Zinc Supplementation and the Effects on Pregnancy Outcomes in Gestational Diabetes: a Randomized, Double-blind, Placebo-controlled Trial

Effects of Zinc Supplementation on Inflammatory Status and Nonalcoholic Steatohepatitis in Overweight or Obese Children: a Randomized Clinical Trial

The purpose of the present clinical trial was to determine the impact of zinc supplementation on serum liver enzymes, steatosis severity, lipid profile, and inflammatory status in overweight or obese children with nonalcoholic steatohepatitis (NASH). This randomized controlled trial was conducted by enrolling 60 children with NASH, aged 10-18 years old. The participants were randomly assigned to two groups that received either 30 mg/day of elemental zinc or placebo for 16 weeks. The severity of liver steatosis was evaluated using liver ultrasonography. Fasting blood samples were collected from each patient at the beginning and after 16 weeks of intervention to measure biochemical parameters. Following a 16-week intervention, zinc supplementation compared with placebo significantly decreased serum alanine aminotransferase (ALT) concentrations and high-sensitivity C-reactive protein and considerably enhanced HDL-cholesterol values. However, zinc intake had no considerable impact on aspartate aminotransferase, the severity of liver steatosis, anthropometric parameters, and other lipid indices versus the placebo group. Overall, zinc supplementation showed a promising impact on serum ALT, HDL-cholesterol, and inflammatory status in overweight or obese children suffering from NASH. Zinc supplementation may be a new strategy for the amelioration of NASH in overweight or obese children. This trial has been registered on the Iranian website for registration of clinical trials with the special ID of IRCT20200531047614N1 ( https://www.irct.ir/trial/48543 ).

The Effect of Oxidative Stress and Antioxidants Treatment on Gestational Diabetes Mellitus Outcome: A Scoping Review

Diagnosing a pregnant woman's glucose intolerance is referred to as gestational diabetes mellitus (GDM). Diabetes has been linked to enhanced oxidative stress. In this condition, oxidative stress may damage nucleic acids, fats, and proteins, which in turn affects cell and tissue functions. The present study highlights the relationship between oxidative stress and GDM, with a particular focus on the role of hyperglycemia-induced processes during reactive oxygen species (ROS) oversupply, followed by it discusses the oxidative stress biomarkers and assesses the effects of antioxidant supplements on glycemic control, inflammatory processes, and oxidative stress among individuals with GDM. Two reviewers conducted a comprehensive literature search utilizing the PubMed®, Web of Science™, and Scopus® databases. Only items published in the English language up until June 2024 were taken into account. We conducted a thorough search of research databases to identify articles that had the terms "oxidative stress" or "antioxidant" and "GDM". From this search, we selected 55 relevant papers to be included in this narrative review. Pregnancy-induced hypertension, postpartum bleeding, lower birth weight, a higher risk of hyperbilirubinemia in their neonates, fetal growth retardation, and birth asphyxia were revealed to be outcomes of women enduring major oxidative stress during pregnancy. Furthermore, tight glycemic control both before and throughout pregnancy as well as oxidative stress treatment may help women highly prone to GDM.

Effect of different nutrients on blood glucose, inflammatory response and oxidative stress in gestational diabetes mellitus: a network meta-analysis

We searched PubMed, Web of Science, Embase, The Cochrane Library, China Biomedical Literature Database and other databases from inception to June 2023. The included studies were randomised controlled trials (RCT). The studies were screened by four authors, divided into two independent pairs. A total of eighteen studies were included, including 1362 patients, involving twelve intervention measures. The different nutrients had a significant effect on improving blood glucose, reducing inflammation levels and reducing oxidative stress compared with placebo (P < 0.05). Cumulative probability ranking showed that vitamin A + vitamin D + vitamin E ranked first in lowering fasting blood glucose (standardised mean difference (SMD) = 41.30, 95 % CI (2.07, 825.60)) and postprandial 2-h blood glucose (SMD = 15.19, 95 % CI (4.16, 55.53)). In terms of insulin resistance index, the first highest probability ranking is vitamin D (SMD = 5.12, 95 % CI (0.76, 34.54)). In terms of reducing the high-sensitivity C-reactive protein level, the first in probability ranking is VE (SMD = 2.58, 95 % CI (1.87,3.55)). The results of cumulative probability ranking showed that Mg + Zn + Ca + VD ranked first in reducing TNF-α (SMD = 1.90, 95% CI (0.40, 9.08)) and IL-6 (SMD = 1.83, 95 % CI (0.37, 9.12)). In terms of reducing malondialdehyde levels, the first ranked probability is VB1 (SMD = 4.99, 95 % CI (1.85, 13.46)). Cumulative probability ranking results showed that Ca + VD ranked first in reducing total antioxidant capacity (SMD = 0.66,95 % CI (0.38, 1.15)) and glutathione (SMD = 1.39, 95 % CI (0.43, 4.56)). In conclusion, nutritional interventions have significant effects on improving blood glucose, inflammatory levels and oxidative stress in patients with gestational diabetes. Due to the high uncertainty in the results and differences in the number and quality of studies included, the reliability of the conclusions still needs to be validated by conducting large-sample, high-quality RCT studies.

The effects of zinc supplementation on the metabolic factors in patients with non-alcoholic fatty liver disease: a randomized, double-blinded, placebo-controlled clinical trial

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with metabolic factors including obesity, dyslipidemia, insulin resistance, oxidative stress, and elevated inflammatory factors. Zinc (Zn) supplementation has been investigated as a potential adjunctive therapy in managing NAFLD outcomes.

METHODS

In this randomized, double-blinded, controlled clinical trial, 50 overweight or obese participants with NAFLD were randomized into 2 groups of 25 and received either 30 mg of daily Zn or a placebo for 8 weeks. Both groups were invited to follow a balanced energy-restricted diet and physical activity recommendations.

RESULTS

Based on the between-group comparison, Zn supplementation caused a significant increase in the Zn level (P < 0.001) and a significant decrease in weight (P = 0.004), body mass index (BMI) (P = 0.002), waist circumference (P = 0.010), aspartate transaminase (AST) (P = 0.033), total cholesterol (TC) (P = 0.045), and low-density lipoprotein cholesterol (LDL-C) (P = 0.014), but it had no significant effect on alanine transaminase (ALT), fasting blood sugar (FBS), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), high-density lipoprotein (HDL), triglyceride (TG), high-sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA), and total antioxidant capacity (TAC) (P > 0.05).

CONCLUSION

The results of the present study indicated that 8-week supplementation of 30 mg daily Zn may increase the Zn serum level and decline anthropometric parameters, AST, TC, and LDL-C in NAFLD patients, so further research is suggested in the future.

TRIAL REGISTRATION

The trial was retrospectively registered at IRCT.ir as IRCT20191015045113N1 (December/8/2019).

The Effect of Pumpkin Seed Biscuits on Nutritional and Zinc Status: A Randomized Controlled Trial in Pregnant Women

BACKGROUND: In several studies in Indonesia, low birth weight (LBW) is shown as the most dominant risk factor for stunting. Some of the causes of LBW are chronic energy deficiency during pregnancy, anemia during pregnancy, lack of nutrient supply during pregnancy, pregnancy complications, maternal parity, and birth spacing. In this case, women commonly suffer from micronutrient deficiencies including iodine, iron, Vitamin A, zinc, and folate. Related to this, about 80% of pregnant women in the world fulfill normative pregnancy needs due to inadequate zinc intake. One source of micronutrients rich in zinc is pumpkin seeds. The nutritional potential of pumpkin seeds is realized in the form of food products for pregnant women, including amino acids. One example of pumpkin seed fortification has been assessed in biscuit products by trained panelists and consumers, obtaining results that 20% additional pumpkin seed flour to biscuits becomes the best treatment. Meanwhile, in the case of this study, we expect that the pumpkin seed biscuits provided can increase the energy intake in pregnant women because when pumpkin seeds are added, the nutrition contained in the biscuits is also increased, in this case, the nutrition includes the zinc and Fe. AIM: The purpose this research is to figure out how pumpkin seed biscuits affect pregnant women concerning their nutrition status and serum zinc levels. METHODS: The method employed was a double-blind and randomized experimental research involving pre- and post-test control groups. The inclusion criteria of the participants involved were pregnant women aged 20–35 years old who were at their first and second trimesters of pregnancy and parity one to three and singleton pregnancy. Meanwhile, the exclusion criteria of the participants were pregnant women suffering from severe complications. There were 89 pregnant women further gathered in this study, but only 66 of them met the criteria and idled into two groups. In this case, one group received the pumpkin seed biscuit intervention, while the other received placebo biscuits. The intervention was conducted for 90 days where the pregnant women were provided with four biscuits for daily consumption. RESULTS: The nutritional status parameter of pregnant women involved in the current research was assessed, including body weight, mid-upper arm circumference (MUAC), and serum zinc levels. In this case, the average serum zinc level obtained was 48.75 g/dL from 60 pregnant women. Furthermore, a significant increase occurred in nutritional status for each group, marked by body weight gain, and increased MUAC. However, no significant difference emerged between the pumpkin seed biscuit group and the placebo biscuit group with p = 0.914 and p = 0.916, respectively. A significant increase in zinc levels was observed in both groups. In this case, changes in zinc levels between the two groups were significantly different (13.72 ± 1.84 vs. 9.81 ± 11.81, p = 0.007). CONCLUSION: Giving pumpkin seed biscuits contribute to weight gain and increase the MUAC the pregnant women which, in turn, improves their nutritional status and serum zinc.

Relationship between gestational diabetes and serum trace element levels in pregnant women from Eastern Iran: a multivariate approach

The prevalence of gestational diabetes mellitus (GDM) has increased over the recent decades. Exposure to environmental contaminants may be a risk factor for the development of GDM, but this is heavily dependent on particular circumstances. Studies on various areas linking various factors are therefore needed. We examined the associations between serum trace element levels and incidents of GDM among 102 pregnant women (diabetic n = 60 and healthy n = 42) living in Birjand (Iran). Blood serum samples were analyzed for concentrations of elements linked to particulate matter air pollution such as As, Cd, Cu, Hg, Mn, Ni, V, and Zn. Concentrations of As (8.58 vs. 3.15 μg/L), Cd (6.74 vs. 0.52 μg/L), and Hg (2.60 vs. 0.90 μg/L) were significantly higher in women with GDM. Risk difference (RD) estimation showed that As, 0.516 (0.355, 0.677); Cd, 0.719 (0.534, 0.904); and Hg, 0.505 (0.276, 0.735) increase GDM probability, while V lower that risk, -0.139 (-0.237, -0.042). With the principal component analysis, we were able to separate subjects according to their GDM status based on element levels. Such classification revealed very high efficiency with a true positive rate of 93%, according to linear discriminant analysis. GDM subjects presented higher levels of As, Cd, and Hg, indicating that these elements may disturb insulin metabolism and promote the development of GDM. Therefore, we conclude that systematic monitoring of trace elements followed by multivariate modeling in women planning pregnancy should be carried out to prevent the development of GDM.

Is serum zinc status related to gestational diabetes mellitus? A meta-analysis

Gestational diabetes mellitus (GDM) is a common medical disorder that begins during pregnancy. The present work aimed to investigate the relationship of maternal or foetal circulatory zinc levels with GDM. Related studies were retrieved against the PubMed/Medline, Web of Science, Scopus databases till July 2020. The overall effects were expressed as standard mean difference (SMD). Furthermore, the random effects model was used to assess the summarised risk ratios (SRRs) to determine the relationship between zinc and the risk of GDM. A total of 15 articles involving were retrieved for meta‐analysis; in the meantime, 4955 subjects including 1549 GDM cases were enrolled for quantitative analysis. Compared with normal control, GDM cases had decreased circulating zinc level on the whole, but the difference was not statistically significant (SMD = −0.40, 95%CI: −0.80 to −0.00, P = 0.05). Interestingly, upon subgroup analysis stratified by serum zinc content but not plasma zinc concentration, there was significant difference in zinc content between GDM cases and normal controls (SMD = −0.56; 95%CI: −1.07 to −0.04, P = 0.03). Meanwhile, subgroup analysis also revealed similar tendency among the Asians and during the 2nd trimester, but not among the Caucasians or during the 1st or 3rd trimester. Data extracted from four studies that compared pregnant women with GDM in the high level of zinc and GDM in the low level of zinc yielded an SRR of 0.929 (95%CI: 0.905–0.954). According to existing evidence, the serum zinc content decreases among GDM cases compared with subjects with no abnormality in glucose tolerance, in particular among the Asians and during the second trimester. Nonetheless, more well designed prospective study should be carried out for understanding the dynamic relationship of zinc level with the incidence of GDM.

The Effect of Dietary Supplements on Oxidative Stress in Pregnant Women with Gestational Diabetes Mellitus: A Network Meta-Analysis

BACKGROUND

Gestational diabetes mellitus (GDM) exacerbates the oxidative stress status of the pregnant women. Τo improve the oxidative stress status, several therapeutic interventions have been suggested. The aim of this network meta-analysis is to assess the effect of different dietary supplements on the oxidative stress status in pregnant women with GDM.

METHODS

A network meta-analysis of randomized control trials was performed comparing the changes delta (Δ) in total antioxidant capacity (TAC) and concentration of malondialdehyde (MDA) as primary outcomes, following different therapeutic interventions with dietary supplements in pregnant women with GDM. Four electronic databases and grey literature sources were searched. The secondary outcomes were other markers of oxidative stress.

RESULTS

The meta-analysis included 16 studies of 1173 women with GDM. Regarding ΔTAC: probiotics and omega-3 with vitamin E were superior to placebo/no intervention. Regarding ΔMDA: vitamin D with calcium, omega-3, vitamin D, omega-3 with vitamin E, magnesium with zinc and calcium, and probiotics were superior to placebo/no intervention.

CONCLUSIONS

Administration of dietary supplements in women with GDM can be helpful in limiting the oxidative stress which develop in these pregnancies.

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus

BACKGROUND

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus (GDM) have not been well established. We conduct a meta-analysis to evaluate the effects of vitamin and mineral supplementation on glycemic control, inflammation and oxidative stress for women with GDM.

METHODS

A systematic search of randomized controlled trials (RCTs) was conducted from PubMed, Embase, Web of Science and Cochrane Library up to July, 2020. Various results were pooled by using Review manager 5.3 and Stata 12.0. Mean difference (MD) with 95% confidence interval (CI) was estimated. Heterogeneity between studies was assessed by I-squared (I²) tests.

RESULTS

Six hundred ninety-eight patients from 12 trials were included in our meta-analysis. Magnesium, zinc, selenium, calcium, vitamin D and E (alone or in combination) were found to significantly improve glycemic control in women with GDM compared to those receiving placebos: fasting plasma glucose (FPG) (MD = - 9.02; 95% CI: - 12.09, - 5.96; P < 0.00001), serum insulin (MD = - 4.33; 95% CI: - 5.35, - 3.32; P < 0.00001), homeostasis model assessment-insulin resistance (HOMA-IR) (MD = - 1.34; 95% CI: - 1.60, - 1.07; P < 0.00001), and homeostasis model of assessment for β cell function (HOMA-B) (MD = - 15.58; 95% CI: - 23.70, - 7.46; P = 0.0002). Vitamin and mineral supplementation was found to attenuated inflammation and oxidative stress through decreasing high-sensitivity C-reactive protein (hs-CRP) (MD = - 1.29; 95% CI: - 1.82, - 0.76; P < 0.00001), malondialdehyde (MDA) (MD = - 0.71; 95% CI: - 0.97, - 0.45; P < 0.00001), and increasing total antioxidant capacity (TAC) (MD = 45.55; 95% CI: 22.02, 69.08; P = 0.0001).

CONCLUSIONS

This meta-analysis shows that vitamin and mineral supplementation significantly improved glycemic control, attenuated inflammation and oxidative stress in women with GDM.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy, such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although these associations have not yet been established. This is an update of a review first published in 1997 and subsequently updated in 2007, 2012 and 2015.

OBJECTIVES

1. To compare the effects on maternal, fetal, neonatal and infant outcomes in healthy pregnant women receiving zinc supplementation versus no zinc supplementation, or placebo. 2. To assess the above outcomes in a subgroup analysis reviewing studies performed in women who are, or are likely to be, zinc-deficient.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 July 2020), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation versus no zinc supplementation or placebo administration during pregnancy, earlier than 27 weeks' gestation. We excluded quasi-randomised controlled trials. We intended to include studies presented only as abstracts, if they provided enough information or, if necessary, by contacting authors to analyse them against our criteria; we did not find any such studies.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

For this update, we included 25 randomised controlled trials (RCTs) involving over 18,000 women and their babies. The overall risk of bias was low in half of the studies. The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence). Further, zinc supplementation may make little or no difference in reducing the risk of stillbirth (RR 1.22, 95% CI 0.80 to 1.88; 7 studies, 3295 participants; low-certainty evidence), or perinatal deaths (RR 1.10, 95% CI 0.81 to 1.51; 2 studies, 2489 participants; low-certainty evidence). It is unclear whether zinc supplementation reduces neonatal death, because the certainty of the evidence is very low. Finally, for other birth outcomes, zinc supplementation may make little or no difference to mean birthweight (MD 13.83, 95% CI -15.81 to 43.46; 22 studies, 7977 participants; low-certainty evidence), and probably makes little or no difference in reducing the risk of low birthweight (RR 0.94, 95% CI 0.79 to 1.13; 17 studies, 7399 participants; moderate-certainty evidence) and small-for-gestational age babies when compared to placebo or no zinc supplementation (RR 1.02, 95% CI 0.92 to 1.12; 9 studies, 5330 participants; moderate-certainty evidence). We did not conduct subgroup analyses, as very few studies used normal zinc populations.

AUTHORS' CONCLUSIONS

There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes. Future research to address ways of improving the overall nutritional status of pregnant women, particularly in low-income regions, and not looking at zinc in isolation, should be an urgent priority.

Comments on "Zinc supplementation is associated with a reduction in serum markers of inflammation and oxidative stress in adults: A systematic review and meta-analysis of randomized controlled trials"

We carefully read the meta-analysis by Hosseini et al. (1) on the effects of Zinc supplementation on inflammation and oxidative stress markers, which was recently published in Cytokine journal. The authors show that Zinc supplementation significantly decreased CRP, TNF, and MDA while having no significant effect on IL-6. Although respecting the authors' efforts, we are concerned about different aspects of the current review: the inadequate search strategy, the methodological flaws, the interpretation of data, and the reporting of the results that might lead to biased results.

Progress of Clinical Trials for the Treatment of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common and severe complications of pregnancy, which is not only associated with perinatal complications but also has a long-term adverse effect on maternal and their offsprings. At present, the treatment of GDM focuses on the control of maternal blood glucose. Although lifestyle changes, hypoglycemic drugs, blood glucose monitoring, and other medicines that can improve maternal blood glucose to a certain extent, there are still some patients affected and have adverse pregnancy outcomes. The prevention of GDM and the treatment of improving pregnancy outcomes are urgently needed. This review summarized recently published clinical trials related with the treatment of GDM, aiming to provide additional options for the treatment of GDM.

Associations of Dietary Bioactive Compounds with Maternal Adiposity and Inflammation in Gestational Diabetes: An Update on Observational and Clinical Studies

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that adversely affects maternal and offspring health. Maternal obesity, oxidative stress, and inflammation have been implicated in GDM. In non-pregnant adults, intakes of dietary bioactive compounds inversely associate with insulin resistance and inflammation. However, associations of dietary bioactive compounds with biomarkers of adiposity, antioxidant vitamin and mineral status, oxidative stress, and inflammation in GDM have not been fully elucidated. We addressed this gap by conducting a semi-quantitative review of observational studies and randomized controlled trials published between 2010 and 2020 and retrieved from Google Scholar, Medline, and PubMed. Our analysis revealed that women with GDM are more likely to consume a pro-inflammatory diet before pregnancy and tend to consume fewer antioxidant vitamins and minerals during pregnancy than healthy pregnant women. Women with GDM also have lower blood levels of vitamins A, C, and D and certain adipokines. Several dietary bioactive compounds were noted to improve antioxidant status and biomarkers of inflammation. The Dietary Approaches to Stop Hypertension (DASH) diet and soybean oligosaccharides increased antioxidant enzyme levels. Supplementing n-3 fatty acids, probiotics, synbiotics, and trace elements increased antioxidant enzymes and reduced hs-CRP and MDA. Improvements in inflammation by vitamin D may be contingent upon co-supplementation with other dietary bioactive compounds.

Safety and efficacy of supplements in pregnancy

Pregnancy is a time where expectant mothers often focus on their diet to improve their own health and to preserve the future health of their children. There is much conflicting information in the public domain about the safety and/or efficacy of nutritional supplements during pregnancy. Despite this, the market for supplements is growing. This review discusses the roles of critical nutrients in pregnancy and the available evidence on the use of supplements to reduce risks and improve maternal and fetal outcomes. Recommendations are made for pregnant women, taking into account safety data and tolerable upper intakes set for pregnant women. It is important for dieticians, nutritionists, physicians, and other healthcare providers to be able to offer accurate and evidence-based advice on supplement use in pregnancy. Routine supplementation may not be necessary for all, but individuals at risk are identified.

The Role of Fe, Zn, and Cu in Pregnancy

Iron (Fe), copper (Cu), and zinc (Zn) are microelements essential for the proper functioning of living organisms. These elements participatein many processes, including cellular metabolism and antioxidant and anti-inflammatory defenses, and also influence enzyme activity, regulate gene expression, and take part in protein synthesis. Fe, Cu, and Zn have a significant impact on the health of pregnant women and in the development of the fetus, as well as on the health of the newborn. A proper concentration of these elements in the body of women during pregnancy reduces the risk of complications such as anemia, induced hypertension, low birth weight, preeclampsia, and postnatal complications. The interactions between Fe, Cu, and Zn influence their availability due to their similar physicochemical properties. This most often occurs during intestinal absorption, where metal ions compete for binding sites with transport compounds. Additionally, the relationships between these ions have a great influence on the course of reactions in the tissues, as well as on their excretion, which can be stimulated or delayed. This review aims to summarize reports on the influence of Fe, Cu, and Zn on the course of single and multiple pregnancies, and to discuss the interdependencies and mechanisms occurring between Fe, Cu, and Zn.

The influence of zinc supplementation on metabolic status in gestational diabetes: a meta-analysis of randomized controlled studies

INTRODUCTION

Zinc supplementation has emerged as an important approach to improve metabolic status in gestational diabetes. However, its use has not been well established. We conduct a systematic review and meta-analysis to evaluate the efficacy of zinc supplementation to improve metabolic status for gestational diabetes.

METHODS

PubMed, Embase, and the Cochrane Central Register of Controlled Trials are searched. Randomized controlled trials (RCTs) assessing the influence of zinc supplementation (or its combination) versus placebo on metabolic status of gestational diabetes are included. Two investigators independently have searched articles, extracted data, and assessed the quality of included studies. Meta-analysis is performed using the random-effect model.

RESULTS

Five RCTs involving 263 patients are included in the meta-analysis. Compared with control intervention for gestational diabetes, zinc supplementation is associated with significantly reduced FPG (std. MD = -0.52; 95% CI = -0.82 to -0.21; p = .0008), insulin (std. MD = -0.68; 95% CI = -0.98 to -0.37; p < .0001), HOMA-IR (std. MD = -0.77; 95% CI = -1.08 to -0.45; p < .00001), and increased QUICKI (std. MD = 0.58; 95% CI = 0.28-0.89; p = .0002) as well as zinc change (std. MD = 0.90; 95% CI = 0.58-1.21; p < .00001), but has no remarkable influence on LDL-cholesterol (std. MD = -0.13; 95% CI = -0.43-0.17; p = .40), and total cholesterol (std. MD = -0.28; 95% CI = -0.63-0.07; p = .11).

CONCLUSIONS

Zinc supplementation is effective to decrease FPG, insulin, HOMA-IR and improve QUICKI in gestational diabetes, but has no significant impact on LDL-cholesterol and total cholesterol.

Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Although many studies have shown that low zinc status is associated with diabetes, the putative effects of zinc supplementation on glycemic control are inconclusive.

OBJECTIVES

The aim of this meta-analysis of randomized controlled trials was to assess the effects of zinc supplementation in preventing and managing diabetes.

METHODS

PubMed, Embase, and the Cochrane Library were searched for articles that were published through February 10, 2019 and contained estimates for the outcomes of interest. The pooled results were then analyzed with the use of a random-effects model.

RESULTS

Thirty-two placebo-controlled interventions were extracted from 36 publications, involving a total of 1700 participants in 14 countries. Overall, compared with their respective control groups, the subjects in the zinc-supplementation group had a statistically significant reduction in fasting glucose [FG, weighted mean difference (WMD): -14.15 mg/dL; 95% CI: -17.36, -10.93 mg/dL], 2-h postprandial glucose (WMD: -36.85 mg/dL; 95% CI: -62.05, -11.65 mg/dL), fasting insulin (WMD: -1.82 mU/L; 95% CI: -3.10, -0.54 mU/L), homeostasis model assessment for insulin resistance (WMD: -0.73; 95% CI: -1.22, -0.24), glycated hemoglobin (WMD: -0.55%; 95% CI: -0.84, -0.27%), and high-sensitivity C-reactive protein (WMD: -1.31 mg/L; 95% CI: -2.05, -0.56 mg/L) concentrations. Moreover, subgroup analyses revealed that the effects of zinc supplementation on FG are significantly influenced by diabetic status and the formulation of the zinc supplement.

CONCLUSIONS

Our analysis revealed that several key glycemic indicators are significantly reduced by zinc supplementation, particularly the FG in subjects with diabetes and in subjects who received an inorganic zinc supplement. Together, these findings support the notion that zinc supplementation may have clinical potential as an adjunct therapy for preventing or managing diabetes. This trial was registered at PROSPERO as CRD42018111838.

The effects of magnesium-zinc-calcium-vitamin D co-supplementation on biomarkers of inflammation, oxidative stress and pregnancy outcomes in gestational diabetes

BACKGROUND

Diabetes is the most common medical condition in pregnant women and its complications affect both mother and fetus. The beneficial effects of vitamin D on gestational diabetes have been shown, though data on the effects of co-administration of vitamin D with other nutrients on pregnancy outcomes in gestational diabetes (GDM) are scarce. This study was aimed to determine the effects of magnesium-zinc-calcium-vitamin D co-supplementation on parameters of inflammation and oxidative stress, and pregnancy outcomes among women with GDM.

METHODS

This randomized, double-blinded, placebo-controlled trial was conducted on 60 women with GDM not taking oral hypoglycemic agents. Patients were randomly assigned to take magnesium-zinc-calcium-vitamin D supplements (n = 30) or placebo (n = 30) for 6 weeks. Fasting blood samples were collected from participants at baseline and after the 6-week intervention to measure related biomarkers.

RESULTS

Magnesium-zinc-calcium-vitamin D co-supplementation resulted in a significant reduction in serum high-sensitivity C-reactive protein (- 1.2 ± 3.5 vs. + 0.8 ± 2.0 mg/L, P = 0.01) and plasma malondialdehyde concentrations (- 0.3 ± 0.3 vs. + 0.3 ± 1.1 μmol/L, P = 0.003), as well as a significant increase in total antioxidant capacity levels (+ 38.2 ± 76.5 vs. -16.3 ± 93.5 mmol/L, P = 0.01), compared to placebo. We found a decreasing trend in newborns' weight (3089.8 ± 519.9 vs. 3346.3 ± 411.1 g, P = 0.05) and the rate of macrosomia (3.3% vs. 16.7%, P = 0.08) in the magnesium-zinc-calcium-vitamin D supplemented women.

CONCLUSIONS

Overall, the findings of this study have demonstrated that magnesium-zinc-calcium-vitamin D co-supplementation for 6 weeks to women with GDM may reduce biomarkers of inflammation and oxidative stress. This study was retrospectively registered on 25 April 2017 in the Iranian website ( www.irct.ir ) for clinical trials registration ( http://www.irct.ir : IRCT201704225623N109).

Implications of impaired zinc homeostasis in diabetic cardiomyopathy and nephropathy

Impaired zinc homeostasis is observed in diabetes mellitus (DM2) and its complications. Zinc has a specific role in pancreatic β-cells via insulin synthesis, storage, and secretion. Intracellular zinc homeostasis is tightly controlled by zinc transporters (ZnT and Zip families) and metallothioneins (MT) which modulate the uptake, storage, and distribution of zinc. Several investigations in animal models demonstrate the protective role of MT in DM2 and its cardiovascular or renal complications, while a copious literature shows that a common polymorphism (R325W) in ZnT8, which affects the protein's zinc transport activity, is associated with increased DM2 risk. Emerging studies highlight a role of other zinc transporters in β-cell function, suggesting that targeting them could make a possible contribution in managing the hyperglycemia in diabetic patients. This article summarizes the current findings concerning the role of zinc homeostasis in DM2 pathogenesis and development of diabetic cardiomyopathy and nephropathy and suggests novel therapeutic targets. © 2017 BioFactors, 43(6):770-784, 2017.

The effects of zinc supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

This study was performed to determine the effects of zinc supplementation on wound healing and metabolic status in patients with diabetic foot ulcer. The current randomized, double-blind, placebo-controlled trial was conducted among 60 patients (aged 40-85 years old) with grade 3 diabetic foot ulcer. Participants were randomly divided into two groups (30 participants in each group) to take either 220 mg zinc sulfate supplements containing 50 mg elemental zinc or placebo daily for 12 weeks. After the 12-week intervention, compared with the placebo, zinc supplementation was associated with significant reductions in ulcer length (-1.5 ± 0.7 vs. -0.9 ± 1.2 cm, p = 0.02) and width (-1.4 ± 0.8 vs. -0.8 ± 1.0 cm, p = 0.02). In addition, changes in fasting plasma glucose (-40.5 ± 71.0 vs. -3.9 ± 48.5 mg/dl, p = 0.02), serum insulin concentration (-8.0 ± 15.4 vs. +1.1 ± 10.3 µIU/ml, p = 0.009), homeostasis model of assessment-estimated insulin resistance (-3.9 ± 7.1 vs. +0.8 ± 5.9, p = 0.007), the quantitative insulin sensitivity check index (+0.01 ± 0.03 vs. -0.002 ± 0.02, p = 0.04) and HbA1c (-0.5 ± 0.8 vs. -0.1 ± 0.5%, p = 0.01) in the supplemented group were significantly different from the changes in these indicators in the placebo group. Additionally, significant increases in serum HDL-cholesterol (+4.1 ± 4.3 vs. +1.1 ± 5.1 mg/dl, p = 0.01), plasma total antioxidant capacity (+91.7 ± 213.9 vs. -111.9 ± 188.7 mmol/L, p < 0.01) and total glutathione (+68.1 ± 140.8 vs. -35.0 ± 136.1 µmol/L, p = 0.006), and significant decreases in high sensitivity C-reactive protein (-20.4 ± 24.6 vs. -6.8 ± 21.3 µg/ml, p = 0.02) and plasma malondialdehyde concentrations (-0.6 ± 0.9 vs. -0.2 ± 0.7 µmol/L, p = 0.03) were seen following supplementation with zinc compared with the placebo. Zinc supplementation for 12 weeks among diabetic foot ulcer patients had beneficial effects on parameters of ulcer size and metabolic profiles.