Changes in circulating vitamin D levels with loss of adipose tissue

Are There Any Correlations between Vitamin D, Calcium, and Magnesium Intake and Coronary and Obesity Indices?

OBJECTIVE

The association between nutrient intake and obesity and coronary problems has received great attention. So, this study aimed to examine the association between vitamin D, calcium, and magnesium intake and obesity and coronary indices.

METHODS

A total of 491 male and female university employees (18-64 years) were randomly included in a cross-sectional study. Blood samples were drawn, and the lipid profile was analyzed. Different anthropometrics were measured. Obesity and coronary indices were calculated based on standard formulas. A 24-h recall was used to measure the average dietary intake of vitamin D, calcium, and magnesium.

RESULTS

For the total sample, vitamin D had a significantly weak correlation with the abdominal volume index (AVI) and weight-adjusted waist index (WWI). However, calcium intake had a significant moderate correlation with the AVI and a weak correlation with the conicity index (CI), body roundness index (BRI), body adiposity index (BAI), WWI, lipid accumulation product (LAP), and atherogenic index of plasma (AIP). In males, there was a significant weak correlation between calcium and magnesium intake and the CI, BAI, AVI, WWI, and BRI. Additionally, magnesium intake had a weak correlation with the LAP. In female participants, calcium and magnesium intake had a weak correlation with CI, BAI, AIP, and WWI. Additionally, calcium intake showed a moderate correlation with the AVI and BRI and a weak correlation with the LAP.

CONCLUSION

Magnesium intake had the greatest impact on coronary indices. Calcium intake had the greatest impact on obesity indices. Vitamin D intake had minimal effects on obesity and coronary indices.

Bariatric surgery and calcifediol treatment, Gordian knot of severe-obesity-related comorbidities treatment

Background

Obesity (OB) is a chronic metabolic disease with important associated comorbidities and mortality. Vitamin D supplementation is frequently administered after bariatric surgery (BS), so as to reduce OB-related complications, maybe including chronic inflammation.

Aim

This study aimed to explore relations between vitamin D metabolites and components of the inflammasome machinery in OB before and after BS and their relations with the improvement of metabolic comorbidities.

Patients and methods

Epidemiological/clinical/anthropometric/biochemical evaluation was performed in patients with OB at baseline and 6 months after BS. Evaluation of i) vitamin-D metabolites in plasma and ii) components of the inflammasome machinery and inflammatory-associated factors [NOD-like-receptors (NLRs), inflammasome-activation-components, cytokines and inflammation/apoptosis-related components, and cell-cycle and DNA-damage regulators] in peripheral blood mononuclear cells (PBMCs) was performed at baseline and 6 months after BS. Clinical and molecular correlations/associations were analyzed.

Results

Significant correlations between vitamin D metabolites and inflammasome-machinery components were observed at baseline, and these correlations were significantly reduced 6 months after BS in parallel to a decrease in inflammation markers, fat mass, and body weight. Treatment with calcifediol remarkably increased 25OHD levels, despite 24,25(OH)2D3 remained stable after BS. Several inflammasome-machinery components were associated with improvement in metabolic comorbidities, especially hypertension and dyslipidemia.

Conclusion

The beneficial effects of vitamin D on OB-related comorbidities after BS patients are associated with significant changes in the molecular expression of key inflammasome-machinery components. The expression profile of these inflammasome components can be dynamically modulated in PBMCs after BS and vitamin D supplementation, suggesting that this profile could likely serve as a sensor and early predictor of the reversal of OB-related complications after BS.

Unraveling the Connection: Visceral Adipose Tissue and Vitamin D Levels in Obesity

Vitamin D deficiency and insufficiency are widespread on a global scale, with multiple factors playing a role in their development, such as limited exposure to sunlight, inadequate dietary consumption, as well as obesity and abdominal fat accumulation. Abdominal obesity, assessed with waist circumference (WC), is associated with metabolic syndrome and has been linked to low vitamin D levels. This study aimed to investigate the relationship between visceral adipose tissue (VAT) and vitamin D levels, particularly examining the potential threshold for vitamin D storage and sequestration using adipose tissue. The study was conducted between 2020 and 2022 with 58 patients from an internal medicine outpatient department. Patients with certain medical conditions and those taking medications affecting bone metabolism were excluded. Blood samples were collected at baseline and after 6 months of monthly cholecalciferol supplementation. Ultrasonography was used to evaluate adipose tissue measurements, including subcutaneous adipose tissue thickness, VAT, preperitoneal adipose tissue (PPAT), and prerenal adipose tissue (PRAT). Anthropometric measures such as the waist-to-hip ratio and waist-to-height ratio were also assessed. The results showed that all subjects had significant hypovitaminosis D at baseline. After 6 months of supplementation, the mean increase in vitamin D levels was 9.6 ng/mL, with 55.2% of subjects becoming deficient. The study revealed a significant correlation between follow-up vitamin D levels and waist circumference, hip circumference, and VAT. VAT exhibited a strong correlation not only with vitamin D levels but also with waist circumference. When analyzing gender differences, males showed a higher weight and waist-to-hip ratio, while females had higher body adiposity indexes and subcutaneous adipose tissue measurements. In conclusion, this study highlights the relationship between VAT and vitamin D levels, emphasizing the potential role of adipose tissue in vitamin D availability. Waist circumference was identified as a surrogate measure for VAT evaluation. Furthermore, the study showed variations in vitamin D response to supplementation between genders, with a higher percentage of males reaching normal vitamin D levels. Predictive factors for vitamin D levels differed between genders, with waist circumference being a significant predictor in males and body adiposity index in females.

Evaluating the effect of body mass index and 25-hydroxy-vitamin D level on basal cell carcinoma using Mendelian randomization

Basal cell carcinoma (BCC) is the most common cancer with a rising incidence among white-skinned individuals. A number of epidemiological studies have suggested that obesity and serum 25-hydroxy-vitamin D (25(OH)D) levels may affect the arising of BCC. To address this, we selected 443 and 96 single nucleotide polymorphisms (SNPs) associated with body mass index (BMI) and serum level of 25(OH)D from large-scale genome-wide association studies (GWAS), respectively. The univariable and multivariable two-sample Mendelian randomization (MR) analyses were conducted with a series of sensitivity analyses to ensure the results were reliable and reproducible. The results of univariable two-sample MR analysis showed that higher BMI was related to lower risk for BCC (Odds ratio(OR) = 0.90; 95% confidence interval (CI),[0.81,0.99]; p = 0.02). In addition, this causal effect of BMI on BCC still remained (OR = 0.88; 95%CI,[- 0.22, - 0.03], p-value = 0.008) after adjusting for 25(OH)D level in the multivariable MR analysis. However, the results suggested that 25(OH)D level was not associated with BCC(OR = 1.02; 95%CI, [0.94,1.09], p-value = 0.67). In conclusion, similar to the conclusions of retrospective observational studies, the MR results indicate that high BMI is an independent protective factor for BCC. Meanwhile, vitamin D levels may not be causally associated with the risk of basal cell carcinoma and increasing vitamin D supplementation is unlikely to reduce the risk.

Clarifying the Heterogeneity in Response to Vitamin D in the Development, Prevention, and Treatment of Type 2 Diabetes Mellitus: A Narrative Review

In this review, we explore the potential drivers of heterogeneity in response to Vitamin D (VitD) therapy, such as bioavailability, sex-specific response, and autoimmune pathology, in those at risk for and diagnosed with T2DM. In addition, we propose distinct populations for future interventions with VitD. The literature concerning VitD supplementation in the prevention, treatment, and remission of type 2 diabetes mellitus (T2DM) spans decades, is complex, and is often contradictory with mixed findings upon intervention. By association, VitD status is powerfully predictive with deficient subjects reporting greater risk for T2DM, conversion to T2DM from prediabetes, and enhanced response to VitD therapy. Preclinical models strongly favor intervention with VitD owing to the pleiotropic influence of VitD on multiple systems. Additional research is crucial as there remain many questions unanswered that are related to VitD status and conditions such as T2DM. Future research must be conducted to better understand the potentially spurious relationships between VitD status, supplementation, sun exposure, health behaviors, and the diagnosis and management of T2DM. Public health practice can greatly benefit from a better understanding of the mechanisms by which we can reliably increase VitD status and how this can be used to develop education and improve health behaviors.

Association of Vitamin D Status With Metabolic Syndrome and Its Individual Risk Factors: A Cross-Sectional Study

Background Vitamin D deficiency has been associated with metabolic syndrome and its related outcomes, including type 2 diabetes mellitus, cardiovascular disease, myocardial infarction, and stroke. However, studies in Indian populations have provided conflicting results. Methods This single-center cross-sectional study was conducted in a tertiary care hospital in north India to determine the prevalence of vitamin D deficiency in patients with metabolic syndrome and to study the correlations of individual components of metabolic syndrome with 25 hydroxy vitamin D levels. The study included 235 patients aged between 30 to 70 years who met the criteria for metabolic syndrome. Patients with diabetes, hypothyroidism, Cushing's, and other disorders affecting vitamin D status, on supplements of vitamin D or anti-dyslipidaemic drugs were excluded. Information regarding socio-demographic characteristics, medical history, and anthropometric measurements were collected. Blood samples were collected to assess vitamin D levels. Results The prevalence of vitamin D deficiency (<20 ng/ml) was 76% among the study population. There was a significant negative correlation between vitamin D levels and diastolic blood pressure (Spearman's rho: -0.134, 95% CI: -0.82,-0.260, p=0.040), fasting blood glucose (Spearman's rho: -0.142, 95% CI: -0.101,-0.269, p=0.029), A weak correlation was also found between vitamin D3 levels and total cholesterol (Spearman's rho: -0.246, 95% CI: -0.119,-0.367, p<0.001), triglyceride levels (Spearman's rho: -0.246, 95% CI: -0.118,-0.370, p<0.001) and low-density lipoprotein (LDL) levels (Spearman's rho: -0.229, 95% CI: -0.102,-0.351, p<0.001). Conclusion The study findings suggest that vitamin D deficiency is prevalent among patients with metabolic syndrome in north India. There is a significant negative correlation between vitamin D levels and some components of metabolic syndrome. This highlights the need for further research to understand the underlying mechanisms and potential benefits of vitamin D supplementation in this population. Identification of high-risk individuals for hypovitaminosis D can aid in streamlining treatment guidelines and preventing unnecessary prescription of investigations in developing countries.

Circulating 25-hydroxyvitamin D is associated with metabolic phenotypes of obesity: National Food and Nutrition Surveillance

Different phenotypes of obesity are each related with different complications and comorbidities. We hypothesized that suboptimal vitamin D status is directly associated with an unhealthy metabolic status, especially if allied with obesity. This cross-sectional study was performed in the framework of the National Food and Nutrition Surveillance. Overall, 1098 men and women participated in this study. In addition to height and weight, serum concentrations of 25-hydroxyvitamin D (25(OH)D) and glycemic and lipidemic status were evaluated. Then participants were classified into 4 groups based on body mass index and lipidemic and glycemic profile status, as follows: hyperglycemic-dyslipidemic obese (HDO), hyperglycemic-dyslipidemic nonobese (HDNO), normoglycemic-normolipidemic obese (NNO), and normoglycemic-normolipidemic nonobese (NNNO). In this study, 31.6% of participants were classified as HDO, 7.5% as HDNO, 34.5% as NNO, and 26.4% as NNNO. The frequency of suboptimal vitamin D status was more prevalent in HDO (81.8%) than in other phenotypes (HDNO, 80%; NNO, 77.6%; NNNO, 73.8%; P = .015). In the multivariate model, suboptimal vitamin D status significantly increased the odds of being NNO (odds ratio [OR], 1.28; 95% CI, 0.84-1.95), HDNO (OR, 1.48; 95% CI, 0.77-2.83), and HDO (OR, 1.73; 95% CI, 1.11-2.7) compared with the NNNO group. Likewise, in multivariate model, per each unit (ng/mL) increment in 25(OH)D concentration, the odds of HDNO and HDO decreased significantly by 4% (OR, 0.96; 95% CI, 0.94-0.98) and 7% (OR, 0.93; 95% CI, 0.92-0.95), respectively. The results of the study showed a significant relationship between serum 25(OH)D concentrations and metabolic obesity phenotypes; these data confirm the association between suboptimal vitamin D status and metabolic complications, especially in obese individuals.

High Prevalence of Hypovitaminosis D in Adolescents Attending a Reference Centre for the Treatment of Obesity in Switzerland

Background: Hypovitaminosis D is common in populations with obesity. This study aimed at assessing (1) the prevalence of hypovitaminosis D and (2) the associations between vitamin D levels and cardiovascular risk factors in adolescents attending a reference centre for the treatment of obesity. Design: Cross-sectional pilot study conducted in the paediatric obesity unit of the Lausanne university hospital, Switzerland. Methods: Participants were considered eligible if they (1) were aged between 10 to 16.9 years and (2) consulted between 2017 and 2021. Participants were excluded if (1) they lacked vitamin D measurements or (2) the vitamin D measurement was performed one month after the base anthropometric assessment. Hypovitaminosis D was considered if the vitamin D level was <30 ng/mL (<75 nmol/L). Severe obesity was defined as a BMI z-score > 3 SD. Results: We included 52 adolescents (31% girls, mean age 13 ± 2 years, 33% with severe obesity). The prevalence of hypovitaminosis D was 87.5% in girls and 88.9% in boys. The vitamin D levels were inversely associated with BMI, Spearman r and 95% CI: −0.286 (−0.555; −0.017), p = 0.037; they were not associated with the BMI z-score: −0.052 (−0.327; 0.224), p = 0.713. The vitamin D levels were negatively associated with the parathormone levels (−0.353 (−0.667; −0.039), p = 0.028) and positively associated with the calcium levels (0.385 (0.061; 0.708), p = 0.020), while no association was found between vitamin D levels and blood pressure and lipid or glucose levels. Conclusion: almost 9 out of 10 adolescents with obesity in our cohort presented with hypovitaminosis D. Hypovitaminosis D does not seem to be associated with a higher cardiovascular risk profile in this group.

Association between anthropometric markers of adiposity, adipokines and vitamin D levels

Inverse association between serum levels of vitamin D and obesity has been pointed out in several studies. Our aim was to identify to the associations between vitamin D levels and a large panel of anthropometric markers and adipokines. Cross-sectional study including 6485 participants. Anthropometric markers included body mass index (BMI), % body fat, waist, waist-to-hip (WHR), waist-to-height (WHtR), conicity index, body roundness index (BRI) and a body shape index (ABSI). 55.7% of women and 60.1% of men presented with vitamin D deficiency. Vitamin D levels were negatively associated with most anthropometric markers, with correlation coefficients ranging between -0.017 (ABSI) and -0.192 (BMI) in women and between -0.026 (weight) and -0.130 (% body fat) in men. Vitamin D levels were inversely associated with leptin levels in both sexes and positively associated with adiponectin levels in women only. The likelihood of vitamin D deficiency increased with increasing adiposity levels, except for ABSI (women) and BMI (men). Total body fat, rather than localized or unevenly distributed body fat, is the adiposity marker most associated with decreased vitamin D levels. Monitoring vitamin D levels in people with overweight/obesity is essential.

Effect of vitamin D supplementation on cardiac-metabolic risk factors in elderly: a systematic review and meta-analysis of clinical trials

BACKGROUND

There has been a longstanding interest in the potential effect of vitamin D in preventing cardiac-metabolic diseases. However, there are divergent results regarding the impact of vitamin D supplementation (VDS) on managing cardiac-metabolic outcomes in the elderly population.

MATERIAL AND METHOD

We systematically searched electronic databases; Web of Science, PubMed, Scopus, EMBASE, Cochrane, and ProQuest. We included all trials that evaluated the effect of VDS on cardiac-metabolic risk factors in the elderly population, which were published until 30 September 2021. The effects of VDS on cardiac-metabolic outcomes were assessed using standardized mean difference (SMD). A random-effect model was used to pool the SMD and 95% confidence interval (CI).

RESULT

The literature search identified 4409 studies, of which 12 trials met inclusion criteria. Results of random effect meta-analysis indicated a significant reduction in total cholesterol (TC) (SMD: - 0.14 mg/dl; 95% CI: - 0.25, - 0.02) and triglyceride (TG) (SMD: - 0.45 mg/dl; 95% CI: - 0.86, - 0.04) with VDS compared to the placebo. The subgroup analyses revealed that the reduction of TG in patients with diabetes and vitamin D deficiency was significant. Furthermore, short-term intervention (≤ 6 months) induced a significantly lower level of TG and insulin in comparison to longer duration (> 6 months).

CONCLUSION

The study suggests that VDS could improve insulin concentration and dyslipidemia in the elderly population. The systematic review was registered in Alborz university of medical sciences with 2060-01-03-1397 number and the Ethics council IR.ABZUMS.REC.1397.207 number.

Interaction between Dietary Fat Intake and Metabolic Genetic Risk Score on 25-Hydroxyvitamin D Concentrations in a Turkish Adult Population

Previous studies have pointed out a link between vitamin D status and metabolic traits, however, consistent evidence has not been provided yet. This cross-sectional study has used a nutrigenetic approach to investigate the interaction between metabolic-genetic risk score (GRS) and dietary intake on serum 25-hydroxyvitamin D [25(OH)D] concentrations in 396 unrelated Turkish adults, aged 24-50 years. Serum 25(OH)D concentration was significantly lower in those with a metabolic-GRS ≥ 1 risk allele than those with a metabolic-GRS < 1 risk allele (p = 0.020). A significant interaction between metabolic-GRS and dietary fat intake (energy%) on serum 25(OH)D levels was identified (Pinteraction = 0.040). Participants carrying a metabolic-GRS ≥ 1 risk allele and consuming a high fat diet (≥38% of energy = 122.3 ± 52.51 g/day) had significantly lower serum 25(OH)D concentration (p = 0.006) in comparison to those consuming a low-fat diet (<38% of energy = 82.5 ± 37.36 g/d). In conclusion, our study suggests a novel interaction between metabolic-GRS and dietary fat intake on serum 25(OH)D level, which emphasises that following the current dietary fat intake recommendation (<35% total fat) could be important in reducing the prevalence of vitamin D deficiency in this Turkish population. Nevertheless, further larger studies are needed to verify this interaction, before implementing personalized dietary recommendations for the maintenance of optimal vitamin D status.

Relationship of Vitamin D Deficiency and Fatty Liver in Children as Defined by Multiple Imaging and Histologic Endpoints

Objectives

The relationship between vitamin D deficiency (VDD) and pediatric nonalcoholic fatty liver disease (NAFLD) remains uncertain due to conflicting results and few studies with histologic endpoints. We therefore used multiple imaging and histologic NAFLD endpoints to more comprehensively assess the association between VDD and NAFLD in a large pediatric population.

Methods

Data were obtained from an ongoing pediatric NAFLD study in Bronx, NY. Briefly, overweight and obese children aged 2-18 years with alanine aminotransferase (ALT) levels ≥ 35 U/L were serially enrolled. Liver biopsy was obtained in accordance with clinical guidelines. All participants had liver imaging, namely, controlled attenuation parameter (CAP; Echosens, France) to assess steatosis and, to assess fibrosis, vibration controlled transient elastography (VCTE; FibroScan™, Echosens, France) and acoustic radiation force impulse (ARFI; Philips, Netherlands) imaging. Levels of 25-hydroxyvitamin D were measured serologically.

Results

N=276 (88%) of 315 participants had 25-OH vitamin D results, of whom 241 (87%) were Hispanic, 199 (72%) were male, and 92 (33%) underwent liver biopsy. VDD was univariately associated with high waist circumference (p=0.004), high-density lipoprotein level (p=0.01), season (p=0.009), and CAP score (p=0.01). In multivariate analysis, only waist circumference (p=0.0002) and biopsy inflammation grade (p=0.03) were associated with VDD, though the latter had not approximated statistical significance in univariate analysis (p=0.56). There was no association between VDD and hepatic steatosis, ballooning, NAFLD Activity Score, ARFI or VCTE elasticity scores.

Conclusions

VDD was not associated with NAFLD defined by imaging and histologic endpoints, except for a possible relation with histologic inflammation grade.

Conundrum of vitamin D on glucose and fuel homeostasis

As an endocrine hormone, vitamin D plays an important role in bone health and calcium homeostasis. Over the past two decades, the non-calcemic effects of vitamin D were extensively examined. Although the effect of vitamin D on beta cell function were known for some time, the effect of vitamin D on glucose and fuel homeostasis has attracted new interest among researchers. Yet, to date, studies remain inconclusive and controversial, in part, due to a lack of understanding of the threshold effects of vitamin D. In this review, a critical examination of interventional trials of vitamin D in prevention of diabetes is provided. Like use of vitamin D for bone loss, the benefits of vitamin D supplementation in diabetes prevention were observed in vitamin D-deficient subjects with serum 25-hydroxyvitamin D < 50 nmol/L (20 ng/mL). The beneficial effect from vitamin D supplementation was not apparent in subjects with serum 25-hydroxyvitamin D > 75 nmol/L (30 ng/mL). Furthermore, no benefit was noted in subjects that achieved serum 25-hydroxyvitamin D > 100 nmol/L (40 ng/mL). Further studies are required to confirm these observations.

Impact of the vitamin D deficiency on COVID-19 infection and mortality in Asian countries

BACKGROUND AND AIMS

COVID-19 is a pandemic that has affected beyond 100 million and caused nearly 3 million deaths globally. Vitamin D is a known risk factor for COVID-19. Therefore, we aimed to investigate the association of prevalence of vitamin D deficiency and mean vitamin D level with COVID-19 infection and mortality in Asia, predicting with other confounding factors such as median age, obesity, and diabetes.

METHODS

COVID-19 infections and mortalities among the Asian countries were retrieved from the Worldometer website. Information on prevalence of vitamin D deficiency and mean vitamin D values in each Asian country was retrieved through literature searching on PubMed® and Google scholar. The associations between COVID-19 infections and mortalities with prevalence of vitamin D deficiency and mean vitamin D level were explored with correlation coefficients. As a predictive analysis, multiple linear regression was carried out with all confounders.

RESULTS

Positive correlations were observed for prevalence of vitamin D deficiency with COVID-19 infections (r = 0.55; p = 0.01; R2 = 0.31) and mortalities (r = 0.50; p = 0.01; R2 = 0.25). Moreover, the associations for the COVID-19 infections and mortalities improved to r = 0.76 (p = 0.002; R2 = 0.58) and r = 0.65 (p = 0.03; R2 = 0.42), respectively, after predicting with confounding factors. Similarly, mean vitamin D level had a significant negative correlation with COVID-19 infections (r = -0.77; p = 0.04; R2 = 0.59) and mortalities (r = -0.80; p = 0.03; R2 = 0.63) when combining with confounders.

CONCLUSION

Prevalence of vitamin D deficiency is significantly positively associated whereas the mean vitamin D level is significantly negatively associated with both infection and mortality rate of COVID-19 among Asian countries upon predicting with all confounders.

Long-Term Iron and Vitamin B12 Deficiency Are Present after Bariatric Surgery, Despite the Widespread Use of Supplements

There are few long-term nutritional studies in subjects undergoing bariatric surgery that have assessed weight regain and nutritional deficiencies. In this study, we report data 8 years after surgery on weight loss, use of dietary supplements and deficit of micronutrients in a cohort of patients from five centres in central and northern Italy. The study group consisted of 52 subjects (age: 38.1 ± 10.6 y, 42 females): 16 patients had Roux-en-Y gastric bypass (RYGB), 25 patients had sleeve gastrectomy (SG) and 11 subjects had adjustable gastric banding (AGB). All three bariatric procedures led to sustained weight loss: the average percentage excess weight loss, defined as weight loss divided by excess weight based on ideal body weight, was 60.6% ± 32.3. Despite good adherence to prescribed supplements, 80.7% of subjects (72.7%, AGB; 76.7%, SG; 93.8 %, RYGB) reported at least one nutritional deficiency: iron (F 64.3% vs. M 30%), vitamin B12 (F 16.6% vs. M 10%), calcium (F 33.3% vs. M 0%) and vitamin D (F 38.1% vs. M 60%). Long-term nutritional deficiencies were greater than the general population among men for iron and among women for vitamin B12.

Cellular Senescence and Vitamin D Deficiency Play a Role in the Pathogenesis of Obesity-Associated Subclinical Atherosclerosis: Study of the Potential Protective Role of Vitamin D Supplementation

The exact link between obesity, vitamin D deficiency, and their relation to cellular senescence in the pathogenesis of subclinical atherosclerosis is still under debate. Therefore, the current study aims to verify the possible role of vitamin D deficiency and cellular senescence in the pathogenesis of obesity-related subclinical atherosclerosis. Moreover, it aims to investigate the possible protective role of vitamin D supplementation. Fifty-seven male albino rats were enrolled in the study and classified into four groups: negative (10) and positive control groups (10), an obese model group (24), and a vitamin-D-supplemented obese group (13). Aortic tissue samples and fasting blood samples were collected. The following biochemical investigations were performed: serum cholesterol, triglycerides, HDL-C, LDL-C, ALT, AST, CPK, CK-MB, and hs-cTnt. HOMA-IR was calculated. Moreover, serum SMP-30, 25 (OH)Vitamin D3, and eNOS were determined by the ELISA technique. Aortic gene expression of eNOS, SMP-30, and P53 was estimated by real-time qRT-PCR. Serum 25(OH) D3 and SMP-30 were lower in the obese group. In addition, the obese group showed higher serum lipid profile, HOMA-IR, eNOS, ALT, AST, CPK, CK-MB, and hs-cTnt than the control groups, while decreased levels were found in the vitamin-D-treated obese group. Gene expression of eNOS and SMP-30 were in accordance with their serum levels. A positive correlation was found between vitamin D level and SMP-30. In conclusion, obesity is associated with vitamin D deficiency and enhanced cellular senescence. They could play a role in the pathogenesis of obesity-associated subclinical atherosclerosis and endothelial dysfunction. Vitamin D supplements could play a protective role against such obesity-related comorbidity.

Supplementation with vitamin D and insulin homeostasis in healthy overweight and obese adults: A randomized clinical trial

INTRODUCTION

Hypovitaminosis D which is a frequent problem in overweight and obese individuals, seems to interfere with cells responsible for control of glycemic status. Therefore, the current research intended to study the impact of supplementation with vitamin D on insulin homeostasis among healthy obese and overweight individuals.

METHODS

The current study was conducted among obese or overweight individuals who had hypovitaminosis D. After separation of participants into two groups, one group received vitamin D pearls (50,000 IU/weekly) for eight weeks, whereas another group received a placebo over the same period. Next, the level of vitamin D, fasting blood sugar (FBS), fasting insulin, Homeostasis Model Assessment 2 for Insulin Resistance (HOMA2-IR), Function of β-cell (HOMA2-β), and Insulin Sensitivity (HOMA2-S) and lipid profile of participants were evaluated.

RESULTS

Overall, 67.2% of the participants were female. No considerable difference was observed concerning biochemical parameters among the study groups at baseline. After eight weeks, the mean (SD) level of vitamin D was significantly lower in the placebo group than those in the vitamin D group. (38.6 ± 8.1 vs. 14.9 ± 6.4; P < 0.001). The patients who received vitamin D had significant lower levels of FBS (P < 0.001), fasting insulin (P < 0.001), HOMA2-IR (P < 0.001), and HOMA2-β (P = 0.03), than the placebo group. The HOMA2-S was significantly enhanced in vitamin D group, while it reduced in another group (P < 0.001). However, no considerable decrease was found in triglyceride, cholesterol, high-density lipoprotein or low-density lipoprotein.

CONCLUSION

Supplementation with vitamin D improved sensitivity to insulin and pancreatic function of β cells of healthy overweight and obese adults.

Vitamin D in obesity and obesity-related diseases: an overview

Hypovitaminosis D and obesity represent two pandemic conditions sometimes associated with each other. Although it is known that there is a close relationship between these two health problems, the underlying pathophysiological mechanism has not yet been fully clarified. In fact, on the one hand, obesity per se seems to involve low circulating levels of vitamin D due to low sun exposure, physical activity, and intake of foods rich in vitamin D, volumetric dilution and sequestration in the adipose tissue. Conversely, since preadipocytes and adipocytes express the receptors and are involved in the metabolism of vitamin D it would seem that low levels of this vitamin may be involved in adipogenesis and therefore in the development of obesity. This connection is extremely important when considering obesity-related diseases. In fact, low vitamin D levels and severe obesity are significantly associated with some cardio-metabolic risk factors, including high Body Mass Index, waist circumference, blood pressure, impaired lipid and glycemic profile and insulin resistance, as they would seem associated with worse cardiovascular outcomes and higher cancer incidence and mortality. Therefore, the purpose of this review was to examine the recent evidence linking low vitamin D status, obesity and obesity-related diseases, highlighting the scientific achievements and the gaps to be filled with further investigations.

Effects of Vitamin D Supplementation on General and Central Obesity: Results from 20 Randomized Controlled Trials Involving Apparently Healthy Populations

Background: The obesity pandemic has been paralleled by a high prevalence of vitamin D deficiency (VDD). There is growing epidemiological evidence linking low vitamin D status with obesity events. In addition, observational studies also show that obesity may increase the risk of VDD. However, there is insufficient knowledge to understand whether there is a causality between the two. Moreover, the impact of vitamin D supplementation on obesity indices has shown inconsistent outcomes. Objective: This meta-analysis aimed to assess whether vitamin D supplementation modified general and central obesity indices in apparently healthy populations. Methods: A systematic retrieval of relevant randomized controlled trials (RCTs) was undertaken using Pubmed, Embase, Web of Knowledge and Chinese National Knowledge Infrastructure databases. The pooled weighted mean difference (WMD) and 95% confidence intervals (CI) were used to assess the changes in body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and 25-hydroxyvitamin D (25[OH]D) from baseline. Results: Twenty RCTs involving 3,153 participants reporting either BMI, WC, WHR or 25(OH)D met the inclusion criteria. When compared with placebo, vitamin D supplementation had no significant decreases in BMI (WMD = –0.09 kg/m2, 95% CI –0.19 to 0.01, p = 0.08), WC (WMD = –0.71 cm, 95% CI –1.58 to 0.16, p = 0.112) or WHR (WMD = 0.00, 95% CI –0.01 to 0.01, p = 0.749). However, in the subgroups of females, Asia region studies and intervention duration ≥6 months, a beneficial and significant reduction in BMI and WC was noted (all p < 0.026). On the other hand, pooled results showed that there was a significant increase in serum 25(OH)D levels (WMD = 13.20 ng/mL, 95% CI 9.83–16.58, p < 0.001) after vitamin D intervention. No publication bias was found in our study. Conclusions: Overall, supplementation with vitamin D produced no significant effect on the BMI, WC or WHR of healthy adults.

Avoidance of vitamin D deficiency to slow the COVID-19 pandemic

Vitamin D deficiency, which impedes good immune function, is common during winter and spring in regions of high latitude. There is good evidence that vitamin D deficiency contributes to the seasonal increase of virus infections of the respiratory tract, from the common cold to influenza, and now possibly also COVID-19. This communication explores key factors that make it more likely, particularly in combination, that individuals are vitamin D deficient. These factors include old age, obesity, dark skin tone and common genetic variants that impede vitamin D status. Precision nutrition is an approach that aims to consider known personal risk factors and health circumstances to provide more effective nutrition guidance in health and disease. In regard to avoiding vitamin D deficiency, people with excess body fat, a dark skin tone or older age usually need to use a moderately dosed daily vitamin D supplement, particularly those living in a high-latitude region, getting little ultraviolet B exposure due to air pollution or staying mostly indoors. Carriers of the GC (group-specific component) rs4588 AA genotype also are more likely to become deficient. Very high-dosed supplements with more than 4000 IU vitamin D are rarely needed or justified. A state-by-state Mendelian randomisation analysis of excess COVID-19 mortality of African-Americans in the USA shows a greater disparity in northern states than in southern states. It is conceivable that vitamin D adequacy denies the virus easy footholds and thereby slows spreading of the contagion. This finding should drive home the message that vitamin D supplementation is particularly important for individuals with dark skin tones. Vitamin D deficiency, even for a few months during the winter and spring season, must be rigorously remedied because of its many adverse health impacts that include decreased life expectancy and increased mortality. Slowing the spread of COVID-19 would be an added bonus.

Steroid Hormone Vitamin D: Implications for Cardiovascular Disease

Understanding of vitamin D physiology is important because about half of the population is being diagnosed with deficiency and treated with supplements. Clinical guidelines were developed based on observational studies showing an association between low serum levels and increased cardiovascular risk. However, new randomized controlled trials have failed to confirm any cardiovascular benefit from supplementation in the general population. A major concern is that excess vitamin D is known to cause calcific vasculopathy and valvulopathy in animal models. For decades, administration of vitamin D has been used in rodents as a reliable experimental model of vascular calcification. Technically, vitamin D is a misnomer. It is not a true vitamin because it can be synthesized endogenously through ultraviolet exposure of the skin. It is a steroid hormone that comes in 3 forms that are sequential metabolites produced by hydroxylases. As a fat-soluble hormone, the vitamin D-hormone metabolites must have special mechanisms for delivery in the aqueous bloodstream. Importantly, endogenously synthesized forms are carried by a binding protein, whereas dietary forms are carried within lipoprotein particles. This may result in distinct biodistributions for sunlight-derived versus supplement-derived vitamin D hormones. Because the cardiovascular effects of vitamin D hormones are not straightforward, both toxic and beneficial effects may result from current recommendations.

Vitamin D Deficiency: Consequence or Cause of Obesity?

Obesity is defined as an excess amount of body fat and represents a significant health problem worldwide. High prevalence of vitamin D (VD) deficiency in obese subjects is a well-documented finding, most probably due to volumetric dilution into the greater volumes of fat, serum, liver, and muscle, even though other mechanisms could not completely be excluded, as they may contribute concurrently. Low VD could not yet be excluded as a cause of obesity, due to its still incompletely explored effects through VD receptors found in adipose tissue (AT). VD deficiency in obese people does not seem to have consequences for bone tissue, but may affect other organs, even though studies have shown inconsistent results and VD supplementation has not yet been clearly shown to benefit the dysmetabolic state. Hence, more studies are needed to determine the actual role of VD deficiency in development of those disorders. Thus, targeting lifestyle through healthy diet and exercise should be the first treatment option that will affect both obesity-related dysmetabolic state and vitamin D deficiency, killing two birds with one stone. However, VD supplementation remains a treatment option in individuals with residual VD deficiency after weight loss.

Potential Role for the Gut Microbiota in Modulating Host Circadian Rhythms and Metabolic Health

This article reviews the current evidence associating gut microbiota with factors that impact host circadian-metabolic axis, such as light/dark cycles, sleep/wake cycles, diet, and eating patterns. We examine how gut bacteria possess their own daily rhythmicity in terms of composition, their localization to intestinal niches, and functions. We review evidence that gut bacteria modulate host rhythms via microbial metabolites such as butyrate, polyphenolic derivatives, vitamins, and amines. Lifestyle stressors such as altered sleep and eating patterns that may disturb the host circadian system also influence the gut microbiome. The consequent disruptions to microbiota-mediated functions such as decreased conjugation of bile acids or increased production of hydrogen sulfide and the resultant decreased production of butyrate, in turn affect substrate oxidation and energy regulation in the host. Thus, disturbances in microbiome rhythms may at least partially contribute to an increased risk of obesity and metabolic syndrome associated with insufficient sleep and circadian misalignment. Good sleep and a healthy diet appear to be essential for maintaining gut microbial balance. Manipulating daily rhythms of gut microbial abundance and activity may therefore hold promise for a chrononutrition-based approach to consolidate host circadian rhythms and metabolic homeorhesis.

Association between vitamin D status and metabolic syndrome risk factors

BACKGROUND

The concern with the incidence of chronic-degenerative diseases is increasing worldwide, and many studies have shown that insufficiency of vitamin D (VD) can be linked to several metabolic disorders.

AIMS

Thus, the objective of this study was to evaluate the association of the metabolic syndrome risk factors, atherogenic indices and VD in a group of patients attended at a Cardiology Center.

METHODS

For this study, we invited 200 patients of both sexes attended in a Cardiology Center (Medical School of Marilia - São Paulo - Brazil). Most were female (n = 111) and aged between 41 and 70 years (from march to august, 2017).

RESULTS

Our results showed that only 20.0% of the patients presented normal levels of VD. Patients with altered values for this vitamin presented significantly higher values for glycemia, HbA1c, Total cholesterol, LDL-c, triglycerides, Castelli Index I, Castelli Index II, Body Mass Index, waist circumference, non-HDL-c and the estimative of the size of the LDL-c particle. Vitamin D correlated negatively with glycemia, HbA1C, triglycerides, atherogenic indices, Body Mass Index, and blood pressure. Multiple Regression Model showed that for an individual to maintain metabolic parameters, at least at borderline values, the levels of VD should be 37.64 that is not in accordance with the reference values.

CONCLUSIONS

These results showed a remarkable prevalence of low concentrations of Vitamin D in patients with cardiovascular risk factors.

Effect of Multi-Ingredient Supplement Containing Satiereal, Naringin, and Vitamin D on Body Composition, Mood, and Satiety in Overweight Adults

The purpose of this investigation was to examine the effects of 28 days of a dietary supplement on body composition, mood, and satiety in overweight adults. Twenty healthy adults (25.5 ± 3.8 years; 87.3 ± 20.7 kg; 169.9 ± 10.6 cm; 29.9 ± 5.1 body mass index) participated in this randomized, double-blind, placebo-controlled investigation. Ten participants were provided with a dietary supplement containing 178 mg satiereal, 100 mg naringin, and 2,000 IU vitamin D3 daily (SUPP), and ten participants were provided a placebo (PL) for 28 days. Baseline (PRE) and post (POST) assessments included body mass, BMI, and waist circumference measures. In addition, participants provided self-reported food records and completed study questionnaires twice weekly. Questionnaires consisted of profile of mood states, visual analog scales, modified trait food-cravings questionnaire, and a modified state food-cravings questionnaire. No significant differences were noted between groups for total calorie or macronutrient intake (p = 0.65-0.92), body mass (p = 0.34), BMI (p = 0.24), or waist circumference measures (p = 0.56-0.94). In addition, no significant differences between groups were observed for mood states, subjective measures of food cravings, or feelings of anxiety, fullness, bloating, hunger, craving, and stress (p >.05). In conclusion, 28 days of a dietary supplement containing satiereal, naringin, and vitamin D3 did not have any detectable beneficial effects on body-weight management.

Low vitamin D status and obesity: Role of nutritionist

Low vitamin D status and obesity have concomitantly reached epidemic levels worldwide. Up to now the direction of the association between low vitamin D status and obesity, the exact mechanisms responsible for this association and the clinical usefulness to increase vitamin D status for reducing adiposity still warrant further evaluation. The aim of the present review was to examine the current evidence linking low vitamin D status and obesity in relation to the role of the nutritionist. On the one side, considering obesity as a causal factor, low sun exposure in obese individuals due to their sedentary lifestyle and less outdoor activity, vitamin D sequestration in adipose tissue, and volumetric dilution of ingested or cutaneously synthesized vitamin D₃ in the large fat mass of obese patients, might represent some of the factors playing a major role in the pathogenesis of the low vitamin D status. On the other side, the expression of both vitamin D₃ receptors and enzymes responsible for vitamin D₃ metabolism in adipocytes depicted a role for the low vitamin D status per se in the development of obesity by modulating adipocyte differentiation and lipid metabolism. Nutritionists need to accurately address the aspects influencing the low vitamin D status in obesity and the vitamin D supplementation in obese individuals.

A Randomized Double-Blind Placebo-Controlled Trial of the Effect of Vitamin D3 Supplementation on Breast Density in Premenopausal Women

Background: This double-blind, placebo-controlled parallel group trial assessed whether oral supplementation with 1,000, 2,000, or 3,000 IU/day vitamin D₃ over one year reduces percent mammographic breast density in premenopausal women.Methods: The trial was conducted between October 2012 and June 2015, among premenopausal female volunteers from Quebec City (Quebec, Canada). Women were randomized with ratio 1:1:1:1 to one of four study arms (1,000, 2,000, or 3,000 IU/day vitamin D₃ or placebo). The primary outcome was mean change in percent mammographic breast density. Participants and research team were blinded to study arm assignment.Results: Participants (n = 405) were randomized to receive 1,000 (n = 101), 2,000 (n = 104), or 3,000 IU/day (n = 101) vitamin D₃, or a placebo (n = 99). The primary analysis included 391 participants (96, 99, 100, and 96, respectively). After the one-year intervention, mean ± SE change in percent breast density in the arms 1,000 IU/day (-5.5% ± 0.5%) and 2,000 IU/day (-5.9% ± 0.5%) vitamin D₃ was similar to that in the placebo arm (-5.7% ± 0.5%) (P values = 1.0). In the 3,000 IU/day vitamin D₃ arm, percent breast density also declined but slightly less (-3.8% ± 0.5%) compared with placebo arm (P = 0.03). Adherence to intervention was excellent (92.8%), and reporting of health problems was comparable among study arms (P ≥ 0.95). All participants had normal serum calcium.Conclusions: In premenopausal women, one-year supplementation with 1,000, 2,000, or 3,000 IU/day vitamin D₃ resulted in a reduction of percent breast density no greater than that seen with the placebo.Impact: At doses of 1,000-3,000 IU/day, vitamin D supplementation will not reduce breast cancer risk through changes in breast density. Cancer Epidemiol Biomarkers Prev; 26(8); 1233-41. ©2017 AACR.