is available regarding the effect of this combination on SCFA and lactic acid production. Crl:CD1(ICR) mice were fed a Mg-free diet with 5% resistant dextrin, followed by oral administration of MgO. We collected the cecum contents and measured SCFA and lactic acid levels. Additionally, the human subjects received resistant dextrin and Mg supplements as part of their habitual diet. The results of this study demonstrate that intestinal microbiota cannot promote SCFA and lactic acid production in the absence of Mg. In a mouse model, low doses of MgO promoted the production of SCFA and lactic acid, whereas high doses decreased their production. In humans, the combined consumption of resistant dextrin and Mg supplements increased the production of SCFA and lactic acid. The production of SCFA and lactic acid from dietary fiber may be augmented by the presence of MgO.

Gegen-Qinlian decoction alleviates anxiety-like behaviors in methamphetamine-withdrawn mice by regulating Akkermansia and metabolism in the colon

BACKGROUND

Anxiety is a prominent withdrawal symptom of methamphetamine (Meth) addiction. Recently, the gut microbiota has been regarded as a promising target for modulating anxiety. Gegen-Qinlian decoction (GQD) is a classical Traditional Chinese Medicine applied in interventions of various gut disorders by balancing the gut microbiome. We aim to investigate whether GQD could alleviate Meth withdrawal anxiety through balancing gut microbiota and gut microenvironment.

METHODS

Meth withdrawal anxiety models were established in mice. GQD were intragastric administrated into Meth-withdrawn mice and controls. Gut permeability and inflammatory status were examined in mice. Germ-free (GF) and antibiotics-treated (Abx) mice were used to evaluate the role of gut bacteria in withdrawal anxiety. Gut microbiota was profiled with 16s rRNA sequencing in feces. Metabolomics in colon tissue and in Akkermansia culture medium were performed.

RESULTS

Meth withdrawal enhanced anxiety-like behaviors in wild-type mice, and altered gut permeability, and inflammatory status, while GQD treatment during the withdrawal period efficiently alleviated anxiety-like behaviors and improved gut microenvironment. Next, we found Germ-free (GF) and antibiotics-treated (Abx) mice did not develop anxiety-like behaviors by Meth withdrawal, indicating the essential role of gut bacteria in Meth withdrawal induced anxiety. Then, it was observed that gut microbiota was greatly affected in Meth-withdrawn mice, especially the reduction in Akkermansia. GQD can rescue the gut microbiota and reverse Akkermansia abundance in Meth-withdrawn mice. Meanwhile, GQD can also restore the Meth-impaired Akkermansia growth in vitro. Further, GQD restored several common metabolite levels both in colon in vivo and in Akkermansia in vitro.

CONCLUSIONS

We revealed a novel effect of GQD on Meth withdrawal anxiety and identified its pharmacological target axis as "Akkermansia-Akkermansia metabolites-gut metabolites-gut microenvironment". Our findings indicated that targeting gut bacteria with TCM, such as GQD, might be a promising therapeutic strategy for addiction and related withdrawal symptoms.

Gut microbiota-induced microRNA-206-3p increases anxiety-like behaviors by inhibiting expression of Cited2 and STK39

BACKGROUND

Anxiety disorder is highly prevalent worldwide and represents a chronic and functionally disabling condition, with high levels of psychological stress characterized by cognitive and physiological symptoms. The purpose of this study is to evaluate the clinical significance of gut microbiota regulating microRNA (miR)-206-3p as a biomarker in the anxiety-like behaviors.

METHODS

Initially, bioinformatics analysis was performed to predict the related factors for gut microbiota affecting anxiety-like behaviors. Next, the anxiety-like behaviors in mice were measured by multiple experiments. Western blot analysis, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were utilized to measure the levels of 5-hydroxytryptamine (5-HT), brain derived neurotrophic factor (BDNF), and neutrophil expressed (NE) in brain tissues and serum and cAMP responsive element binding protein 1 (CREB) phosphorylation in brain tissues of germ-free (GF) mice. Dual-luciferase reporter gene assay was employed to verify the relationship between miR-206-3p and Cbp/p300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 2 (Cited2)/serine/threonine kinase 39 (STK39). Ectopic expression and depletion experiments of miR-206-3p were conducted to determine the expression of miR-206-3p and mRNA and protein levels of Cited2, and STK39 in HT22 cells and brain tissues. Finally, transmission electron microscope (TEM) was used to observe the effects of miR-206-3p on hippocampal mitochondria and synapses.

RESULTS

Gut microbiota could elevate miR-206-3p expression in brain tissues to increase the anxiety-like behaviors. GF mice displayed the increased levels of 5-HT, BDNF, and NE in brain tissues and serum and CREB phosphorylation in brain tissues. Cited2/STK39 was identified as the target genes of miR-206-3p. Upregulated miR-206-3p increased anxiety-like behaviors by promoting degeneration of mitochondria and synapses in hippocampus via downregulation of Cited2 and STK39.

CONCLUSIONS

In conclusion, the key findings of the current study demonstrate that gut microbiota aggravated anxiety-like behaviors via the miR-206-3p/Cited2/STK39 axis.

Alteration in Gut Microbiota Associated with Zinc Deficiency in School-Age Children

Zinc deficiency could lead to a dynamic variation in gut microbial composition and function in animals. However, how zinc deficiency affects the gut microbiome in school-age children remains unclear. The purpose of this study was to profile the dynamic shifts in the gut microbiome of school-age children with zinc deficiency, and to determine whether such shifts are associated with dietary intake. A dietary survey, anthropometric measurements, and serum tests were performed on 177 school-age children, and 67 children were selected to explore the gut microbial community using amplicon sequencing. School-age children suffered from poor dietary diversity and insufficient food and nutrient intake, and 32% of them were zinc deficient. The inflammatory cytokines significantly increased in the zinc deficiency (ZD) group compared to that in the control (CK) group (p < 0.05). There was no difference in beta diversity, while the Shannon index was much higher in the ZD group (p < 0.05). At the genus level, Coprobacter, Acetivibrio, Paraprevotella, and Clostridium_XI were more abundant in the ZD group (p < 0.05). A functional predictive analysis showed that the metabolism of xenobiotics by cytochrome P450 was significantly depleted in the ZD group (p < 0.05). In conclusion, gut microbial diversity was affected by zinc deficiency with some specific bacteria highlighted in the ZD group, which may be used as biomarkers for further clinical diagnosis of zinc deficiency.

Magnesium Orotate and the Microbiome-Gut-Brain Axis Modulation: New Approaches in Psychological Comorbidities of Gastrointestinal Functional Disorders

Magnesium orotate has been cited in the medical literature for the past three years as a possible adjuvant in some pediatric and adult gastroenterological disorders associated with dysbiosis. Studies also focus on the possibility of adding magnesium orotate in psychiatric disorders' treatment, such as major depression and anxiety. The most relevant element in these studies is the efficiency of magnesium orotate therapy in cases with both gastroenterological and psychiatric symptoms. This article proposes a literature review, focused on the studies published in the last three years, targeting magnesium orotate treatment and probiotic supplementation in patients with both digestive and psychiatric symptoms. Moreover, this review will compare the efficiency of magnesium orotate and probiotics within both the pediatric and adult communities, focusing on the possibility of gut-brain axis modulation and its involvement in the clinical evolution of these patients.

Antioxidant/anti-inflammatory effect of Mg2+ in coronavirus disease 2019 (COVID-19)

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), characterised by high levels of inflammation and oxidative stress (OS). Oxidative stress induces oxidative damage to lipids, proteins, and DNA, causing tissue damage. Both inflammation and OS contribute to multi-organ failure in severe cases. Magnesium (Mg²⁺ ) regulates many processes, including antioxidant and anti-inflammatory responses, as well as the proper functioning of other micronutrients such as vitamin D. In addition, Mg²⁺ participates as a second signalling messenger in the activation of T cells. Therefore, Mg²⁺ deficiency can cause immunodeficiency, exaggerated acute inflammatory response, decreased antioxidant response, and OS. Supplementation with Mg²⁺ has an anti-inflammatory response by reducing the levels of nuclear factor kappa B (NF-κB), interleukin (IL) -6, and tumor necrosis factor alpha. Furthermore, Mg²⁺ supplementation improves mitochondrial function and increases the antioxidant glutathione (GSH) content, reducing OS. Therefore, Mg²⁺ supplementation is a potential way to reduce inflammation and OS, strengthening the immune system to manage COVID-19. This narrative review will address Mg²⁺ deficiency associated with a worse disease prognosis, Mg²⁺ supplementation as a potent antioxidant and anti-inflammatory therapy during and after COVID-19 disease, and suggest that randomised controlled trials are indicated.

Gut microbiome-micronutrient interaction: The key to controlling the bioavailability of minerals and vitamins?

Micronutrients, namely, vitamins and minerals, are necessary for the proper functioning of the human body, and their deficiencies can have dramatic short- and long-term health consequences. Among the underlying causes, certainly a reduced dietary intake and/or poor absorption in the gastrointestinal tract play a key role in decreasing their bioavailability. Recent evidence from clinical and in vivo studies suggests an increasingly important contribution from the gut microbiome. Commensal microorganisms can in fact regulate the levels of micronutrients, both by intervening in the biosynthetic processes and by modulating their absorption. This short narrative review addresses the pivotal role of the gut microbiome in influencing the bioavailability of vitamins (such as A, B, C, D, E, and K) and minerals (calcium, iron, zinc, magnesium, and phosphorous), as well as the impact of these micronutrients on microbiome composition and functionality. Personalized microbiome-based intervention strategies could therefore constitute an innovative tool to counteract micronutrient deficiencies by modulating the gut microbiome toward an eubiotic configuration capable of satisfying the needs of our organism, while promoting general health.

Dietary Magnesium Alleviates Experimental Murine Colitis through Modulation of Gut Microbiota

Nutritional deficiencies are common in inflammatory bowel diseases (IBD). In patients, magnesium (Mg) deficiency is associated with disease severity, while in murine models, dietary Mg supplementation contributes to restoring mucosal function. Since Mg availability modulates key bacterial functions, including growth and virulence, we investigated whether the beneficial effects of Mg supplementation during colitis might be mediated by gut microbiota. The effects of dietary Mg modulation were assessed in a murine model of dextran sodium sulfate (DSS)-induced colitis by monitoring magnesemia, weight, and fecal consistency. Gut microbiota were analyzed by 16S-rRNA based profiling on fecal samples. Mg supplementation improved microbiota richness in colitic mice, increased abundance of Bifidobacterium and reduced Enterobacteriaceae. KEEG pathway analysis predicted an increase in biosynthetic metabolism, DNA repair and translation pathways during Mg supplementation and in the presence of colitis, while low Mg conditions favored catabolic processes. Thus, dietary Mg supplementation increases bacteria involved in intestinal health and metabolic homeostasis, and reduces bacteria involved in inflammation and associated with human diseases, such as IBD. These findings suggest that Mg supplementation may be a safe and cost-effective strategy to ameliorate disease symptoms and restore a beneficial intestinal flora in IBD patients.

Elevation of brain magnesium with Swiss chard and buckwheat extracts in an animal model of reduced magnesium dietary intake

OBJECTIVES

Inadequate dietary magnesium (Mg) intake is a growing public health concern. Mg is critical for diverse metabolic processes including energy production, macromolecule biosynthesis, and electrolyte homeostasis. Inadequate free Mg²⁺ ion concentration ([Mg²⁺]) in the brain is associated with several neurological and behavioral disorders. Elevating [Mg²⁺]in the brain using oral Mg supplementation has proven to be challenging due to the tight regulation of Mg²⁺ transport to the brain. This study explored the effect of short-term moderate reduction in dietary Mg intake (87% of normal Mg diet for 30 days) on [Mg²⁺] in the cerebrospinal fluid (CSF) ([Mg²⁺]_CSF) and red blood cells (RBCs) ([Mg²⁺]_RBC) in adult male rats. In addition, we investigated the effectiveness of magnesium-rich blend of Swiss chard and buckwheat extracts (SC/BW extract) in increasing brain [Mg²⁺] compared to various Mg salts commonly used as dietary supplements.

METHODS

Animals were assigned to either normal or low Mg diet for 30 - 45 days. Following this, animals maintained on low Mg diet were supplemented with various Mg compounds. [Mg²⁺]_CSF and [Mg²⁺]_RBC were measured at baseline and following Mg administration. Anxiety-like behavior and cognitive function were also evaluated.

RESULTS

The present study showed that a short-term and moderate reduction in Mg dietary intake results in a significant decline in [Mg²⁺]_CSF and [Mg²⁺]_RBC and the emergence of anxiety-like behavior in comparison to animals maintained on normal Mg diet. Supplementation with SC/BW extract significantly elevated [Mg²⁺]_CSF and improved animal performance in the novel object recognition test in comparison with animals maintained on reduced Mg intake and supplemented with various Mg compounds.

DISCUSSION

These observations indicate that brain [Mg²⁺] is more sensitive to a short-term and moderate reduction in Mg dietary intake than previously thought and emphasizes the importance of dietary Mg in replenishing brain Mg²⁺ reserves.

Diet and the Microbiota-Gut-Brain Axis: Sowing the Seeds of Good Mental Health

Over the past decade, the gut microbiota has emerged as a key component in regulating brain processes and behavior. Diet is one of the major factors involved in shaping the gut microbiota composition across the lifespan. However, whether and how diet can affect the brain via its effects on the microbiota is only now beginning to receive attention. Several mechanisms for gut-to-brain communication have been identified, including microbial metabolites, immune, neuronal, and metabolic pathways, some of which could be prone to dietary modulation. Animal studies investigating the potential of nutritional interventions on the microbiota-gut-brain axis have led to advancements in our understanding of the role of diet in this bidirectional communication. In this review, we summarize the current state of the literature triangulating diet, microbiota, and host behavior/brain processes and discuss potential underlying mechanisms. Additionally, determinants of the responsiveness to a dietary intervention and evidence for the microbiota as an underlying modulator of the effect of diet on brain health are outlined. In particular, we emphasize the understudied use of whole-dietary approaches in this endeavor and the need for greater evidence from clinical populations. While promising results are reported, additional data, specifically from clinical cohorts, are required to provide evidence-based recommendations for the development of microbiota-targeted, whole-dietary strategies to improve brain and mental health.

Modulation of Gut Microbiota for the Prevention and Treatment of COVID-19

The gut microbiota is well known to exert multiple benefits on human health including protection from disease causing pathobiont microbes. It has been recognized that healthy intestinal microbiota is of great importance in the pathogenesis of COVID-19. Gut dysbiosis caused by various reasons is associated with severe COVID-19. Therefore, the modulation of gut microbiota and supplementation of commensal bacterial metabolites could reduce the severity of COVID-19. Many approaches have been studied to improve gut microbiota in COVID-19 including probiotics, bacterial metabolites, and prebiotics, as well as nutraceuticals and trace elements. So far, 19 clinical trials for testing the efficacy of probiotics and synbiotics in COVID-19 prevention and treatment are ongoing. In this narrative review, we summarize the effects of various approaches on the prevention and treatment of COVID-19 and discuss associated mechanisms.

Bioaccessibility and Bioavailability of Minerals in Relation to a Healthy Gut Microbiome

Adequate amounts of a wide range of micronutrients are needed by body tissues to maintain health. Dietary intake must be sufficient to meet these micronutrient requirements. Mineral deficiency does not seem to be the result of a physically active life or of athletic training but is more likely to arise from disturbances in the quality and quantity of ingested food. The lack of some minerals in the body appears to be symbolic of the modern era reflecting either the excessive intake of empty calories or a negative energy balance from drastic weight-loss diets. Several animal studies provide convincing evidence for an association between dietary micronutrient availability and microbial composition in the gut. However, the influence of human gut microbiota on the bioaccessibility and bioavailability of trace elements in human food has rarely been studied. Bacteria play a role by effecting mineral bioavailability and bioaccessibility, which are further increased through the fermentation of cereals and the soaking and germination of crops. Moreover, probiotics have a positive effect on iron, calcium, selenium, and zinc in relation to gut microbiome composition and metabolism. The current literature reveals the beneficial effects of bacteria on mineral bioaccessibility and bioavailability in supporting both the human gut microbiome and overall health. This review focuses on interactions between the gut microbiota and several minerals in sport nutrition, as related to a physically active lifestyle.

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.

Diet and depression: exploring the biological mechanisms of action

The field of nutritional psychiatry has generated observational and efficacy data supporting a role for healthy dietary patterns in depression onset and symptom management. To guide future clinical trials and targeted dietary therapies, this review provides an overview of what is currently known regarding underlying mechanisms of action by which diet may influence mental and brain health. The mechanisms of action associating diet with health outcomes are complex, multifaceted, interacting, and not restricted to any one biological pathway. Numerous pathways were identified through which diet could plausibly affect mental health. These include modulation of pathways involved in inflammation, oxidative stress, epigenetics, mitochondrial dysfunction, the gut microbiota, tryptophan-kynurenine metabolism, the HPA axis, neurogenesis and BDNF, epigenetics, and obesity. However, the nascent nature of the nutritional psychiatry field to date means that the existing literature identified in this review is largely comprised of preclinical animal studies. To fully identify and elucidate complex mechanisms of action, intervention studies that assess markers related to these pathways within clinically diagnosed human populations are needed.

The Way to a Human's Brain Goes Through Their Stomach: Dietary Factors in Major Depressive Disorder

Globally, more than 250 million people are affected by depression (major depressive disorder; MDD), a serious and debilitating mental disorder. Currently available treatment options can have substantial side effects and take weeks to be fully effective. Therefore, it is important to find safe alternatives, which act more rapidly and in a larger number of patients. While much research on MDD focuses on chronic stress as a main risk factor, we here make a point of exploring dietary factors as a somewhat overlooked, yet highly promising approach towards novel antidepressant pathways. Deficiencies in various groups of nutrients often occur in patients with mental disorders. These include vitamins, especially members of the B-complex (B6, B9, B12). Moreover, an imbalance of fatty acids, such as omega-3 and omega-6, or an insufficient supply with minerals, including magnesium and zinc, are related to MDD. While some of them are relevant for the synthesis of monoamines, others play a crucial role in inflammation, neuroprotection and the synthesis of growth factors. Evidence suggests that when deficiencies return to normal, changes in mood and behavior can be, at least in some cases, achieved. Furthermore, supplementation with dietary factors (so called "nutraceuticals") may improve MDD symptoms even in the absence of a deficiency. Non-vital dietary factors may affect MDD symptoms as well. For instance, the most commonly consumed psychostimulant caffeine may improve behavioral and molecular markers of MDD. The molecular structure of most dietary factors is well known. Hence, dietary factors may provide important molecular tools to study and potentially help treat MDD symptoms. Within this review, we will discuss the role of dietary factors in MDD risk and symptomology, and critically discuss how they might serve as auxiliary treatments or preventative options for MDD.

Magnesium and inflammation: Advances and perspectives

Magnesium is an essential element of life, involved in the regulation of metabolism and homeostasis of all the tissues. It also regulates immunological functions, acting on the cells of innate and adaptive immune systems. Magnesium deficiency primes phagocytes, enhances granulocyte oxidative burst, activates endothelial cells and increases the levels of cytokines, thus promoting inflammation. Consequently, a low magnesium status, which is often underdiagnosed, potentiates the reactivity to various immune challenges and is implicated in the pathophysiology of many common chronic diseases. Here we summarize recent advances supporting the link between magnesium deficiency, inflammatory responses and diseases, and offer new hints towards a better understanding of the underlying mechanisms.

Effect of Dietary Magnesium Content on Intestinal Microbiota of Rats

Background: Magnesium is a mineral that modulates several physiological processes. However, its relationship with intestinal microbiota has been scarcely studied. Therefore, this study aimed to assess the role of dietary magnesium content to modulate the intestinal microbiota of Wistar male rats. Methods: Rats were randomly assigned one of three diets: a control diet (C-Mg; 1000 mg/kg), a low magnesium content diet (L-Mg; 60 mg/kg), and a high magnesium content diet (H-Mg; 6000 mg/kg), for two weeks. After treatment, fecal samples were collected. Microbiota composition was assessed by sequencing the V3–V4 hypervariable region. Results: The C-Mg and L-Mg groups had more diversity than H-Mg group. CF231, SMB53, Dorea, Lactobacillus and Turibacter were enriched in the L-Mg group. In contrast, the phyla Proteobacteria, Parabacteroides, Butyricimonas, and Victivallis were overrepresented in the H-Mg group. PICRUSt analysis indicated that fecal microbiota of the L-Mg group were encoded with an increased abundance of metabolic pathways involving carbohydrate metabolism and butanoate metabolism. Conclusion: Dietary magnesium supplementation can result in intestinal dysbiosis development in a situation where there is no magnesium deficiency. Conversely, low dietary magnesium consumption is associated with microbiota with a higher capacity to harvest energy from the diet.

Inflammation in Mental Disorders: Is the Microbiota the Missing Link?

Research suggests that inflammation is important in the pathophysiology of mental disorders. In addition, a growing body of evidence has led to the concept of the microbiota-gut-brain axis. To understand the potential interactions, we begin by exploring the liaison between the immune system and mental disorders, then we describe the evidence that the microbiota impact the immune response in the developing brain. Next, we review the literature that has documented microbiome alterations in major mental disorders. We end with a summary of therapeutic applications, ranging from psycho-biotics to immunomodulatory drugs that could affect the microbiota-gut-brain axis, and potential treatments to alleviate the adverse effects of antipsychotics. We conclude that there is promising evidence to support the position that the microbiota plays an important role in the immunological pathophysiology of mental disorders with an emphasis on psychotic disorders and mood disorders. However, more research is needed to elucidate the mechanisms.

Role of Dietary Nutrients in the Modulation of Gut Microbiota: A Narrative Review

Understanding how dietary nutrients modulate the gut microbiome is of great interest for the development of food products and eating patterns for combatting the global burden of non-communicable diseases. In this narrative review we assess scientific studies published from 2005 to 2019 that evaluated the effect of micro- and macro-nutrients on the composition of the gut microbiome using in vitro and in vivo models, and human clinical trials. The clinical evidence for micronutrients is less clear and generally lacking. However, preclinical evidence suggests that red wine- and tea-derived polyphenols and vitamin D can modulate potentially beneficial bacteria. Current research shows consistent clinical evidence that dietary fibers, including arabinoxylans, galacto-oligosaccharides, inulin, and oligofructose, promote a range of beneficial bacteria and suppress potentially detrimental species. The preclinical evidence suggests that both the quantity and type of fat modulate both beneficial and potentially detrimental microbes, as well as the Firmicutes/Bacteroides ratio in the gut. Clinical and preclinical studies suggest that the type and amount of proteins in the diet has substantial and differential effects on the gut microbiota. Further clinical investigation of the effect of micronutrients and macronutrients on the microbiome and metabolome is warranted, along with understanding how this influences host health.

Anthropometry before Day 46 and Growth Velocity before 6 Months of Guatemalan Breastfed Infants Are Associated with Subclinical Mastitis and Milk Cytokines, Minerals, and Trace Elements

BACKGROUND

Subclinical mastitis (SCM) is an inflammatory condition of the mammary gland, but its association with human milk composition and infant growth is not well described.

OBJECTIVES

We investigated whether SCM, milk cytokines, and/or estimated intakes of milk minerals and trace elements were associated with infant anthropometry or growth velocity before 6 mo.

METHODS

Breast milk was collected from Mam-Mayan mothers (n = 114) at both early (2-46 d) and established (4-6 mo) lactation. Concentrations of 9 elements (sodium, potassium, calcium, magnesium, copper, iron, manganese, selenium, zinc) analyzed by inductively-coupled plasma mass spectrometry were used to estimate infants' daily intakes. Concentrations of 4 cytokines were measured. Milk concentrations and infants' estimated elemental intakes and anthropometric measurements during early and established lactation were compared by SCM status. Multiple regression was used to identify factors associated with infant growth attainment (<46 d) for infant weight- (WAZ), length- (LAZ), and head circumference-for-age (HCAZ) and weight-for-length (WLZ) z scores and with growth velocity (expressed as Δ/d) from early to established lactation.

RESULTS

SCM prevalence was higher in early (30%) than established (10%) lactation. Breast milk of SCM mothers had higher cytokine concentrations and higher magnesium in early and higher selenium concentrations in both early and established lactation (Padj < 0.0121). At day 46, regression models showed inverse associations of SCM with WLZ and IL-1β with LAZ (Padj < 0.0150). In contrast, linear growth velocity was positively associated with IL-1β measured in early lactation (Padj < 0.0124), whereas cranial growth velocity was positively associated with IL-8 measured during established lactation ( Padj < 0.0124).

CONCLUSIONS

Despite a high prevalence of inadequate intakes, only infants' intake of milk magnesium during early lactation was associated with linear growth velocity in breastfed infants <6 mo. Evidence shows that SCM, breast-milk cytokines, and infants' estimated intakes of select elements are independently associated with growth attainment and growth velocity during lactation.

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.

Dietary Supplementation with a Magnesium-Rich Marine Mineral Blend Enhances the Diversity of Gastrointestinal Microbiota

Accumulating evidence demonstrates that dietary supplementation with functional food ingredients play a role in systemic and brain health as well as in healthy ageing. Conversely, deficiencies in calcium and magnesium as a result of the increasing prevalence of a high fat/high sugar "Western diet" have been associated with health problems such as obesity, inflammatory bowel diseases, and cardiovascular diseases, as well as metabolic, immune, and psychiatric disorders. It is now recognized that modulating the diversity of gut microbiota, the population of intestinal bacteria, through dietary intervention can significantly impact upon gut health as well as systemic and brain health. In the current study, we show that supplementation with a seaweed and seawater-derived functional food ingredient rich in bioactive calcium and magnesium (0.1% supplementation) as well as 70 other trace elements, significantly enhanced the gut microbial diversity in adult male rats. Given the significant impact of gut microbiota on health, these results position this marine multi-mineral blend (MMB) as a promising digestive-health promoting functional food ingredient.

Dysbiotic drift and biopsychosocial medicine: how the microbiome links personal, public and planetary health

The emerging concept of planetary health emphasizes that the health of human civilization is intricately connected to the health of natural systems within the Earth’s biosphere; here, we focus on the rapidly progressing microbiome science - the microbiota-mental health research in particular - as a way to illustrate the pathways by which exposure to biodiversity supports health. Microbiome science is illuminating the ways in which stress, socioeconomic disadvantage and social polices interact with lifestyle and behaviour to influence the micro and macro-level biodiversity that otherwise mediates health. Although the unfolding microbiome and mental health research is dominated by optimism in biomedical solutions (e.g. probiotics, prebiotics), we focus on the upstream psychosocial and ecological factors implicated in dysbiosis; we connect grand scale biodiversity in the external environment with differences in human-associated microbiota, and, by extension, differences in immune function and mental outlook. We argue that the success of planetary health as a new concept will be strengthened by a more sophisticated understanding of the ways in which individuals develop emotional connections to nature (nature relatedness) and the social policies and practices which facilitate or inhibit the pro-environmental values that otherwise support personal, public and planetary health.

Association between the gut microbiota and mineral metabolism

The aim of this review is to present the most recent scientific evidence of interactions between the intestinal microbiota and minerals, and the effect of this interaction on the health of the host. The Web of Science database from the years 2013-2017 on this topic was reviewed. Numerous in vitro studies have shown that iron significantly affects the intestinal microbiota. However, Bifidobacteriaceae are capable of binding iron in the large intestine, thereby limiting the formation of free radicals synthesized in the presence of iron, and thus reducing the risk of colorectal cancer. Animal studies have revealed that supplementation with probiotics, prebiotics and synbiotics has a significant effect on bone calcium, phosphate and bone metabolism. The dynamic interaction between microbiota and zinc was shown. Human studies have provided evidence of the influence of probiotic bacteria on parathormone, calcium and phosphate levels and thus on bone resorption. Recent studies have produced new information mainly on the impact of the intestinal bacteria on the metabolism of calcium and iron. From a scientific perspective, the most urgent fields that remain to be investigated are the identification of all human gut microbes and new therapies targeting the interaction between intestinal bacteria and minerals. © 2017 Society of Chemical Industry.

Impact of prebiotics on metabolic and behavioral alterations in a mouse model of metabolic syndrome

Mounting evidence shows that the gut microbiota, an important player within the gut-brain communication axis, can affect metabolism, inflammation, brain function and behavior. Interestingly, gut microbiota composition is known to be altered in patients with metabolic syndrome (MetS), who also often display neuropsychiatric symptoms. The use of prebiotics, which beneficially alters the microbiota, may therefore be a promising way to potentially improve physical and mental health in MetS patients. This hypothesis was tested in a mouse model of MetS, namely the obese and type-2 diabetic db/db mice, which display emotional and cognitive alterations associated with changes in gut microbiota composition and hippocampal inflammation compared to their lean db/+ littermates. We assessed the impact of chronic administration (8weeks) of prebiotics (oligofructose) on both metabolic (body weight, food intake, glucose homeostasis) and behavioral (increased anxiety-like behavior and impaired spatial memory) alterations characterizing db/db mice, as well as related neurobiological correlates, with particular attention to neuroinflammatory processes. Prebiotic administration improved excessive food intake and glycemic dysregulations (glucose tolerance and insulin resistance) in db/db mice. This was accompanied by an increase of plasma anti-inflammatory cytokine IL-10 levels and hypothalamic mRNA expression of the anorexigenic cytokine IL-1β, whereas unbalanced mRNA expression of hypothalamic orexigenic (NPY) and anorexigenic (CART, POMC) peptides was unchanged. We also detected signs of improved blood-brain-barrier integrity in the hypothalamus of oligofructose-treated db/db mice (normalized expression of tight junction proteins ZO-1 and occludin). On the contrary, prebiotic administration did not improve behavioral alterations and associated reduction of hippocampal neurogenesis displayed by db/db mice, despite normalization of increased hippocampal IL-6 mRNA expression. Of note, we found a relationship between the effect of treatment on dentate gyrus neurons and spatial memory. These findings may prove valuable for introducing novel approaches to treat some of the comorbidities associated with MetS.

The Effects of Magnesium Supplementation on Subjective Anxiety and Stress-A Systematic Review

BACKGROUND

Anxiety related conditions are the most common affective disorders present in the general population with a lifetime prevalence of over 15%. Magnesium (Mg) status is associated with subjective anxiety, leading to the proposition that Mg supplementation may attenuate anxiety symptoms. This systematic review examines the available evidence for the efficacy of Mg supplementation in the alleviation of subjective measures of anxiety and stress.

METHODS

A systematic search of interventions with Mg alone or in combination (up to 5 additional ingredients) was performed in May 2016. Ovid Medline, PsychInfo, Embase, CINAHL and Cochrane databases were searched using equivalent search terms. A grey literature review of relevant sources was also undertaken.

RESULTS

18 studies were included in the review. All reviewed studies recruited samples based upon an existing vulnerability to anxiety: mildly anxious, premenstrual syndrome (PMS), postpartum status, and hypertension. Four/eight studies in anxious samples, four/seven studies in PMS samples, and one/two studies in hypertensive samples reported positive effects of Mg on subjective anxiety outcomes. Mg had no effect on postpartum anxiety. No study administered a validated measure of subjective stress as an outcome.

CONCLUSIONS

Existing evidence is suggestive of a beneficial effect of Mg on subjective anxiety in anxiety vulnerable samples. However, the quality of the existing evidence is poor. Well-designed randomised controlled trials are required to further confirm the efficacy of Mg supplementation.

The Role of Elements in Anxiety

Elements (bioelements) are necessary factors required for the physiological function of organisms. They are critically involved in fundamental processes of life. Extra- and intracellular message and metabolic pathway factors as well as structural components include one or many elements in their functional structure. Recent years have seen an intensification in terms of knowledge gained about the roles of elements in anxiety disorders. In this chapter we present a review of the most important current data concerning the involvement of zinc, magnesium, copper, lithium, iron, and manganese, and their deficiency, in the pathophysiology and treatment of anxiety.

The Microbiome and Mental Health: Looking Back, Moving Forward with Lessons from Allergic Diseases

Relationships between gastrointestinal viscera and human emotions have been documented by virtually all medical traditions known to date. The focus on this relationship has waxed and waned through the centuries, with noted surges in interest driven by cultural forces. Here we explore some of this history and the emerging trends in experimental and clinical research. In particular, we pay specific attention to how the hygiene hypothesis and emerging research on traditional dietary patterns has helped re-ignite interest in the use of microbes to support mental health. At present, the application of microbes and their structural parts as a means to positively influence mental health is an area filled with promise. However, there are many limitations within this new paradigm shift in neuropsychiatry. Impediments that could block translation of encouraging experimental studies include environmental forces that work toward dysbiosis, perhaps none more important than westernized dietary patterns. On the other hand, it is likely that specific dietary choices may amplify the value of future microbial-based therapeutics. Pre-clinical and clinical research involving microbiota and allergic disorders has predated recent work in psychiatry, an early start that provides valuable lessons. The microbiome is intimately connected to diet, nutrition, and other lifestyle variables; microbial-based psychopharmacology will need to consider this contextual application, otherwise the ceiling of clinical expectations will likely need to be lowered.