High Dietary Magnesium Intake is Significantly and Independently Associated with Higher Insulin Sensitivity in a Mexican-Mestizo Population: A Brief Cross-Sectional Report

Reduced Insulin Resistance Partly Mediated the Association of High Dietary Magnesium Intake with Less Metabolic Syndrome in a Large Chinese Population

PURPOSE

High dietary magnesium intake may reduce insulin resistance (IR) and metabolic syndrome (MetS). The aim of the cross-sectional analysis was to evaluate the association between dietary magnesium intake, IR, and MetS using data from China Health and Nutrition Survey.

METHODS

Dietary magnesium intake was defined as daily dietary magnesium intake divided by body weight. Logistic regression analysis was used to calculate the odds ratio (OR) for IR and the prevalence of MetS across the quartile categories of dietary magnesium intake. In addition, we used the macro PROCESS to perform the mediation analyses.

RESULTS

A total of 8120 participants were included in the final analysis. We found a significant negative association between dietary magnesium intake and IR, the multivariable-adjusted OR for HOMA-IR comparing the highest to the lowest quartile of dietary magnesium intake was 0.435 (95% confidence intervals [CI] 0.376 to 0.502). The prevalence of the MetS was 38.6%, 28.9%, 22.5%, and 16.5% for increasing quartiles of dietary magnesium intake (p <0.001). The mediation model analysis displayed that insulin resistance mediated the effect of dietary magnesium on MetS. The direct effect and indirect effect of dietary magnesium on MetS were found significant, and the calculated percentage of mediation by insulin resistance was 19.6%.

CONCLUSION

Our study demonstrated a significant and independent negative relationship among weight-adjusted dietary magnesium intake, HOMA-IR, and MetS in a large Chinese population. IR partly mediated the relationship between dietary magnesium intake and MetS.

Association between Serum Magnesium and Erythropoietin Responsiveness in Hemodialysis Patients: A Cross-Sectional Study

BACKGROUND/AIMS

As shown in the China Health and Nutrition Survey, serum magnesium is associated with anemia. However, the roles of magnesium in anemia and erythropoietin (EPO) responsiveness remain unclear in maintenance hemodialysis (MHD) patients. This study aims to investigate the level of serum magnesium and its relationship with EPO responsiveness in MHD patients.

METHODS

A total of 307 MHD patients were recruited for this survey. Laboratory data and anthropometrics were collected. EPO responsiveness was evaluated by the erythropoietin resistance index (ERI). The subjects were divided into 3 groups according to serum magnesium concentrations (group A, the lowest tertile; group B, the middle tertiles; and group C, the highest tertile). Multivariate logistic regressions were conducted to evaluate the factors that may be associated with EPO responsiveness.

RESULTS

The mean serum magnesium level was significantly higher than normal levels in MHD patients, while no hypomagnesemia was observed. A multivariate logistic regression model revealed that high-sensitivity C-reactive protein, intact parathyroid hormone, serum albumin, and magnesium levels were correlated with a high ERI. The OR of a high ERI was found to be 2.57 (95% CI 1.330-4.975, p = 0.005) for group A and 1.66 (95% CI 0.878--3.140, p > 0.05) for group B compared with the OR for group C.

CONCLUSION

Serum magnesium levels were higher than normal levels in MHD patients. A high serum magnesium level was correlated with good EPO responsiveness and was therefore suggested to be a protective factor for EPO hyporesponsiveness.

Higher dietary magnesium intake is associated with lower body mass index, waist circumference and serum glucose in Mexican adults

BACKGROUND

Obesity and diabetes mellitus (DM) are public health concerns in Mexico of top-level priority due to their high prevalence and their growth rate in recent decades. The accumulation of adipose tissue leads to an unbalanced release of pro-oxidant factors, which causes cellular damage and favors the development of comorbidities. Recent evidence suggests that oxidative stress also promotes the accumulation of adipose tissue and the development of insulin resistance. The objective of this study is to evaluate the association between usual intake of antioxidant nutrients, specifically vitamins A, C, E and magnesium with body mass index (BMI), waist circumference (WC) and serum glucose concentrations in a representative sample of Mexican adults.

METHODOLOGY

We analyzed data on diet, BMI, WC and serum glucose from the Mexican National Health and Nutrition Survey 2012. Analysis included 20- to 65-year-old adults without a known diagnosis of DM (n = 1573). Dietary information was obtained using the five-step multiple-pass method developed by the United States Department of Agriculture and adapted to the Mexican context. Nutrient usual intake distributions were estimated using the Iowa State University method, through the "Software for Intake Distribution Estimation" (PC-Side) v.1.02. Associations were analyzed using multivariate regression models.

RESULTS

Higher dietary magnesium intake was associated with lower markers of adiposity, so that an increase in 10 mg per 1000 kcal/day of magnesium was associated with an average decrease in BMI of 0.72% (95% CI: -1.36, - 0.08) and 0.49 cm (95% CI: -0.92, - 0.07) of WC. Additionally, in women with normal glucose concentrations, an increase in magnesium intake was associated with an average decrease in serum glucose by 0.59% (95% CI: -1.08, - 0.09).

CONCLUSION

The results suggest that magnesium intake is associated with lower BMI, WC and serum glucose in Mexican population. However, more studies are required to elucidate the nature of this association.

A Higher Fructose Intake Is Associated with Greater Albuminuria in Subjects with Type 2 Diabetes Mellitus

The aim of this single center cross-sectional study was to investigate the association between fructose intake and albuminuria in subjects with type 2 diabetes mellitus (T2DM). This is a single center cross-sectional study. One hundred and forty-three subjects with T2DM were recruited from the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran. The median daily fructose intake was estimated with a prospective food registry during 3 days (2 week-days and one weekend day) and they were divided into low fructose intake (<25 g/day) and high fructose intake (≥ 25 g/day). Complete clinical and biochemical evaluations were performed, including anthropometric variables and a 24-hour urine collection for albuminuria determination. One hundred and thirty-six subjects were analyzed in this study. We found a positive significant association between daily fructose intake and albuminuria (ρ= 0.178, p=0.038) in subjects with type 2 diabetes mellitus. Other variables significantly associated with albuminuria were body mass index (BMI) (ρ= 0.170, p=0.048), mean arterial pressure (MAP) (ρ= 0.280, p=0.001), glycated hemoglobin (A1c) (ρ= 0.197, p=0.022), and triglycerides (ρ= 0.219, p=0.010). After adjustment for confounding variables we found a significant and independent association between fructose intake and albuminuria (β= 13.96, p=0.006). We found a statistically significant higher albuminuria (60.8 [12.8-228.5] versus 232.2 [27.2-1273.0] mg/day, p 0.002), glycated hemoglobin (8.6±1.61 versus 9.6±2.1 %), p= 0.003, and uric acid (6.27±1.8 versus 7.2±1.5 mg/dL), p=0.012, in the group of high fructose intake versus the group with low fructose intake, and a statistically significant lower creatinine clearance (76.5±30.98 mL/min versus 94.9±36.8, p=0.014) in the group with high fructose intake versus the group with low fructose intake. In summary we found that a higher fructose intake is associated with greater albuminuria in subjects with T2DM.