The Effect of Vitamin D Supplementation on Glycemic Control in Type 2 Diabetes Patients: A Systematic Review and Meta-Analysis

Serum 25-Hydroxyvitamin D Is Associated With Prediabetes, Type 2 Diabetes Mellitus, and Insulin Resistance in Children: A Systematic Review and Dose-Response Meta-analysis of Epidemiologic Studies

CONTEXT

Although several investigations have been conducted on the association between serum vitamin D levels and prediabetes and type 2 diabetes mellitus (T2DM) in children and adolescents, their findings are inconsistent.

OBJECTIVE

We conducted a systematic review and dose-response meta-analysis to summarize this subject.

DATA SOURCES

The electronic databases of ISI Web of Science, Scopus, PubMed, and motor engineering of Google Scholar were comprehensively searched up to May 2023.

DATA EXTRACTION

Epidemiologic studies that investigated the risk of hyperglycemia and insulin resistance in relation to serum 25-hydroxy vitamin D levels in children and adolescents were included.

DATA ANALYSIS

Twenty-two investigations, with a total of 38 622 participants, were systematically reviewed. Meta-analysis of 15 studies (n = 32 720 participants) showed that participants with the highest serum vitamin D levels had 42% lower risk of hyperglycemia, compared with those in the lowest category of serum vitamin D levels (relative risk [RR] = 0.58; 95%CI, 0.48, 0.71). Moreover, pooling 8 studies (n = 10 465 participants) illustrated that highest serum vitamin D level was associated with a 44% lower risk of insulin resistance compared with the lowest serum vitamin D level (RR = 0.56; 95%CI, 0.37, 0.83). Based on linear dose-response analysis, each 10 nmol/L increment in serum 25-hydroxy vitamin D was associated with a 6% decreased risk of hyperglycemia and insulin resistance in children. Furthermore, nonlinear dose-response analysis revealed that increasing serum vitamin D concentration from 40 nmol/L to sufficient values (>50 nmol/L) was associated with a decreasing trend in risk of hyperglycemia and insulin resistance.

CONCLUSION

This meta-analysis revealed inverse associations between serum vitamin D levels and hyperglycemia and insulin resistance in children and adolescents, in a dose-response manner. Increasing serum vitamin D concentration from 40 nmol/L to sufficient values (>50 nmol/L) was associated with a decreasing trend in hyperglycemia and insulin resistance risk. Systematic Review Registration: PROSPERO registration no. CRD42023458155.

Inverse association of triglyceride-glucose and triglyceride/HDL-c indexes with serum 25(OH) vitamin D levels in US adults

The triglyceride-glucose index (TyG) and the triglyceride to high-density lipoprotein ratio (TG/HDL-c) are novel indicators for assessing insulin resistance (IR) in epidemiological studies. This study aimed to evaluate the association between 25-hydroxy-vitamin D [25(OH)D] levels and these two indicators in the adult population of the United States. 14,380 participants aged 20 years and older were included from the National Health and Nutrition Examination Survey (NHANES). Multivariable linear regression models were used to analyze the association between 25(OH)D and TyG, as well as TG/HDL-c. Smooth fitting curves were employed to identify potential non-linear relationships between 25(OH)D, TyG, and TG/HDL-c. The findings revealed a negative association between 25(OH)D and TyG, with the effect being more pronounced in males and individuals with diabetes (p < 0.01). Similarly, 25(OH)D was negatively associated with TG/HDL-c, with a stronger impact observed in males compared to females. The study population was divided into four quartiles based on 25(OH)D concentration, and TyG and TG/HDL-c levels in Q3 and Q4 were lower than those in Q1. Furthermore, a non-linear relationship was observed between 25(OH)D and TyG, with an inflection point at 19.352 ng/mL. A non-linear relationship was also found between TG/HDL-c and 25(OH)D, with an inflection point at 37.211 ng/mL. 25(OH)D is an independent factor significantly associated with TyG and TG/HDL-c indexes. This negative association may be related to the role of 25(OH)D in insulin resistance.

Vitamin D: Evidence-Based Health Benefits and Recommendations for Population Guidelines

Vitamin D offers numerous under-recognized health benefits beyond its well-known role in musculoskeletal health. It is vital for extra-renal tissues, prenatal health, brain function, immunity, pregnancy, cancer prevention, and cardiovascular health. Existing guidelines issued by governmental and health organizations are bone-centric and largely overlook the abovementioned extra-skeletal benefits and optimal thresholds for vitamin D. In addition, they rely on randomized controlled trials (RCTs), which seldom show benefits due to high baseline 25-hydroxyvitamin D [25(OH)D] concentrations, moderate supplementation doses, and flawed study designs. This review emphasizes the findings from prospective cohort studies showing that higher 25(OH)D concentrations reduce the risks of major diseases and mortality, including pregnancy and birth outcomes. Serum concentrations > 30 ng/mL (75 nmol/L) significantly lower disease and mortality risks compared to <20 ng/mL. With 25% of the U.S. population and 60% of Central Europeans having levels <20 ng/mL, concentrations should be raised above 30 ng/mL. This is achievable through daily supplementation with 2000 IU/day (50 mcg/day) of vitamin D3, which prevent diseases and deaths. Furthermore, a daily dose between 4000 and 6000 IU of vitamin D3 to achieve serum 25(OH)D levels between 40 and 70 ng/mL would provide greater protection against many adverse health outcomes. Future guidelines and recommendations should integrate the findings from observational prospective cohort studies and well-designed RCTs to improve public health and personalized care.

Omega-3 Fatty Acid and Vitamin D Supplementations Partially Reversed Metabolic Disorders and Restored Gut Microbiota in Obese Wistar Rats

Obesity is a global public health issue linked to various comorbidities in both humans and animals. This study investigated the effects of vitamin D (VD) and omega-3 fatty acids (ω3FA) on obesity, gut dysbiosis, and metabolic alterations in Wistar rats. After 13 weeks on a standard (S) or High-Fat, High-Sugar (HFHS) diet, the rats received VD, ω3FA, a combination (VD/ω3), or a control (C) for another 13 weeks. The HFHS diet led to increased weight gain, abdominal circumference, glucose intolerance, insulin resistance, and gut dysbiosis. VD supplementation improved their fasting blood glucose and reduced liver damage, while ω3FA slowed BMI progression, reduced abdominal fat, liver damage, and intestinal permeability, and modulated the gut microbiota. The combination of VD/ω3 prevented weight gain, decreased abdominal circumference, improved glucose tolerance, and reduced triglycerides. This study demonstrates that VD and ω3FA, alone or combined, offer significant benefits in preventing obesity, gut dysbiosis, and metabolic alterations, with the VD/ω3 combination showing the most promise. Further research is needed to explore the mechanisms behind these effects and their long-term potential in both animal and human obesity management.

Vitamin D 1,25-Dihydroxyvitamin D3 reduces lipid accumulation in hepatocytes by inhibiting M1 macrophage polarization

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), which is a significant liver condition associated with metabolic syndrome, is the leading cause of liver diseases globally and its prevalence is on the rise in most nations. The protective impact of vitamin D on NAFLD and its specific mechanism remains unclear.

AIM

To examine the role of vitamin D in NAFLD and how vitamin D affects the polarization of hepatic macrophages in NAFLD through the vitamin D receptor (VDR)-peroxisome proliferator activated receptor (PPAR)γ pathway.

METHODS

Wild-type C57BL/6 mice were provided with a high-fat diet to trigger NAFLD model and administered 1,25-dihydroxy-vitamin D [1,25(OH)2D3] supplementation. 1,25(OH)2D3 was given to RAW264.7 macrophages that had been treated with lipid, and a co-culture with AML12 hepatocytes was set up. Lipid accumulation, lipid metabolism enzymes, M1/M2 phenotype markers, proinflammatory cytokines and VDR-PPARγ pathway were determined.

RESULTS

Supplementation with 1,25(OH)2D3 relieved hepatic steatosis and decreased the proinflammatory M1 polarization of hepatic macrophages in NAFLD. Administration of 1,25(OH)2D3 suppressed the proinflammatory M1 polarization of macrophages induced by fatty acids, thereby directly relieving lipid accumulation and metabolism in hepatocytes. The VDR-PPARγ pathway had a notable impact on reversing lipid-induced proinflammatory M1 polarization of macrophages regulated by the administration of 1,25(OH)2D3.

CONCLUSION

Supplementation with 1,25(OH)2D3 improved hepatic steatosis and lipid metabolism in NAFLD, linked to its capacity to reverse the proinflammatory M1 polarization of hepatic macrophages, partially by regulating the VDR-PPARγ pathway. The involvement of 1,25(OH)2D3 in inhibiting fatty-acid-induced proinflammatory M1 polarization of macrophages played a direct role in relieving lipid accumulation and metabolism in hepatocytes.

Vitamin D and Molecules Related to Vitamin D Metabolism in Children with Sepsis

Objective

This study aimed to evaluate the association between vitamin D and molecules related to vitamin D metabolism in children with sepsis.

Methods

A total of 98 hospitalized children with sepsis were included in this study. Blood samples were collected within the first 4 h of admission. Blood vitamin D; molecules related to vitamin D metabolism including vitamin-D-binding protein (VDBP), 7-dehydrocholesterol reductase (DHCR7), 25-hydroxylase (CYP2R1), 24-hydroxylase (CYP24A1), and cathelicidin (CATH); and other inflammatory markers including interleukin-6 (IL-6), procalcitonin (PCT), C-reactive protein (CRP), and white blood cell count (WBC) were measured.

Results

Of the enrolled children, 23.47% (23/98) were confirmed to have severe sepsis, and 10.20% (10/98) died. The prevalence of hypovitaminosis D was 46.94% (46/98) in the children with sepsis. Children with hypovitaminosis D had lower levels of CYP2R1 and CATH and higher levels of CYP24A1, PCT, and IL-6 compared to children with vitamin D sufficiency. Blood vitamin D level was positively correlated with blood VDBP, CYP2R1, and CATH and negatively correlated with CYP24A1, PCT, and IL-6. Blood vitamin D was not independently associated with severe sepsis and mortality, but it was independently associated with the requirement of intensive care unit (ICU) stay.

Conclusion

Molecules related to vitamin D metabolism such as VDBP, CYP2R1, and CYP24A1 are involved in regulating the levels of circulating vitamin D. Children with sepsis had a high prevalence of hypovitaminosis D. Hypovitaminosis D was independently associated with the requirement of ICU stay in children with sepsis.

Efficacy of vitamin D supplementation on glycaemic control in type 2 diabetes: An updated systematic review and meta-analysis of randomized controlled trials

AIM

To assess the effects of vitamin D interventions on glycaemic control in subjects with type 2 diabetes (T2D).

METHODS

We searched PubMed, EMBASE, Web of Science and the Cochrane Library for relevant studies. Serum 25(OH)D, fasting blood glucose (FBG), HbA1c, fasting insulin and Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) were analysed.

RESULTS

We identified 39 randomized controlled trials involving 2982 subjects. Results showed a significant decline in the vitamin D group, as shown by the FBG weighted mean difference (WMD; -0.49 [95% confidence interval {CI}: -0.69 to -0.28] mmol/L), HbA1c (WMD -0.30% [95% CI: -0.43 to -0.18]), HOMA-IR (WMD -0.39 [95% CI -0.64 to -0.14]) and insulin (WMD -1.31 [95% CI: -2.06 to -0.56] μIU/mL). Subgroup analyses indicated that the effects of vitamin D supplementation on glycaemic control depend on the dosage and duration of supplementation, baseline 25(OH)D levels and the body mass index of patients with T2D.

CONCLUSIONS

Vitamin D supplementation can significantly reduce serum FBG, HbA1c, HOMA-IR and fasting insulin levels in T2D patients; the effects were especially prominent when vitamin D was given in a short-term, high dosage to patients with a vitamin D deficiency, who were overweight, or had an HbA1c of 8% or higher at baseline. Our study suggests that vitamin D supplements can be recommended as complementary treatment for T2D patients.

Vitamin D and major chronic diseases

Numerous observational studies have demonstrated a significant inverse association between vitamin D status and the risk of major chronic disease, including type 2 diabetes (T2D), cardiovascular disease (CVD), and cancer. However, findings from Mendelian randomization (MR) studies and randomized controlled trials (RCTs) suggest minimal or no benefit of increased vitamin D levels. We provide an overview of recent literature linking vitamin D to major chronic diseases. Because emerging evidence indicates a potential threshold effect of vitamin D, future well-designed studies focused on diverse populations with vitamin D deficiency or insufficiency are warranted for a more comprehensive understanding of the effect of maintaining sufficient vitamin D status on the prevention of major chronic diseases.

Biomarkers of glucose-insulin homeostasis and incident type 2 diabetes and cardiovascular disease: results from the Vitamin D and Omega-3 trial

BACKGROUND

Dysglycemia and insulin resistance increase type 2 diabetes (T2D) and cardiovascular disease (CVD) risk, yet associations with specific glucose-insulin homeostatic biomarkers have been inconsistent. Vitamin D and marine omega-3 fatty acids (n-3 FA) may improve insulin resistance. We sought to examine the association between baseline levels of insulin, C-peptide, HbA1c, and a novel insulin resistance score (IRS) with incident cardiometabolic diseases, and whether randomized vitamin D or n-3 FA modify these associations.

METHODS

VITamin D and OmegA-3 TriaL (NCT01169259) was a randomized clinical trial testing vitamin D and n-3 FA for the prevention of CVD and cancer over a median of 5.3 years. Incident cases of T2D and CVD (including cardiovascular death, myocardial infarction, stroke, and coronary revascularization) were matched 1:1 on age, sex, and fasting status to controls. Conditional logistic regressions adjusted for demographic, clinical, and adiposity-related factors were used to assess the adjusted odds ratio (aOR) per-standard deviation (SD) and 95%CI of baseline insulin, C-peptide, HbA1c, and IRS (Insulin×0.0295 + C-peptide×0.00372) with risk of T2D, CVD, and coronary heart disease (CHD).

RESULTS

We identified 218 T2D case-control pairs and 715 CVD case-control pairs including 423 with incident CHD. Each of the four biomarkers at baseline was separately associated with incident T2D, aOR (95%CI) per SD increment: insulin 1.46 (1.03, 2.06), C-peptide 2.04 (1.35, 3.09), IRS 1.72 (1.28, 2.31) and HbA1c 7.00 (3.76, 13.02), though only HbA1c remained statistically significant with mutual adjustments. For cardiovascular diseases, we only observed significant associations of HbA1c with CVD (1.19 [1.02, 1.39]), and IRS with CHD (1.25 [1.04, 1.50]), which persisted after mutual adjustment. Randomization to vitamin D and/or n-3 FA did not modify the association of these biomarkers with the endpoints.

CONCLUSIONS

Each of insulin, C-peptide, IRS, and HbA1c were associated with incident T2D with the strongest association noted for HbA1c. While HbA1c was significantly associated with CVD risk, a novel IRS appears to be associated with CHD risk. Neither vitamin D nor n-3 FA modified the associations between these biomarkers and cardiometabolic outcomes.

Prediabetes and insulin resistance: effect of vitamin D

PURPOSE OF REVIEW

The impact of vitamin D on improving insulin resistance in prediabetes remains controversial. The purpose of this review is to examine whether vitamin D supplementation improves insulin resistance in adults with prediabetes, and if so, to identify the mechanisms and the specific populations.

RECENT FINDINGS

Global prevalence of prediabetes is increasing, and prevention is a critical issue because these people with prediabetes will develop type 2 diabetes soon, which will put pressure on healthcare costs. Recent evidence on the effectiveness of vitamin D administration in improving insulin resistance and preventing the onset of type 2 diabetes in adults with prediabetes has been accumulating. The 2024 updated clinical practice guideline of the American Diabetes Association states that vitamin D administration to patients with prediabetes potentially benefits type 2 diabetes incidence in specific populations. There are also reports that vitamin D administration improves insulin resistance via increased serum osteocalcin levels, a marker of bone turnover.

SUMMARY

Vitamin D is likely to improve insulin resistance, which is already present at the time of prediabetes. However, the effectiveness may vary depending on ethnic differences and blood vitamin D levels at the start of administration.

Vitamin D Supplementation: Shedding Light on the Role of the Sunshine Vitamin in the Prevention and Management of Type 2 Diabetes and Its Complications

As the incidence of type 2 diabetes mellitus (T2DM) continues to increase globally, researchers are keen to investigate various interventions to mitigate its impact. Among these, vitamin D supplementation has attracted significant attention due to its influence on insulin secretion from the pancreas and insulin receptors in body cells. A substantial body of evidence indicates that vitamin D supplementation can reduce low-grade inflammation, a critical factor in developing insulin resistance. In addition, vitamin D aids in sustaining low resting concentrations of reactive oxygen species and free radicals, normalizes Ca2+ signaling, diminishes the expression of cytokines that are pro-inflammatory, and enhances the production of cytokines that are anti-inflammatory. This review discusses the effects of vitamin D on the glycemic control of individuals with T2DM and evaluates the impact of vitamin D supplementation on glycemic markers in this population. The investigation employs a comprehensive analysis of the existing literature with a special focus on recent studies published in the past decade. Based on the findings in the literature, it can be concluded that vitamin D supplementation alongside anti-diabetic medications may enhance glycemic control and potentially reduce the risk of diabetic complications. The evidence supports the notion that vitamin D supplementation can be a valuable addition to pharmacological agents for the management of T2DM, potentially enhancing glycemic control and overall health outcomes in affected individuals.

The prevention and improvement effects of vitamin D on type 2 diabetes mellitus: evidence from an umbrella review on Meta-analyses of cohort studies and randomized controlled trials

Background

To clarify whether Vitamin D prevent the occurrence of type 2 diabetes mellitus (T2DM) and improve glucose control in T2DM patients, we conducted this umbrella review, taking into account the inconsistent results of existing Meta-analyses. We aim to reveal the causal relationship between Vitamin D and T2DM through summarizing Meta-analyses of observational studies, and clarify the improvement on glucose control in T2DM patients through summarizing Meta-analyses of RCT studies between Vitamin D supplementation and T2DM patients, especially in T2DM patients with Vitamin D deficiency.

Methods

We collected the Meta-analyses of observational studies and RCTs in PubMed, Scopus, Embase, Web of Science, and Cochrane.

Results

16 Meta-analyses (6 effect sizes for cohort studies and 10 effect sizes for RCTs) were included in the umbrella Meta-analyses. Random-effects model was carried out to calculate the pooled point estimates and their respective 95% confidence intervals (CI). The results revealed that lower 25(OH)D levels increased the risk of T2DM (Pooled ESRR = 1.34; 95%CI: 1.16, 1.53), Vitamin D supplementation ameliorated FBG (ES = -0.56; 95%CI: -1.00, -0.11), HbA1c (ES = -0.11; 95%CI: -0.20, -0.02), insulin (ES = -0.38; 95%CI: -0.59, -0.18) and HOMA-IR (ES = -0.37; 95%CI: -0.57, -0.16) in T2DM patients, especially in those with Vitamin D deficiency (FBG = -0.98; HbA1c = -0.27; HOMA-IR = -0.52).

Conclusion

The present umbrella Meta-analyses demonstrates the potential benefits of higher serum Vitamin D levels and Vitamin D supplementation in reducing the development and symptoms of T2DM.

Association of polychlorinated biphenyls with vitamin D among rural Chinese adults with normal glycaemia and type 2 diabetes mellitus

BACKGROUND

Endocrine function in patients with type 2 diabetes (T2DM) typically differs from those with normal glucose tolerance (NGT). However, few epidemiologic studies have explored how these differences impact the association between exposure to polychlorinated biphenyls (PCBs) and vitamin D levels.

METHODS

This study included 1,705 subjects aged 18-79 years from the Henan Rural Cohort [887 NGT and 818 T2DM]. Linear regression was applied to evaluate the associations between PCB exposure and vitamin D levels. Quantile g-computation regression (QG) and Bayesian kernel machine regression (BKMR) were applied to evaluate the impact of PCB mixtures on vitamin D levels. Interaction effects of ΣPCBs with HOMA2-%β and HOMA2-IR on vitamin D levels were assessed.

RESULTS

Plasma ΣPCBs was positively associated with 25(OH)D2 in the NGT group (β = 0.060, 95% CI: 0.028, 0.092). Conversely, in T2DM group, ΣPCBs was negatively associated with 25(OH)D3 and 25(OH)D (β = -0.049, 95% CI: -0.072, -0.026; β = -0.043, 95% CI: -0.063, -0.023). Similarly, both QG and BKMR analysis revealed a negative association between PCB mixture exposure and vitamin D levels in the T2DM group, contrary to the results observed in the NGT groups. Furthermore, the negative association of ΣPCBs with 25(OH)D2 and 25(OH)D disappeared or changed to a positive association with the increase of HOMA2-%β levels.

CONCLUSIONS

These findings suggest that decreased β cell function may exacerbate the negative effects of PCB exposure on vitamin D levels. Recognizing T2DM patients' sensitivity to PCBs is vital for protecting chronic disease health.

Multifaceted Roles of Vitamin D for Diabetes: From Immunomodulatory Functions to Metabolic Regulations

Numerous studies have established associations between vitamin D and diabetes. The vitamin D receptor is widely distributed throughout the human body, including in pancreatic beta cells (β-cells), hepatocytes, and immune cells. Therefore, vitamin D's effect on the risk, progression, or complications of diabetes may be mediated through various mechanisms. These include the regulation of insulin secretion or sensitivity and modulation of β-cell function and its immunomodulatory and anti-inflammatory effects. This review extensively explores the relationship between vitamin D status and diabetes, as well as the preventive or therapeutic effects of vitamin D supplementation on diabetes from human studies. Additionally, it examines in detail the impact of vitamin D on immune and inflammatory responses in the diabetic milieux and β-cell function to better understand the underlying mechanisms through which vitamin D influences diabetes.

The correlation between serum vitamin D status and the occurrence of diabetic foot ulcers: a comprehensive systematic review and meta-analysis

The association between vitamin D concentrations and the occurrence of diabetic foot ulcers (DFUs) remains a topic of ongoing debate. In order to provide a comprehensive and updated review, we conducted this meta-analysis to further investigate the relationship between vitamin D concentrations and DFUs occurrence. The following databases, including Cochrane Library, EMBASE, Web of Science, PubMed, CBM, CNKI, WANFANG DATA and VIP Database, were systematically searched for studies published up to Dec. 20th, 2023. The combined estimation was calculated using both fixed-effects and random-effects models. The overall effect size was reported as a weighted mean difference (WMD) with a corresponding 95% confidence interval (95%CI). Data analysis was performed utilizing Review Manager 5.4 and Stata 14. The Protocol has been registered in PROSPERO CRD42024503468. This updated meta-analysis, incorporating thirty-six studies encompassing 11,298 individuals with or without DFUs, demonstrated a significant association between vitamin D deficiency/insufficiency and an elevated risk of DFUs occurrence (< 25 nmol/L, OR 3.28, P < 0.00001; < 50 nmol/L, OR 2.25, P < 0.00001; < 75 nmol/L, OR 1.67, P = 0.0003). Vitamin D concentrations were significantly lower in individuals with DFUs compared to those without DFUs (P < 0.00001). Subgroup analyses consistently demonstrated this trend among the older population (> 50 years, P < 0.00001), individuals with long duration of diabetes (> 10 years, P < 0.00001), and those with poor glycemic control (mean HbA1c 8%-9% and > 9%, P < 0.00001).

Levels of plasma 25-hydroxy vitamin D and risk of developing type 2 diabetes in a large Danish primary health care population

AIMS

Plasma levels of Vitamin D (25(OH)D) have been suggested as a predictor for developing type 2 diabetes. The purpose of this study was therefore to investigate if a measurement of plasma 25(OH)D could predict the development of type 2 diabetes in a cohort of 222,311 individuals from primary healthcare in Denmark.

METHODS

The CopD-study database containing data from the Copenhagen General Practitioners Laboratory on blood tests conducted from April 2004 to January 2012 was used for identification of the study population. Incident type 2 diabetes was then defined as having at least two redeemed prescriptions of antidiabetics or at least two hospital contacts due to type 2 diabetes or one redeemed prescription and one hospital contact regarding type 2 diabetes.

RESULTS

A total of 222,311 individuals were included in the study, of whom 7652 (3.4%) developed type 2 diabetes during the follow-up period of minimum one year. Individuals who developed type 2 diabetes had a significantly lower median 25(OH)D level than persons in the non-diabetes group. The hazard ratio for development of type 2 diabetes increased by 15% per 10 n mol/L decrease in 25(OH)D level.

CONCLUSION

In this study of 222,311 persons from primary health care in Denmark, we found a clear inverse relationship between 25(OH)D and the risk of developing type 2 diabetes. Further studies should be conducted to clarify the mechanisms behind the relationship between 25(OH)D and type 2 diabetes and the effect of oral vitamin D supplementation on the development of type 2 diabetes.

Vitamin D and risk of developing type 2 diabetes in the SUN project: a prospective cohort study

PURPOSE

Vitamin D deficiency has been associated with multiple chronic diseases, including metabolic disorders such as insulin resistance and type 2 diabetes (T2D). The aim of the study was to analyze the association between validated predicted serum vitamin D status and the risk of developing T2D in a large prospective cohort based on a Mediterranean population.

METHODS

The SUN project is a prospective and dynamic Spanish cohort that gathers university graduates who have answered lifestyle questionnaires, including a validated Food Frequency Questionnaire. The association between predicted serum vitamin D and the risk of T2D was assessed through Cox regression models according to quartiles (Q) of predicted vitamin D at baseline. The models were adjusted for potential confounders and sensitivity analyses were performed to ensure the robustness of our findings.

RESULTS

Our study included a total of 18,594 participants and after a total follow-up of 238,078 person-years (median follow-up of 13.5 years), 209 individuals were diagnosed with incident T2D. We found a significant inverse association between predicted levels of serum vitamin D and the risk of developing T2D, after adjusting for potential confounders and performing different sensitivity analyses (hazard ratio Q4 vs. Q1: 0.48, 95% CI 0.26-0.88; p for trend = 0.032).

CONCLUSION

The outcomes suggest that higher levels of vitamin D at baseline may be associated with a reduced risk of developing T2D.

Artemisia vulgaris Extract as a Novel Therapeutic Approach for Reversing Diabetic Cardiomyopathy in a Rat Model

Diabetic cardiomyopathy, a severe diabetic complication, impairs heart function, leading to heart failure. Treatment that effectively addresses this condition without causing side effects is urgently needed. Current anti-hyperglycemic therapies are expensive, has side effects and do not effectively prevent cardiac remodeling. Therefore, it is important to explore natural products that may have the potential to reverse cardiac remodeling. That is why the aim of the current study was to determine the left ventricular remodeling potential of the methanolic extract of Artemisia vulgaris in a diabetic cardiomyopathy rat model. Following the initial comprehensive phytochemical evaluation of plant phenolic and flavonoid content, which showed strong anti-hyperglycemic and antioxidant activities, an extract of Artemisia vulgaris was administered in an in vivo experiment. Diabetic cardiomyopathy was induced in Wistar albino rats according to previously described protocols in the literature, and the effect of treatment was checked by serum and histopathological analysis after 45 days. Artemisia vulgaris treatment significantly (p ≤ 0.05) reduced fasting blood glucose (108.5 ± 1.75 mg/dL), glycated hemoglobin (4.03 ± 0.12 %), serum glucose (116.66 ± 3.28 mg/dL), insulin (15.66 ± 0.66 ng/mL), total oxidant status (54.66 ± 3.22 µmol H2O2Equiv.L-1), Malondialdehyde (0.20 ± 0.01 mmol/L), total cholesterol (91.16 ± 3.35 mg/dL), triglycerides (130.66 ± 3.15 mg/dL), low-density lipids (36.57 ± 1.02 mg/dL), sodium (140 ± 3.21 mmol/L), calcium (10.44 ± 0.24 mmol/L), creatine kinase MB (1227.5 ± 17.89 IU/L), lactate dehydrogenase (1300 ± 34.64 IU/L), C-reactive protein (30 ± 0.57 pg/mL), tumor necrosis factor-α (58.66 ± 1.76 pg/mL), atrial natriuretic peptide (2.53 ± 0.04 pg/mL), B-type natriuretic peptide (10.66 ± 0.44 pg/mL), aspartate aminotransferase (86.5 ± 4.99 U/L), Alanine Transaminase (55.33 ± 2.90 U/L), urea (25.33 ± 1.15 mg/dL) and creatinine (0.64 ± 0.02 mg/dL) but significantly increased (p ≤ 0.05) total antioxidant capacity (1.73 ± 0.07 mmol Trolox Equil./L), high-density lipids (40 ± 1.59 mg/dL) and potassium (3.82 ± 0.04 mmol/L) levels. ECG and histopathology confirmed the significant improvement in remodeling and the reversal of structural changes in the heart and pancreas. In conclusion, Artemisia vulgaris possesses significant left ventricular remodeling potential in course of diabetes-induced cardiomyopathy.

Significance of vitamin D responsiveness on the etiology of vitamin D-related diseases

Vitamin D resistance (VDRES) explains the necessity for higher doses of Vitamin D (VD) than those recommended for treatment success. VD receptor (VDR) signaling blockade, such as that caused by infections and poisons, is one basis for VDRES etiology. Mutations within genes affecting the VD system cause susceptibility to developing low VD responsiveness and autoimmunity. In contrast, VD hypersensitivity (VDHY) occurs if there is extra VD in the body; for example, as a result of an overdose of a VD supplement. Excess 1,25(OH)2D3 is produced in lymphomas and granulomatous diseases. The placenta produces excess 1,25(OH)2D3. Gene mutations regulating the production or degradation of 1,25(OH)2D3 enhance the effects of 1,25(OH)2D3. Increased 1,25(OH)2D3 levels stimulate calcium absorption in the gut, leading to hypercalcemia. Hypercalcemia can result in the calcification of the kidneys, circulatory system, or placenta, leading to kidney failure, cardiovascular disease, and pregnancy complications. The primary treatment involves avoiding exposure to the sun and VD supplements. The prevalence rates of VDRES and VDHY remain unclear. One estimate was that 25%, 51%, and 24% of the patients had strong, medium, and poor responses, respectively. Heavy-dose VD therapy may be a promising method for the treatment of autoimmune diseases; however, assessing its potential side effects is essential. To avoid VD-mediated hypercalcemia, responsiveness must be considered when treating pregnancies or cardiovascular diseases associated with VD. Furthermore, how VD is associated with the related disorders remains unclear. Investigating responsiveness to VD may provide more accurate results.

Association between Vitamin D Deficiency and Prediabetes Phenotypes: A Population-Based Study in Henan, China

The evidence remains inconsistent regarding whether vitamin D deficiency (VDD) increases the risk of prediabetes. This study aimed to examine whether there is sex-specific association between VDD and impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) in Henan. The data were sourced from the survey of chronic diseases and nutrition in Henan. Multinomial logistic regression models based on complex sampling design and weight were developed to estimate the odds ratio (OR) and confidence interval (95%CI) for measuring the association between VDD and IFG/IGT. The prevalence rate of IGT in men was 20.1% in the VDD group, significantly higher than that in the non-VDD group (10.5%), but no significant difference was observed in women between the VDD and non-VDD groups; there were no significant differences in IFG prevalence between the VDD and non-VDD groups in either men or women. It was found that the association between VDD and IGT was statistically significant in men. The adjusted OR (95%CI) of VDD was 1.99 (1.24-3.19) for IGT in men and 14.84 (4.14-53.20) for IGT in men having a family history of DM. Thus, men with VDD were more likely to live with IGT than those without VDD, especially for men having a family history of diabetes.

Chinese Guidelines for Medical Nutrition Therapy for Patients with Diabetes (2022 Edition)

Medical nutrition therapy (MNT) is the foundation of the comprehensive treatment of patients with diabetes. In 2010, the Chinese Clinical Nutritionist Center of the Chinese Medical Doctor Association developed the first Chinese guideline on MNT for patients with diabetes, and it was updated in 2015. Since then, new evidence has emerged in the field of MNT and metabolic therapy in patients with diabetes. The Nutrition and Metabolic Management Branch of the China International Exchange and Promotive Association for Medical and Health Care organized a team of experts from related institutions, including the Clinical Nutrition Branch of the Chinese Nutrition Society, Chinese Diabetes Society, Chinese Society for Parenteral and Enteral Nutri-tion, and Chinese Clinical Nutritionist Center of the Chinese Medical Doctor Association. Their task was to develop the Chinese Guidelines of Medical Nutrition Therapy in Diabetes (2022 Edition) in accordance with the requirements of the Guidelines for the Formulation/Revision of Clinical Guidelines in China (2022 Edition) by combining the questions raised and evidence gathered in clinical practices in China, to guide and standardize the clinical MNT.

Vitamin D deficiency and inflammatory markers in type 2 diabetes: Big data insights

The objective of this study was to investigate the prevalence of vitamin D deficiency or insufficiency and its association with inflammatory markers and type 2 diabetes. We conducted our research at Qingdao Endocrine and Diabetes Hospital, where serum 25-hydroxyvitamin D3 levels were determined for 2,806 individuals with type 2 diabetes aged 30 and older between January 2018 and December 2019. Medical records were analyzed, and data on health, blood lipids, HbA1c, and inflammation were collected. Our results revealed a high prevalence of vitamin D deficiency in the population. Among male and female patients, median serum 25(OH)D3 levels were 22.46 and 19.00 ng/mL, respectively. More than 60% of female patients had vitamin D deficiency, with over 80% having levels below 30 ng/mL. We observed a favorable connection between high-density lipoprotein cholesterol and 25(OH)D3, while triglycerides and HbA1c showed negative correlations. As 25(OH)D3 levels increased, inflammatory markers such as hypersensitive C-reactive protein (hsCRP), erythrocyte sedimentation rate (ESR), white blood cell count, neutrophil count, and monocyte count decreased (trend test, p < 0.05), although peripheral blood lymphocytes initially increased and then decreased. After controlling for age and gender, multiple linear regression analysis indicated negative correlations between ESR, hsCRP, and white blood cell count with 25(OH)D3 (p < 0.05). In conclusion, our study demonstrates that individuals with type 2 diabetes often exhibit vitamin D deficiency or insufficiency, which is associated with elevated levels of inflammatory markers in the blood.

Diabetes and vitamin D: The effect of insulin sensitivity and gut microbial health

Current global estimation suggests that about 10% of adults worldwide have diabetes, thus, various strategies are needed to address the issue, including dietary factors such as vitamin D. Various studies have suggested an inverse associations between vitamin D and the risks and pathogenesis of all forms of diabetes (type 1, type 2 and gestational diabetes). The underlying mechanism is not fully understood; however, the expression of vitamin D receptors in pancreatic beta cells suggests an important physiological role for vitamin D in beta cell function. Vitamin D deficiency may impair blood glucose control and decrease insulin sensitivity by reducing insulin secretion from beta cells. Many studies suggest that vitamin D intervention may be beneficial; however, there is inconclusive evidence of the effectiveness of vitamin D supplementation on reducing the risks or managing the pathogenesis of all forms of diabetes. Part of the pathogenesis of vitamin D for reducing diabetes is thought to be related to its impact on gut microbiota profile, via the suggested prebiotic properties of vitamin D.

The Power of Vitamin D: Is the Future in Precision Nutrition through Personalized Supplementation Plans?

In the last few decades, vitamin D has undeniably been one of the most studied nutrients. Despite our ability to produce vitamin D through sunlight exposure, its presence in several natural food sources and fortified foods, and its widespread availability as a dietary supplement, vitamin D deficiency is a serious public health problem, affecting nearly 50% of the global population. Low serum levels of vitamin D are being associated with increased susceptibility to numerous health conditions, including respiratory infections, mental health, autoimmune diseases, and different cancer types. Although the association between vitamin D status and health is well-established, the exact beneficial effects of vitamin D are still inconclusive and indefinite, especially when considering the prevention and treatment of different health conditions and the determination of an appropriate dosage to exert those beneficial effects in various population groups. Therefore, further research is needed. With constant improvements in our understanding of individual variations in vitamin D metabolism and requirements, in the future, precision nutrition and personalized supplementation plans could prove beneficial.

Association of vitamin D and cognition in people with type 2 diabetes: a systematic review

CONTEXT

There is a high prevalence of vitamin D deficiency and impaired cognitive function in people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To critically and systematically review the literature on the association between vitamin D status and cognitive performance in people with type 2 diabetes.

DATA SOURCES

This review was conducted according to PRISMA recommendations. MEDLINE, SCOPUS, the Cochrane Library, and Web of Science databases were searched using the terms "Diabetes Mellitus, Type 2", "Cognitive Function", and "Vitamin D".

DATA EXTRACTION

Eight observational and 1 randomized study were included, containing data of 14 648 adult and elderly individuals (19-74 y). All extracted data were compiled, compared, and critically analyzed.

DATA ANALYSIS

There is no strong evidence that lower serum concentrations of vitamin D and vitamin D-binding protein are associated with worsening cognitive function in individuals with T2DM. Vitamin D supplementation (12 wk) improved the scores of some executive functioning tests, although there was no difference between low doses (5000 IU/wk) and high doses (50 000 IU/wk).

CONCLUSIONS

There is no high-quality evidence demonstrating an association between vitamin D status and cognitive function, or clinical benefits on cognition from vitamin D supplementation in individuals with T2DM. Future studies are needed. Systematic Review Registration: PROSPERO registration no. CRD42021261520.

Association between circulating micronutrient pattern, glycemic control, and insulin resistance in type 2 diabetes mellitus

The circulating micronutrient pattern in type 2 diabetes mellitus (T2DM) may impact glycemic control and insulin resistance; however, there is a scarcity of studies that have evaluated the circulating micronutrient pattern in the T2DM population. Therefore, our objective was to identify circulating micronutrient pattern and their association with markers of glycemic control and insulin resistance in individuals with T2DM. We developed a cross-sectional observational study involving adults with T2DM in Sergipe, Brazil. We assessed plasma levels of magnesium, zinc, calcium, potassium, and serum 25-hydroxyvitamin D. Additionally, also measured fasting glucose levels, the percentage of glycated hemoglobin (%HbA1c), and calculated the homeostatic model assessment for insulin resistance (HOMA-IR). Patterns of body reserve were established using principal component analysis and categorized into quartiles. Binary logistic regression models were employed. We evaluated 114 individuals (63.7% women), with a median age and body mass index of 49 years and 29.6 kg/m², respectively. Two circulating micronutrient patterns were identified, explaining 62.5% of the variance: Pattern 1 (positive contributions from magnesium, zinc, calcium, and potassium) and Pattern 2 (positive contributions from 25-hydroxyvitamin D and zinc, with a negative contribution from potassium). Lowest quartile for Pattern 1 and Pattern 2 exhibiting a 4.32-fold (p = 0.019) and 3.97-fold (p = 0.038) higher likelihood of increasing HOMA-IR and %HbA1c values, respectively, compared to the larger quartiles. However, no associations were found between these patterns and fasting glucose values. Lowest quartile for both patterns of micronutrients was associated with inadequate metabolic control in individuals with T2DM.

Optimizing the Production of Probiotic Yogurt as a New Functional Food for Diabetics with Favorable Sensory Properties Using the Response Surface Methodology

This study aimed to optimize the processing of probiotic yogurt supplemented with cumin essential oil (CEO), vitamin C, D3 (Vit D), and reduction of fermentation time using response surface methodology as a new functional food for diabetics with desirable sensory properties. The central composite design (CCD) was used to analyze the effect of these independent variables on the growth of the Lactobacillus plantarum A7 (LA7), starter culture, and overall acceptability. Differences between treatments were analyzed. The data were evaluated by analysis of variance at the significance level of 0.05. The effective concentration of CEO and fermentation time had the significant effect on the Lactobacillus plantarum A7 (LA7) number. Variance analysis and three-dimensional graphs show that almost the only effective factor on the overall acceptability of probiotic yogurt containing essential oil and vitamin D3 was CEO. According to the obtained data from the analysis, the optimal amount of independent variables for probiotic yogurt formulation such as CEO, D3, and fermentation time was 0.02% (v/v), 400 IU, and 9 h, respectively. This functional product can be considered an efficient food to reduce or eliminate the complications of diabetes.

Vitamin D Deficiency in Patients Hospitalized for Heart Failure Living in the Tropics

Background and Objectives

Vitamin D, as a steroid hormone, has multiple effects on human body and its deficiency has been associated with an increased risk of heart failure (HF) and unfavorable outcomes. The present study investigated the prevalence of vitamin D deficiency (VDD) and its relationship with cardiometabolic parameters in patients hospitalized for HF living in the city of Recife (latitude 8° South).

Methods

Analytical cross-sectional study, with men and women aged 40-64 years. The HF group was recruited during hospitalization due to decompensation. A matched control group was recruited from the general endocrine clinics. Vitamin D status was assessed by measuring serum 25-hydroxyvitamin D (25OHD), considering deficiency when 25OHD <20 ng/mL (<50 nmol/L).

Results

A total of 243 patients were evaluated (HF group: 161, control group: 82). Lower serum 25OHD levels were observed in the HF group (25.2±9.4 vs. 30.0±7.7ng/mL; p<0.001), as well as a higher prevalence of VDD (27.3% vs. 9.8%; prevalence ratio, 2.80; 95% confidence interval, 1.38-5.67; p=0.002). In patients with HF, VDD was associated with diabetes mellitus (65.9% vs. 41.0%; p=0.005) and female sex (65.9% vs. 44.4%; p=0.015). In the subgroup with VDD, higher values of hemoglobin A1c (7.9% [6.0-8.9] vs. 6.2% [5.7-7.9]; p=0.006) and dyslipidemia were also observed.

Conclusions

We found higher rates of VDD in patients hospitalized for HF and this was associated with deleterious laboratory metabolic parameters.

Aerobic training with moderate or high doses of vitamin D improve liver enzymes, LXRα and PGC-1α levels in rats with T2DM

Dysregulation of key transcription factors involved in hepatic energy metabolism, such as peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and liver X receptor alpha (LXRα), has been observed in T2DM. The present study aims to investigate the effects of aerobic training and vitamin D supplementation on liver enzyme levels and the levels of PGC-1α and LXRα proteins in hepatocytes, in a rat model of T2DM. The study involved 56 male Wistar rats, divided into two groups: one was non-diabetic and acted as a control group (n = 8), and the other had induced diabetes (n = 48). The diabetic rats were then split into six subgroups: two groups received high or moderate doses of vitamin D and aerobic training (D + AT + HD and D + AT + MD); two groups received high or moderate doses of vitamin D alone (D + HD and D + MD); one group underwent aerobic training with vehicle (sesame oil; D + AT + oil), and one group was a diabetic control receiving only sesame oil (oil-receiving). The D + AT + HD and D + HD groups received 10,000 IU of vitamin D, while the D + AT + MD and D + MD groups received 5000 IU of vitamin D once a week by injection. The D + AT + oil group and the sham group received sesame oil. After eight weeks of treatment, body weight, BMI, food intake, serum insulin, glucose, 25-hydroxyvitamin D, ALT, AST, and visceral fat were measured. The levels of PGC-1α and LXRα proteins in the liver was assessed by western blotting. Statistical analysis was performed using the paired t-test, one-way analysis of variance (ANOVA), and the Tukey post hoc test at a significance level of P < 0.05. Body weight, food intake, and BMI decreased significantly in the D + AT + HD, D + AT + MD, D + AT + oil, D + HD, and D + MD groups with the highest reduction being observed in body weight and BMI in the D + AT + HD group. The D + AT + HD group exhibited the lowest levels of insulin, glucose, and HOMA-IR while the D + C group exhibited the highest levels among the diabetic groups. The D + AT + HD and D + AT + MD groups had lower levels of ALT and AST enzymes compared to the other groups with no significant difference between D + AT + HD and D + AT + MD. D + AT + HD (p = 0.001), D + AT + MD (p = 0.001), D + HD (p = 0.023), D + MD (p = 0.029), and D + AT + oil (p = 0.011) upregulated LXRα compared to D + C. Among these groups, D + AT + HD exhibited a more profound upregulation of LXRα than D + AT + MD, D + AT + oil, D + HD, and D + MD (p = 0.005; p = 0.002, p = 0.001, and p = 0.001, respectively). Similarly, D + AT + HD showed a more notable upregulation of PGC-1α compared to D + AT + oil, D + HD, and D + MD (p = 0.002; p = 0.001, and p = 0.001, respectively). Pearson correlation tests showed significant and negative correlations between serum 25-hydroxyvitamin levels and both visceral fat (r = - 0.365; p = 0.005) and HOMA-IR (r = - 0.118; p = 0.009); while positive and significant correlations between the liver-to-bodyweight ratio with both ALT and AST enzymes and also between QUICKI levels with LXRα (r = 0.578; p = 0.001) and PGC-1α (r = 0.628; p = 0.001). Combined administration of aerobic training and vitamin D supplementation potentially improves liver enzymes in type-2 diabetic rats that were simultaneous with upregulating the levels of PGC-1α and LXRα proteins in hepatocytes. These improvements were more significant when combining exercise with high-dose vitamin D supplementation. This study highlights the potential of this combination therapy as a new diabetes treatment strategy.

Metabolic disorders in prediabetes: From mechanisms to therapeutic management

Diabetes, one of the world's top ten diseases, is known for its high mortality and complication rates and low cure rate. Prediabetes precedes the onset of diabetes, during which effective treatment can reduce diabetes risk. Prediabetes risk factors include high-calorie and high-fat diets, sedentary lifestyles, and stress. Consequences may include considerable damage to vital organs, including the retina, liver, and kidneys. Interventions for treating prediabetes include a healthy lifestyle diet and pharmacological treatments. However, while these options are effective in the short term, they may fail due to the difficulty of long-term implementation. Medications may also be used to treat prediabetes. This review examines prediabetic treatments, particularly metformin, glucagon-like peptide-1 receptor agonists, sodium glucose cotransporter 2 inhibitors, vitamin D, and herbal medicines. Given the remarkable impact of prediabetes on the progression of diabetes mellitus, it is crucial to intervene promptly and effectively to regulate prediabetes. However, the current body of research on prediabetes is limited, and there is considerable confusion surrounding clinically relevant medications. This paper aims to provide a comprehensive summary of the pathogenesis of pre-diabetes mellitus and its associated therapeutic drugs. The ultimate goal is to facilitate the clinical utilization of medications and achieve efficient and timely control of diabetes mellitus.

Vitamin D and cardiovascular diseases

Vitamin D has an established role in calcium homeostasis but its deficiency is emerging also as a new risk factor for cardiovascular disease (CVD). In particular, several epidemiological and clinical studies have reported a close association between low vitamin D levels and several cardiovascular risk factors and major CVDs, such as coronary artery disease, heart failure, and cardiac arrhythmias. In all these clinical settings, vitamin D deficiency seems to predispose to increased morbidity, mortality, and recurrent cardiovascular events. Despite this growing evidence, interventional trials with supplementation of vitamin D in patients at risk of or with established CVD are still controversial. In this chapter, we summarize the currently available evidence on the links between vitamin D deficiency and major cardiovascular risk factors and CVD, in terms of both clinical relevance and potential therapeutic implications.

Research Progress on the Weak Immune Response to the COVID-19 Vaccine in Patients with Type 2 Diabetes

Coronavirus Disease 2019 (COVID-19) is generally susceptible to the population, highly infectious, rapidly transmitted, and highly fatal. There is a lack of specific drugs against the virus at present and vaccination is the most effective strategy to prevent infection. However, studies have found that some groups, particularly patients with diabetes, show varying degrees of weak immune reactivity to various COVID-19 vaccines, resulting in poor preventive efficacy against the novel coronavirus in patients with diabetes. Therefore, in this study, patients with type 2 diabetes mellitus (T2DM) who had weak immune response to the COVID-19 vaccine in recent years were analyzed. This article reviews the phenomenon, preliminary mechanism, and related factors affecting weak vaccine response in patients with T2DM, which is expected to help in the development of new vaccines for high-risk groups for COVID-19.

Vitamin D supplementation modulates glycated hemoglobin (HBA1c) in diabetes mellitus

Diabetes is a metabolic illness that increases protein glycosylation in hyperglycemic conditions, which can have an impact on almost every organ system in the body. The role of vitamin D in the etiology of diabetes under RAGE (receptor for advanced glycation end products) stress has recently received some attention on a global scale. Vitamin D's other skeletal benefits have generated a great deal of research. Vitamin D's function in the development of type 1 and type 2 diabetes is supported by the discovery of 1,25 (OH)2D3 and 1-Alpha-Hydroylase expression in immune cells, pancreatic beta cells, and several other organs besides the bone system. A lower HBA1c level, metabolic syndrome, and diabetes mellitus all seems to be associated with vitamin D insufficiency. Most of the cross-sectional and prospective observational studies that were used to gather human evidence revealed an inverse relationship between vitamin D level and the prevalence or incidence of elevated HBA1c in type 2 diabetes. Several trials have reported on the impact of vitamin D supplementation for glycemia or incidence of type 2 diabetes, with varying degrees of success. The current paper examines the available data for a relationship between vitamin D supplementation and HBA1c level in diabetes and discusses the biological plausibility of such a relationship.

High glucose-induced injury in human umbilical vein endothelial cells is alleviated by vitamin D supplementation through downregulation of TIPE1

BACKGROUND

Diabetes mellitus (DM) and its associated vascular complications have become a worldwide health concern. The effects and mechanism of vitamin D supplementation on endothelial function under high glucose condition remain elusive.

METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with 35 mM glucose, then 100 nM vitamin D were added. Transwell migration assay, CCK-8, immunofluorescence, flow cytometry, autophagy flux and transmission electric microscope were performed.

RESULTS

Vitamin D reduced apoptosis, promoted migration and enhanced viability of HUVECs, decreased TIPE1 (Tumor necrosis factor-α-induced protein 8-like 1) under high glucose conditions. Overexpression of TIPE1 reverses the effects of vitamin D by increasing ROS production, inflammation, cell apoptosis, and suppressing autophagy, cell migration and viability. And vitamin D negatively correlated with TIPE1 mRNA level in DM patients.

CONCLUSIONS

Vitamin D reverses the harmful effects of high glucose on HUVECs by reducing TIPE1 expression. And vitamin D supplementation could help to alleviate high glucose-induced injury in type 2 diabetes mellitus patients with microvascular complications.

The Vicious Cycle of Type 2 Diabetes Mellitus and Skeletal Muscle Atrophy: Clinical, Biochemical, and Nutritional Bases

Today, type 2 diabetes mellitus (T2DM) and skeletal muscle atrophy (SMA) have become increasingly common occurrences. Whether the onset of T2DM increases the risk of SMA or vice versa has long been under investigation. Both conditions are associated with negative changes in skeletal muscle health, which can, in turn, lead to impaired physical function, a lowered quality of life, and an increased risk of mortality. Poor nutrition can exacerbate both T2DM and SMA. T2DM and SMA are linked by a vicious cycle of events that reinforce and worsen each other. Muscle insulin resistance appears to be the pathophysiological link between T2DM and SMA. To explore this association, our review (i) compiles evidence on the clinical association between T2DM and SMA, (ii) reviews mechanisms underlying biochemical changes in the muscles of people with or at risk of T2DM and SMA, and (iii) examines how nutritional therapy and increased physical activity as muscle-targeted treatments benefit this population. Based on the evidence, we conclude that effective treatment of patients with T2DM-SMA depends on the restoration and maintenance of muscle mass. We thus propose that regular intake of key functional nutrients, along with guidance for physical activity, can help maintain euglycemia and improve muscle status in all patients with T2DM and SMA.

Combined Administration of Metformin and Vitamin D: A Futuristic Approach for Management of Hyperglycemia

Diabetes is a series of metabolic disorders that can be categorized into three types depending on different aspects associated with age at onset, intensity of insulin resistance, and beta- cell dysfunction: Type 1 and 2 Diabetes, and Gestational Diabetes Mellitus. Type 2 Diabetes Mellitus (T2DM) has recently been found to account for more than 85% of diabetic cases. The current review intends to raise awareness among clinicians/researchers that combining vitamin D3 with metformin may pave the way for better T2DM treatment and management. An extensive literature survey was performed to analyze vitamin D's role in regulating insulin secretion, their action on the target cells and thus maintaining the normal glucose level. On the other side, the anti-hyperglycemic effect of metformin as well as its detailed mechanism of action was also studied. Interestingly both compounds are known to exhibit the antioxidant effect too. Literature supporting the correlation between diabetic phenotypes and deficiency of vitamin D was also explored further. To thoroughly understand the common/overlapping pathways responsible for the antidiabetic as well as antioxidant nature of metformin and vitamin D3, we compared their antihyperglycemic and antioxidant activities. With this background, we are proposing the hypothesis that it would be of great interest if these two compounds could work in synergy to better manage the condition of T2DM and associated disorders.

A Quest for Potential Role of Vitamin D in Type II Diabetes Mellitus Induced Diabetic Kidney Disease

Diabetes mellitus is a metabolic disorder characterized by high blood sugar levels. In recent years, T2DM has become a worldwide health issue due to an increase in incidence and prevalence. Diabetic kidney disease (DKD) is one of the devastating consequences of diabetes, especially owing to T2DM and the key clinical manifestation of DKD is weakened renal function and progressive proteinuria. DKD affects approximately 1/3rd of patients with diabetes mellitus, and T2DM is the predominant cause of end-stage kidney disease (ESKD). Several lines of studies have observed the association between vitamin D deficiency and the progression and etiology of type II diabetes mellitus. Emerging experimental evidence has shown that T2DM is associated with various kinds of kidney diseases. Recent evidence has also shown that an alteration in VDR (vitamin D receptor) signaling in podocytes leads to DKD. The present review aims to examine vitamin D metabolism and its correlation with T2DM. Furthermore, we discuss the potential role of vitamin D and VDR in diabetic kidney disease.

The Associations of Cardiometabolic and Dietary Variables with Clinical Periodontitis in Adults with and without Type 2 Diabetes: A Cross-Sectional Study

Periodontitis is a commonly occurring inflammatory oral disease affecting a large proportion of global and US adults and is characterized by the destruction of the tooth-supporting apparatus. Its etiology is multifactorial, and type 2 diabetes and diet play critical roles in its remission and progression. However, few studies have addressed nutritional and serum vitamin D status in adults with periodontitis in the presence of diabetes. A cross-sectional study (n = 78), and a sub-set of age- and BMI-matched case-control studies (n = 50), were conducted to examine differences in dietary and cardiometabolic variables, and serum vitamin D in adults with periodontitis with or without diabetes. Participants provided fasting blood samples and 24-h diet recalls on at least two different days. Data on health history, body weight, height, nutritional habits, and clinical features of periodontitis were also collected. The Mann-Whitney U Test (with exact p-value estimation by Monte Carlo simulation) was used to examine differences by diabetes status in continuous and ordinal variables. Results revealed significantly lower serum vitamin D, and dietary intake of fruits, vegetables, dairy, vitamins A and C in adults with periodontitis with vs. without diabetes in the sub-study (all p < 0.05). In the overall sample, adults with diabetes presented with higher caries risk measures and lower numbers of teeth than those without diabetes; plaque and bleeding scores did not differ by diabetes status. Finally, a significant associations of food habits was observed, especially consuming protein-rich foods twice a day with a lower bleeding score, and daily consumption of fried or fast foods with a fewer number of teeth present (all p < 0.05). The present findings show significant dietary and serum vitamin D inadequacies among adults with periodontitis, and diabetes further aggravates the observed malnourishment and oral health.

Effects of vitamin D supplementation on cardiometabolic parameters among patients with metabolic syndrome: A systematic review and GRADE evidence synthesis of randomized controlled trials

Various pathophysiologic mechanisms were proposed to underlie the effect of vitamin D on MetS components. In this systematic review, we reviewed randomized control clinical trials to verify whether vitamin D supplementation (VDS) at different doses is effective concomitantly in controlling high-density lipoprotein cholesterol (HDL-c), triglycerides (TG), fasting glucose level, blood pressure, and central obesity in adults diagnosed with MetS. The following scientific databases were searched from 1998 until April 2023: EMBASE, MEDLINE (PubMed), Web of Science, Latin American and Caribbean Health Sciences Literature (Lilacs), the Cochrane Central Register of Controlled Trials, clinicaltrial.gov, and Google Scholar. No language restrictions were applied. Seven studies were included, and they showed a high level of heterogeneity. All studies reported a significant increase in serum 25(OH)D levels in the intervention groups. Of these, only two noted a significant decrease in triglyceride (TG) level and waist circumference. However, the certainty levels of the evidence rating were very low and low for triglyceride (TG) level and waist circumference, respectively, and moderate for fasting glucose level, blood pressure, and HDL-c. In conclusion, despite these benefits, considering the low certainty, the evidence does not support that VDS decreases triglyceride (TG) level and waist circumference in adults with MetS.

Vitamin D: immune function, inflammation, infections and auto-immunity

Vitamin D plays an active role beyond mineral metabolism and skeletal health, including regulation of the immune system. Vitamin D deficiency is widely prevalent, and observational studies link low vitamin D status to a risk of infections and auto-immune disorders. Reports indicate an inverse relationship between vitamin D status and such conditions. This review details vitamin D signalling interactions with the immune system and provides experimental and clinical evidence evaluating vitamin D status, vitamin D supplementation and host susceptibility to infections, inflammation and auto-immunity. The published literature including related reviews, systematic reviews, meta-analyses, randomised controlled trials (RCTs), observational studies and basic science reports have been synthesised. Meta-analyses of observational studies have demonstrated a link between low vitamin D status and risk of acute respiratory infections, COVID-19 disorders, multiple sclerosis, type 1 diabetes (T1DM), inflammatory bowel disease (IBD), systemic lupus erythematosus and other auto-immune disorders. Observational studies suggest that vitamin D supplementation may protect against several infectious and auto-immune conditions. Meta-analyses of RCTs had mixed results, demonstrating a small protective role for vitamin D supplementation against acute respiratory infections, especially in those with vitamin D deficiency and children, and providing modest benefits for the management of T1DM and IBD. Vitamin D status is inversely associated with the incidence of several infectious and auto-immune conditions. Supplementation is recommended for those with vitamin D deficiency or at high risk of deficiency, and it might provide additional benefit in acute respiratory infections and certain auto-immune conditions.

Serum 25-hydroxyvitamin D level is associated with short-term glycemic variability metrics derived from continuous glucose monitoring in T2DM

This study aims to investigate the association between 25-hydroxyvitamin D (25OHD) and continuous glucose monitoring-assessed short-term glycemic variability (GV) and HbA1c among patients with type 2 diabetes mellitus (T2DM). We conducted a cross-sectional study recruiting 325 patients. The association between 25OHD and GV metrics (mean amplitude of glycemic excursions [MAGE], coefficient of variation [CV], standard deviation of sensor glucose [SD], and TIR) and HbA1c were analyzed using multivariable linear and logistic regression analyses. The 25OHD level and GV metrics showed significant differences among HbA1c groups (P < 0.01). CV, MAGE, SD and HbA1c decreased, and TIR increased with ascending 25OHD tertiles (P < 0.05). Serum 25OHD was inversely associated with CV (β = - 0.211 [- 0.350 to - 0.071], P < 0.01) and HbA1c (β = - 0.061 [- 0.114 to - 0.031], P < 0.01), and further multivariable analyses confirmed these results (P < 0.05). However, no association of HbA1c and 25OHD was found with the highest tertile of CV. These findings revealed that increased GV and HbA1c were both associated with lower 25OHD, and the relationship between HbA1c and 25OHD was attenuated with higher glucose CV in T2DM. Taken together, the analyses suggest that increasing vitamin D status has effects on improvements in long-term glycemic control and low glycemic variability.

The Role of Vitamin D and Its Molecular Bases in Insulin Resistance, Diabetes, Metabolic Syndrome, and Cardiovascular Disease: State of the Art

In the last decade, an increasing awareness was directed to the role of Vitamin D in non-skeletal and preventive roles for chronic diseases. Vitamin D is an essential hormone in regulating calcium/phosphorous balance and in the pathogenesis of inflammation, insulin resistance, and obesity. The main forms of vitamin D, Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2) are converted into the active form (1,25-dihydroxyvitamin D) thanks to two hydroxylations in the liver, kidney, pancreas, and immune cells. Some anti-inflammatory cytokines are produced at higher levels by vitamin D, while some pro-inflammatory cytokines are released at lower levels. Toll-Like Receptor (TLR) expression is increased, and a pro-inflammatory state is also linked to low levels of vitamin D. Regardless of how it affects inflammation, various pathways suggest that vitamin D directly improves insulin sensitivity and secretion. The level of vitamin D in the body may change the ratio of pro- to anti-inflammatory cytokines, which would impact insulin action, lipid metabolism, and the development and function of adipose tissue. Many studies have demonstrated an inverse relationship between vitamin D concentrations and pro-inflammatory markers, insulin resistance, glucose intolerance, metabolic syndrome, obesity, and cardiovascular disease. It is interesting to note that several long-term studies also revealed an inverse correlation between vitamin D levels and the occurrence of diabetes mellitus. Vitamin D supplementation in people has controversial effects. While some studies demonstrated improvements in insulin sensitivity, glucose, and lipid metabolism, others revealed no significant effect on glycemic homeostasis and inflammation. This review aims to provide insight into the molecular basis of the relationship between vitamin D, insulin resistance, metabolic syndrome, type 1 and 2 diabetes, gestational diabetes, and cardiovascular diseases.

The effect of vitamin D supplementation on some metabolic parameters in patients with nonalcoholic fatty liver disease: A systematic review and meta-analysis of 8 RCTs

BACKGROUND

To systematically evaluate the effects of vitamin D supplementation in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

National Library of Medicine, Cochrane Library, Elsevier, China National Knowledge Infrastructure, Web of Science, WANFANG databases, and Google Scholar were retrieved to collect relevant randomized controlled trials, which are published from the earliest records the time the database was created to April 2023. Meta-analysis was conducted by using Review Manager 5.4 software after evaluating in terms of inclusion and exclusion criteria. The outcome indicators include 25-hydroxyvitamin D [25(OH)D] levels, insulin resistance index (homeostasis model assessment of insulin resistance), fasting blood glucose, and fasting insulin levels (FINS).

RESULTS

Eight randomized controlled trials with a total of 657 patients are included. Vitamin D supplementation increased 25(OH)D levels significantly (mean difference [MD] = 2.01, 95% confidence intervals [CI]: 0.94 to 3.08, P < .05) and vitamin D supplementation had a significant effect on insulin resistance index (MD = -0.54, 95% CI: -1.28 to 0.20, P = .16), fasting glucose (MD = -0.59, 95% CI: -1.50 to 0.32, P = .20), and FINS levels (MD = -0.30, 95% CI: -0.77 to 0.17, P = .21) had no significant effect.

CONCLUSION

Vitamin D supplementation improves 25(OH)D levels in patients with nonalcoholic fatty liver disease, but there is no effect on homeostasis model assessment of insulin resistance, fasting blood glucose, or FINS.

Effects of Vitamin D Deficiency on Sepsis

A prospective cohort study was conducted to evaluate the effect of vitamin D deficiency on sepsis. A total of 129 patients were enrolled. The median age was 74 years old, with a median SOFA score of 7; septic shock was observed in 60 patients. The median vitamin D level in the overall population was 13 ng/mL. A total of 96 patients had vitamin D deficiency, whereas 62 patients were described to have severe vitamin D deficiency. Severe vitamin D deficiency significantly increased the 14-day mortality (adjusted hazard ratio (aHR) 2.57; 95% confidence interval [CI]: 1.03-6.43; p = 0.043), 28-day mortality (aHR 2.28; 95% CI: 1.17-4.45; p = 0.016), and in-hospital mortality (aHR 2.11; 95% CI: 1.02-4.36; p = 0.044). In Kaplan-Meier analysis, the severe vitamin D deficiency group had significantly higher 14-day and 28-day mortality rates compared with the non-deficient group. Evaluating the vitamin D levels in sepsis patients may become necessary in an aging society. Severe vitamin D deficiency can independently affect poor prognosis related to sepsis. Further studies are needed to evaluate whether vitamin D supplementation in sepsis patients with vitamin D deficiency can help improve the prognosis of sepsis in addition to improving bone mineral metabolism.

Different doses of vitamin D supplementation to nonsurgical treatment for vitamin-D-insufficient patients with diabetic periodontitis and the effect on gingival BMP-2 levels

Epidemiological data show people with diabetes mellitus (DM) have three-fold increase in risk of periodontitis. A vitamin D insufficiency can affect the progression of DM and periodontitis. This study evaluated the effects of different-dose vitamin D supplementation to nonsurgical periodontal therapy for vitamin-D-insufficient diabetic patients coexisting with periodontitis and changes of gingival bone morphogenetic protein-2 (BMP-2) levels. The study included 30 vitamin-D-insufficient patients receiving nonsurgical treatment followed by administration of 25,000 international units (IU) vitamin D3 per week (the low-VD group) and 30 patients receiving 50,000 UI vitamin D per week (the high-VD group). The decreases of probing pocket depth, clinical attachment loss, bleeding index, and periodontal plaque index values of patients after the six-month supplementation of 50,000 UI vitamin D3 per week to nonsurgical treatment were more significant than those after the six-month supplementation of 25,000 UI vitamin D3 per week to nonsurgical treatment. It was found that 50,000 IU per week vitamin D supplementation for 6 months could lead to a better glycemic control for vitamin-D-insufficient diabetic patients coexisting with periodontitis after nonsurgical periodontal therapy. Increased levels of serum 25(OH) vitamin D3 and gingival BMP-2 were found in both low- and high-dose VD groups, and the high-dose VD group exhibited higher levels than the low-dose VD group. Vitamin D supplementation in large doses for 6 months tended to improve the treatment of periodontitis and increase gingival BMP-2 levels in diabetic patients coexisting with periodontitis who were vitamin D deficient.

Co-exposure to multiple vitamins and the risk of all-cause mortality in patients with diabetes

Objective

Although the effect of vitamins on the risk of mortality in diabetic patients has been reported, most studies focus on individual vitamins. However, humans are often exposed to multiple vitamins simultaneously in daily life. Therefore, it is worth exploring the effects of co-exposure to multiple vitamins on the risk of mortality in diabetic patients.

Methods

This study included diabetic patients aged ≥20WD years who participated in NHANES from 2003 to 2006. An unsupervised K-means clustering method was used to cluster eight vitamins in serum into several patterns of co-exposure to multiple vitamins, and the Cox proportional hazards model was used to evaluate the impact of different patterns of co-exposure to multiple vitamins on the risk of all-cause mortality in diabetic patients.

Results

Three patterns of co-exposure to multiple vitamins were generated based on K-means clustering, namely, low-level, moderate-level, and high-level. Among the 484 diabetic patients, with a median follow-up of 13.7 years, a total of 211 deaths occurred. After adjusting for covariates, the individual vitamins had varying effects on the risk of all-cause mortality in diabetic patients. Compared to the low-level group of co-exposure to multiple vitamins, the high-level group significantly reduced the risk of all-cause mortality in diabetic patients, with a HR of 0.42 (95% CI: 0.20, 0.87). Subgroup analysis demonstrated that high levels of co-exposure to multiple vitamins significantly reduced the risk of all-cause mortality in males, individuals aged ≥ 60 years, and non-Hispanic White people with diabetes compared to the low-level group, with HR of 0.42 (95% CI: 0.18, 0.98), 0.53 (95% CI: 0.26, 0.98), and 0.26 (95% CI: 0.12, 0.58) respectively.

Conclusion

While individual vitamins had different effects on the risk of all-cause mortality in patients with diabetes, high-level co-exposure to multiple vitamins significantly reduced the risk of all-cause mortality in patients with diabetes, with differences observed among genders, ages, and race. This suggests that when developing vitamin intervention strategies for patients with diabetes, consideration should be given not only to the dosage of individual vitamins but also to the variations between different population groups.

Pitaya as a New Alternative Crop for Iberian Peninsula: Biology and Edaphoclimatic Requirements

Pitaya is one of the fruit species whose demand has increased in recent years due to the numerous health benefits and lucrative price of the fruit and its by-products. In Europe, the Iberian Peninsula and other Mediterranean countries are the ones with favorable climatic conditions for its cultivation. This document describes much of the history of pitaya in the Iberian Peninsula and the difficulties related to its cultivation. A bibliographical survey was carried out on the culture of pitaya in the world, focusing on the edaphoclimatic requirements, and on the possibility of this becoming a consolidated crop in the Iberian Peninsula. The relatively low water requirement of pitaya makes this crop sustainable among crops that require irrigation. In addition, we provide a perspective for use and research of this emerging crop. There has been an exponential growth of scientific publications on pitaya in the last decade; however, much more needs to be researched to know how to increase productivity as well as the sensory quality of fruits in different regions. This sustainable crop is a good option to diversify fruit production in the Iberian Peninsula.