Improved insulin response and action by chronic magnesium administration in aged NIDDM subjects

Oral magnesium supplementation does not affect insulin sensitivity in people with insulin-treated type 2 diabetes and a low serum magnesium: a randomised controlled trial

AIMS/HYPOTHESIS

Hypomagnesaemia has been associated with insulin resistance and an increased risk of type 2 diabetes. Whether magnesium supplementation improves insulin sensitivity in people with type 2 diabetes and a low serum magnesium level is unknown.

METHODS

Using a randomised, double-blind (both participants and investigators were blinded to the participants' treatment sequences), placebo-controlled, crossover study design, we compared the effect of oral magnesium supplementation (15 mmol/day) for 6 weeks with that of matched placebo in individuals with insulin-treated type 2 diabetes (age ≥18 years, BMI 18-40 kg/m2, HbA1c <100 mmol/mol [11.3%], serum magnesium ≤0.79 mmol/l). Participants were recruited from the outpatient clinic and through advertisements. Randomisation to a treatment sequence order was done using a randomisation list. We used block randomisation and the two possible treatment sequences were evenly distributed among the trial population. The primary outcome was the mean glucose infusion rate during the final 30 min of a hyperinsulinaemic-euglycaemic clamp (i.e. M value). Secondary outcomes included variables of glucose control, insulin need, BP, lipid profile and hypomagnesaemia-related symptoms during follow-up.

RESULTS

We recruited 14 participants (50% women, 100% White, mean ± SD age 67±6 years, BMI 31±5 kg/m2, HbA1c 58±9 mmol/mol [7.4±0.9%]) with insulin-treated type 2 diabetes. Magnesium supplementation increased both mean ± SEM serum magnesium level (0.75±0.02 vs 0.70±0.02 mmol/l, p=0.016) and urinary magnesium excretion (magnesium/creatinine ratio, 0.23±0.02 vs 0.15±0.02, p=0.005), as compared with placebo. The M value of the glucose clamp did not differ between the magnesium and placebo study arms (4.6±0.5 vs 4.4±0.6 mg kg-1 min-1, p=0.108). During the 6 weeks of treatment, continuous glucose monitoring outcomes, HbA1c, insulin dose, lipid profile and BP also did not differ, except for a lower HDL-cholesterol concentration after magnesium compared with placebo (1.14±0.08 vs 1.20±0.09 mmol/l, p=0.026). Symptoms potentially related to hypomagnesaemia were similar for both treatment arms.

CONCLUSIONS/INTERPRETATION

Despite an albeit modest increase in serum magnesium concentration, oral magnesium supplementation does not improve insulin sensitivity in people with insulin-treated type 2 diabetes and low magnesium levels.

TRIAL REGISTRATION

EudraCT number 2021-001243-27.

FUNDING

This study was supported by a grant from the Dutch Diabetes Research Foundation (2017-81-014).

Effects of magnesium supplementation on improving hyperglycemia, hypercholesterolemia, and hypertension in type 2 diabetes: A pooled analysis of 24 randomized controlled trials

Background

Previous studies have demonstrated that diabetes is often accompanied with lower magnesium status. However, practical details regarding the influences of magnesium intervention on hyperglycemia, hypercholesterolemia, and hypertension in type 2 diabetes (T2D) need to be further investigated.

Methods

Web of Science, ScienceDirect, and PubMed were searched for relevant literatures published through April 30, 2022, and high-quality data were pooled to evaluate the effects of magnesium supplementation on glycemic, circulating lipids, and blood pressure control in T2D, and to explore the associated practical details.

Results

Pooled analyses of 24 randomized controlled trials with 1,325 T2D individuals revealed that subjects who received magnesium supplementation had statistically significant reductions in fasting plasma glucose, glycated hemoglobin, systolic blood pressure and diastolic blood pressure, with WMD values of -0.20 mM (95% CI: -0.30, -0.09), -0.22% (95% CI: -0.41, -0.03), -7.69 mmHg (95% CI: -11.71, -3.66) and -2.71 mmHg (95% CI: -4.02, -1.40), respectively. Detailed subgroup analyses demonstrated that health status of participants including age, body mass index, country, duration of disease, baseline magnesium level and baseline glycemic control condition as well as magnesium formulation, dosage and duration of intervention influenced the effects of magnesium addition. Dose-effect analysis showed that 279 mg/d for 116 d, 429 mg/d for 88 d and 300 mg/d for 120 d are the average optimal dosages and durations for improving glycemic, circulating lipids, and blood pressure controls, respectively.

Conclusion

Our findings provide clinically relevant information on the adjuvant therapy of magnesium for improving hyperglycemia, hypercholesterolemia, and hypertension in T2D.

The effects of oral magnesium supplementation on glycaemic control in patients with type 2 diabetes: a systematic review and dose-response meta-analysis of controlled clinical trials

The current systematic review and meta-analysis were conducted to evaluate the effects of oral Mg supplementation on glycaemic control in type 2 diabetes mellitus (T2DM) patients. Related articles were found by searching the PubMed, SCOPUS, Embase and Web of Science databases (from inception to 30 February 2020). A one-stage robust error meta-regression model based on inverse variance weighted least squares regression and cluster robust error variances was used for the dose-response analysis between Mg supplementation and duration of intervention and glycaemic control factors. Eighteen eligible randomised clinical trials were included in our final analysis. The dose-response testing indicated that the estimated mean difference in HbA1c at 500 mg/d was -0·73 % (95 % CI: -1·25, -0·22) suggesting modest improvement in HbA1c with strong evidence (P value: 0·004). And in fasting blood sugar (FBS) at 360 mg/d was -7·11 mg/dl (95 % CI: -14·03, -0·19) suggesting minimal amelioration in FBS with weak evidence (P value: 0·092) against the model hypothesis at this sample size. The estimated mean difference in FBS and HbA1c at 24 weeks was -15·58 mg/dl (95 % CI: -24·67, -6·49) and -0·48 (95 % CI: -0·77, -0·19), respectively, suggesting modest improvement in FBS (P value: 0·034) and HbA1c (P value: 0·001) with strong evidence against the model hypothesis at this sample size. Oral Mg supplementation could have an effect on glycaemic control in T2DM patients. However, the clinical trials so far are not sufficient to make guidelines for clinical practice.

Does the association of therapeutic exercise and supplementation with sucrosomial magnesium improve posture and balance and prevent the risk of new falls?

Background

Fracture of the proximal femur is the most feared complication of osteoporosis. Given the numerous physiological functions that magnesium performs in our body, in the literature there is a correlation between osteoporosis and low serum levels of magnesium.

Aim

Evaluate the incidence of hypomagnesemia in patients with lateral fragility fracture of the proximal femur, the possible correlation between serum magnesium levels and fractures, and the effectiveness of supplementing Sucrosomial^® magnesium associated with therapeutic exercise on the outcome of these patients.

Methods

We divided the study into two parts. In the first part, we assessed the preoperative incidence of hypomagnesemia in patients using a blood test. In the second part, patients with hypomagnesemia were divided, in the post-operative period, into two groups, who received, respectively, only therapeutic exercise or oral supplementation with sucrosomial magnesium associated with therapeutic exercise.

Results

Half of the patients with fragility femoral fracture had hypomagnesemia, with a higher incidence of the subclinical form. From the comparison between the two groups, the T1 treatment group showed a significant improvement in blood levels of magnesium (2.11 ± 0.15 vs. 1.94 ± 0.11; p < 0.05), on the NRS scale (5.7 ± 0.81 vs. 6.6 ± 1.18; p < 0.05), the Tinetti scale (17.3 ± 1.15 vs. 15.2 ± 2.98; p < 0.05) and the SarQoL questionnaire (47.3 ± 5.21 vs. 44.9 ± 5.54; p < 0.05).

Conclusions

More attention would be needed in the diagnosis and correction of subclinical hypomagnesemia and not just the simple and clinically evident one, including hypomagnesemia among the modifiable risk factors for osteoporosis.

Circulating magnesium status is associated with type 2 diabetes remission after Roux-en-Y gastric bypass surgery: a long-term cohort study

BACKGROUND

Low serum magnesium levels predict cardiovascular and all-cause mortality in patients with typ 2 diabetes.

SETTING

Outpatient clinic of obesity and central hospital.

OBJECTIVES

To assess long-term alterations in circulating magnesium status after Roux-en-Y gastric bypass (RYGB) surgery and associations with remission of type 2 diabetes (T2D).

METHODS

Retrospective analysis of 5-year outcomes of plasma magnesium (p-Mg) and glucometabolic statuses in patients who underwent primary RYGB and who completed the annual follow-up program. Data were investigated from 84 patients without diabetes and 62 with T2D before RYGB, who showed either prolonged remission (n = 30), temporary remission (n = 16), or no remission (n = 16) after surgery.

RESULTS

Body mass indexes before RYGB were similar in patients with and without T2D, irrespective of remission. The patients not achieving remission showed longer diabetes durations; higher circulating glucose levels; more intensive antidiabetic drug treatment, including insulin; and significantly lower p-Mg concentrations (.73 [±.08] mmol/L compared with .80-.82 [±.07] mmol/L, respectively; P < .01) than the groups showing remission or without diabetes before surgery. After RYGB, the p-Mg increased similarly, by 10-12% in the groups with T2D before surgery, irrespective of remission; however, the nonremission group did not reach the p-Mg levels registered in the other groups after follow-up. The nonremission group reached .82 (.09) mmol/L, compared with .87 (.06) and .88 (.08) mmol/L (P < .05), respectively, in patients with remission or without a history of diabetes.

CONCLUSION

The p-Mg concentrations increased after RYGB, with similar increments irrespective of T2D remission; however, the nonremission group started from an inferior level and did not reach the p-Mg concentrations seen in the groups achieving remission or without a history of diabetes before surgery.

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

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

Antiobesity Effect of Biochanin-A: Effect on Trace Element Metabolism in High Fat Diet-Induced Obesity in Rats

BACKGROUND

Imbalanced diets have contributed to the increased prevalence of obesity and other metabolic disorders in the modern world including trace element metabolism. However, the underlying mechanisms are not fully understood.

AIM AND OBJECTIVES

The present study investigated the effects of Biochanin A (BCA) on the changes in element metabolism induced by HFD-induced obese rats.

METHODS

BCA was administered orally for 30 days to experimental obese rats. Changes in body weight, glucose, insulin resistance and lipid profiles of plasma, as well as the level of trace elements (Fe, Zn, Mg and Cu) in various tissues (liver, kidney, heart and pancreas) and hepsidine and heme oxygenase, were observed in experimental rats.

RESULTS

The administration of BCA elicited a significant (p<0.05) reduction in, glucose, insulin, ferritin, total cholesterol, phospholipids, free fatty acids, VLDL-C, LDL-C, triglycerides and hepsidin. Significant alterations were observed in trace elements level, HDL-C, transferrin, bilirubin and HO - 1 level.

CONCLUSION

These findings suggested that HFD results in derangement of trace elements in the tissues of rats fed with HFD. BCA may alleviate the derangement of HFD induced trace elements metabolism by modulating hyperglycemic and insulin resistance status and altering hepcidin and HO-1.

Low extracellular magnesium does not impair glucose-stimulated insulin secretion

There is an increasing amount of clinical evidence that hypomagnesemia (serum Mg²⁺ levels < 0.7 mmol/l) contributes to type 2 diabetes mellitus pathogenesis. Amongst other hypotheses, it has been suggested that Mg²⁺ deficiency affects insulin secretion. The aim of this study was, therefore, to investigate the acute effects of extracellular Mg²⁺ on glucose-stimulated insulin secretion in primary mouse islets of Langerhans and the rat insulinoma INS-1 cell line. Here we show that acute lowering of extracellular Mg²⁺ concentrations from 1.0 mM to 0.5 mM did not affect glucose-stimulated insulin secretion in islets or in insulin-secreting INS-1 cells. The expression of key genes in the insulin secretory pathway (e.g. Gck, Abcc8) was also unchanged in both experimental models. Knockdown of the most abundant Mg²⁺ channel Trpm7 by siRNAs in INS-1 cells resulted in a 3-fold increase in insulin secretion at stimulatory glucose conditions compared to mock-transfected cells. Our data suggest that insulin secretion is not affected by acute lowering of extracellular Mg²⁺ concentrations.

Intakes of Zinc, Potassium, Calcium, and Magnesium of Individuals with Type 2 Diabetes Mellitus and the Relationship with Glycemic Control

The role of the concomitant intake of zinc, potassium, calcium, and magnesium in the glycemic control of individuals with type 2 diabetes mellitus (T2DM) has not been extensively discussed. We evaluated the relationship between the dietary intake of these micronutrients and glycemic markers in 95 individuals with T2DM (mean age 48.6 ± 8.4 years). Hierarchical grouping analysis was used to divide the individuals into two clusters according to their micronutrient intake, and differences between clusters were statistically assessed. Effects of individual and combination intake of micronutrients on glycated hemoglobin percentage (%HbA1c) were assessed using multiple linear regression and binary logistic regression analysis. We observed a high likelihood of inadequate intake of the four micronutrients. The group with lower micronutrient intake (cluster 1) displayed higher %HbA1c (p = 0.006) and triglyceride (p = 0.010) levels. High %HbA1c showed an association with cluster 1 (odds ratio (OR) = 3.041, 95% confidence interval (CI) = 1.131; 8.175) and time of T2DM diagnosis (OR = 1.155, 95% CI = 1.043; 1.278). Potassium (β = -0.001, p = 0.017) and magnesium (β = -0.007, p = 0.015) intakes were inversely associated with %HbA1c. Reduced concomitant intake of the four micronutrients studied proved to be associated with risk of increased %HbA1c in individuals with T2DM, which was particularly predicted by magnesium and potassium intakes.

Salts and energy balance: A special role for dietary salts in metabolic syndrome

BACKGROUND

Dietary salts sodium (Na⁺), potassium (K⁺), magnesium (Mg2⁺), and calcium (Ca2⁺) are important in metabolic diseases. Yet, we do not have sufficient understanding on the salts global molecular network in these diseases. In this systematic review we have pooled information to identify the general effect of salts on obesity, insulin resistance and hypertension.

AIMS

To assess the roles of salts in metabolic disorders by focusing on their individual effect and the network effect among these salts.

METHODS

We searched articles in PubMed, EMBASE and Google Scholar. We selected original laboratory research, systematic reviews, clinical trials, observational studies and epidemiological data that focused on dietary salts and followed the preferred reporting items for systematic review in designing the present systematic review.

RESULTS

From the initial search of 2898 studies we selected a total of 199 articles that met our inclusion criteria and data extraction. Alterations in metabolic pathways associated with the sensitivity of sodium, potassium, magnesium and calcium may lead to obesity, hypertension, and insulin resistance. We found that the results of most laboratory research, animal studies and clinical trials are coherent but some research outcome are either inconsistent or inconclusive.

CONCLUSION

Important of salts in metabolic disorder is evident. In order to assess the effects of dietary salts in metablic diseases, environmental factors, dietary habits, physical activity, and the microbiome, should be considered in any study. Although interest in this area of research continues to grow, the challenge is to integrate the action of these salts in metabolic syndrom.

Intakes of magnesium, calcium and risk of fatty liver disease and prediabetes

OBJECTIVE

Obesity and insulin resistance play important roles in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Mg intake is linked to a reduced risk of metabolic syndrome and insulin resistance; people with NAFLD or alcoholic liver disease are at high risk of Mg deficiency. The present study aimed to investigate whether Mg and Ca intakes were associated with risk of fatty liver disease and prediabetes by alcohol drinking status.

DESIGN

We analysed the association between Ca or Mg intake and fatty liver disease, prediabetes or both prediabetes and fatty liver disease in cross-sectional analyses.

SETTING

Third National Health and Nutrition Examination Survey (NHANES III) follow-up cohort of US adults.

SUBJECTS

Nationally representative sample of US adults in NHANES (n 13 489).

RESULTS

After adjusting for potential confounders, Mg intake was associated with approximately 30 % reduced odds of fatty liver disease and prediabetes, comparing the highest intake quartile v. the lowest. Mg intake may only be related to reduced odds of fatty liver disease and prediabetes in those whose Ca intake is less than 1200 mg/d. Mg intake may also only be associated with reduced odds of fatty liver disease among alcohol drinkers.

CONCLUSIONS

The study suggests that high intake of Mg may be associated with reduced risks of fatty liver disease and prediabetes. Further large studies, particularly prospective cohort studies, are warranted to confirm the findings.

Increased circulating magnesium concentrations after Roux-en-Y gastric bypass surgery in patients with type 2 diabetes

BACKGROUND

Low circulating magnesium concentrations predict cardiovascular and all-cause mortality in patients with type 2 diabetes (T2D). Epidemiologic and clinical studies have indicated lower extra- and intracellular magnesium concentrations in patients with diabetes.

OBJECTIVE

We aimed to describe alterations, if any, in circulating magnesium concentrations after laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in patients with obesity and T2D.

SETTING

Outpatient clinic of obesity and central hospital.

METHODS

Retrospective analysis of 1-year outcome of plasma magnesium (p-Mg) and glucometabolic status in all consecutive patients who underwent primary LRYGBP and who completed the follow-up visits, including biochemical test panels 6 and 12 months after surgery.

RESULTS

LRYGBP and complete follow-up visits were performed in 51 patients with T2D and 86 patients without T2D. All patients were given similar dietary advice and multivitamin and mineral supplementation after surgery. Before RYGB, the patients with T2D showed lower p-Mg compared with patients without T2D (.79 ± .06 mM and .82 ± .05 mM, respectively, P<.01). P-Mg was inversely correlated to fasting blood glucose and glycosylated hemoglobin levels. After surgery, mean p-Mg increased by 5.2% in the group with T2D compared with 1.4% in the patients without T2D (P<.01), ending at an equal level of .83 mM. The alterations in p-Mg were inversely related to the changes in fasting glucose and glycosylated hemoglobin concentrations.

CONCLUSION

The lowered p-Mg associated with impaired glucometabolic status in patients with T2D was increased after LRYGBP, reaching similar concentrations as in patients without T2D.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hypomagnesemia and increased risk of new-onset diabetes mellitus after transplantation in pediatric renal transplant recipients

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a significant co-morbidity following kidney transplantation. Lower post-transplant serum magnesium levels have been found to be an independent risk factor for NODAT in adult kidney transplant recipients.

METHODS

We undertook a retrospective analysis of risk factors for NODAT in pediatric renal transplant recipients at our institution with the aim of determining if hypomagnesemia confers a significant risk of developing NODAT in this patient population.

RESULTS

A total of 173 children with a median age at transplantation of 7.0 (range 1.3-17.5) years were included. Hypomagnesemia was found to be a significant independent risk factor for NODAT (p = 0.01). High trough tacrolimus levels were also independently associated with NODAT (p < 0.001). There was no significant association between NODAT and body mass index at the time of transplantation, monthly cumulative steroid dose or post-transplant cytomegalovirus viremia (p = 0.9, 0.6 and 0.7, respectively).

CONCLUSIONS

This study identifies hypomagnesemia as a significant independent risk factor for the development of NODAT in pediatric renal transplant recipients. Given the clear association between hypomagnesemia and NODAT in both adults and children following renal transplantation, further studies are merited to clarify the etiology of this association and to examine the effect of magnesium supplementation on NODAT.

Efficacy of Magnesium Supplementation on Glycemic Control in Type 2 Diabetes Patients: A Meta-analysis

Objective

To evaluate if magnesium supplementation, in addition to standard therapy, improves fasting blood sugar (FBS) and/or glycosylated hemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM) compared to placebo or other comparator.

Methodology

We searched MEDLINE/PubMed, Cochrane Library, Acta Medica Philippina, Health Research and Development Information Network (HERDIN) and references of reviewed journals from 1966 to July 2015 using the following search terms: “magnesium” OR “magnesium supplementation” OR “magnesium replacement”, AND randomized controlled trial AND diabetes OR diabetes mellitus OR non-insulin dependent diabetes mellitus OR diabetic OR diab* (with MeSH, where available). Studies were retrieved and rated independently using the standards provided by The Cochrane Collaboration. High quality trials were included in a systematic review and meta-analysis.

Results

Of the 689 records screened, 10 studies were included in the qualitative synthesis and 7 studies in the meta-analysis. Pooled data showed a non-significant trend towards improvement in glycemic control in the magnesium-treated group (mean difference -0.19, CI -0.58 to 0.21). There was a stronger but still non-significant trend in T2DM patients with hypomagnesemia (mean difference -1.16, CI -2.92 to 0.6).

Conclusion

Routine magnesium supplementation for improvement in glycemic control in T2DM patients cannot be recommended based on data from included studies in this meta-analysis.

Association of Insulin Resistance, β-Cell Function Impairment and Calcium, Magnesium, and Fetuin-A Concentrations in Women with Type 2 Diabetes Mellitus

Insulin resistance and β-cell function impairment play a role in the pathogenesis of type 2 diabetes (T2DM). Insulin signaling is inhibited by fetuin-A, an abundant plasma protein. Fetuin-A is also a candidate marker of the T2DM risk. This case-control study aimed to determine whether fetuin-A serum level is related to insulin resistance, β-cell function impairment, and total and ionized Ca and Mg serum levels in Erbil patients with T2DM.

A total of 60 patients with T2DM were recruited, and 30 healthy persons were included in the control group. Fetuin-A and insulin concentrations were measured through ELISA. Other biochemical parameters were determined spectrophotometrically. Insulin resistance (HOMA2IR), insulin sensitivity (HOMA2%S), and β-cell function were examined by using a homeostatic model assessment 2 (HOMA2).

Fasting serum insulin, fetuin-A serum levels, and HOMA2IR were significantly increased. HOMA2%S of the patients with diabetes was significantly lower than that of the control group. The total serum and ionized Ca and Mg contents and the Ca/Mg ratio were reduced in the patients.

Therefore, fetuin-A is related to T2DM pathogenesis and is strongly associated with insulin resistance and glycemic control in T2DM patients. Future large-scale studies are necessary to validate fetuin-A as an indicator of IR in T2DM patients.

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

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

Dietary magnesium, calcium:magnesium ratio and risk of reflux oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma: a population-based case-control study

Evidence suggests a role of Mg and the ratio of Ca:Mg intakes in the prevention of colonic carcinogenesis. The association between these nutrients and oesophageal adenocarcinoma - a tumour with increasing incidence in developed countries and poor survival rates - has yet to be explored. The aim of this investigation was to explore the association between Mg intake and related nutrients and risk of oesophageal adenocarcinoma and its precursor conditions, Barrett's oesophagus and reflux oesophagitis. This analysis included cases of oesophageal adenocarcinoma (n 218), Barrett's oesophagus (n 212), reflux oesophagitis (n 208) and population-based controls (n 252) recruited between 2002 and 2005 throughout the island of Ireland. All the subjects completed a 101-item FFQ. Unconditional logistic regression analysis was applied to determine odds of disease according to dietary intakes of Mg, Ca and Ca:Mg ratio. After adjustment for potential confounders, individuals consuming the highest amounts of Mg from foods had significant reductions in the odds of reflux oesophagitis (OR 0·31; 95 % CI 0·11, 0·87) and Barrett's oesophagus (OR 0·29; 95 % CI 0·12, 0·71) compared with individuals consuming the lowest amounts of Mg. The protective effect of Mg was more apparent in the context of a low Ca:Mg intake ratio. No significant associations were observed for Mg intake and oesophageal adenocarcinoma risk (OR 0·77; 95 % CI 0·30, 1·99 comparing the highest and the lowest tertiles of consumption). In conclusion, dietary Mg intakes were inversely associated with reflux oesophagitis and Barrett's oesophagus risk in this Irish population.

Association between magnesium intake and risk of colorectal cancer among postmenopausal women

PURPOSE

Data relating to magnesium intake and colorectal cancer (CRC) risk in postmenopausal women are incomplete. We investigated the association between total magnesium intake and the risk of CRC in an ethnically diverse cohort of postmenopausal women enrolled in the Women's Health Initiative.

METHODS

Self-reported dietary and supplemental magnesium were combined to form total magnesium intake. Invasive incident CRC was the primary outcome. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI).

RESULTS

During an average follow-up of 13 years (1,832,319 person-years), of the 140,601 women included for analysis, 2,381 women were diagnosed with CRC (1,982 colon cancer and 438 rectal cancer). After adjustment for potential confounding variables, an inverse association was observed in the highest quintile of total magnesium intake compared to the lowest quintile for risk of CRC (HR 0.79, 95% CI 0.67, 0.94, p trend < 0.0001) and colon cancer (HR 0.80, 95% CI 0.66, 0.97, p trend < 0.0001). A borderline significant inverse association was detected in the highest versus the lowest quintile of total magnesium intake for rectal cancer (HR 0.76, 95% CI 0.51, 1.13, p trend < 0.001).

CONCLUSIONS

Findings from this study support the hypothesis that magnesium intake around 400 mg/day from both dietary and supplemental sources is associated with a lower incidence of CRC in postmenopausal women.

Magnesium and disturbances in carbohydrate metabolism

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

Magnesium in disease

Although the following text will focus on magnesium in disease, its role in healthy subjects during physical exercise when used as a supplement to enhance performance is also noteworthy. Low serum magnesium levels are associated with metabolic syndrome, Type 2 diabetes mellitus (T2DM) and hypertension; consequently, some individuals benefit from magnesium supplementation: increasing magnesium consumption appears to prevent high blood pressure, and higher serum magnesium levels are associated with a lower risk of developing a metabolic syndrome. There are, however, conflicting study results regarding magnesium administration with myocardial infarction with and without reperfusion therapy. There was a long controversy as to whether or not magnesium should be given as a first-line medication. As the most recent trials have not shown any difference in outcome, intravenous magnesium cannot be recommended in patients with myocardial infarction today. However, magnesium has its indication in patients with torsade de pointes and has been given successfully to patients with digoxin-induced arrhythmia or life-threatening ventricular arrhythmias. Magnesium sulphate as an intravenous infusion also has an important established therapeutic role in pregnant women with pre-eclampsia as it decreases the risk of eclamptic seizures by half compared with placebo.

Intakes of magnesium, potassium, and calcium and the risk of stroke among men

BACKGROUND

Intakes of magnesium, potassium, and calcium have been inversely associated with the incidence of hypertension, a known risk factor for stroke. However, only a few studies have examined intakes of these cations in relation to risk of stroke.

AIM

The aim of this study was to investigate whether high intake of magnesium, potassium, and calcium is associated with reduced stroke risk among men.

METHODS

We prospectively examined the associations between intakes of magnesium, potassium, and calcium from diet and supplements, and the risk of incident stroke among 42 669 men in the Health Professionals Follow-up Study, aged 40 to 75 years and free of diagnosed cardiovascular disease and cancer at baseline in 1986. We calculated the hazard ratio of total, ischemic, and haemorrhagic strokes by quintiles of each cation intake, and of a combined dietary score of all three cations, using multivariate Cox proportional hazard models.

RESULTS

During 24 years of follow-up, 1547 total stroke events were documented. In multivariate analyses, the relative risks and 95% confidence intervals of total stroke for men in the highest vs. lowest quintile were 0·87 (95% confidence interval, 0·74-1·02; P, trend = 0·04) for dietary magnesium, 0·89 (95% confidence interval, 0·76-1·05; P, trend = 0·10) for dietary potassium, and 0·89 (95% confidence interval, 0·75-1·04; P, trend = 0·25) for dietary calcium intake. The relative risk of total stroke for men in the highest vs. lowest quintile was 0·74 (95% confidence interval, 0·59-0·93; P, trend = 0·003) for supplemental magnesium, 0·66 (95% confidence interval, 0·50-0·86; P, trend = 0·002) for supplemental potassium, and 1·01 (95% confidence interval, 0·84-1·20; P, trend = 0·83) for supplemental calcium intake. For total intake (dietary and supplemental), the relative risk of total stroke for men in the highest vs. lowest quintile was 0·83 (95% confidence interval, 0·70-0·99; P, trend = 0·04) for magnesium, 0·88 (95% confidence interval, 0·75-4; P, trend = 6) for potassium, and 3 (95% confidence interval, 79-09; P, trend = 84) for calcium. Men in the highest quintile for a combined dietary score of all three cations had a multivariate relative risk of 0·79 (95% confidence interval, 0·67-0·92; P, trend = 0·008) for total stroke, compared with those in the lowest.

CONCLUSIONS

A diet rich in magnesium, potassium, and calcium may contribute to reduced risk of stroke among men. Because of significant collinearity, the independent contribution of each cation is difficult to define.

Magnesium in CKD: more than a calcification inhibitor?

Magnesium fulfils important roles in multiple physiological processes. Accordingly, a tight regulation of magnesium homeostasis is essential. Dysregulated magnesium serum levels, in particular hypomagnesaemia, are common in patients with chronic kidney disease (CKD) and have been associated with poor clinical outcomes. In cell culture studies as well as in clinical situations magnesium levels were associated with vascular calcification, cardiovascular disease and altered bone-mineral metabolism. Magnesium has also been linked to diseases such as metabolic syndrome, diabetes, hypertension, fatigue and depression, all of which are common in CKD. The present review summarizes and discusses the latest clinical data on the impact of magnesium and possible effects of higher levels on the health status of patients with CKD, including an outlook on the use of magnesium-based phosphate-binding agents in this context.

Magnesium in man: implications for health and disease

Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.

Dietary magnesium and genetic interactions in diabetes and related risk factors: a brief overview of current knowledge

Nutritional genomics has exploded in the last decade, yielding insights—both nutrigenomic and nutrigenetic—into the physiology of dietary interactions and our genes. Among these are insights into the regulation of magnesium transport and homeostasis and mechanisms underlying magnesium’s role in insulin and glucose handling. Recent observational evidence has attempted to examine some promising research avenues on interaction between genetics and dietary magnesium in relation to diabetes and diabetes risk factors. This brief review summarizes the recent evidence on dietary magnesium’s role in diabetes and related traits in the presence of underlying genetic risk, and discusses future potential research directions.

Nut consumption and risk of pancreatic cancer in women

Background:

Increasing nut intake has been associated with reduced risk of diabetes mellitus, which is a risk factor for pancreatic cancer.

Methods:

We prospectively followed 75 680 women in the Nurses' Health Study, and examined the association between nut consumption and pancreatic cancer risk. Participants with a previous history of cancer were excluded. Nut consumption was assessed at baseline and updated every 2 to 4 years. Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazards models.

Results:

We documented 466 incident cases of pancreatic cancer. After adjusting for age, height, smoking, physical activity, and total energy intake, women who consumed a 28-g (1 oz) serving size of nuts ⩾2 times per week experienced a significantly lower risk of pancreatic cancer (RR, 0.65; 95% CI, 0.47–0.92; P for trend=0.007) when compared with those who largely abstained from nuts. The results did not appreciably change after further adjustment for body mass index (BMI) and history of diabetes mellitus (RR, 0.68; 95% CI, 0.48–0.95; P for trend=0.01). The inverse association persisted within strata defined by BMI, physical activity, smoking, and intakes of red meat, fruits, and vegetables.

Conclusion:

Frequent nut consumption is inversely associated with risk of pancreatic cancer in this large prospective cohort of women, independent of other potential risk factors for pancreatic cancer.

Whole grains, type 2 diabetes, coronary heart disease, and hypertension: links to the aleurone preferred over indigestible fiber

Higher whole grain cereal intakes are associated with substantially lower risks of type 2 diabetes, coronary heart disease, and hypertension. These reduced risks have been established in large prospective studies that now include millions of person-years of follow-up. We analyze the results of 11 major prospective studies to provide recommendations about whole grain consumption. The following review establishes the amount of whole grains that should ideally be consumed based on prospective evidence; defines the nature of whole grains; identifies that the whole grain evidence is robust and not due to confounding; and provides a detailed assessment of several potential mechanisms for the effect of whole grains on health. We draw the following conclusions. Firstly, to maintain health, 40 grams or more of whole grains should be consumed daily. This is about a bowl of whole grain breakfast cereal daily, but 80% of the population does not achieve this. Secondly, aleurone in bran is a critical grain component generally overlooked in favor of indigestible fiber. Live aleurone cells constitute 50% of millers' bran. They store minerals, protein, and the antioxidant ferulic acid, and are clearly more than just indigestible fiber. Finally, we suggest potential roles for magnesium, zinc, and ferulic acid in the development of chronic disease. If the results of prospective studies were applied to the life-style practices of modern societies there exists the potential for enormous personal health and public financial benefits.

Lower intake of magnesium and dietary fiber increases the incidence of type 2 diabetes in Taiwanese

BACKGROUND/PURPOSE

Several studies have indicated an inverse association between the incidence of diabetes mellitus and magnesium and dietary fiber intake. Few studies have examined both of these associations together, not to mention in Asian populations with prospective study design. We therefore aimed to study how dietary magnesium and fiber intake levels affect diabetes incidence separately or in combination, in a prospective study in Taiwan.

METHODS

The study subjects were recruited for a longitudinal study, CardioVascular Disease risk FACtor Two-township Study cycle 2 from November 1990. Data from complete baseline information on dietary and biochemical profile and at least one additional follow-up visit were gathered on a total of 1604 healthy subjects aged 30 years and over. Cox proportional hazard model was used to study the association between diabetes incidence and dietary magnesium and fiber intake level estimated from a food frequency questionnaire.

RESULTS

A total of 141 diabetes mellitus events were identified and confirmed during the 4.6 years of follow-up (7365.1 person-years). A significantly higher diabetes risk was observed for people in the lowest quintile of total dietary fiber intake (hazard ratio = 2.04; 95% CI = 1.17-3.53) and magnesium intake (hazard ratio = 2.61; 95% CI = 1.42-4.79) compared with the highest quintile after adjusting for traditional cardiovascular disease risk factors. Similar inverse associations for total dietary fiber were also shown for vegetable fiber and fruit fiber.

CONCLUSION

Lower magnesium, lower total dietary fiber intake, or lower intake of both was associated with higher risk of diabetes in the Taiwanese population. Clinical trials are required to confirm the protective effects of the adequate intake of fiber, magnesium, and/or their combination.

Magnesium intake, plasma C-peptide, and colorectal cancer incidence in US women: a 28-year follow-up study

Background:

Laboratory studies suggest a possible role of magnesium intake in colorectal carcinogenesis but epidemiological evidence is inconclusive.

Method:

We tested magnesium–colorectal cancer hypothesis in the Nurses’ Health Study, in which 85 924 women free of cancer in 1980 were followed until June 2008. Cox proportional hazards regression models were used to estimate multivariable relative risks (MV RRs, 95% confidence intervals).

Results:

In the age-adjusted model, magnesium intake was significantly inversely associated with colorectal cancer risk; the RRs from lowest to highest decile of total magnesium intake were 1.0 (ref), 0.93, 0.81, 0.72, 0.74, 0.77, 0.72, 0.75, 0.80, and 0.67 (P_trend<0.001). However, in the MV model adjusted for known dietary and non-dietary risk factors for colorectal cancer, the association was significantly attenuated; the MV RRs were 1.0 (ref), 0.96, 0.85, 0.78, 0.82, 0.86, 0.84, 0.91, 1.02, and 0.93 (P_trend=0.77). Similarly, magnesium intakes were significantly inversely associated with concentrations of plasma C-peptide in age-adjusted model (P_trend=0.002) but not in multivariate-adjusted model (P_trend=0.61). Results did not differ by subsite or modified by calcium intakes or body mass index.

Conclusion:

These prospective results do not support an independent association of magnesium intake with either colorectal cancer risk or plasma C-peptide levels in women.

Magnesium intake and prevalence of metabolic syndrome in adults: Tehran Lipid and Glucose Study

Objective

We examined the association of metabolic syndrome (MetS) and its components with dietary intakes of Mg in Tehran adults.

Design

In a cross-sectional study, dietary intakes were assessed using a valid and reliable FFQ. MetS was defined according to the modified guidelines of the National Cholesterol Education Program Adult Treatment Panel III. Waist circumference (WC) was coded according to the newly introduced cut-off points for Iranian adults (≥95 cm for both genders).

Setting

Participants of the Tehran Lipid and Glucose Study (2006–2008).

Subjects

Adults (n2504; 1120 men and 1384 women) aged 18–74 years.

Results

The mean age of participants was 40·8 (sd14·6) years and 38·2 (sd13·5) years for men and women, respectively. The reported mean intake of Mg was 349 (sd109) mg/d. After adjustment for confounding factors, dietary Mg intake was inversely associated with fasting blood glucose (β= −0·08,P= 0·006), TAG (β= −0·058,P= 0·009) and WC (β= −0·013,P= 0·006); however, there were no associations between dietary Mg and diastolic blood pressure, systolic blood pressure or HDL cholesterol. An association was observed between MetSZ-score and Mg intake (crudeβ= −0·017,P= 0·001), independent of age, gender, smoking, physical activity and BMI; this association was attenuated following further adjustment for dietary factors and menopausal status (β= −0·034,P= 0·061).

Conclusions

Our findings suggest a significant inverse association between dietary Mg, MetS and its components.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

A prospective study of magnesium and iron intake and pancreatic cancer in men

Many studies have investigated the relation between magnesium and iron intake and diabetes and, separately, between diabetes and pancreatic cancer. However, no known study has examined the direct association of magnesium and iron intake with pancreatic cancer risk. The authors obtained magnesium and iron intake data using food frequency questionnaires from the US male Health Professionals Follow-up Study, which began in 1986. During 851,476 person-years and 20 years of follow-up, 300 pancreatic cancer cases were documented. Cox proportional hazards models were used to estimate relative risks, adjusting for age, smoking, and body mass index. No associations were observed between magnesium or iron intake and pancreatic cancer (highest vs. lowest quintile: relative risk (RR) = 0.94, 95% confidence interval (CI): 0.66, 1.32 and RR = 0.93, 95% CI: 0.65, 1.34, respectively). Similarly, iron or magnesium supplement use was not related to pancreatic cancer. A statistically significant inverse relation was noted between magnesium and pancreatic cancer for subjects with a body mass index of > or =25 kg/m(2) (RR = 0.67, 95% CI: 0.46, 0.99; P-trend = 0.04). Although, overall, no relation between magnesium or iron intake and pancreatic cancer was observed in this cohort of men, an inverse association with magnesium was suggested among overweight individuals, which should be examined in other studies.

Coffee and Tea Consumption and Risk of Stroke Subtypes in Male Smokers

Background and Purpose— Coffee and tea consumption could potentially reduce the risk of stroke because these beverages have antioxidant properties, and coffee may improve insulin sensitivity. We examined the associations of coffee and tea consumption with risk of stroke subtypes.

Methods— We used prospective data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a cohort study of 26 556 male Finnish smokers aged 50 to 69 years without a history of stroke at baseline. Coffee and tea consumption was assessed at baseline using a validated food-frequency questionnaire. During a mean follow-up of 13.6 years, from 1985 through December 2004, 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were ascertained from national registries.

Results— After adjustment for age and cardiovascular risk factors, both consumption of coffee and tea was statistically significantly inversely associated with the risk of cerebral infarction but not intracerebral or subarachnoid hemorrhage. The multivariate relative risk of cerebral infarction for men in the highest category of coffee consumption (≥8 cups/d) was 0.77 (95% CI, 0.66 to 0.90; P for trend <0.001) compared with those in the lowest category (<2 cups/d). The corresponding relative risk comparing men in the highest category of tea consumption (≥2 cups/d) with those in the lowest category (nondrinkers) was 0.79 (95% CI, 0.68 to 0.92; P for trend=0.002).

Conclusions— These results suggest that high consumption of coffee and tea may reduce the risk of cerebral infarction among men, independent of known cardiovascular risk factors.

The effects of a whole grain-enriched hypocaloric diet on cardiovascular disease risk factors in men and women with metabolic syndrome

BACKGROUND

Whole-grain foods are associated in observational studies with a lower body mass index and lower cardiovascular disease (CVD) risk. However, few clinical trials have tested whether incorporating whole grains into a hypocaloric diet increases weight loss and improves CVD risk factors.

OBJECTIVE

The aim of this study was to determine whether including whole-grain foods in a hypocaloric (reduced by 500 kcal/d) diet enhances weight loss and improves CVD risk factors.

DESIGN

Obese adults (25 M, 25 F) with metabolic syndrome were randomly assigned to receive dietary advice either to avoid whole-grain foods or to obtain all of their grain servings from whole grains for 12 wk. All participants were given the same dietary advice in other respects for weight loss.

RESULTS

Body weight, waist circumference, and percentage body fat decreased significantly (P<0.001) in both groups over the study period, but there was a significantly (P=0.03) greater decrease in percentage body fat in the abdominal region in the whole-grain group than in the refined-grain group. C-reactive protein (CRP) decreased 38% in the whole-grain group independent of weight loss but was unchanged in the refined-grain group (P=0.01 for group x time interaction). Total, LDL, and HDL cholesterol decreased in both diet groups (P<0.05). Dietary fiber and magnesium intakes increased in the whole-grain but not the refined-grain group (P=0.007 and P<0.001, respectively, for group x time interaction).

CONCLUSIONS

Both hypocaloric diets were effective means of improving CVD risk factors with moderate weight loss. There were significantly (P<0.05) greater decreases in CRP and percentage body fat in the abdominal region in participants consuming whole grains than in those consuming refined grains.

Beneficial effect of 3% milled-rice on blood glucose level and serum lipid concentrations in spontaneously non-insulin-dependent diabetic rats

Three percent milled-rice was evaluated for beneficial effect on blood glucose level and serum lipid concentrations in an experiment with Otsuka Long-Evans Tokushima Fatty (OLETF) rats, used as model animals for spontaneously non-insulin-dependent diabetes mellitus. The same experiment was carried out using Long-Evans Tokushima Otsuka (LETO) rats, the control of the OLETF rats. The results obtained from the rats given a diet containing 3% milled-rice (3% MRD) ad libitum were compared with those from rats given polished rice. During the feeding period of 140 d, body weight of the OLETF rats receiving the 3% MRD was significantly lower than that of the rats fed on the diet containing polished rice (PRD) from the 48th to the 124th days. The body weight of the LETO rats during the both periods of 90 to 104 d and 114 to 140 d was lower than that of the rats receiving the PRD. Though food intakes of the rats receiving 3% MRD were significantly lower in the OLETF and LETO rats during the two periods of days 48 to 124 and days 1 to 140 than in the rats of the PRD group, the feed efficiency of the OLETF or LETO rats did not show significant difference between the 3% MRD and the PRD groups during the same experimental periods. The excretion rate of feces of the OLETF rats receiving the 3% MRD was significantly higher than that of the rats receiving the PRD, both on the 126th day and during the period of days 129 to 131. The fasting blood glucose levels were significantly lower in the OLETF rats receiving the 3% MRD than the rats receiving the PRD on the 84th day, the 105th day and the 127th day, and also lower in the LETO rats receiving the 3% MRD on the 84th day and the 105th day. The incremental areas under the curve of blood glucose concentrations (IAUC-Glc) for 120 min after oral administration of glucose on the 133rd day was lower in the OLETF rats receiving 3% MRD than that of the PRD. The ratio of IAUC-Glc in the 3% MRD to PRD group, after ingestion of diets for 1 h after fasting for 18 h on the 138th day, was 0.89 in the OLETF rats, and 0.74 in the LETO rats. Compared with the PRD group, the amounts of cholesterol and bile acid in the feces of the OLETF rats in the 3% MRD group were significantly higher on days 129-131, and the cholesterol excretion was significantly higher on the 84th day in the OLETF rats in the 3% MRD group. The liver weight, the level of total lipids in liver, and the concentrations of triglyceride and total cholesterol in liver and serum of the OLETF rats on the 140th day were significantly lower in the 3% MRD than those of the PRD group. These results indicate that 3% milled-rice has beneficial effects on blood glucose level and serum lipid concentrations in spontaneously non-insulin-dependent diabetic rats.

Magnesium intake and risk of type 2 diabetes: a meta-analysis

OBJECTIVE

To assess the association between magnesium intake and risk of type 2 diabetes.

DESIGN

Meta-analysis of prospective cohort studies.

DATA SOURCES

We retrieved studies published in any language by systematically searching MEDLINE from 1966 to February 2007 and by manually examining the references of the original articles.

STUDY SELECTION

We included prospective cohort studies reporting relative risks with 95% confidence intervals for the association between magnesium intake and incidence of type 2 diabetes.

RESULTS

The seven identified cohort studies of magnesium intake [from foods only (n = 4) or from foods and supplements combined (n = 3)] and incidence of type 2 diabetes included 286,668 participants and 10,912 cases. All but one study found an inverse relation between magnesium intake and risk of type 2 diabetes, and in four studies the association was statistically significant. The overall relative risk for a 100 mg day(-1) increase in magnesium intake was 0.85 (95% CI, 0.79-0.92). Results were similar for intake of dietary magnesium (RR, 0.86; 95% CI, 0.77-0.95) and total magnesium (RR, 0.83; 95% CI, 0.77-0.89). There was no evidence of publication bias (P = 0.99).

CONCLUSIONS

Magnesium intake was inversely associated with incidence of type 2 diabetes. This finding suggests that increased consumption of magnesium-rich foods such as whole grains, beans, nuts, and green leafy vegetables may reduce the risk of type 2 diabetes.

Intake of dietary magnesium and the prevalence of the metabolic syndrome among U.S. adults

OBJECTIVE

Limited data suggest that people with the metabolic syndrome have lower intakes or circulating concentrations of magnesium than those who do not have the syndrome. The aim of this study was to examine the associations between dietary intake of magnesium and the prevalence of the metabolic syndrome in a nationally representative sample of U.S. adults.

RESEARCH METHODS AND PROCEDURES

We used data for 7669 participants > or =20 years of age of the Third National Health and Nutrition Examination Survey (1988 to 1994). The metabolic syndrome was defined using the criteria of the National Cholesterol Education Program. Magnesium intake was determined from a single dietary 24-hour recall.

RESULTS

The unadjusted prevalences of the metabolic syndrome were 29.0% (quintile of lowest magnesium intake), 27.5%, 25.8%, 23.9%, and 21.8% for increasing quintiles of magnesium intake (p for trend = 0.002). After multiple adjustment, the odds ratios for the second through the fifth quintiles (highest intake) of magnesium intake among all participants included in the analysis were 0.84 [95% confidence interval (CI): 0.58, 1.23], 0.76 (95% CI: 0.54, 1.07), 0.62 (95% CI: 0.40, 0.98), and 0.56 (95% CI: 0.34, 0.92), respectively (p for trend = 0.029). The associations were similar for men and women.

DISCUSSION

Our results showing an inverse association between dietary magnesium intake and the prevalence of the metabolic syndrome add to the evidence that adequate magnesium intake or a diet rich in magnesium may be important for maintaining good cardiometabolic health.

Increased magnesium intake prevents hyperlipidemia and insulin resistance and reduces lipid peroxidation in fructose-fed rats

Studies have suggested that type 2 diabetes mellitus is associated with abnormal lipid metabolism, oxidative stress and insulin resistance. Increased magnesium intake may improve dyslipidemia, oxidative stress and insulin insensitivity in type 2 diabetes. Therefore, the present study investigated the influence of increasing dietary magnesium from 0.1% to 1.0% for 4 weeks on plasma lipids, lipid peroxidation, l-ascorbic acid and insulin sensitivity in male Wistar rats fed a high-fructose diet. The rats were divided into control (CR), fructose-fed (FRU-fed) and fructose-fed supplemented with magnesium (FRU-Mg-fed) groups (n=8 per group). Homeostasis model assessment for insulin resistance (HOMA-IR) and plasma thiobarbituric acid-reactive substances (TBARS) were used as indices of insulin sensitivity and lipid peroxidation, respectively. When compared with controls, the FRU-fed group had significantly higher values of HOMA-IR, fasting plasma glucose, insulin, triglyceride, total cholesterol/HDL-cholesterol ratio (atherogenic index), and TBARS. Their values in FRU-Mg-fed group were close to those of the controls. FRU-Mg-fed group had also significantly higher plasma magnesium and l-ascorbic acid levels, but significantly lower LDL-cholesterol levels than those in control and Fru-fed groups.

CONCLUSION

increased magnesium intake improved insulin sensitivity, hyperglycemia, hyperlipidemia and reduced lipid peroxidation in fructose-fed rats.

Algorithm for Complementary and Alternative Medicine Practice and Research in Type 2 Diabetes

OBJECTIVE

To develop a model to direct the prescription of nutritional and botanical medicines in the treatment of type 2 diabetes for both clinical and research purposes.

METHODS

Available literature on nutritional and botanical medicines was reviewed and categorized as follows: antioxidant/anti-inflammatory; insulin sensitizer; and beta-cell protectant/insulin secretagogue. Literature describing laboratory assessment for glycemic control, insulin resistance, and beta-cell reserve was also reviewed and a clinical decision tree was developed.

RESULTS

Clinical algorithms were created to guide the use of nutritional and botanic medicines using validated laboratory measures of glycemic control, insulin sensitivity, and beta-cell reserve. Nutrient and botanic medicines with clinical trial research support include coenzyme Q10, carnitine, alpha-lipoic acid, N-acetylcysteine, vitamin D, vitamin C, vitamin E, chromium, vanadium, omega-3 fatty acids, cinnamon (Cinnamomum cassia), fenugreek (Trigonella foenum-graecum), and gymnema (Gymnema sylvestre).

CONCLUSIONS

Clinical algorithms can direct supplementation in clinical practice and provide research models for clinical investigation. Algorithms also provide a framework for integration of future evidence as it becomes available. Research funding to investigate potentially beneficial practices in complementary medicine is critically important for optimal patient care and safety.

Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials

AIMS

The aim of this study was to assess the evidence on the effect of oral magnesium supplementation on glycaemic control in patients with Type 2 diabetes.

METHODS

We searched the electronic databases of medline, embase and the Cochrane Controlled Trials Register up to January 2005. We identified nine randomized double-blind controlled trials with a total of 370 patients with Type 2 diabetes and of duration 4-16 weeks. The median dose of oral magnesium supplementation was 15 mmol/day (360 mg/day) in the treatment groups. The primary outcome was glycaemic control, as measured by glycated haemoglobin (HbA(1c)) or fasting blood glucose levels; the secondary outcomes included body mass index, blood pressure (BP) and lipids. Using a random-effects model, we calculated the weighted mean differences (WMD) and 95% confidence interval (CI).

RESULTS

After a median duration of 12 weeks, the weighted mean post-intervention fasting glucose was significantly lower in the treatment groups compared with the placebo groups [-0.56 mmol/l (95% CI, -1.10 to -0.01); P for heterogeneity = 0.02]. The difference in post-intervention HbA(1c) between magnesium supplementation groups and control groups was not significant [-0.31% (95% CI, -0.81 to 0.19); P for heterogeneity = 0.10]. Neither systolic nor diastolic BP was significantly changed. Magnesium supplementation increased on high-density lipoprotein (HDL) cholesterol levels [0.08 mmol/l (95% CI, 0.03 to 0.14); P for heterogeneity = 0.36] but had no effect on total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride.

CONCLUSIONS

Oral magnesium supplementation for 4-16 weeks may be effective in reducing plasma fasting glucose levels and raising HDL cholesterol in patients with Type 2 diabetes, although the long-term benefits and safety of magnesium treatment on glycaemic control remain to be determined.

Deficiência de magnésio e resistência à insulina em pacientes com diabetes mellitus tipo 2

O magnésio é um íon predominantemente intra-celular, que participa como co-fator de mais de 300 reações enzimáticas, dentre elas na atividade da tirosino-cinase. Sua deficiência pode aumentar a resistência periférica à insulina, especialmente em pacientes com síndrome metabólica e diabetes mellitus tipo 2 (DM2). Este trabalho avaliou, em 27 pacientes com DM2 descompensado, o conteúdo intra-celular de magnésio, correlacionando-o com índices laboratoriais de resistência insulínica e controle glicêmico. Hipomagnesemia foi encontrada em 75% dos pacientes e déficit intra-celular em 30,8%. Houve correlação negativa do Mg intra-celular (Mg IC) com HbA1 e com IMC. 59,2% dos pacientes apresentaram HOMA IR > 3,5, e tendência para correlação negativa com o Mg IC, porém sem significância estatística. Apesar do número pequeno de pacientes, ressalta-se que uma vez que deficiência de magnésio é comum em pacientes com diabetes, sua relação com resistência insulínica deve ser mais estudada.

Effects of dietary magnesium and short-duration transportation on stress response, postmortem muscle metabolism, and meat quality of finishing swine1

Crossbred pigs, heterozygous for the halothane gene, were used to determine the effects of long-term dietary supplementation of magnesium mica (MM) and short-duration transportation stress on performance, stress response, postmortem metabolism, and pork quality. Pigs were blocked by weight, penned in groups (six pigs per pen), and pens (three pens per diet) were assigned randomly either to a control corn-soybean meal diet or the control diet supplemented with 2.5% MM (as-fed basis; supplemented at the expense of corn). Diets were fed during the early-finisher (0.95% lysine, as-fed basis; 43.7 to 68 kg) and late-finisher (0.85% lysine, as-fed basis; 68 to 103 kg) periods. At the conclusion of the 71-d feeding trial, 12 pigs from each dietary treatment were selected randomly and subjected either to no stress (NS) or 3 h of transportation stress (TS). Dietary MM had no effect (P > or = 0.40) on ADG or ADFI; however, G:F was improved (P < 0.05) during the early-finisher period when pigs were fed MM-supplemented diets. Plasma glucose concentrations were increased in TS pigs fed the control diet, but transportation did not affect plasma glucose in pigs fed 2.5% MM (diet x transportation stress; P = 0.02). Dietary MM did not affect blood lactate, cortisol, insulin, NEFA, Ca, or Mg concentrations in response to TS (diet x transportation stress; P > or = 0.13); however, circulating lactate, cortisol, and glucose concentrations increased in TS pigs (transportation stress x time; P < 0.01). The LM from TS pigs fed MM had higher initial (0-min) and 45-min pH values than the LM from NS pigs fed the control diet (diet x transportation stress x time; P = 0.07). Lactic acid concentration and glycolytic potential were greater in the LM of TS pigs fed MM than TS pigs fed control diets (diet x transportation stress; P < or = 0.01). Although some trends were identified, neither MM (P > or = 0.15) nor TS (P > or = 0.11) altered the color or water-holding capacity of the LM and semimembranosus. The transportation model elicited the expected changes in endocrine and blood metabolites, but dietary MM did not alter the stress response in pigs. Conversely, although pork quality traits were not improved by dietary MM, delaying postmortem glycolysis and elevating 0- and 45-min muscle pH by feeding finishing diets fortified with MM may benefit the pork industry by decreasing the incidence of PSE pork in pigs subjected to short-duration, routine stressors.

Magnesium deficiency is associated with insulin resistance in obese children

OBJECTIVE

Magnesium deficiency has been associated with insulin resistance (IR) and increased risk for type 2 diabetes in adults. This study was designed to determine whether obese children exhibit serum or dietary magnesium deficiency and its potential association with IR.

RESEARCH DESIGN AND METHODS

We studied 24 obese nondiabetic children (BMI > or =85th percentile) and 24 sex- and puberty-matched lean control subjects (BMI <85th percentile). We measured serum magnesium, indexes of insulin sensitivity, dietary magnesium intake (using a food frequency questionnaire), and body composition (by air displacement plethysmography).

RESULTS

Serum magnesium was significantly lower in obese children (0.748 +/- 0.015 mmol/l, means +/- SE) compared with lean children (0.801 +/- 0.012 mmol/l) (P = 0.009). Serum magnesium was inversely correlated with fasting insulin (r(s) = -0.36 [95% CI -0.59 to -0.08]; P = 0.011) and positively correlated with quantitative insulin sensitivity check index (QUICKI) (0.35 [0.06-0.58]; P = 0.015). Dietary magnesium intake was significantly lower in obese children (obese: 0.12 +/- 0.004 vs. lean: 0.14 +/- 0.004 mg/kcal; P = 0.003). Dietary magnesium intake was inversely associated with fasting insulin (-0.43 [-0.64 to -0.16]; P = 0.002) and directly correlated with QUICKI (0.43 [0.16-0.64]; P = 0.002).

CONCLUSIONS

The association between magnesium deficiency and IR is present during childhood. Serum magnesium deficiency in obese children may be secondary to decreased dietary magnesium intake. Magnesium supplementation or increased intake of magnesium-rich foods may be an important tool in the prevention of type 2 diabetes in obese children.

Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system

Type 2 diabetes mellitus is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of type 2 diabetes is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with type 2 diabetes and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of type 2 diabetes in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (Valsartan Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of type 2 diabetes: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of type 2 diabetes by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of type 2 diabetes that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of type 2 diabetes.

Magnesium may mediate the favorable impact of whole grains on insulin sensitivity by acting as a mild calcium antagonist

Recent epidemiology has linked high consumption of whole grains with reduced risk for diabetes, coronary disease, stroke, and various types of cancer; there is reason to suspect that improved insulin sensitivity is largely responsible for this protection. This phenomenon may be partially explained by the lower glycemic indices of some whole grain food products in comparison to their fiber-depleted analogs. Nonetheless, the fact that whole wheat flour promotes insulin sensitivity relative to white flour--and yet has a near-identical glycemic index--suggests that certain nutrients or phytochemicals in whole wheat, depleted by the refining process, promote preservation of insulin sensitivity. Magnesium is a likely candidate in this regard; magnesium deficiency promotes insulin resistance in rodents and in humans, whereas supplemental magnesium has been found to prevent type 2 diabetes in rodent models of this syndrome, and to improve the insulin sensitivity of elderly or diabetic humans. Magnesium-rich diets as well as above-average serum magnesium are associated with reduced diabetes risk in prospective epidemiology, and with greater insulin sensitivity in cross-sectional studies; moreover, other types of magnesium-rich foods--dairy products, legumes, and nuts--have been linked to decreased diabetes risk in prospective studies. The biochemical role of magnesium in support of insulin function is still poorly understood. In light of evidence that magnesium can function as a mild natural calcium antagonist, it is interesting to note suggestive evidence that increases in intracellular free calcium may compromise the insulin responsiveness of adipocytes and skeletal muscle, and may indeed play a pathogenic role in the insulin resistance syndrome. Thus, it is proposed that some or all of the favorable impact of good magnesium status on insulin function may reflect antagonism of the induction or effects of increased intracellular free calcium. Further research concerning the potential health benefits of long-term magnesium supplementation is clearly warranted. These considerations, however, should not detract from efforts to better inform the public regarding the strong desirability of choosing whole grain products in preference to refined grains.

Renin-angiotensin system inhibition prevents type 2 diabetes mellitus

The inhibition of the renin-angiotensin system (RAS) with either angiotensin converting enzyme inhibitors (ACEIs) or AT1 angiotensin receptor blockers (ARBs) consistently and significantly reduces the incidence of type 2 diabetes in patients with hypertension or congestive heart failure. The mechanisms underlying this protective effect appear to be complex and may involve an improvement of both insulin sensitivity and insulin secretion. These two effects may result, at least in part, from the well known effects of these pharmacological agents on the vascular system on the one hand, on the ionic balance on the other hand. Indeed, the vasodilation induced by ACEIs or ARBs could improve the blood circulation in skeletal muscles, thus favouring peripheral insulin action, but also in the pancreas, thus promoting insulin secretion. Preserving cellular potassium and magnesium pools by blocking the aldosterone effects could also improve both cellular insulin action and insulin secretion. However, besides these classical effects, new mechanisms have been recently suggested. A direct effect of the inhibition of angiotensin and/or of the enhancement of bradykinin on various steps of the insulin cascade signalling has been described as well an increase in GLUT4 glucose transporters after RAS inhibition. Furthermore, it has been demonstrated that angiotensin II inhibits adipogenic differentiation of human adipocytes via A1 receptors and, therefore, it has been hypothesised that RAS blockade may prevent diabetes by promoting the recruitment and differentiation of adipocytes. Finally, some lipophilic ARBs appear to induce PPAR-gamma activity in the adipose tissue. Hence, the protection against type 2 diabetes observed after RAS inhibition may be partially linked to a thiazolidinedione-like effect. In conclusion, numerous physiological and biochemical mechanisms could explain the protective effect of RAS inhibition against the development of type 2 diabetes in individuals with arterial hypertension or congestive heart failure. What might be the main mechanism in the overall protection effect of ACEIs or ARBs remains an open question.

Whole grain intake and insulin sensitivity: evidence from observational studies

Observational studies have found that diets rich in whole-grain foods are associated with improved insulin sensitivity. The improved insulin sensitivity may be mediated in part by magnesium and dietary fiber, two nutrients found in whole-grain foods. By incorporating whole-grain foods into the diet, therefore, insulin sensitivity might be improved.