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

Adherence to the nordic diet is associated with anxiety, stress, and depression in recovered COVID-19 patients, a case-control study

BACKGROUND

Follow-up of COVID-19 recovered patients to discover important adverse effects on other organs is required. The psychological health of COVID-19 patients may be affected after recovery.

AIM

We aimed to evaluate the association between adherence to the Nordic diet (ND) and psychological symptoms caused by COVID-19 after recovery.

METHOD

Dietary data on 246 qualified adults (123 cases and 123 controls). The dietary intake in this case-control study was calculated by a reliable and valid food frequency questionnaire (FFQ). Depression Anxiety Stress Scale (DASS), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Short-Form Health Survey (SF-36) were used to analyze participant's anxiety, stress, depression, sleep quality, insomnia, and quality of life of participants.

RESULTS

There was a significant inverse relationship between total anxiety, stress, and depression scores and the intake of whole grains (P < 0.05). Furthermore, there was a significant inverse association between depression and fruit intake (P < 0.05). A significant negative correlation was found between insomnia and sleep quality and the intake of root vegetables (P < 0.05). In the multinomial-regression model, a significant association between the Nordic diet and anxiety, stress, and depression was found only in the case group (OR = 0.719, 95% CI 0.563-0.918, p-value = 0.008; OR = 0.755, 95% CI 0.609-0.934, P-value = 0.010, and, OR = 0.759, 95% CI 0.602-0.956, P-value = 0.019 respectively).

CONCLUSION

Adherence to the Nordic diet might reduce anxiety, stress, and depression in recovered COVID-19 patients.

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

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

MR-PheWAS for the causal effects of serum magnesium on multiple disease outcomes in Caucasian descent

Magnesium is integral to many physiological processes, whereas variations in its levels, even within the normal range, can have critical implications for health. To explore the broad clinical effects of varying serum magnesium levels, we performed a two-sample Mendelian randomization and phenome-wide association study (MR-PheWAS) in the UK Biobank cohort. In total, MR-PheWAS analysis implicated a causal role of serum magnesium levels in five disease groups and six disease outcomes. In addition, our study indicated the gender-specific effects of nine disease groups/outcomes in MR estimated effects. The protein-protein interaction network demonstrated an interaction between the serum magnesium-associated gene DCDC1 and the cataract- associated gene PAX6. The present study verified several previously reported disease outcomes and identified novel potential disease outcomes for serum magnesium levels. The DCDC1 gene and the PAX6 gene may be the new targets for promoting the treatments of cataracts using magnesium intervention.

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MR-PheWAS implicates a causal role of serum Mg in 11 disease groups/outcomes

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Our study indicates gender-specific effects of 9 disease groups/outcomes

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Mg intervention may promote cataracts treatments through the DCDC1 and PAX6 genes

Upregulating Effect of Wheat on Brain-Derived Neurotrophic Factor in Human Lung Adenocarcinoma A549 Cells

The neurotrophic hypothesis of depression, that is, a deficiency in hippocampal brain-derived neurotrophic factor (BDNF) leads to depression, has gained widespread acceptance. BDNF is synthesized in various peripheral tissues such as the lung, kidney, liver, heart and testis, besides the brain. Peripheral BDNF can traverse the blood-brain barrier and reach the hippocampus; accordingly, substances that upregulate BDNF production in peripheral tissues may be useful in the treatment of depression. The Mediterranean diet, containing high amounts of whole grains including unrefined wheat, vegetables, fruits, nuts, and olive oil, reportedly reduces the risk of depression. The association between the high consumption of unrefined wheat in the Mediterranean diet and BDNF production in peripheral tissues is unclear. In this study, we investigated the BDNF production capacity of human lung adenocarcinoma cell line A549 and the effect of wheat on BDNF production in the cells. Methanol extracts of whole-wheat flour and wheat bran, which are forms of unrefined wheat, increased the BDNF level in the culture medium of A549 cells. However, methanol extract of wheat endosperm had no effect on the BDNF level in these cells. Our findings suggest that wheat bran contains ingredients that upregulate BDNF production in peripheral tissues, and unrefined wheat potentially contributes to the elevation in peripheral BDNF level.

Cross-sectional analysis of the health profile and dietary intake of a sample of Canadian adults diagnosed with non-alcoholic fatty liver disease

Background

Dietary intake is an important factor in the development and management of non-alcoholic fatty liver disease (NAFLD); however, optimal dietary composition remains unclear. Moreover, there is minimal evidence on the relationship between dietary intake and markers of liver health in Canadian adults diagnosed with NAFLD.

Objective

The aim of this study is to characterize the dietary intake of a sample of Canadian adults diagnosed with NAFLD and examine the correlations with markers of liver health.

Design

Forty-two adults recruited from the community and hepatology clinics in Calgary, Canada from 2016 to 2019 completed a 3-day food record. Anthropometrics, blood biomarkers, liver stiffness (FibroScan), and liver fat (magnetic resonance imaging) were measured. Nutrient intake was compared with the data from the 2004 and 2015 Canadian Community Health Surveys. Relationships were assessed using Pearson’s correlation and regression analysis.

Results

Relative to Canadian dietary recommendations, participants consumed lower magnesium, fiber, calcium, vitamin D, and vitamin E, and higher cholesterol, saturated fat, total fat, fructose, iron, vitamin B12, selenium, phosphorus, and sodium. Compared with the national average, participants consumed more energy, fiber, sodium, total fat, and saturated fat. Systolic blood pressure (P = 0.012), serum α-2 macroglobulin (P = 0.008), carbohydrate (P = 0.022), total fat (P = 0.029), and saturated fat intakes (P = 0.029) were associated with FibroScan scores. Liver fat was correlated with serum triglycerides (P < 0.001), trunk fat (P = 0.029), added sugar (P = 0.042), phosphorus (P = 0.017), and magnesium intake (P = 0.013). In females, selenium intake was associated with liver fat (P = 0.015) and FibroScan score (P = 0.05), while in males, liver fat was associated with trunk fat (P = 0.004), body weight (P = 0.004), high-density lipoprotein (P < 0.001), and fructose intake (P = 0.037). Regression analysis showed that increasing magnesium intake corresponds to a decrease in liver fat.

Conclusion

Despite the higher energy intake of participants, overall nutrient intake is low, suggesting lower diet quality. Associations between select micronutrients and liver health markers warrant further investigation.

Association between whole grain intake and all-cause mortality: a meta-analysis of cohort studies

Some observational studies have examined the association between dietary whole grain intake and all-cause mortality, but the results were inconclusive. We therefore conducted a meta-analysis to summarize the evidence from cohort studies regarding the association between whole grain intake and all-cause mortality. Pertinent studies were identified by searching PubMed, Embase and Web of Knowledge, up to February 28, 2016. Study-specific estimates were combined using random-effects models. Eleven prospective cohort studies involving 101,282 deaths and 843,749 participants were included in this meta-analysis. The pooled relative risk of all-cause mortality for the highest category of whole grain intake versus lowest category was 0.82 (95% confidence interval: 0.78, 0.87). There was a 7% reduction in risk associated with each 1 serving/day increase in whole grain intake (relative risk = 0.93; 95% confidence interval: 0.89, 0.97). No publication bias was found. This analysis indicates that higher intake of whole grain is associated with a reduced risk of all-cause mortality. The findings support current recommendations for increasing whole grain consumption to promote health and overall longevity.

Dietary total, animal, vegetable calcium and type 2 diabetes incidence among Korean adults: The Korean Multi-Rural Communities Cohort (MRCohort)

BACKGROUND AND AIMS

Although a possible mechanism for developing type 2 diabetes in relation to calcium intake has been suggested, there is currently little epidemiological evidence on the association between dietary calcium and type 2 diabetes (T2D). This study aimed to evaluate the prospective association between dietary calcium and T2D incidence among adults 40 years of age or over, from the Multi-rural Communities Cohort (MRCohort), South Korea.

METHODS AND RESULTS

In total, 8313 participants (3033 men and 5280 women) who did not have diabetes at baseline were recruited between 2005 and 2013. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (31,570 person-years), 322 T2D cases were newly diagnosed. Dietary calcium (total and vegetable calcium) were inversely associated with the risk of T2D incidence among women (IRR = 0.61, 95% CI = 0.43-0.86, P for trend = 0.007 in third tertile of baseline total calcium intake comparing to the first tertile; IRR = 0.57, 95% CI = 0.39-0.84, P for trend = 0.006 for baseline vegetable calcium intake), not for men. The tendency of those inverse associations remained in both the normal fasting blood glucose group and the impaired fasting blood glucose group and were independent of obesity, smoking, and magnesium intake.

CONCLUSIONS

Total and vegetable calcium may be inversely associated with T2D incidence among women, regardless of impaired fasting blood glucose group or normal group. The associations may be potentially dose-responsive. Moderate dietary calcium may be related to lower risk of T2D incidence comparing to low intake group among women.

Association of Serum Selenium, Zinc and Magnesium Levels with Glycaemic Indices and Insulin Resistance in Pre-diabetes: a Cross-Sectional Study from South India

A growing understanding of antioxidant mechanisms and insulin-like actions of trace elements selenium and zinc has rekindled researchers' interest towards their role in diabetes mellitus, nutritional management of which concentrates predominantly on macronutrient intake. However, selenium studies limiting largely to diabetes have yielded inconsistent results with sparse knowledge in the pre-diabetes population. This hospital-based cross-sectional study screened 300 people who came to the institutional hospital laboratory with fasting plasma glucose and glycosylated haemoglobin requisition over a period of 6 months. Thirty-five pre-diabetes subjects aged 25-45 years and 35 age-matched healthy controls were selected as per inclusion criteria and clinical history. Serum selenium was estimated by inductively coupled plasma-mass spectrometry, zinc and magnesium by colorimetric end-point methods and insulin by enzyme-linked immunosorbent assay, and insulin resistance was calculated using a homeostasis model assessment (HOMA) 2 calculator. Data analysis was done using SPSS ver. 16 employing an independent sample t test for intergroup comparison of means and Pearson's correlation for correlation analysis. Serum mineral levels in the pre-diabetes group (selenium 63.01 ± 17.6 μg/L, zinc 55.78 ± 13.49 μg/dL, magnesium 1.37 ± 0.38 mg/dL) were significantly reduced (p < 0.05) in comparison to the healthy controls (selenium 90.98 ± 15.81 μg/L, zinc 94.53 ± 15.41 μg/dL, magnesium 2.12 ± 0.22 mg/dL). A significant negative correlation was seen with glycaemic indices and insulin resistance. This study conducted in pre-diabetes subjects highlights a considerable deficiency of serum selenium, zinc and magnesium observed at a much earlier pre-clinical phase. This coupled with the evidence of a strong inverse association with glycaemic indices and insulin resistance postulates the role of mineral alterations in the pathophysiology of hyperglycaemia and insulin resistance.

Magnesium and type 2 diabetes

Type 2 diabetes is frequently associated with both extracellular and intracellular magnesium (Mg) deficits. A chronic latent Mg deficit or an overt clinical hypomagnesemia is common in patients with type 2 diabetes, especially in those with poorly controlled glycemic profiles. Insulin and glucose are important regulators of Mg metabolism. Intracellular Mg plays a key role in regulating insulin action, insulin-mediated-glucose-uptake and vascular tone. Reduced intracellular Mg concentrations result in a defective tyrosine-kinase activity, postreceptorial impairment in insulin action and worsening of insulin resistance in diabetic patients. A low Mg intake and an increased Mg urinary loss appear the most important mechanisms that may favor Mg depletion in patients with type 2 diabetes. Low dietary Mg intake has been related to the development of type 2 diabetes and metabolic syndrome. Benefits of Mg supplementation on metabolic profiles in diabetic patients have been found in most, but not all clinical studies and larger prospective studies are needed to support the potential role of dietary Mg supplementation as a possible public health strategy in diabetes risk. The aim of this review is to revise current evidence on the mechanisms of Mg deficiency in diabetes and on the possible role of Mg supplementation in the prevention and management of the disease.

Association between dietary whole grain intake and risk of mortality: two large prospective studies in US men and women

IMPORTANCE

Higher intake of whole grains has been associated with a lower risk of major chronic diseases, such as type 2 diabetes mellitus and cardiovascular disease (CVD), although limited prospective evidence exists regarding whole grains' association with mortality.

OBJECTIVE

To examine the association between dietary whole grain consumption and risk of mortality.

DESIGN, SETTING, AND PARTICIPANTS

We investigated 74 341 women from the Nurses' Health Study (1984-2010) and 43 744 men from the Health Professionals Follow-Up Study (1986-2010), 2 large prospective cohort studies. All patients were free of CVD and cancer at baseline.

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) for total mortality and mortality due to CVD and cancer according to quintiles of whole grain consumption, which was updated every 2 or 4 years by using validated food frequency questionnaires.

RESULTS

We documented 26 920 deaths during 2 727 006 person-years of follow-up. After multivariate adjustment for potential confounders, including age, smoking, body mass index, physical activity, and modified Alternate Healthy Eating Index score, higher whole grain intake was associated with lower total and CVD mortality but not cancer mortality: the pooled HRs for quintiles 1 through 5, respectively, of whole grain intake were 1 (reference), 0.99 (95% CI, 0.95-1.02), 0.98 (95% CI, 0.95-1.02), 0.97 (95% CI, 0.93-1.01), and 0.91 (95% CI, 0.88-0.95) for total mortality (P fortrend < .001); 1 (reference), 0.94 (95% CI, 0.88-1.01), 0.94 (95% CI, 0.87-1.01), 0.87 (95% CI, 0.80-0.94), and 0.85 (95% CI, 0.78-0.92) for CVD mortality (P fortrend < .001); and 1 (reference), 1.02 (95% CI, 0.96-1.08), 1.05 (95% CI, 0.99-1.12), 1.04 (95% CI, 0.98-1.11), and 0.97 (95% CI, 0.91-1.04) for cancer mortality (P fortrend = .43). We further estimated that every serving (28 g/d) of whole grain consumption was associated with a 5% (95% CI, 2%-7%) lower total morality or a 9% (95% CI, 4%-13%) lower CVD mortality, whereas the same intake level was nonsignificantly associated with lower cancer mortality (HR, 0.98; 95% CI, 0.94-1.02). Similar inverse associations were observed between bran intake and CVD mortality, with a pooled HR of 0.80 (95% CI, 0.73-0.87; P fortrend < .001), whereas germ intake was not associated with CVD mortality after adjustment for bran intake.

CONCLUSIONS AND RELEVANCE

These data indicate that higher whole grain consumption is associated with lower total and CVD mortality in US men and women, independent of other dietary and lifestyle factors. These results are in line with recommendations that promote increased whole grain consumption to facilitate disease prevention.

Serum zinc and magnesium concentrations in type 2 diabetes mellitus with periodontitis

AIM

The purpose of the study was to evaluate the serum levels of zinc (Zn) and magnesium (Mg) in type 2 diabetes mellitus (DM) with periodontitis patients and to correlate them with the levels of serum cholesterol, high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c), and triglycerides among the study subjects.

MATERIALS AND METHODS

A total of 600 subjects participated in the study, who were divided into four groups as control healthy individuals (group I), type 2 DM without periodontitis (group II), type 2 DM with periodontitis (group III), and periodontitis subjects without DM (group IV), matched for age, sex, and duration of diabetes. Serum concentrations of glucose, total cholesterol, triglycerides, HDL-c, Zn, and Mg were measured using enzymatic methods in an UV absorption spectrophotometer, and LDL-c was calculated using Friedwald's formula. Student's t-test, Pearson correlations, and analysis of variance (ANOVA) tests were used for statistical analysis.

RESULTS

The serum zinc level was found to be significantly increased in type 2 DM without periodontitis (group II) and periodontitis subjects without type 2 DM (group IV) (P < 0.0001), and the level was lowered in type 2 DM with periodontitis (group III) when compared to control. The serum Mg level was found to be significantly decreased (P < 0.0001) in group II, group III, and in group IV, when compared to control. We found a significant increased level of serum total cholesterol and LDL-c and decreased triglycerides and HDL-c in type 2 DM subjects with periodontitis (group III, P < 0.0001).

CONCLUSION

Patients with DM and periodontitis had altered metabolism of Zn and Mg which were linked to increased values of serum cholesterol and LDL-c and decreased HDL-c, contributing to the progression and complications of type 2 DM with periodontitis.

Magnesium in disease prevention and overall health

Magnesium is the fourth most abundant mineral and the second most abundant intracellular divalent cation and has been recognized as a cofactor for >300 metabolic reactions in the body. Some of the processes in which magnesium is a cofactor include, but are not limited to, protein synthesis, cellular energy production and storage, reproduction, DNA and RNA synthesis, and stabilizing mitochondrial membranes. Magnesium also plays a critical role in nerve transmission, cardiac excitability, neuromuscular conduction, muscular contraction, vasomotor tone, blood pressure, and glucose and insulin metabolism. Because of magnesium's many functions within the body, it plays a major role in disease prevention and overall health. Low levels of magnesium have been associated with a number of chronic diseases including migraine headaches, Alzheimer's disease, cerebrovascular accident (stroke), hypertension, cardiovascular disease, and type 2 diabetes mellitus. Good food sources of magnesium include unrefined (whole) grains, spinach, nuts, legumes, and white potatoes (tubers). This review presents recent research in the areas of magnesium and chronic disease, with the goal of emphasizing magnesium's role in disease prevention and overall health.

Fiber-free white flour with fructose offers a better model of metabolic syndrome

Background

The metabolic syndrome (MS) is a combination of metabolic abnormalities that lead to an increased risk of cardiovascular diseases. Due to its rising incidence and demanding life-long use of multiple drugs, there is a growing interest in testing and developing new allopathic, complementary and alternative therapies for controlling or curing disorders of MS. The discovery of new therapeutic modalities requires animal models of disease and currently available models have limitations. Developing an appropriate animal model for MS to achieve various therapeutic targets remains a challenge and this study aims to develop a rat model which closely depicts MS in humans.

Methodology

Rat model of MS was developed by replacing 60% of diet with fructose. Four groups of Sprague–Dawley rats were either given whole wheat or refined flour with and without fructose for 8 weeks. Data were analyzed on SPSS and Graphpad Prism using ANOVA with Tukey’s and Bonferonni tests for multiple group comparison. A p-value of less than 0.05 was considered significant for differences between groups.

Results

Replacing whole wheat with refined wheat flour in rat chow in 60% fructose-fed Sprague–Dawley rats resulted in hypertension (p 0.01), hyper-insulinemia (p < 0.001), hyperglycemia (p 0.03) and a reduction in HDL levels (p 0.002) at 4 weeks while hyper-triglyceridemia (p 0.001) with endothelial dysfunction was observed at 8 weeks.

Conclusion

It is concluded that the refined wheat flour with 60% fructose in diet hastens the development of metabolic syndrome in 4 weeks and replacing whole wheat flour with refined flour in diet induces a more effective abnormality including a low HDL. Further studies may be directed to assess the associated pathological changes, which can be used to study the effect of different therapeutic modalities on an animal model of MS with low HDL.

Effects of dietary carbohydrate replaced with wild rice (Zizania latifolia (Griseb) Turcz) on insulin resistance in rats fed with a high-fat/cholesterol diet

Wild rice (WR) is a very nutritious grain that has been used to treat diabetes in Chinese medicinal practice. City diet (CD) is based on the diet consumed by Asian area residents in modern society, which is rich in saturated fats, cholesterol and carbohydrates. The present study was aimed at evaluating the effects of replacing white rice and processed wheat starch of CD with WR as the chief source of dietary carbohydrates on insulin resistance in rats fed with a high-fat/cholesterol diet. Except the rats of the low-fat (LF) diet group, the rats of the other three groups, including to high-fat/cholesterol (HFC) diet, CD and WR diet, were fed with high-fat/cholesterol diets for eight weeks. The rats fed with CD exhibited higher weight gain and lower insulin sensitivity compared to the rats consuming a HFC diet. However, WR suppressed high-fat/cholesterol diet-induced insulin resistance. WR decreased liver homogenate triglyceride and free fatty acids levels, raised serum adiponectin concentration and reduced serum lipocalin-2 and visfatin concentrations. In addition, the WR diet potently augmented the relative expressions of adiponectin receptor 2, peroxisome proliferator-activated receptors, alpha and gamma, and abated relative expressions of leptin and lipocalin-2 in the tissues of interest. These findings indicate that WR is effective in ameliorating abnormal glucose metabolism and insulin resistance in rats, even when the diet consumed is high in fat and cholesterol.

Low serum magnesium level is associated with microalbuminuria in chinese diabetic patients

Whether serum magnesium deficiency is independently associated with the prevalence of microalbuminuria is still unclear. The objective of the present study was to elucidate the association between serum magnesium and microalbuminuria in diabetic patients. A cross-sectional study was conducted in 1829 diabetic subjects (aged ≥ 40 years) from Shanghai, China. Subjects were divided into three groups according to serum magnesium tertiles. A first-voided early-morning spot urine sample was obtained for urinary albumin-creatinine ratio (UACR) measurement. Microalbuminuria was defined as 30 mg/g ≤ UACR < 300 mg/g. Overall, 208 (11.37%) of the study population had microalbuminuria, with similar proportions in both genders (P = 0.44). The prevalence of microalbuminuria in tertile 1 of serum magnesium was higher than the prevalence in tertile 2 and tertile 3 (15.98%, 9.72%, and 8.46%, resp.; P for trend <0.0001). After adjustment for age, sex, BMI, blood pressure, lipidaemic profile, HbA1c, eGFR, history of cardiovascular disease, HOMA-IR, antihypertensive and antidiabetic medication, and diabetes duration, we found that, compared with the subjects in tertile 3 of serum magnesium, those in tertile 1 had 1.85 times more likeliness to have microalbuminuria. We concluded that low serum magnesium level was significantly associated with the prevalence of microalbuminuria in middle-aged and elderly Chinese.

Whole grains: benefits and challenges

Inclusion of whole grains (WG) in the diet is recommended in dietary guidance around the world because of their associations with increased health and reduced risk of chronic disease. WGs are linked to reduced risk of obesity or weight gain; reduced risk of cardiovascular disease (CVD), including coronary heart disease (CHD), hypertension, and stroke; improved gut health and decreased risk of cancers of the upper gut; perhaps reduced risk of colorectal cancer; and lower mortality rate. The 2005 United States Dietary Guidelines Advisory Committee has recommended that consumers make "half their grains whole." Yet, whole grains are puzzling both consumers and scientists. Scientists are trying to determine whether their health benefits are due to the synergy of WG components, individual WG components, or the fact that WG eaters make many of the recommended diet and lifestyle choices. Consumers need to understand the WG benefits and how to identify WG foods to have incentive to purchase and use such foods. Industry needs to develop great-tasting, clearly-labeled products. With both these factors working together, it will be possible to change WG consumption habits among consumers.

Whole grain cereals: functional components and health benefits

Cereal-based food products have been the basis of the human diet since ancient times. Dietary guidelines all over the world are recommending the inclusion of whole grains because of the increasing evidence that whole grains and whole-grain-based products have the ability to enhance health beyond the simple provision of energy and nutrients. In this review we will examine the main chemical components present in whole grains that may have health enhancing properties (dietary fiber, inulin, beta-glucan, resistant starch, carotenoids, phenolics, tocotrienols, and tocopherols) and the role that whole grains may play in disease prevention (cardiovascular diseases and strokes, hypertension, metabolic syndrome, type 2 diabetes mellitus, obesity, as well as different forms of cancer). The knowledge derived from the functional properties of the different chemical components present in whole grains will aid in the formulation and development of new food products with health enhancing characteristics.

Association of macrovascular complications of type 2 diabetes mellitus with serum magnesium levels

BACKGROUND

Diabetes mellitus and its complications are a significant cause of morbidity and mortality worldwide. Micronutrients have been evaluated as potential preventive and therapeutic measures in diabetes. The present study evaluated serum magnesium levels in diabetic patients-uncomplicated and those with macrovascular complications.

METHOD

This study was done on 150 subjects (60 normal, healthy controls and 90 diabetics). The 90 diabetic patients were selected in the following categories-30 patients without complications (Study Group I), 30 diabetic patients with coronary artery disease (Study Group II) and 30 diabetic patients with peripheral vascular disease (Study Group III). Plasma glucose, glycated hemoglobin and serum magnesium levels were estimated in all the patients.

RESULTS

Fasting plasma glucose and glycated hemoglobin levels were significantly higher in all the 3 study groups as compared to the controls, however, serum magnesium levels were significantly lower (p<0.05). In diabetic patients with coronary atherosclerosis or peripheral vascular disease, a significant negative correlation was observed between serum magnesium and fasting plasma glucose and glycated hemoglobin indicating the role of hypomagnesemia in diabetic complications.

CONCLUSION

Dietary supplementation with magnesium in addition to classical therapies for diabetes may help in prevention of diabetic complications.

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.

Inverse association between insulin resistance and frequency of milk consumption in low-income Argentinean school children

OBJECTIVE

To determine the association between milk consumption, lifestyle, components of the metabolic syndrome, and insulin resistance in school children.

STUDY DESIGN

Students (n = 365 [175M]) age 10 +/- 2.3 years from 2 poor suburbs of Buenos Aires were examined for body mass index, waist circumference, blood pressure, and Tanner stage in April 2007. Fasting concentrations of lipids, insulin, and glucose were determined. Mothers completed questionnaires about their children's lifestyle.

RESULTS

Approximately 14.0% of the children were obese, and 12.1% were overweight by use of norms from the Centers for Disease Control and Prevention. Half were at Tanner I. Mean values of waist circumference, systolic blood pressure, insulin resistance, and insulin were higher as subjects consumed more glasses of milk. Multiple regression analysis with insulin resistance as the dependent variable showed that there was a significant and positive association with triglyceridemia (beta = 0.007) and waist circumference (beta = 0.024), and a negative association with milk consumption (beta = -0.135) adjusted for blocks walked daily, TV viewing, soft drink consumption, parental educational level, sex, age, high-density lipoprotein (HDL) cholesterol, and systolic blood pressure (R(2) = 0.27).

CONCLUSIONS

Increased milk consumption was associated with greater insulin sensitivity, suggesting that it might reduce the risk of type 2 diabetes.

Grain foods and health: a primer for clinicians

Preventing many chronic diseases in North America requires substantial changes in dietary habits. Achieving a better balance of grain-based foods through the inclusion of whole grains is one scientifically supported dietary recommendation. Epidemiological and other types of research continue to document health benefits for diverse populations who have adequate intakes of both folic acid-fortified grain foods and whole grains. Folic acid fortification of grains is associated with reduced incidence of neural tube and other birth defects and may be related to decreased risk of other chronic disease. Whole grain intake is associated with reduced risk of chronic disease. Specifically, there is a decreased risk of obesity, coronary heart disease, hypertension, stroke, metabolic syndrome, type 2 diabetes, and some cancers observed among the highest whole grain eaters compared with those eating little or no whole grains. Nationally promulgated dietary recommendations such as those in the US Dietary Guidelines or by health promotion organizations such as the American Heart Association have incorporated the science on whole grains, recommending that consumers increase their whole grain intake. The US Dietary Guidelines state that consumers select half of the recommended bread and cereal servings as whole grain. Thus, the recommendations recognize the importance of adequate folic acid intake from refined, fortified grains to reduce the risk of birth defects and other disorders and to reflect the existing science on whole grains. The association between whole grains and decreased chronic disease is not surprising because whole grains are a source of vitamins, minerals, fatty acids, anti oxidants, and other phytochemicals and dietary fiber. Each of these components can act singly or in tandem to contribute to specific health-maintaining and disease-preventing mechanisms. Health professionals should be aware of these benefits and advocate these dietary strategies to help prevent chronic disease and to improve overall health.

KEYWORDS

nutrition; whole grain; folic acid; disease prevention; diet; mortality; diabetes; cereal; pseudocereal; phytochemicals; anti-oxidants.

Coffee intake and risk of incident diabetes in Puerto Rican men: results from the Puerto Rico Heart Health Program

OBJECTIVE

To study prospectively the association of coffee intake with incident diabetes in the Puerto Rico Heart Health Program cohort, comprising 9824 middle-aged men (aged 35-79 years).

METHODS

Of 9824 men, 3869 did not provide a fasting blood sample at baseline, 1095 had prevalent diabetes and 131 were not given fasting glucose tests at any subsequent study visit. Thus, the present analysis includes 4685 participants. Diabetes was ascertained at baseline and at two study visits between 1968 and 1975 using fasting glucose tests and self-reports of physician-diagnosed diabetes or use of insulin or hypoglycaemic medication. Logistic regression analysis was used to assess the association of coffee intake with risk of incident diabetes while adjusting for covariates (age, BMI, physical activity, smoking, education, alcohol intake, family history of diabetes, intakes of milk and sugar).

RESULTS

Five hundred and nineteen participants met the criteria for incident diabetes. Compared with those reporting intake of 1-2 servings of coffee/d, coffee abstainers were at reduced risk (OR = 0.64; 95 % CI 0.43, 0.94). Among coffee drinkers, there was a significant trend of decreasing risk by intake (P = 0.02); intake of >/=4 servings/d was associated with an odds ratio of 0.75 (95 % CI 0.58, 0.97).

CONCLUSIONS

Study findings support a protective effect of coffee intake on diabetes risk, while also suggesting that abstainers may be at reduced risk.

Minerals as ergogenic aids

Chromium, magnesium, zinc, and selenium are essential minerals for humans. They all are involved in a number of metabolic reactions in the body; many of these reactions are involved in energy metabolism, and hence it is thought that they may exert an ergogenic effect. However, the data on their effects as ergogenic aids have been equivocal. Longitudinal research is required (including supplementation studies) to follow athletes over time and properly evaluate effects of these minerals upon performance. The purpose of this review is to evaluate the ergogenic effects of chromium, magnesium, zinc, and selenium.

Magnesium, the metabolic syndrome, insulin resistance, and type 2 diabetes mellitus

Magnesium is an essential mineral and has been established as a cofactor for over 300 metabolic reactions in the body. Some research has indicated that lower intakes of magnesium and lower serum magnesium concentrations may lead to and are associated with the metabolic syndrome, insulin resistance, and/or type 2 diabetes mellitus. The goal of this review is to examine the research conducted on: 1) magnesium status, metabolic syndrome, insulin resistance, and type 2 diabetes mellitus, and 2) the effects of magnesium intake and/or supplementation on metabolic syndrome, insulin resistance, and type 2 diabetes mellitus. To make this review as current as possible, the majority of research articles reviewed were from 2000 to the present.

A prospective study of dairy consumption in relation to changes in metabolic risk factors: the Hoorn Study

OBJECTIVE

Higher dairy consumption has been suggested to reduce the risk of obesity and metabolic disturbances. The aim of our study was to investigate the prospective association between dairy consumption and changes in weight and metabolic disturbances.

METHODS AND PROCEDURES

Baseline dairy intake (servings/day) was assessed by a semi-quantitative food-frequency questionnaire in 1,124 participants of the Hoorn Study. Linear and logistic regression analyses were performed to investigate the association between dairy intake and 6.4-year change in weight, fat distribution, and metabolic risk factors (glucoses, lipids, blood pressure) and the incidence of metabolic syndrome (MS).

RESULTS

Baseline dairy consumption was not associated with changes in fasting and post-load glucose concentrations, serum lipid levels (high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and triglycerides), or blood pressure, nor with the risk of developing the MS in 6.4 years (odds ratio with 95% confidence interval was 0.86 (0.52-1.42) comparing highest with lowest quartile of dairy consumption). In subjects with BMI < 25 kg/m(2), higher dairy consumption was significantly associated with an increase in BMI, weight, waist, and a decrease in high-density lipoprotein.

DISCUSSION

Our results do not support the hypothesis that a higher dairy consumption protects against weight gain and development of metabolic disturbances in a Dutch elderly population.

Relationship between serum magnesium values, lipids and anthropometric risk factors

Serum magnesium (SMg) has been reported to negatively correlate with an atherogenic lipid profile in individuals with diabetes mellitus (DM) and metabolic syndrome. This study examines whether the relationships between SMg levels and biochemical and anthropometric risk factors for these conditions are also present in the general adult population.

DESIGN AND METHODS

Biochemical parameters and anthropometric variables were assessed in 1318 healthy adult subjects recruited from the Newfoundland population.

RESULTS

SMg positively correlated with age, and serum phosphate, calcium, albumin, total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride levels. SMg negatively correlated with HOMA-beta and percent body fat measured by DEXA. On sub-grouping subjects according to sex, menopausal status or after excluding subjects with DM, only a significant correlation of SMg with albumin, calcium, phosphate, and total cholesterol was common to all. Stepwise linear regression analysis revealed albumin, phosphate, age, total cholesterol, glucose, and body mass index as independent predictors of SMg levels.

CONCLUSIONS

These results indicate that SMg levels positively correlate with total cholesterol and possibly all lipoproteins in a large adult study population which suggests that variation of SMg with serum lipid levels may be different in healthy individuals compared with those with DM. We speculate on a possible binding interaction.

Breakfast cereals and risk of type 2 diabetes in the Physicians' Health Study I

OBJECTIVE

To examine the association between breakfast cereal consumption and the risk of type 2 diabetes (DM).

RESEARCH METHODS AND PROCEDURES

We analyzed prospectively data from 21,152 male participants of the Physicians' Health Study I. Consumption of breakfast cereals was estimated using an abbreviated food questionnaire, and incident DM was ascertained through yearly follow-up questionnaires.

RESULTS

The average age was 53.6 +/- 9.4 years (range, 39.7 to 85.9) during the initial assessment of cereal intake (1981 to 1983). During a mean follow-up of 19.1 years, 1958 cases of DM occurred. The crude incidence rates of DM were 57.7, 53.8, 43.5, and 35.4 cases/10,000 person-years for people reporting breakfast cereal intake of 0, <or=1, 2 to 6, and >or=7 servings/wk, respectively. In a Cox regression model adjusting for age, cigarette smoking, BMI, physical activity, vegetable consumption, and alcohol intake, hazard ratios (95% confidence interval) for DM were 1.0 (reference), 0.89 (0.79 to 1.00), 0.76 (0.67 to 0.86), and 0.63 (0.55 to 0.72) from the lowest to the highest category of cereal consumption, respectively (p for trend < 0.0001). In secondary analyses, the inverse association between cereal intake and DM was stronger with whole-grain than refined cereals.

DISCUSSION

These results suggest that intake of breakfast cereals might confer a lower risk of DM. Consumption of whole-grain products may help lower the risk of DM.

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.

Is higher dairy consumption associated with lower body weight and fewer metabolic disturbances? The Hoorn Study

BACKGROUND

Dairy consumption has been postulated to reduce the risk of obesity and metabolic disturbances.

OBJECTIVE

The aim of this study was to evaluate the associations of dairy consumption with body weight and other components of the metabolic syndrome.

DESIGN

We used cross-sectional data for 2064 men and women aged 50-75 y who participated in the Hoorn Study. The metabolic syndrome was defined according to the National Cholesterol Education Program Expert Panel. Dairy consumption was assessed by using a semiquantitative food-frequency questionnaire.

RESULTS

The median consumption of total dairy products was 4.1 servings/d. After adjustment for potential confounders (ie, dietary factors, physical activity, smoking, income, educational level, and antihypertensive medication), total dairy consumption was significantly associated with lower diastolic blood pressure (beta +/- SE: -0.31 +/- 0.12 mm Hg/serving) and higher fasting glucose concentrations (0.04 +/- 0.02 mmol/L per serving), but not with body weight or other metabolic variables (ie, lipids, postload glucose, or insulin). When different dairy products were distinguished, borderline significant (P < 0.10) inverse associations were observed for dairy desserts, milk, and yogurt with systolic (-1.26 +/- 0.58, -0.57 +/- 0.34, and -1.28 +/- 0.74 mm Hg/serving, respectively) and diastolic (-0.58 +/- 0.31, -0.57 +/- 0.18, and -0.35 +/- 0.40 mm Hg/serving, respectively) blood pressure, whereas cheese consumption was positively associated with body mass index (0.15 +/- 0.08/serving).

CONCLUSION

In an elderly Dutch population, higher dairy consumption was not associated with lower weight or more favorable levels of components of the metabolic syndrome, except for a modest association with lower blood pressure.

Magnesium metabolism in type 2 diabetes mellitus, metabolic syndrome and insulin resistance

Type 2 diabetes is characterized by cellular and extracellular Mg depletion. Epidemiologic studies showed a high prevalence of hypomagnesaemia and lower intracellular Mg concentrations in diabetic subjects. Insulin and glucose are important regulators of Mg metabolism. Intracellular Mg plays a key role in regulating insulin action, insulin-mediated-glucose uptake and vascular tone. Reduced intracellular Mg concentrations result in a defective tyrosine-kinase activity, post-receptorial impairment in insulin action, and worsening of insulin resistance in diabetic patients. Mg deficit has been proposed as a possible underlying common mechanism of the "insulin resistance" of different metabolic conditions. Low dietary Mg intake is also related to the development of type 2 diabetes. Benefits of Mg supplementation on metabolic profile in diabetic subjects have been found in most, but not all clinical studies, and larger prospective studies are needed to support the potential role of dietary Mg supplementation as a possible public health strategy in diabetes risk.

Toward a core nutraceutical program for cancer management

As previously suggested, it may be feasible to impede tumorevoked angiogenesis with a nutraceutical program composed of glycine, fish oil, epigallocatechin-3-gallate, selenium, and silymarin, complemented by a low-fat vegan diet, exercise training, and, if feasible, a salicylate and the drug tetrathiomolybdate. It is now proposed that the scope of this program be expanded to address additional common needs of cancer patients: blocking the process of metastasis; boosting the cytotoxic capacity of innate immune defenses (natural killer [NK] cells); preventing cachexia, thromboembolism, and tumor-induced osteolysis; and maintaining optimal micronutrient status. Modified citrus pectin, a galectin-3 antagonist, has impressive antimetastatic potential. Mushroombeta-glucans and probiotic lactobacilli can amplify NK activity via stimulatory effects on macrophages. Selenium, beta-carotene, and glutamine can also increase the number and/or cytotoxic activity of NK cells. Cachectic loss of muscle mass can be opposed by fish oil, glutamine, and beta-hydroxy-beta-methylbutyrate. Fish oil, policosanol, and vitamin D may have potential for control of osteolysis. High-dose aspirin or salicylates, by preventing NF-B activation, can be expected to aid prevention of metastasis and cachexia while down-regulating osteolysis, but their impacts on innate immune defenses will not be entirely favorable. A nutritional insurance formula crafted for the special needs of cancer patients can be included in this regimen. To minimize patient inconvenience, this complex core nutraceutical program could be configured as an oil product, a powder, and a capsule product, with the nutritional insurance formula provided in tablets. It would be of interest to test this program in nude mouse xenograft models.

PKC-mediated modulation of L-type calcium channels may contribute to fat-induced insulin resistance

Increased intracellular free calcium [Ca2+]i has been noted in adipocytes, platelets, and leukocytes of subjects with insulin resistance syndrome or allied disorders. In rodent studies, measures which increase [Ca2+]i in adipocytes and skeletal muscle are associated with impaired insulin signaling, attributable at least in part to diminished ability of insulin to activate phosphoserine phosphatase-1 (PP-1). In fat-fed insulin resistant rats, pre-treatment with a drug that selectively chelates intracellular calcium eliminates about half of the decrement in insulin-stimulated glucose uptake induced by fat feeding; since this chelator does not influence the insulin sensitivity of chow-fed rats, it is reasonable to suspect that fat feeding boosts [Ca2+]i in skeletal muscle, and that this effect is partially responsible for the associated reduction in insulin sensitivity. Clinical insulin resistance is associated with increased levels of triglycerides and other fatty acid metabolites in muscle fibers; this can give rise to diacylglycerol-mediated activation of PKC, which in turn compromises insulin signaling by triggering kinase cascades that phosphorylate IRS-1 on key serine residues. Yet there is also evidence that, in skeletal muscle, PKC activity up-regulates the function of L-type calcium channels, increasing their maximal conductance while left-shifting their voltage dependence. Thus, the PKC activation associated with fat overexposure might be expected to boost basal [Ca2+]i in skeletal muscle, potentially impeding insulin-mediated activation of PP-1. This hypothesis is consistent with several clinical studies demonstrating that long-acting inhibitors of L-type calcium channels can improve insulin sensitivity in overweight hypertensives; it should be readily testable in rodent models of fat-induced insulin resistance. Since parathyroid hormone can act on adipocytes and muscle to boost [Ca2+]i, mild secondary hyperparathyroidism associated with low calcium intakes and poor vitamin D status may contribute to insulin resistance, consistent with certain clinical and epidemiological findings. Magnesium, often thought of as a mild calcium antagonist, appears to have favorable effects on insulin sensitivity and risk for diabetes, and recent evidence indicates that increases of intracellular magnesium within the physiological range can diminish calcium influx through phosphorylated L-type calcium channels. It will be of interest to determine whether calcium antagonism does indeed underlie the favorable influence of good magnesium status on insulin function. A report that chromium picolinate can induce the plasmalemmal Ca2+-ATPase in smooth muscle cells, raises the possibility that modulation of calcium transport might play a role in the insulin-sensitizing efficacy of bioactive chromium.

Nutraceutical resources for diabetes prevention--an update

There is considerable need for safe agents that can reduce risk for diabetes in at-risk subjects. Although certain drugs--including metformin, acarbose, and orlistat--have shown diabetes-preventive activity in large randomized studies, nutraceuticals have potential in this regard as well. Natural agents which slow carbohydrate absorption may mimic the protective effect of acarbose; these include: soluble fiber--most notably glucomannan; chlorogenic acid--likely responsible for reduction in diabetes risk associated with heavy coffee intake; and legume-derived alpha-amylase inhibitors. There does not appear to be a natural lipase inhibitor functionally equivalent to orlistat, although there are poorly documented claims for Cassia nomame extracts. Metformin's efficacy reflects activation of AMP-activated kinase; there is preliminary evidence that certain compounds in barley malt have similar activity, without the side effects associated with metformin. In supraphysiological concentrations, biotin directly activates soluble guanylate cyclase; this implies that, at some sufficient intake, biotin should exert effects on beta cells, the liver, and skeletal muscle that favor good glucose tolerance and maintenance of effective beta cell function. Good magnesium status is associated with reduced diabetes risk and superior insulin sensitivity in recent epidemiology; ample intakes of chromium picolinate appear to promote insulin sensitivity in many individuals and improve glycemic control in some diabetics; calcium/vitamin D may help preserve insulin sensitivity by preventing secondary hyperparathyroidism. Although conjugated linoleic acid--like thiazolidinediones, a PPAR-gamma agonist--has not aided insulin sensitivity in clinical trials, the natural rexinoid phytanic acid exerts thiazolidinedione-like effect in animals and cell cultures, and merits clinical examination. Other natural agents with the potential to treat and possibly prevent diabetes include extracts of bitter melon and of cinnamon. Nutraceuticals featuring meaningful doses of combinations of these agents would likely have substantial diabetes-preventive efficacy, and presumably could be marketed legally as aids to good glucose tolerance and insulin sensitivity.