Naghmeh Mirhosseini

The Effect of Improved Serum 25-Hydroxyvitamin D Status on Glycemic Control in Diabetic Patients: A Meta-Analysis.

Background: Type 2 diabetes is a global health concern, with an increased prevalence and high cost of treatment. Objective: The aim of this systematic review and meta‐analysis was to determine the effect of vitamin D supplementation and improved vitamin D status on glycemia and insulin resistance in type 2 diabetic patients. Data Source: We searched PUBMED/Medline, Cumulative Index to Nursing and Allied Health, and Cochrane Library (until January 2017). Study Selection: Prospective clinical trials were selected evaluating the impact of vitamin D supplementation on glycosylated hemoglobin (HbA1c), serum fasting plasma glucose (FPG), and homeostatic model assessment of insulin resistance (HOMA‐IR) in diabetic patients. Data Extraction and Synthesis: We used a random‐effects model to synthesize quantitative data, followed by a leave‐one‐out method for sensitivity analysis. The systematic review registration was CRD42017059555. From a total of 844 entries identified via literature search, 24 controlled trials (1528 individuals diagnosed with type 2 diabetes) were included. The meta‐analysis indicated a significant reduction in HbA1c [mean difference: ‐0.30%; 95% confidence interval (CI): ‐0.45 to ‐0.15, P < 0.001], FPG [mean difference: ‐4.9 mg/dL (‐0.27 mmol/L); 95% CI: ‐8.1 to ‐1.6 (‐0.45 to ‐0.09 mmol/L), P = 0.003], and HOMA‐IR (mean difference: ‐0.66; 95% CI: ‐1.06 to ‐0.26, P = 0.001) following vitamin D supplementation and significant increase in serum 25‐hydroxyvitamin D levels [overall increase of 17 ± 2.4 ng/mL (42 ± 6 nmol/L)]. Conclusions: Vitamin D supplementation, a minimum dose of 100 &mgr;g/d (4000 IU/d), may significantly reduce serum FPG, HbA1c, and HOMA‐IR index, and helps to control glycemic response and improve insulin sensitivity in type 2 diabetic patients.

Cardiovascular responses to lead are biphasic, while methylmercury, but not inorganic mercury, monotonically increases blood pressure in rats.

Cardiovascular diseases, such as heart attack and stroke, are the major cause of death worldwide. It is well known that a high number of environmental and physiological risk factors contribute to the development of cardiovascular diseases. Although risk factors are additive, increased blood pressure (hypertension) is the greatest risk factor. Over the last two decades, a growing number of epidemiological studies associate environmental exposure to lead or mercury species with hypertension. However, cardiovascular effects beyond blood pressure are rarely studied and thresholds for effect are not yet clear. To explore effects of lead or mercury species on the cardiovascular system, normal male Wistar rats were exposed to a range of doses of lead, inorganic mercury or methylmercury through the drinking water for four weeks. High-resolution ultrasound was used to measure heart and vascular function (carotid artery blood flow) at baseline and at the end of the exposure, while blood pressure was measured directly in the femoral artery at the end of the 4-week exposure. After 4 weeks, blood pressure responses to lead were biphasic. Low lead levels decreased blood pressure, dilated the carotid artery and increased cardiac output. At higher lead doses, rats had increased blood pressure. In contrast, methylmercury-exposed rats had increased blood pressure at all doses despite dilated carotid arteries. Inorganic mercury did not show any significant cardiovascular effects. Based on the current study, the benchmark dose level 10% (BMDL10s) for systolic blood pressure for lead, inorganic mercury and methylmercury are 1.1, 1.3 and 1.0 μg/kg-bw/d, respectively. However, similar total mercury blood levels attributed to inorganic mercury or methylmercury produced strikingly different results with inorganic mercury having no observable effect on the cardiovascular system but methylmercury increasing systolic and pulse pressures. Therefore, adverse cardiovascular effects cannot be predicted by total blood mercury level alone and the mercury species of exposure must be taken into account.

The Association between Serum 25(OH)D Status and Blood Pressure in Participants of a Community-Based Program Taking Vitamin D Supplements

Background: Vitamin D deficiency is a risk factor for hypertension. Methods: We assessed 8155 participants in a community-based program to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) status and blood pressure (BP) and the influence of vitamin D supplementation on hypertension. Participants were provided vitamin D supplements to reach a target serum 25(OH)D > 100 nmol/L. A nested case-control study was conducted to examine the effect of achieving physiological vitamin D status in those who were hypertensive and not taking BP-lowering medication, and hypertensive participants that initiated BP-lowering medication after program entry. Results: At baseline, 592 participants (7.3%) were hypertensive; of those, 71% were no longer hypertensive at follow-up (12 ± 3 months later). There was a significant negative association between BP and serum 25(OH)D level (systolic BP: coefficient = −0.07, p < 0.001; diastolic BP: coefficient = −0.1, p < 0.001). Reduced mean systolic (−18 vs. −14 mmHg) and diastolic (−12 vs. −12 mmHg) BP, pulse pressure (−5 vs. −1 mmHg) and mean arterial pressure (−14 vs. −13 mmHg) were not significantly different between hypertensive participants who did and did not take BP-lowering medication. Conclusion: Improved serum 25(OH)D concentrations in hypertensive individuals who were vitamin D insufficient were associated with improved control of systolic and diastolic BP.

A Randomized Double-Blinded, Placebo-Controlled Trial Investigating the Effect of Fish Oil Supplementation on Gene Expression Related to Insulin Action, Blood Lipids, and Inflammation in Gestational Diabetes Mellitus-Fish Oil Supplementation and Gestational Diabetes

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, and it is mostly associated with postpartum diabetes, insulin resistance, and dyslipidemia. Fish oil (omega-3) supplementation has been shown to reduce the risk of different chronic diseases such as cardiovascular disease, type 2 diabetes, and cancers, though the evidence of its impact on gestational diabetes is scarce. Our goal in this study was to determine the effect of fish oil administration on gene expression related to insulin action, blood lipids, and inflammation in women with GDM. Participants with GDM (n = 40), aged 18–40 years, were randomized to take either 1000 mg fish oil capsules, containing 180 mg eicosapentaenoic acid and 120 mg docosahexaenoic acid (n = 20), or placebo (n = 20) twice a day for 6 weeks. Gene expression related to insulin, lipids, and inflammation was quantified in peripheral blood mononuclear cells (PBMCs) of GDM women using Reverse Transcription Polymerase Chain Reaction (RT-PCR) method. Results of RT-PCR indicated that omega-3 supplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.04) in PBMCs of patients with GDM, compared with the placebo. In addition, gene expression of the low-density lipoprotein receptor (LDLR) (P < 0.001), interleukin-1 (IL-1) (P = 0.007), and tumor necrosis factor alpha (TNF-α) (P = 0.01) was downregulated in PBMCs of women with GDM, following omega-3 supplementation. No significant effect of omega-3 supplementation was indicated on gene expression of IL-8 in PBMCs of patients with GDM. Overall, fish oil supplementation for 6 weeks in women with GDM significantly improved gene expression of PPAR-γ, IL-1, and TNF-α, but not gene expression of IL-8.

Vitamin D Supplementation, Glycemic Control, and Insulin Resistance in Prediabetics: A Meta-Analysis

Abstract Diabetes prevention is a public health priority. Vitamin D supplementation may help prevent the development of diabetes in persons at increased risk. We performed a meta-analysis of controlled clinical trials that assessed glycemic outcome measures among adults at risk for type 2 diabetes, including prediabetes, overweight, or obesity. We searched PUBMED/ MEDLINE, CINAHL, and Google Scholar databases for trials published prior to April 2017. Placebo-controlled clinical trials with random allocation to vitamin D with or without calcium supplementation were selected. Data collection included country, study design, inclusion criteria, sample size, form, and dose of vitamin D, supplementation interval, control group, duration, participant characteristics, comorbidities, baseline and follow-up serum 25-hydroxyvitamin D [25(OH)D] concentration, and available outcome measures [glycosylated hemoglobin (HbA1c), fasting plasma glucose, plasma glucose after 2-hour oral glucose tolerance test, and homeostatic model assessment of insulin resistance (HOMA-IR)]. Data synthesis was conducted using random-effect models (PROSPERO registration no. CRD42017055326). Twenty-eight trials, representing 3848 participants, met the eligibility criteria. Compared with the control group, vitamin D supplementation significantly reduced HbA1c level by –0.48% (95% CI, –0.79 to –0.18), fasting plasma glucose level by –0.46 mmol/L (95% CI, –0.74 to –0.19), and HOMA-IR level by –0.39 (95% CI, –0.68 to –0.11). Subgroup analysis revealed that the effects of vitamin D supplementation on different glycemic measures were influenced by age, calcium coadministration, vitamin D deficiency, serum 25(OH)D level after supplementation, and duration of supplementation. Vitamin D supplementation and improved vitamin D status improved glycemic measures and insulin sensitivity and may be useful as part of a preventive strategy for type 2 diabetes.

The Effects of Coenzyme Q10 Supplementation on Lipid Profiles Among Patients with Metabolic Diseases: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND AND OBJECTIVE Oxidative stress and inflammation are key parameters in developing metabolic disorders. Hence, antioxidant intake might be an appropriate approach. Several studies have evaluated the effect of coenzyme Q10 (CoQ10) supplementation on lipid profile among patients with metabolic diseases, though findings are controversial. The aim of this systematic review and meta-analysis was to determine the effects of CoQ10 supplementation on lipid profile in patients with metabolic disorders. METHODS We searched PubMed, EMBASE, Web of Science and Cochrane Library databases until July 2017. Prospective clinical trials were selected assessing the effect of CoQ10 supplementation on different biomarkers. Two reviewers independently assessed the eligibility of studies, extracted data, and evaluated the risk of bias of included studies. A fixed- or random-effects model was used to pool the data, which expressed as a standardized mean difference with 95% confidence interval. Heterogeneity was measured using a Q-test and with I2 statistics. RESULTS A total of twenty-one controlled trials (514 patients and 525 controls) were included. The meta-analysis indicated a significant reduction in serum triglycerides levels (SMD -0.28; 95% CI, -0.56, -0.005). CoQ10 supplementation also decreased total-cholesterol (SMD -0.07; 95% CI, -0.45, 0.31), increased LDL- (SMD 0.04; 95% CI, -0.27, 0.36), and HDL-cholesterol levels (SMD 0.10; 95% CI, -0.32, 0.51), not statistically significant. CONCLUSION CoQ10 supplementation may significantly reduce serum triglycerides levels, and help to improve lipid profiles in patients with metabolic disorders. Additional prospective studies are recommended using higher supplementation doses and longer intervention period.

Physiological serum 25-hydroxyvitamin D concentrations are associated with improved thyroid function—observations from a community-based program

PurposeVitamin D deficiency has been associated with an increased risk of hypothyroidism and autoimmune thyroid disease. Our aim was to investigate the influence of vitamin D supplementation on thyroid function and anti-thyroid antibody levels.MethodsWe constructed a database that included 11,017 participants in a health and wellness program that provided vitamin D supplementation to target physiological serum 25-hydroxyvitmain D [25(OH)D] concentrations (>100 nmol/L). Participant measures were compared between entry to the program (baseline) and follow-up (12 ± 3 months later) using an intent-to-treat analysis. Further, a nested case-control design was utilized to examine differences in thyroid function over 1 year in hypothyroid individuals and euthyroid controls.ResultsMore than 72% of participants achieved serum 25(OH)D concentrations >100 nmol/L at follow-up, with 20% above 125 nmol/L. Hypothyroidism was detected in 2% (23% including subclinical hypothyroidism) of participants at baseline and 0.4% (or 6% with subclinical) at follow-up. Serum 25(OH)D concentrations ≥125 nmol/L were associated with a 30% reduced risk of hypothyroidism and a 32% reduced risk of elevated anti-thyroid antibodies. Hypothyroid cases were found to have higher mean serum 25(OH)D concentrations at follow-up, which was a significant positive predictor of improved thyroid function.ConclusionThe results of the current study suggest that optimal thyroid function might require serum 25(OH)D concentrations above 125 nmol/L. Vitamin D supplementation may offer a safe and economical approach to improve thyroid function and may provide protection from developing thyroid disease.

Both high and low plasma levels of 25-hydroxy vitamin D increase blood pressure in a normal rat model

The lower threshold plasma 25-hydroxy vitamin D (25(OH)D) level for optimal cardiovascular health is unclear, whereas the toxicity threshold is less clear. The aim of this study was to examine the cardiovascular-vitamin D dose-response curve in a normal rat model. Doses of cholecalciferol ranged from deficiency to toxic levels (equivalent to human doses of 0, 0·015, 0·25 and 3·75mg/d) for 4 weeks, and then cardiovascular health was examined using blood pressure telemetry and high-resolution ultrasound in normal male rats (n 16/group, 64 rats total). After 1 month, only the 0·25mg/d group had plasma 25(OH)D that was within current recommended range (100-125 nmol/l), and all groups failed to change plasma Ca or phosphate. Systolic blood pressure increased significantly (10-15 mmHg) in the rat groups with plasma 25(OH)D levels at both 30 and 561 nmol/l (groups fed 0 and 3·75mg/d) compared with the group fed the equivalent to 0·015mg/d (43 nmol/l 25(OH)D). Although not significant, the group fed the equivalent to 0·25mg/d (108 nmol/l 25(OH)D) also showed a 10 mmHg increase in systolic blood pressure. Carotid artery diameter was significantly smaller and wall thickness was larger, leading to higher peak carotid systolic blood velocity in these two groups. Despite these vascular changes, cardiac function did not differ among treatment groups. The key finding in this study is that arterial stiffness and systolic blood pressure both showed a U-shaped dose-response for vitamin D, with lowest values (best cardiovascular health) observed when plasma 25(OH)D levels were 43 nmol/l in normal male rats.

The effects of melatonin administration on disease severity and sleep quality in children with atopic dermatitis: A randomized, double-blinded, placebo-controlled trial

The aim of this clinical trial was to determine the effects of melatonin administration on disease severity and sleep quality in children diagnosed with atopic dermatitis (AD).

Database Analysis of Depression and Anxiety in a Community Sample—Response to a Micronutrient Intervention

Background: Depression and anxiety are common mental health concerns worldwide. Broad-spectrum multi-vitamin/mineral approaches have been found to alleviate a number of psychiatric symptoms. We investigated the effects of a nutrient intervention program, which includes optimizing vitamin D levels, on depression and anxiety outcomes from community-based program. Methods: We evaluated self-reported health measures of depression and anxiety collected as part of a community-based program focused on optimizing overall health through nutritional supplementation, education and lifestyle advice. Results: Data were collected from 16,020 participants, with measures including European Quality of Life Five Dimensions (EQ-5D) and Targeted Symptoms List (TSL) providing self-reported depression and anxiety. More than 56% of participants were identified as having elevated levels of depression and anxiety at baseline as reported on the EQ-5D. After one year in the program, 49.2% (n = 7878) of participants who reported any level of depression or anxiety at baseline reported improvement at follow-up. Of those who reported severe/extreme depression at baseline (n = 829), 97.2% reported improvement after one year. Regression analyses revealed a significant association of improvement in depression and anxiety with higher vitamin D status (>100 nmol/L) and more strenuous physical activity. Conclusion: Overall, people from the general population who suffer from mood and anxiety problems may benefit from improved nutritional status achieved with nutritional supplements.