Interrelationship of magnesium and estrogen in cardiovascular and bone disorders, eclampsia, migraine and premenstrual syndrome

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

Association Between Combined Polymetallic Exposure and Osteoporosis

Combined polymetallic exposure may be an influential factor in osteoporosis. This study aimed to explore the association between polymetallic combined exposure and osteoporosis. A total of 2115 participants were included. Plasma concentrations of 22 metals were determined by inductively coupled plasma mass spectrometry. Osteoporosis was defined as a T ≤  - 2.5. The least absolute shrinkage and selection operator (LASSO) regression, binary logistics regression, and Bayesian kernel machine regression (BKMR) model were used to explore the association between plasma metals and osteoporosis. LASSO regression showed that 10 metals were associated with osteoporosis in the total population (magnesium, calcium, manganese, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum) and women (magnesium, calcium, molybdenum, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum), and four metals associated with men (magnesium, cobalt, aluminum, iron). Logistics regression showed that in total population, magnesium (ORQ3 = 0.653, 95% CI = 0.446-0.954) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.569, 95% CI = 1.095-2.248, ORQ4 = 1.616, 95% CI = 1.109-2.354) and cadmium (ORQ4 = 1.989, 95% CI = 1.379-2.870) were positively correlated; in women, magnesium (ORQ3 = 0.579, 95% CI = 0.379-0.883) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.563, 95% CI = 1.051-2.326, ORQ4 = 1.543, 95% CI = 1.024-2.326) and cadmium (ORQ3 = 1.482, 95% CI = 1.003-2.191, ORQ4 = 1.740, 95% CI = 1.167-2.596) were positively correlated. BKMR model showed that combined polymetallic exposure had an overall positive effect on osteoporosis, magnesium was negatively associated with osteoporosis, and cadmium, selenium, and aluminum were positively associated with osteoporosis. Metal mixtures in plasma were associated with osteoporosis risk. Magnesium may reduce the risk of osteoporosis, while cadmium, selenium, and aluminum may increase the risk of osteoporosis. Future studies needed to explore correlations and mechanisms.

Association of dietary mineral mixture with depressive symptoms: A combination of Bayesian approaches

The relationships between mixtures of multiple minerals and depression have not been explored. Therefore, we analyzed the relationship between the mixture of nine dietary minerals [calcium (Ca), phosphorus, magnesium (Mg), iron (Fe), zinc, copper (Cu), sodium, potassium (K), and selenium (Se)] and depressive symptoms in the general population. We screened 20,342 participants from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. We fitted the general linear regression, Bayesian kernel machine regression (BKMR), and Bayesian semiparametric regression models to explore associations and interactions. We obtained the relative importance of dietary minerals by calculating posterior inclusion probabilities (PIPs). The dietary intakes of minerals were obtained using the 24-h dietary recall interview, and depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9). The linear analysis showed that nine minerals were negatively associated with PHQ-9 scores. The BKMR analysis showed a negative association between the dietary mineral mixture and PHQ-9 scores, with Se having the largest PIP at 1.0000, followed by K (0.7784). We also observed potential interactions between Ca and Fe, Se and Fe, and K and Mg. Among them, the interaction of Ca and Fe had the largest PIP of 0.986. In addition, the overall effect was more pronounced in females than males, and Cu's PIP (0.8376) was higher in females. Two sensitivity analyses showed that our results were robust. Our study provides a basis for formulating nutritional intervention programs for depression in the future.

Effects of Ovariectomy and Exercise Training on Mineral Status in a High-Fat Diet-Induced Obesity Rat Model

Osteoporosis is a growing public health issue for an aging society. Previous studies have found both beneficial and detrimental effects of obesity on bone health. The purpose of this study was to investigate the impact of estrogen deficiency and physical activity on bone and blood concentrations of macrominerals (Ca, P, and Mg) and microminerals (Zn, Se, Cu, and Fe) in a high-fat diet-induced obesity rat model. Forty-eight female Wistar rats were divided into six groups: sham-operated and ovariectomized rats that received a standard diet (SD), high-fat diet (HFD), or HFD accompanied by physical exercise. The effect of ovariectomy on bone minerals varied with diet. Ovariectomy significantly decreased femoral Ca and Mg in sedentary rats receiving a SD; femoral Se, Cu, Zn, and Fe in sedentary rats on HFD; and plasma Fe in both sedentary rats on SD and exercising rats on HFD. The interaction of ovariectomy and diet had the strongest impact on Mg and Se concentrations in femur. In ovariectomized rats, HFD showed to have a protective effect on bone mineralization (femoral Ca and Mg), and a negative one on antioxidant microminerals (femoral Se, Cu, and Zn). Physical activity reduced the decline of Se, Cu, Zn, and Fe in the femur of ovariectomized rats on HFD. In the current state of knowledge, it is difficult to suggest if decreased femoral levels of antioxidant microminerals may contribute to the pathophysiology of osteoporosis in obese individuals or just reflect the mineral status in the body.

Mechanisms coupling sodium and magnesium reabsorption in the distal convoluted tubule of the kidney

Hypomagnesaemia is a common feature of renal Na⁺ wasting disorders such as Gitelman and EAST/SeSAME syndrome. These genetic defects specifically affect Na⁺ reabsorption in the distal convoluted tubule, where Mg²⁺ reabsorption is tightly regulated. Apical uptake via TRPM6 Mg²⁺ channels and basolateral Mg²⁺ extrusion via a putative Na⁺ -Mg²⁺ exchanger determines Mg²⁺ reabsorption in the distal convoluted tubule. However, the mechanisms that explain the high incidence of hypomagnesaemia in patients with Na⁺ wasting disorders of the distal convoluted tubule are largely unknown. In this review, we describe three potential mechanisms by which Mg²⁺ reabsorption in the distal convoluted tubule is linked to Na⁺ reabsorption. First, decreased activity of the thiazide-sensitive Na⁺ /Cl^- cotransporter (NCC) results in shortening of the segment, reducing the Mg²⁺ reabsorption capacity. Second, the activity of TRPM6 and NCC are determined by common regulatory pathways. Secondary effects of NCC dysregulation such as hormonal imbalance, therefore, might disturb TRPM6 expression. Third, the basolateral membrane potential, maintained by the K⁺ permeability and Na⁺ -K⁺ -ATPase activity, provides the driving force for Na⁺ and Mg²⁺ extrusion. Depolarisation of the basolateral membrane potential in Na⁺ wasting disorders of the distal convoluted tubule may therefore lead to reduced activity of the putative Na⁺ -Mg²⁺ exchanger SLC41A1. Elucidating the interconnections between Mg²⁺ and Na⁺ transport in the distal convoluted tubule is hampered by the currently available models. Our analysis indicates that the coupling of Na⁺ and Mg²⁺ reabsorption may be multifactorial and that advanced experimental models are required to study the molecular mechanisms.

Relationship between dietary magnesium intake and rheumatoid arthritis in US women: a cross-sectional study

OBJECTIVES

Diet has been shown to be associated with rheumatoid arthritis (RA), and magnesium has been shown to inhibit inflammatory responses, but research on the relationship between dietary magnesium and RA is limited and controversial. In this study, we aimed to explore the non-linear relationship between dietary magnesium intake and RA in US women.

DESIGN

Cross-sectional survey.

SETTING

National Health and Nutrition Examination Survey (NHANES).

PRIMARY AND SECONDARY OUTCOME MEASURES

Non-linear relationship between dietary magnesium intake and prevalence of RA.

PARTICIPANTS

A total of 13 324 women aged 18-80 years (RA n=12 306, non-RA n=1018) were included in this study.

RESULTS

Overall, the absolute risk (AR) of RA was 7.24% in all participants. In the multivariable logistic regression analysis, we found a negative correlation between dietary magnesium intake and RA (OR=0.84, 95% CI 0.75 to 0.95, p=0.006). When we converted dietary magnesium intake into a categorical variable (tertiles), the ARs of the low group, the middle group and the high group were 9%, 7.1% and 4.9%, respectively. We noticed that the ORs between the three groups were not equidistant; then, we detected a U-shaped linking by smooth curve fitting and obtained inflection points at 181 and 446 mg/day. The prevalence of RA decreased when dietary magnesium intake was <181 mg/day (OR=0.7, 95% CI 0.5 to 0.8, p<0.001) and increased when it was >446 mg/day (OR=2.8, 95% CI 1.2 to 6.6, p=0.020), remaining at a minimum when it was between 181 and 446 mg/day (OR=1.0, 95% CI 0.7 to 1.2, p=0.700).

CONCLUSION

There was a U-shaped relationship between dietary magnesium and RA in women, and our study highlights the importance of moderate dietary magnesium intake in possibly exerting a protective role in women with RA.

A systematic review of the interaction and effects generated by antimicrobial metallic substituents in bone tissue engineering

Changes brought about by metal ions and metal nanoparticles within bacterial cells and the damage caused to the cellular membrane upon contact with negatively charged surface components.

Anabolic effects of vitamin D and magnesium in aging bone

Decreased bone mass and an increased risk of bone fractures become more common with age. This condition is often associated with osteoporosis and is caused by an imbalance of bone resorption and new bone formation. Lifestyle factors that affect the risk of osteoporosis include alcohol, diet, hormones, physical activity, and smoking. Calcium and vitamin D are particularly important for the age-related loss of bone density and skeletal muscle mass, but other minerals, such as magnesium, also have an important role. Here, we summarize how optimal magnesium and vitamin D balance improve health outcomes in the elderly, the role of magnesium and vitamin D on bone formation, and the implications of widespread deficiency of these factors in the United States and worldwide, particularly in the elderly population.

Predicting and Testing Bioavailability of Magnesium Supplements

Despite the presumption of the beneficial effects of magnesium supplementation, little is known about the pharmacokinetics of different magnesium formulations. We aimed to investigate the value of two in vitro approaches to predict bioavailability of magnesium and to validate this in subsequent in vivo testing. In vitro assessment of 15 commercially available magnesium formulations was performed by means of a Simulator of the Human Intestinal Microbial Ecosystem (SHIME^®) and by dissolution tests. Two magnesium formulations with contrasting bioavailability prediction from both in vitro tests (best vs. worst) were selected for in vivo testing in 30 subjects. In vivo bioavailability was compared following one acute ingestion by monitoring blood magnesium concentrations up to 6 h following intake. The in vitro tests showed a very wide variation in absorption and dissolution of the 15 magnesium products. In the in vivo testing, a significant different serum magnesium absorption profile was found up to 4 h following supplement ingestion for the two supplements with opposing in vitro test results. Moreover, maximal serum magnesium increase and total area under the curve were significantly different for both supplements (+6.2% vs. +4.6% and 6.87 vs. 0.31 mM.min, respectively). Collectively, poor bioaccessibility and bioavailability in the SHIME model clearly translated into poor dissolution and poor bioavailability in vivo. This provides a valid methodology for the prediction of in vivo bioavailability and effectiveness of micronutrients by specific in vitro approaches.

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.

High Calcium-Magnesium Ratio in Hair Is Associated with Coronary Artery Calcification in Middle-Aged and Elderly Individuals

The interaction between calcium and magnesium as a risk modifier for cardiovascular disease (CVD) has been largely overlooked in previous studies, for the strict regulatory system in blood has been thought to keep such homeostatic interactions under tight control. This study aimed to investigate the association between calcium-magnesium ratio in hair and subclinical coronary artery calcification. Using multiple linear regression analysis, we examined the associations between calcium-magnesium ratio in hair and the coronary calcium score (CCS) in 216 Koreans aged 40 years and above (122 men and 94 women). We found that the calcium-to-magnesium ratio in hair was independently and positively associated with CCS after adjusting for age and sex (regression coefficient 6.051 ± 2.329, P = 0.010). When we assessed the association between the calcium-magnesium ratio and CCS after adjusting for potential cardiovascular risk factors and vascular function modifying drugs, we found that the strength of association with CCS was comparable to before (regression coefficient 5.434 ± 2.523, P = 0.032). Our findings suggest that among middle-aged and elderly Koreans without clinical CVD, the association between coronary artery calcification and hair calcium-magnesium ratio is stronger in those with a higher calcium-magnesium ratio in hair than in those with a lower ratio.

Association between Dietary Magnesium Intake and Hyperuricemia

Objective

To examine the cross-sectional associations between dietary magnesium (Mg) intake and hyperuricemia (HU).

Methods

5168 subjects were included in this study. Dietary intake was assessed using a validated semi-quantitative food frequency questionnaire. Hyperuricemia (HU) was defined as uric acid ≥ 416 μmol/L for male population and ≥ 360 μmol/L for female. A multivariable logistic analysis model was applied to test the associations after adjusting a number of potential confounding factors.

Results

The relative odds of the overall prevalence of HU were decreased by 0.57 times in the fourth quintile of Mg intake (OR 0.57, 95% CI 0.35–0.94) and 0.55 times in the fifth quintile (OR 0.55, 95% CI 0.30–1.01) comparing with the lowest quintile, and P for trend was 0.091. The results of multivariable linear regression also suggested a significant inverse association between serum uric acid and Mg intake (β = -0.028, P = 0.022). For male, the relative odds of HU were decreased by 0.62 times in the third quintile of Mg intake (OR 0.62, 95% CI 0.40–0.97), 0.40 times in the fourth quintile (OR 0.40, 95% CI 0.23–0.72) and 0.35 times in the fifth quintile (OR 0.35, 95% CI 0.17–0.71) comparing with the lowest quintile, and P for trend was 0.006. Multivariable adjusted inverse association was also existed between serum uric acid and Mg intake in male population (β = -0.061, P = 0.002). However, no significant association was observed between dietary Mg intake and HU for female.

Conclusions

The findings of this cross-sectional study indicated that dietary Mg intake is inversely associated with HU, independent of some major confounding factors. In addition, this association remains valid for the male subgroup, but not for the female subgroup.

Level of Evidence

LevelIII, cross-sectional study.

[Fundamental study on effect of high-mineral drinking water for osteogenesis in calciprivia ovariectomized rats]

Since osteoporosis is a major public health problem in Japan, it is important to clarify the effect of high-mineral drinking water consumption on osteogenesis. Therefore, in this study, we investigated the relationship between high-mineral drinking water consumption and osteogenesis in ovariectomized rats that received a low-calcium diet and purified water (PW group) or a low-calcium diet and high-mineral drinking water (CR group). High-mineral drinking water affected the rats' body weight. After 3 months, the bone density of the CR group was higher than that of the PW group (p<0.05). Furthermore, the CR group showed a decrease in the amount of calcium in the bones after 3 months. These results suggest that high-mineral drinking water contributes to the maintenance of bone density and not to the amount of calcium in bone. On the other hand, serum alkaline phosphatase levels in the PW group at 3 months were higher than those in the CR group, which indicates that the blood concentration of calcium in the CR group was maintained. Moreover, the amount of magnesium in the bones and the blood concentration of magnesium in the CR group after 3 months were higher than the corresponding values in the PW group. These results suggest that consumption of high-mineral drinking water could be beneficial for osteogenesis (i.e., for maintaining bone quantity).

Regulation of the epithelial Mg2+ channel TRPM6 by estrogen and the associated repressor protein of estrogen receptor activity (REA)

The maintenance of the Mg(2+) balance of the body is essential for neuromuscular excitability, protein synthesis, nucleic acid stability, and numerous enzymatic systems. The Transient Receptor Potential Melastatin 6 (TRPM6) functions as the gatekeeper of transepithelial Mg(2+) transport. However, the molecular regulation of TRPM6 channel activity remains elusive. Here, we identified the repressor of estrogen receptor activity (REA) as an interacting protein of TRPM6 that binds to the 6(th), 7(th), and 8(th) beta-sheets in its alpha-kinase domain. Importantly, REA and TRPM6 are coexpressed in renal Mg(2+)-transporting distal convoluted tubules (DCT). We demonstrated that REA significantly inhibits TRPM6, but not its closest homologue TRPM7, channel activity. This inhibition occurs in a phosphorylation-dependent manner, since REA has no effect on the TRPM6 phosphotransferase-deficient mutant (K1804R), while it still binds to this mutant. Moreover, activation of protein kinase C by phorbol 12-myristate 13-acetate-PMA potentiated the inhibitory effect of REA on TRPM6 channel activity. Finally, we showed that the interaction between REA and TRPM6 is a dynamic process, as short-term 17beta-estradiol treatment disassociates the binding between these proteins. In agreement with this, 17beta-estradiol treatment significantly stimulates the TRPM6-mediated current in HEK293 cells. These results suggest a rapid pathway for the effect of estrogen on Mg(2+) homeostasis in addition to its transcriptional effect. Together, these data indicate that REA operates as a negative feedback modulator of TRPM6 in the regulation of active Mg(2+) (re)absorption and provides new insight into the molecular mechanism of renal transepithelial Mg(2+) transport.

Changes in serum calcium, magnesium and inorganic phosphorus levels during different phases of the menstrual cycle

BACKGROUND

The menstrual cycle is a complex process involving the interaction of the hypothalamus, the anterior pituitary, the ovaries and the uterus. The hormonal changes occurring during this cyclic process not only affect oocyte maturation and the endometrial and vaginal environments but can also have an effect on a number of other physiological and biochemical phenomena.

AIM AND METHOD

We investigated the changes in serum calcium, magnesium and inorganic phosphorus levels during different phases of the menstrual cycle in fifty healthy young women. We found subtle but significant variations in these levels in the menstrual, follicular and luteal phases.

RESULT

The serum calcium level was highest in the follicular phase whereas the serum magnesium level was lowest in the follicular phase; the serum inorganic phosphorus levels was highest in the menstrual phase.

CONCLUSION

These variations could be due to the impact of the changing estrogen and progesterone secretion on the parathyroid glands.

Impact of seafood and fruit consumption on bone mineral density

OBJECTIVES

Over the past decade, dietary choices and nutrition have proven to be major modulators of bone mineral density (BMD) in men and women. We investigated environmental determinants, specifically dietary habits, of BMD by using multiple regression models in a rural Chinese population.

METHODS

BMDs were measured at the hip and total body in 5848 men and 6207 women, aged 25-64. Dietary and supplemental intakes were assessed by a simple, one-page questionnaire tailored to collect nutritional information from large rural populations. Another questionnaire was used to collect information on the subjects' age, disease history, smoking, alcohol consumption, physical activity as well as women's menstrual status and reproductive history. Multiple regression models were used to assess the relationships among dietary variables and BMD, after adjusting for age, BMI (body mass index), weight, occupation, smoking status, and alcohol consumption.

RESULTS

Increasing seafood consumption was significantly associated with greater BMD in women (p<0.001), especially those consuming more than 250 g per week of seafood. One thousand and three hundred and twenty-four men and 1479 women consumed >250 g of fruit per week. Higher fruit intake was found to be significantly associated with higher BMD in both sexes (p<0.05). High vegetable consumption, however, did not positively impact BMD.

CONCLUSIONS

This study with its large population size has identified preventive measures, as well as some risk factors, involved in bone loss and osteoporosis. Our results highlight the importance of several dietary variables as significant determinants of BMD. It also emphasizes the role of dietary intake in general and shows that specific foods, such as fruits and seafood, can positively impact BMD.

Benefits and risks of sex hormone replacement in postmenopausal women

Because cardiovascular disease (CVD), which is far less common in young women than in men, but increases in prevalence in the postmenopausal years to that of men, estrogen repletion therapy (ERT) or combined hormone replacement therapy (HRT), has been widely used to protect against development of both CVD and osteoporosis, and possibly to delay or prevent cognitive loss or Alzheimer's disease (AD). To test the validity of favorable findings in many small-scale studies, and in clinical practice, a large-scale trial: the Women's Health Initiative (WHI) was undertaken by the National Institutes of Health (NIH), a trial that was prematurely ended because of increased CVD complications, despite some lessening of hip fractures. This paper suggests that the customary high intake of calcium (Ca)-advised to protect against osteoporosis, and the marginal magnesium (Mg) intake in the USA, might well be contributory to the adverse CV effects, that were all thromboembolic in nature. The procoagulant effect of estrogen is intensified by Ca; Mg-which counteracts many steps in the coagulation cascade and inhibits platelet aggregation and adhesion-is commonly consumed in sub-optimal amounts. The high American dietary Ca/Mg ratio might also be contributory to the WHI failure to confirm ERT's favorable mental effects. Discussed are mechanisms by which Mg enhances estrogen's central nervous system protective effects. Mg's improvement of cerebral blood flow, which improves brain metabolism, can also enhance removal of the beta amyloid peptide, accumulation of which is implicated in AD.

Effects of Nutrient and Food Intake on Calcaneous Bone Mass among Healthy Japanese Women in the Predelivery and Postpartum Periods

OBJECTIVE

To clarify the dietary factors affecting change in calcaneous bone mass during the predelivery and postpartum periods in healthy Japanese women.

METHODS

The calcaneous bone mass was measured as the osteo sono-assessment index (OSI) using the quantitative ultrasound method in 76 Japanese women who were pregnant between February and June 2000. These women subsequently experienced normal pregnancy and labor and could be followed until the sixth month after delivery at an obstetrics and gynecology clinic center located in metropolitan Tokyo. After the intraindividual changes in the OSI during the follow-up period were determined, the relationship between the OSI or OSI change from gestation to the postpartum period and the estimates of nutrient and food intake obtained using a 140-item semiquantitative food frequency questionnaire (FFQ) were analyzed using stepwise multiple regression analysis.

RESULTS

Iron intake in gestation was a significant positive correlate with the percentage change in the OSI between week 36 of gestation and day 5 after delivery (p < 0.001) and that between week 36 of gestation and month 6 after delivery (p < 0.001) (partial regression coefficient of energy-adjusted iron intake, beta = 0.493 mg/day and 0.342 mg/day, respectively). Intake of vitamin D and fruits and vegetables during gestation and/or postpartum was positively associated with the OSI change from week 36 of gestation to the postdelivery stage, whereas the OSI change was inversely related to the intake of carotene, sodium chloride, and meat in the gestation or postpartum period.

CONCLUSIONS

Sufficient intake of iron, vitamin D, or fruits and vegetables may be important for the preservation of bone mass after delivery.

The central role of magnesium deficiency in Tourette's syndrome: causal relationships between magnesium deficiency, altered biochemical pathways and symptoms relating to Tourette's syndrome and several reported comorbid conditions

Prior studies have suggested a common etiology involved in Tourette's syndrome and several comorbid conditions and symptomatology. Reportedly, current medications used in Tourette's syndrome have intolerable side-effects or are ineffective for many patients. After thoroughly researching the literature, I hypothesize that magnesium deficiency may be the central precipitating event and common pathway for the subsequent biochemical effects on substance P, kynurenine, NMDA receptors, and vitamin B6 that may result in the symptomatology of Tourette's syndrome and several reported comorbid conditions. These comorbid conditions and symptomatology include allergy, asthma, autism, attention deficit hyperactivity disorder, obsessive compulsive disorder, coprolalia, copropraxia, anxiety, depression, restless leg syndrome, migraine, self-injurious behavior, autoimmunity, rage, bruxism, seizure, heart arrhythmia, heightened sensitivity to sensory stimuli, and an exaggerated startle response. Common possible environmental and genetic factors are discussed, as well as biochemical mechanisms. Clinical studies to determine the medical efficacy for a comprehensive magnesium treatment option for Tourette's syndrome need to be conducted to make this relatively safe, low side-effect treatment option available to doctors and their patients.

Free and total magnesium in lymphocytes of migraine patients - effect of magnesium-rich mineral water intake

Dietary surveys performed in Western countries show magnesium intakes lower than the recommended dietary allowances, suggesting a large prevalence of magnesium deficiency. Low brain magnesium as well as impaired magnesium metabolism have also been reported in various diseases such as migraine. To detect these deficiencies, a non-invasive and sensitive test assessing magnesium status is needed. Because magnesium is an intracellular cation, either total or ionized magnesium (Mg(2+)) of blood cells were suggested as the most adequate tests. Total magnesium levels in plasma, erythrocytes and lymphocytes and Mg(2+) in lymphocytes were analyzed in a group of 29 migraine patients and 18 control subjects. Results show significantly lower concentrations of total magnesium in erythrocytes (50.7+/-4.7 vs. 53.5+/-2.9 mg/l; P<0.01) and of Mg(2+) in lymphocytes (12.0+/-3.5 vs. 14.2+/-3.8 mg/l; P<0.05) in migraine patients as compared to controls. While a significant difference of mean values was noted between migraine patients and controls, an overlap of individual values was observed. These analyses were repeated on migraine patients before and after a 2-week intake of a mineral water containing 110 mg/l magnesium, and a significant increase in all intracellular magnesium concentrations with no effect on plasma magnesium was observed. These increased intracellular magnesium concentrations demonstrate the bioavailability of magnesium from this mineral water. Among the analyzed parameters, Mg(2+) in lymphocytes appears to be the most sensitive index of magnesium deficiency with a 15% decrease in migraine patients when compared to controls and a 16% increase after 2 weeks of a magnesium-rich mineral water intake.

Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women

BACKGROUND

Osteoporosis and related fractures will be growing public health problems as the population ages. It is therefore of great importance to identify modifiable risk factors.

OBJECTIVE

We investigated associations between dietary components contributing to an alkaline environment (dietary potassium, magnesium, and fruit and vegetables) and bone mineral density (BMD) in elderly subjects.

DESIGN

Dietary intake measures were associated with both cross-sectional (baseline) and 4-y longitudinal change in BMD among surviving members of the original cohort of the Framingham Heart Study. Dietary and supplement intakes were assessed by food-frequency questionnaire, and BMD was measured at 3 hip sites and 1 forearm site.

RESULTS

Greater potassium intake was significantly associated with greater BMD at all 4 sites for men and at 3 sites for women (P < 0.05). Magnesium intake was associated with greater BMD at one hip site for both men and women and in the forearm for men. Fruit and vegetable intake was associated with BMD at 3 sites for men and 2 for women. Greater intakes of potassium and magnesium were also each associated with less decline in BMD at 2 hip sites, and greater fruit and vegetable intake was associated with less decline at 1 hip site, in men. There were no significant associations between baseline diet and subsequent bone loss in women.

CONCLUSION

These results support the hypothesis that alkaline-producing dietary components, specifically, potassium, magnesium, and fruit and vegetables, contribute to maintenance of BMD.

Sex steroid hormones modulate serum ionized magnesium and calcium levels throughout the menstrual cycle in women

OBJECTIVE

To determine the serum concentrations of the sex steroid hormones with respect to the concentrations of the biologically active fractions of magnesium and calcium during the different phases of the menstrual cycle.

DESIGN

Controlled clinical study.

SETTING

An academic research environment.

PATIENT(S)

Six parous and four nulliparous healthy cycling female volunteers.

MAIN OUTCOME MEASURE(S)

Concentrations of the sex steroid hormones estrogen, progesterone, and testosterone as well as the ionized Ca and Mg levels were measured in the serum of normal cycling women during five different stages: the menstrual, early follicular, late follicular, ovulatory (ovulatory/early luteal), and luteal phases.

RESULT(S)

In each woman, there was a comparatively high ionized Mg level coincident with the early follicular phase, a statistically significant decrease in ionized Mg around the time of ovulation, a significant decrease in ionized and total Mg when the serum progesterone concentration peaked, and a significant increase in the serum Ca2+/Mg2+ ratio at both the ovulatory and luteal phases. In addition, a decrease in ionized Mg was found with increased testosterone levels.

CONCLUSION(S)

Healthy women of reproductive age demonstrate recurring cycling of ionized Mg and cyclic alterations in the ionized Ca to Mg ratio in their serum. The changes in serum concentrations of these important physiologically active cations, in the range at which they occur, can affect such entities as the vasculature, synaptic transmission, and excitation-secretion coupling and thus can produce the well-known premenstrual syndromes during the luteal phase in women who are somewhat deficient in Mg or in those who have an unusually increased Ca2+/Mg2+ ratio.

Gender-specific correlation of platelet ionized magnesium and serum low-density-lipoprotein cholesterol concentrations in apparently healthy subjects

We previously found an inverse correlation between platelet ionized magnesium concentration ((Mg2+)i) and serum total cholesterol concentration in normal male but not female subjects. In the present study, we determined the platelet (Mg2+)i by using a fluorescent ionized magnesium (Mg2+) indicator, FURAPTRA, and measured the serum concentrations of the following: total cholesterol; very-low-density lipoprotein cholesterol (VLDL-C); low-density lipoprotein cholesterol (LDL-C); high-density lipoprotein cholesterol (HDL-C); antioxidized low-density lipoprotein (LDL) autoantibodies; lipoprotein(a); apolipoproteins A-I (apo A-I) and B (apo B); triglycerides; estradiol-17 (E2); ceruloplasmin (Cp); and selected electrolytes, including total and ionized magnesium and calcium and total protein and albumin. In men, but not in women, platelet (Mg2+)i significantly inversely correlated with serum total cholesterol (r = -0.52, p < 0.02), LDL-C (r = -0.54, p < 0.009 by a "direct" method; r = -0.40, p < 0.05 by an electrophoretic method), and apo B (r = -0.42, p < 0.04). We found no significant correlations between platelet (Mg2+)i and any other variables, including serum total and ionized magnesium, antioxidized LDL autoantibodies, Cp, and E2. We speculate that decreased platelet (Mg2+)i is a possible marker for platelet membrane alterations that may affect platelet involvement in thrombosis and atherogenesis.

Postparturient hypocalcemia of dairy cows: a model for the study of the interdependence of Ca, Pi, and Mg homeostasis

Disorders of calcium, phosphorus and magnesium homeostasis in ruminants provide natural models for the study of the physiology and pathophysiology of these minerals. The knowledge that can be acquired with a better understanding of the pathogenesis of these diseases could give useful clues in the puzzle of human osteoporosis. In the present study, the case of parturient paresis of dairy cows is reexamined with a newly developed technique for the measurements of serum ionized magnesium concentrations (Mg2+). The concentrations of total magnesium (Mgtot), ionized calcium (Ca2+), total calcium (Catot), and inorganic phosphate (Pi) were also determined in the sera of seventeen 3- to 16-year-old Brown Swiss and crossed Simmental/Red Holstein cows during the periparturient period. In each animal, a transient increase of Mg2+ and Mgtot serum concentrations was observed in association with the transient decrease after parturition of Ca2+, Catot and Pi serum concentrations. On average, throughout the study, serum Mg2+ concentrations were 68.5% of those of Mgtot whereas serum Ca2+ concentrations were 52% of those of Catot. The possible mechanisms involved in the transient increase of Mg2+ and Mgtot serum concentrations are discussed and the relevance of this data for osteoporosis is outlined.

Maternal-fetal transfer of ionized serum magnesium during the stress of labor and delivery: a human study

OBJECTIVE

The purpose of this study was to compare levels and fractions of ionized magnesium in maternal venous serum with those in umbilical venous and arterial serum and to determine whether the maternal levels and fractions change during the stress of labor.

METHODS

Utilizing an ion-selective electrode, we determined levels and fractions of ionized magnesium (IMg2+) and levels of ionized calcium (ICa2+) in the maternal venous serum (MVS) of 12 parturients on admission and at the end of labor, as well as in the umbilical venous (UVS) and umbilical arterial serum (UAS) at delivery. A paired-sample study design was used.

RESULTS

Whereas mean levels of ICa2+ did not change significantly (p > 0.05) during labor, the mean (+/- SE) MVS levels of IMg2+ and total magnesium (TMg) fell from 0.50 +/- 0.01 and 0.80 +/- 0.02 mmol/L, respectively, on admission to 0.46 +/- 0.01 and 0.68 +/- 0.01 mmol/L (p < 0.01 and p < 0.001, respectively) at delivery. The ionized fraction, expressed as a percent (IMg2+/TMg x 100), increased from 62.8 +/- 2.1% to 67.8 +/- 1.2% (p < 0.05). In the UVS, the mean IMg2+ level (0.52 +/- 0.02 mmol/L) and the mean ionized fraction (73.6 +/- 1.7%) were higher than in MVS on admission or at delivery (p < 0.05 for all comparisons). The mean IMg2+ level in UAS (0.50 +/- 0.02 mmol/L) was lower than in UVS (p < 0.05), but higher than in MVS at delivery (p < 0.01). Finally, there were significant positive correlations between levels of magnesium (Mg) in MVS and in the UAS or UVS.

CONCLUSIONS

The observation that UAS levels of IMg2+ and TMg were similar to the MVS levels on admission despite the fall in maternal levels during labor points to the presence of homeostatic mechanisms in the fetus and placenta. It is possible that the presence of a higher fraction of unbound, free magnesium in UVS enhances magnesium transport to the fetus and thus homeostasis. Finally, we hypothesize that the fall in the levels of the biologically active form of Mg during labor may be yet another manifestation of the known stress responses to labor.

Ca2+ suppresses cell adhesion to osteopontin by attenuating binding affinity for integrin alpha v beta 3

Osteopontin (OPN) is an extracellular matrix protein that supports osteoclast adhesion to the bone by binding to integrin alpha v beta 3. We measured the binding between OPN and integrin alpha v beta 3 with recombinant human OPN and the urinary form of human OPN, uropontin. Recombinant OPN was expressed in Escherichia coli as a fusion protein with glutathione S-transferase and cleaved from glutathione S-transferase with Factor Xa. The mass of this form of OPN (rOP27) is 27,046 Da. rOP27 is truncated at arginine residue 228, 69 amino acids short of the native carboxyl terminus. Uropontin and rOP27 support RGD-dependent cell adhesion and to bind purified integrin alpha v beta 3 with similar affinities. Further study showed that OPN is the only known naturally occurring RGD-containing protein with a much greater affinity for alpha v beta 3 than for the platelet integrin alpha IIb beta 3. Most importantly, we find that physiologic levels of Ca2+ block cell adhesion to OPN. Measurement of binding constants between rOPN and purified integrin alpha v beta 3 with surface plasmon resonance showed that the affinity between rOPN and alpha v beta 3 is 26-fold lower in Ca2+ (Kd = 1.1 x 10(-8) M) than in Mn2+ (Kd = 4.3 x 10(-10) M) and 9-fold lower than in Mg2+ (Kd = 1.3 x 10(-9) M). In bone, the resorbing osteoclast generates elevated levels of extracellular Ca2+, therefore the findings presented here suggest a previously unappreciated mechanism for the modulation of bone resorption by extracellular Ca2+.

Consequences of magnesium deficiency on the enhancement of stress reactions; preventive and therapeutic implications (a review)

Stress intensifies release of catecholamines and corticosteroids that increase survival of normal animals when their lives are threatened. When magnesium (Mg) deficiency exists, stress paradoxically increases risk of cardiovascular damage including hypertension, cerebrovascular and coronary constriction and occlusion, arrhythmias and sudden cardiac death (SCD). In affluent societies, severe dietary Mg deficiency is uncommon, but dietary imbalances such as high intakes of fat and/or calcium (Ca) can intensify Mg inadequacy, especially under conditions of stress. Adrenergic stimulation of lipolysis can intensify its deficiency by complexing Mg with liberated fatty acids (FA), A low Mg/Ca ratio increases release of catecholamines, which lowers tissue (i.e. myocardial) Mg levels. It also favors excess release or formation of factors (derived both from FA metabolism and the endothelium), that are vasoconstrictive and platelet aggregating; a high Ca/Mg ratio also directly favors blood coagulation, which is also favored by excess fat and its mobilization during adrenergic lipolysis. Auto-oxidation of catecholamines yields free radicals, which explains the enhancement of the protective effect of Mg by anti-oxidant nutrients against cardiac damage caused by beta-catecholamines. Thus, stress, whether physical (i.e. exertion, heat, cold, trauma--accidental or surgical, burns), or emotional (i.e. pain, anxiety, excitement or depression) and dyspnea as in asthma increases need for Mg. Genetic differences in Mg utilization may account for differences in vulnerability to Mg deficiency and differences in body responses to stress.