The effect of vitamin D supplementation on selected inflammatory biomarkers in obese and overweight subjects: a systematic review with meta-analysis

Vitamin D supplementation does not alter inflammatory markers in overweight and obese individuals: A systematic review and meta-analysis of randomized controlled trials

Chronic low-grade inflammation is a common feature of obesity and plays a crucial role in the progression of its complications. Vitamin D (VitD) plays an important role in modulating the immune response and regulating inflammation. Thus, this systematic review and meta-analysis aimed to evaluate the effects of isolated VitD supplementation on main inflammatory markers in overweight and obese individuals with no comorbidities and with VitD deficiency. We hypothesized that the increase in serum VitD concentrations after supplementation would significantly reduce the concentrations of inflammatory markers. The search was conducted in Medline/PubMed, SCOPUS, EMBASE, and Web of Science. Eleven randomized placebo-controlled studies were included in the final analysis, with a total of 504 participants and daily (1000-7000 international units) or bolus (100,000-200,000 international units) doses of VitD lasting from 2 to 26 weeks. The VitD supplementation did not influence C-reactive protein (mean difference [MD]: 0.01; 95% confidence interval [CI] -0.37, 0.39; P = .97), interleukin-6 (MD: -0.34; 95% CI -1.09, 0.42; P = .38), and tumor necrosis factor concentrations (MD: -0.02; 95% CI -0.23, 0.19; P = .85). In the analysis considering the studies with a significant increase in serum VitD concentrations, VitD supplementation also did not influence C-reactive protein (MD: -0.17; 95% CI -0.88, 0.54; P = .64), interleukin-6 (MD: -0.47; 95% CI -1.31, 0.37; P = .27), and tumor necrosis factor concentrations (MD: 0.01; 95% CI -1.34, 1.37; P = .98). This meta-analysis suggests that VitD supplementation does not significantly alter inflammatory markers in overweight and obese individuals.

Effect of Palmitoylethanolamide Compared to a Placebo on the Gut Microbiome and Biochemistry in an Overweight Adult Population: A Randomised, Placebo Controlled, Double-Blind Study

This study investigates the effects of palmitoylethanolamide (PEA) on the gut microbiome of overweight adults. Fifty-eight participants (twenty males, thirty-eight females) aged 18-65 years with a BMI range of 30-40 kg/m2 were recruited. Participants were randomised to receive PEA (n = 36) or a placebo (n = 22) for 12 weeks. Microbiota composition, richness, diversity, and metabolic functions, faecal short chain fatty acids and calprotectin, pathology markers, and health-related questionnaires were analysed throughout the 12 weeks of supplementation. PEA supplementation significantly reduced triglyceride levels and IL-2 concentrations. No significant differences were found in the overall microbiota composition between the groups, and microbiota richness and diversity remained consistent for both groups. Functional analysis demonstrated no differences in functional richness and diversity, but specific pathways were modified. PEA supplementation resulted in a decrease in the abundance of pathways related to aromatic compound degradation, NAD interconversion, and L-glutamate degradation, while pathways associated with molybdopterin biosynthesis and O-antigen building blocks exhibited increased abundance. Increased production of O-antigen results in smooth LPS associated with reduced pathogenic stealth and persistence. PEA supplementation may influence specific microbial species, metabolic pathways, and reduce serum triglyceride and IL-2 concentration, shedding light on the intricate relationship between PEA, the microbiome, and host health.

Association Between Lower Levels of Vitamin D and Inflammation in the Geriatric Population: A Systematic Review and Meta-Analysis

There have been suggestions that vitamin D has anti-inflammatory effects; however, the variabilities of vitamin D levels among specific groups of patients and its association with these inflammatory events have not been demonstrated. This study aims to study the association between vitamin D levels and vitamin D deficiency and inflammatory events among the elderly population. PubMed, Web of Science, Scopus, Science Direct, and ClinicalKey were systematically searched in December 2023 to include the relevant data. Comprehensive Meta-Analysis (version 3.0, Biostat, Inc., Englewood, NJ) was the software used for data analyses. A total of 12 studies were included in this analysis with 14,717 elderly patients. There was an overall significant decrease in vitamin D levels in elderly patients with high inflammatory markers compared to controls (Hedges' g = -0.221, 95% CI: -0.268, -0.173, P < 0.001), and event of vitamin D deficiency was found to be 0.321 (95% CI: 0.305, 0.337, P < 0.001). There is a significant decrease in vitamin D levels among the elderly with different inflammatory conditions. Future longitudinal studies and well-designed, large, randomized controlled trials are required to study the association between vitamin D deficiency and the incidence of inflammatory events in this specific group of patients.

Obesity-related glomerulopathy: recent advances in inflammatory mechanisms and related treatments

Obesity-related glomerulopathy, which is an obesity-triggered kidney damage, has become a significant threat to human health. Several studies have recently highlighted the critical role of inflammation in obesity-related glomerulopathy development. Additionally, excess adipose tissue and adipocytes in patients with obesity produce various inflammatory factors that cause systemic low-grade inflammation with consequent damage to vascular endothelial cells, exacerbating glomerular injury. Therefore, we conducted a comprehensive review of obesity-related glomerulopathy and addressed the critical role of obesity-induced chronic inflammation in obesity-related glomerulopathy pathogenesis and progression, which leads to tubular damage and proteinuria, ultimately impairing renal function. The relationship between obesity and obesity-related glomerulopathy is facilitated by a network of various inflammation-associated cells (including macrophages, lymphocytes, and mast cells) and a series of inflammatory mediators (such as tumor necrosis factor α, interleukin 6, leptin, adiponectin, resistin, chemokines, adhesion molecules, and plasminogen activator inhibitor 1) and their inflammatory pathways. Furthermore, we discuss a recently discovered relationship between micronutrients and obesity-related glomerulopathy inflammation and the important role of micronutrients in the body's anti-inflammatory response. Therefore, assessing these inflammatory molecules and pathways will provide a strong theoretical basis for developing therapeutic strategies based on anti-inflammatory effects to prevent or delay the onset of kidney injury.

From the Sun to the Cell: Examining Obesity through the Lens of Vitamin D and Inflammation

Obesity affects more than one billion people worldwide and often leads to cardiometabolic chronic comorbidities. It induces senescence-related alterations in adipose tissue, and senescence is closely linked to obesity. Fully elucidating the pathways through which vitamin D exerts anti-inflammatory effects may improve our understanding of local adipose tissue inflammation and the pathogenesis of metabolic disorders. In this narrative review, we compiled and analyzed the literature from diverse academic sources, focusing on recent developments to provide a comprehensive overview of the effect of vitamin D on inflammation associated with obesity and senescence. The article reveals that the activation of the NF-κB (nuclear factor kappa B subunit 1) and NLRP3 inflammasome (nucleotide-binding domain, leucine-rich-containing, pyrin domain-containing-3) pathways through the toll-like receptors, which increases oxidative stress and cytokine release, is a common mechanism underlying inflammation associated with obesity and senescence, and it discusses the potential beneficial effect of vitamin D in alleviating the development of subclinical inflammation. Investigating the main target cells and pathways of vitamin D action in adipose tissue could help uncover complex mechanisms of obesity and cellular senescence. This review summarizes significant findings related to opportunities for improving metabolic health.

Effect of oral versus parenteral vitamin D3 supplementation on nuclear factor-κB and platelet aggregation in type 2 diabetic patients

Platelet hyperactivity is one of the key factors implicated in the development and progression of diabetic vascular complications. Activated platelets mediate leukocyte recruitment that further enhances inflammatory responses in vascular wall ultimately resulting in atherosclerotic complications. Since vitamin D insufficiency is highly prevalent in diabetics, we aimed to evaluate the effect of three dosage forms of vitamin D supplementation on lipid profile, NF-κB, platelet aggregation, and platelet calcium content in type 2 diabetic patients. Type 2 diabetic patients were randomized to receive daily (4000 IU/day) or weekly (50 000 IU/week) oral vitamin D3 for 3 months. Another group received a single parenteral dose (300 000 IU) of vitamin D3, whereas the control group received their antidiabetic drug(s) alone. Serum 25(OH)D, total cholesterol, triglycerides, high- and low-density lipoprotein cholesterol, NF-κB, and platelet aggregation were measured at the beginning and 3 months after vitamin D supplementation. Platelet calcium content was evaluated by measuring the fluorescence intensity of Rhod-2-stained platelets by confocal fluorescence microscopy. Results showed that serum 25(OH)D3 levels significantly increased in all vitamin D3-treated groups. However, the mean level for parenteral treated group was significantly lower than oral-treated groups. Oral and parenteral treatment were also able to decrease NF-κB level, platelet aggregation, and platelet calcium content. However, both oral doses of vitamin D3 were superior to the single parenteral dose. In conclusion, restoring normal levels of vitamin D is an important determinant to maintain normal platelet function and reduce inflammation. Nevertheless, further long-term studies are still needed.

Effects of vitamin D supplementation on inflammatory response in patients with cancer and precancerous lesions: Systematic review and meta-analysis of randomized trials

BACKGROUND & AIMS

Inflammation plays a key role in tumor development and progression. Vitamin D has potential tumor suppressing effects through modulation of inflammatory processes. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to summarize and evaluate the effects of vitamin D3 supplementation (VID3S) on serum inflammatory biomarkers among patients with cancer or pre-cancerous lesions.

METHODS

We searched PubMed, Web of Science and Cochrane databases until November 2022. The effects of VID3S were estimated from pooled standardized mean differences (SMDs) with their 95% confidence intervals (CIs) for inflammatory biomarker follow-up levels between intervention and control groups.

RESULTS

Meta-analysis of eight RCTs (total of 592 patients with cancer or pre-cancerous conditions) showed that VID3S significantly lowered levels of serum tumor necrosis factor (TNF)-α (SMD [95%CI]: -1.65 [-3.07; -0.24]). VID3S also resulted in statistically non-significantly lower serum levels of interleukin (IL)-6 (SMD [95%CI]: -0.83, [-1.78; 0.13]) and C-reactive protein (CRP) (SMD [95%CI]: -0.09, [-0.35; 0.16]), whereas IL-10 levels were unaltered (SMD [95%CI]: -0.00, [-0.50; 0.49]).

CONCLUSION

Our study shows evidence of a significant reduction of TNF-α levels by VID3S for patients with cancer or precancerous lesions. Patients with cancer or precancerous lesions may benefit from personalized VID3S in suppressing tumour-promoting inflammatory response.

PROSPERO REGISTRATION NUMBER

CRD42022295694.

Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis

BACKGROUND AND AIMS

Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers.

METHODS

We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603).

RESULTS

Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I² = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I² = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I² = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I² = 0 %). These findings may be dependent on participant characteristics and treatment duration.

CONCLUSIONS

These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.

The Effect of Weekly 50,000 IU Vitamin D3 Supplements on the Serum Levels of Selected Cytokines Involved in Cytokine Storm: A Randomized Clinical Trial in Adults with Vitamin D Deficiency

This research aimed to evaluate the effects of high-dose cholecalciferol (VD₃) supplements (50,000 IU/week) on selected circulating cytokines associated with cytokine storms in adults with vitamin D deficiency. This clinical trial, based in Jordan, included 50 participants receiving vitamin D₃ supplements (50,000 IU/week) for 8 weeks; the exact number was assigned to the control group. Interleukin-6 (IL-6), interleukin-1β (IL-1β), interleukin-10 (IL-10), tumor necrotic factor-α (TNF-α), and leptin were measured in serum at baseline and 10 weeks (wash out: 2 weeks). Our results revealed that vitamin D₃ supplementation significantly increased the serum levels of 25OHD, IL-6, IL-10, IL-1β, and leptin compared with baseline. In contrast, the serum level of TNF-α insignificantly increased in the group receiving vitamin D₃ supplementation. Although the observations of this trial may refer to a potential negative effect of VD₃ supplementation during cytokine storms, further trials are required to clarify the potential benefits of VD₃ supplement during cytokine storms.

Inflammaging as a target for healthy ageing

Life expectancy has been on the rise for the past few decades, but healthy life expectancy has not kept pace, leading to a global burden of age-associated disorders. Advancing age is accompanied by a chronic increase in basal systemic inflammation, termed inflammaging, contributing towards an increased risk of developing chronic diseases in old age. This article reviews the recent literature to formulate hypotheses regarding how age-associated inflammaging plays a crucial role in driving chronic diseases and ill health in older adults. Here, we discuss how non-pharmacological intervention strategies (diet, nutraceutical supplements, phytochemicals, physical activity, microbiome-based therapies) targeting inflammaging restore health in older adults. We also consider alternative existing pharmacological interventions (Caloric restriction mimetics, p38 mitogen-activated protein kinase inhibitors) and explore novel targets (senolytics) aimed at combating inflammaging and optimising the ageing process to increase healthy lifespan.

Concurrent alteration in inflammatory biomarker gene expression and oxidative stress: how aerobic training and vitamin D improve T2DM

Background

Vitamin D (Vit D) supplementation and Aerobic Training (AT) exert several beneficial effects such as antioxidant and anti-inflammatory actions. The literature on the effects of AT and Vit D supplementation on the oxidative stress biomarkers and gene expression of inflammatory cytokines in patients with Type 2 Diabetes Mellitus (T2DM) is limited. The present study aimed to examine the effects of AT and Vit D supplementation on inflammation and oxidative stress signaling pathways in T2DM patients.

Materials and methods

In this single-blinded, randomized, placebo-controlled trial, 48 men with T2DM (aged 35–50 years with Body Mass Index (BMI) of 25–30 kg/m2) were randomly allocated into four groups: AT+Vit D (n = 10); AT + placebo (AT; n = 10); Vit D (n = 10), and Control + placebo (C; n = 10). The eight-week AT program was executed for 20–40 min/day, at 60–75% of heart rate maximum (HRmax), for 3 days/wks. The Vit D group received 50,000 IU of Vit D supplement capsules per week for 8 weeks. The serum levels of oxidative stress biomarkers and gene expression of inflammatory cytokines in the Peripheral Blood Mononuclear Cells (PBMCs) were evaluated using the RT-PCR method. To analyze the data, paired t-tests and one-way analysis of variance and Tukey’s post hoc test were used at the significance level of P < 0.05.

Results

The result shows that serum 25-OH-Vit D, total nitrite, Total Glutathione (GSH), Total Antioxidant Capacity (TAC), Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPX) increased; and insulin, Fasting Blood Glucose (FBG), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), High Sensitivity C-Reactive Protein (hs-CRP), Malondialdehyde (MDA), glycated albumin, and Urinary 8-hydroxydeoxyguanine (8-OHdG) decreased significantly in all groups after 8 weeks, except for C. In addition, results of RT-PCR showed that AT+Vit D, Vit D, and AT significantly downregulated the gene expression of Tumor Necrosis Factor-Alpha (TNF-α), Interleukin-1 Beta (IL-1β), Mitogen-Activated Protein Kinases 1 (MAPK1), Nuclear Factor Kappa B (NF-κB) 1 (p50). It also upregulated Interleukin-4 (IL-4) gene expression, Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ) in T2DM patients compared to the C.

Conclusion

Additionally, the AT+Vit D group showed significantly lower insulin, FBG, HOMA-IR, hs-CRP, MDA, glycated albumin, urinary 8-OHdG, IL-1β, TNF-α, MAPK1, and NF-κB1 (p50) levels and significantly higher serum 25-OH-Vit D, total nitrite, GSH, TAC, CAT, SOD, GPX, IL-4, and PPAR-γ levels compared to the AT and Vit D groups. In T2DM patients, 8 weeks of AT+Vit D had a more significant impact on certain gene expressions related to inflammation and oxidative stress than Vit D or AT alone.

Effects on Serum Inflammatory Cytokines of Cholecalciferol Supplementation in Healthy Subjects with Vitamin D Deficiency

The effects of different cholecalciferol supplementation regimens on serum inflammatory cytokines in healthy subjects with vitamin D deficiency are still lacking. This is a single-center, open-label, randomized, parallel group study involving healthy subjects deficient in vitamin D (baseline 25OHD < 20 ng/mL) receiving oral cholecalciferol with three different dosing regimens: Group A: 10,000 IU/day for 8 weeks followed by 1000 IU/day for 4 weeks; Group B: 50,000 IU/week for 12 weeks and Group C: 100,000 IU every other week for 12 weeks. IL-17A, IL-6, IL-8, IL-10, IL-23 and TNFα were measured at baseline and at week 4, 8, 12, and 16. 75 healthy subjects were enrolled (58.7% female), with an average age of 34.1 ± 10.2 years. No statistical differences were observed among groups at baseline for either IL-6, IL-17A, IL-23, IL-8 or IL-10 at any time point; TNFα was indetectable. Concerning the whole sample, the time trend analysis showed a statistically significant linear trend for decreasing values over the treatment period for IL-6 (p = 0.016) and IL-17A (p = 0.006), while no significant time trends were observed for the other teste cytokines. No significant differences were found in the serum concentrations of the tested cytokines between week 12 and week 16. In young healthy individuals deficient in vitamin D, cholecalciferol administration showed a decrease in the serum IL-6 and IL-17A concentrations, without marked differences using the three regimens.

Is Abdominal Obesity a Risk Factor for the Incidence of Vitamin D Insufficiency and Deficiency in Older Adults? Evidence from the ELSA Study

Cross-sectional studies have demonstrated an association between abdominal obesity, determined by waist circumference (WC), and vitamin D (25(OH)D) deficiency in older adults. However, longitudinal evidence is based only on general obesity determined using body mass index (BMI). We investigated whether abdominal obesity is associated with the incidence of 25(OH)D insufficiency (>30 and ≤50 nmol/L) and deficiency (≤30 nmol/L), and whether vitamin D supplementation modifies these associations. We included 2459 participants aged ≥50 years from the English Longitudinal Study of Ageing (ELSA) with 25(OH)D sufficiency (>50 nmol/L) at baseline. Abdominal obesity was defined as >88 cm for women and >102 cm for men. After 4 years, 25(OH)D concentrations were reassessed. Multinomial logistic regression models controlled by covariates were performed. Abdominal obesity increased the risk of the incidence of 25(OH)D insufficiency (RRR = 1.36; 95% CI: 1.01−1.83) and deficiency (RRR = 1.64; 95% CI: 1.05−2.58). These risks were maintained when excluding individuals who took vitamin D supplementation (RRR = 1.38; 95% CI: 1.02−1.88) and (RRR = 1.62; 95% CI: 1.02−2.56). Abdominal obesity is associated with the risk of incidence of low 25(OH)D concentrations. WC seems to be an adequate tool for screening individuals with obesity and at potential risk of developing these conditions.

Effects of Vitamin D Supplementation on Adipose Tissue Inflammation and NF-κB/AMPK Activation in Obese Mice Fed a High-Fat Diet

Adipose tissue expansion is strongly associated with increased adipose macrophage infiltration and adipocyte-derived pro-inflammatory cytokines, contributing to obesity-associated low-grade inflammation. Individuals with vitamin D deficiency have an increased prevalence of obesity and increased circulating inflammatory cytokines. However, the effect of vitamin D supplementation on obesity-induced inflammation remains controversial. Male C57BL/6J mice received a low-fat (10% fat) or high-fat (HF, 60% fat diet) containing 1000 IU vitamin D/kg diet, or HF supplemented with 10,000 IU vitamin D/kg diet for 16 weeks (n = 9/group). Vitamin D supplementation did not decrease HF-increased body weight but attenuated obesity-induced adipose hypertrophy and macrophage recruitment as demonstrated by the number of crown-like structures. Vitamin D supplementation significantly reduced the mRNA expression of CD11c, CD68, and iNOS, specific for inflammatory M1-like macrophages, and decreased serum levels of NO. In addition, significant reductions in pro-inflammatory gene expression of IL-6, MCP-1, and TNFα and mRNA levels of ASC-1, CASP1, and IL-1β involved in NLRP3 inflammasome were found in obese mice supplemented with vitamin D. Vitamin D supplementation significantly increased obesity-decreased AMPK activity and suppressed HF-increased NF-κB phosphorylation in adipose tissue from obese mice. These observed beneficial effects of vitamin D supplementation on adipose tissue expansion, macrophage recruitment, and inflammation might be related to AMPK/NF-κB signaling.

Association between serum 25-hydroxyvitamin d and myeloperoxidase: A cross-sectional study of a general population in China

Background

Several studies have found a strong association between cardiovascular diseases and myeloperoxidase (MPO) as a marker of oxidative stress. Although the anti-inflammatory effects of vitamin D in adults have been validated, evidence about the relationship between MPO and 25(OH)D is lacking. This study aimed to investigate the relationship between MPO and 25(OH)D in the general Chinese population.

Methods

From November 2018 to August 2019, a total of 6414 subjects were enrolled in a tertiary referral hospital in China, which included 3,122 women and 3,292 men. The dependent and independent variables were MPO and 25(OH)D, respectively. The confounders included age, sex, body mass index, waist-hip ratio, smoking status, alcohol drinking status, calcium, and parathyroid hormone concentration.

Results

In the fully adjusted model, we found that MPO decreased by 0.12 (95% CI −0.16, −0.08), ng/mL for each unit (1 nmol/L) increase in 25(OH)D. When 25(OH) D was divided into quartiles, compared with Q1 (< 41.4 nmol/L), the adjusted beta coefficients (β) of MPO in Q2–Q4 were −2.29 (95% CI, −4.31 to −0.27), −4.76 (95% CI, −6.83 to −2.69), and −6.07 (95% CI, −8.23 to −3.92), respectively (P for the trend < 0.0001). When 25(OH) D was divided according to clinical severity, compared with the severely deficient (< 30 nmol/L) s≥ 30, < 50 nmol/L) and sufficient groups (≥ 50 nmol/L) were −2.59 (95% CI, −5.87 to 0.69) and −5.87 (95% CI, −9.17 to −2.57), respectively (P for the trend < 0.0001).

Conclusion

After adjusting for age, sex, BMI, waist-hip ratio, smoking status, alcohol status, calcium, and PTH, circulating 25(OH)D was negatively associated with MPO.

Vitamin D and Visceral Obesity in Humans: What Should Clinicians Know?

The extraskeletal effect of vitamin D on adipose tissue biology and modulation in human obesity is of great interest and has been extensively investigated. Current evidence from preclinical and clinical studies in human adipose tissue suggests that the anti-inflammatory effects of vitamin D are evident and consistent, whereas the effects of vitamin D on adipocyte differentiation, adipogenesis, and energy metabolism and the effects of vitamin D supplementation on adipokine levels are inconclusive. Interventional studies related to medical and surgical weight loss in humans have shown small or no improvement in vitamin D status. Additionally, the benefit of vitamin D supplementation for the reduction in visceral adipose tissue has only been demonstrated in a few studies. Overall, the findings on the relationship between vitamin D and visceral adipose tissue in humans are still inconclusive. Further studies are required to confirm the beneficial effects of vitamin D on ameliorating adipose tissue dysfunction.

The role of inflammation and the possibilities of inflammation reduction to prevent cardiovascular events

Chronic systemic inflammation is a risk factor for cardiovascular (CV) disease (CVD). Whether this relationship extends to subclinical inflammation, quantified by values of circulating markers associated with inflammation in the high range of the normal interval, remains debatable. This narrative review evaluates evidence exploring this relationship. A review of pharmacological and non-pharmacological interventions, including diet and lifestyle strategies, supplements, nutraceuticals, and other natural substances aimed at reducing inflammation was also conducted, since few reviews have synthesized this literature. PubMed and EMBASE were used to search the literature and several well-studied triggers of inflammation [oxidized LDL, Lp(a), as well as C-reactive protein (CRP)/high-sensitivity CRP (hs-CRP)] were included to increase sensitivity and address the lack of existing reviews summarizing their influence in the context of inflammation. All resulting references were assessed. Overall, there is good data supporting associations between circulating hs-CRP and CV outcomes. However, the same was not seen in studies evaluating triggers of inflammation, such as oxidized LDL or Lp(a). There is also insufficient evidence showing treatments to target inflammation and lead to reductions in hs-CRP result in improvements in CV outcomes, particularly in those with normal baseline levels of hs-CRP. Regarding pharmacological interventions, statins, bempedoic acid, and apabetalone significantly reduce circulating hs-CRP, unlike PCSK-9 inhibitors. A variety of natural substances and vitamins were also evaluated and none reduced hs-CRP. Regarding non-pharmacological interventions, weight loss was strongly associated with reductions in circulating hs-CRP, whereas various dietary interventions and exercise regimens were not, unless accompanied by weight loss.

The effect of vitamin D supplementation on tobacco-related disorders in individuals with a tobacco use disorder: a randomized clinical trial

Vitamin D deficiency in cigarette smokers (CS) might associate with several complications, including metabolic deficits, depression and anxiety. This study evaluated the effects of vitamin D on mental health symptoms, nicotine misuse, and biomarkers of metabolic diseases in individuals with a tobacco use disorder. A randomized, double-blind, placebo-controlled trial was conducted with 60 CS subjects receiving either 50,000 IU vitamin D supplements (n = 30) or placebo (n = 30) every 2 weeks for 24-weeks. Nicotine misuse, mental health scale, and metabolic parameters were measured before and after the intervention in the CS subjects. Compared with the placebo-group, after the 24-weeks intervention, serum 25 (OH) vitamin D levels increased in the intervention group (β 2.96; 95% CI, 0.91, 5.01; P = 0.006). In addition, vitamin D supplementation significantly improved Beck Depression Inventory (BDI) (β -2.06; 95% CI, -3.84, -0.28; P = 0.02). In addition, vitamin D administration significantly decreased fasting plasma glucose (FPG) (β -4.56; 95% CI, -8.94, -0.19; P = 0.04), insulin (β -0.50; 95% CI, -0.88, -0.13; P = 0.009), and homeostasis model of assessment-estimated insulin resistance (HOMA-IR) levels (β -0.21; 95% CI, -0.33, -0.08; P = 0.001). Furthermore, vitamin D resulted in a significant elevation in total antioxidant capacity (TAC) (β 81.20; 95% CI, 18.30, 144.11; P = 0.01), and plasma glutathione (GSH) levels (β 73.05; 95% CI, 18.56, 127.54; P = 0.01), compared with the placebo-group. Administration of vitamin D for 24-weeks to CS subjects had beneficial effects on symptoms of depression and several metabolic biomarkers. While this preliminary study suggests that vitamin D might have beneficial effects, its clinical efficacy in individuals with a tobacco use disorder should be further validated in future clinical trials.

The Action of Vitamin D in Adipose Tissue: Is There the Link between Vitamin D Deficiency and Adipose Tissue-Related Metabolic Disorders?

Adipose tissue plays an important role in systemic metabolism via the secretion of adipocytokines and storing and releasing energy. In obesity, adipose tissue becomes dysfunctional and characterized by hypertrophied adipocytes, increased inflammation, hypoxia, and decreased angiogenesis. Although adipose tissue is one of the major stores of vitamin D, its deficiency is detective in obese subjects. In the presented review, we show how vitamin D regulates numerous processes in adipose tissue and how their dysregulation leads to metabolic disorders. The molecular response to vitamin D in adipose tissue affects not only energy metabolism and adipokine and anti-inflammatory cytokine production via the regulation of gene expression but also genes participating in antioxidant defense, adipocytes differentiation, and apoptosis. Thus, its deficiency disturbs adipocytokines secretion, metabolism, lipid storage, adipogenesis, thermogenesis, the regulation of inflammation, and oxidative stress balance. Restoring the proper functionality of adipose tissue in overweight or obese subjects is of particular importance in order to reduce the risk of developing obesity-related complications, such as cardiovascular diseases and diabetes. Taking into account the results of experimental studies, it seemed that vitamin D may be a remedy for adipose tissue dysfunction, but the results of the clinical trials are not consistent, as some of them show improvement and others no effect of this vitamin on metabolic and insulin resistance parameters. Therefore, further studies are required to evaluate the beneficial effects of vitamin D, especially in overweight and obese subjects, due to the presence of a volumetric dilution of this vitamin among them.

Vitamin D Effects on Selected Anti-Inflammatory and Pro-Inflammatory Markers of Obesity-Related Chronic Inflammation

BACKGROUND

Obesity is related to changes in adipokine secretion, activity of adipose tissue macrophages, helper T cells, and regulatory T cells. It has been confirmed that vitamin D has potent anti-inflammatory properties. It contributes to reduction in pro-inflammatory mediators and an increase in anti-inflammatory cytokines. There is also evidence that vitamin D could decrease C-reactive protein (CRP) and affect selected haematological indices.

AIM OF THE STUDY

We aimed to evaluate the effect of vitamin D on interleukin (IL)-10, IL-17, CRP, blood leukocyte profile, and platelet (PLT) count in overweight and obese children before and after six months of vitamin D supplementation.

MATERIAL AND METHODS

The study group consisted of 67 overweight and obese children aged 9.08-17.5 years. The control group included 31 normal weight peers age- and sex-matched. None of the studied children had received vitamin D supplementation before the study. Data were analyzed at baseline and after vitamin D supplementation.

RESULTS

The study group had lower baseline 25(OH)D (p<0.001) and higher white blood cell (WBC) (p=0.014), granulocyte (p=0.015), monocyte (p=0.009) and CRP (p=0.002) compared to the control group. In the study group, vitamin D levels were related negatively to nutritional status. Leukocyte profile parameters, PLT, CRP, IL-10 or IL-17 were not related to baseline 25(OH)D. Baseline IL-17 levels correlated with monocytes (R= 0.36, p=0.003) independently on 25(OH)D deficit. In children with vitamin D <15ng/ml, the baseline 25(OH)D was related to CRP (R=-0.42, p=0.017). After six months of vitamin D supplementation, we noticed a decrease in CRP levels (p=0.0003). Serum 25(OH)D correlated with IL-10 in that period (R=0.27, p=0.028). Moreover, we noticed that IL-10 correlated with monocyte (R=-0.28, p=0.023). We did not find any significant associations between 25(OH)D and leukocyte profile parameters, PLT, or IL-17. The multivariable stepwise regression analysis identified IL-10 as the parameter positively associated with 25(OH)D.

CONCLUSIONS

Our study confirmed beneficial effects of vitamin D supplementation in overweight and obese paediatric populations. Vitamin D intake seems to exert its anti-inflammatory effect mainly via decreasing the CRP level and protecting stabile values of IL-10, rather than its impact on pro-inflammatory factors such as lL-17 and leukocyte profile parameters.

The Role of Vitamin D Supplementation in Children with Autism Spectrum Disorder: A Narrative Review

Children with autism spectrum disorder (ASD) present with persistent deficits in both social communication and interactions, along with the presence of restricted and repetitive behaviors, resulting in significant impairment in significant areas of functioning. Children with ASD consistently reported significantly lower vitamin D levels than typically developing children. Moreover, vitamin D deficiency was found to be strongly correlated with ASD severity. Theoretically, vitamin D can affect neurodevelopment in children with ASD through its anti-inflammatory properties, stimulating the production of neurotrophins, decreasing the risk of seizures, and regulating glutathione and serotonin levels. A Title/Abstract specific search for publications on Vitamin D supplementation trials up to June 2021 was performed using two databases: PubMed and Cochrane Library. Twelve experimental studies were included in the synthesis of this review. Children with ASD reported a high prevalence of vitamin D deficiency or insufficiency. In general, it was observed that improved vitamin D status significantly reduced the ASD severity, however, this effect was not consistently different between the treatment and control groups. The variations in vitamin D dose protocols and the presence of concurrent interventions might provide an explanation for the variability of results. The age of the child for introducing vitamin D intervention was identified as a possible factor determining the effectiveness of the treatment. Common limitations included a small number of participants and a short duration of follow-ups in the selected studies. Long-term, well-designed randomized controlled trials are warranted to confirm the effect of vitamin D on severity in children with ASD.

Impact of Vitamin D Supplementation on Inflammatory Markers' Levels in Obese Patients

In view of research suggesting a possible beneficial impact of vitamin D on systemic inflammatory response, the authors decided to investigate an influence of vitamin D supplementation on serum levels of certain inflammatory markers in obese patients. The current study included such biomarkers as interleukin-6 (IL-6), pituitary adenylate cyclase-activating peptide (PACAP), advanced oxidation protein products (AOPP), C-X3-C Motif Chemokine Ligand 1 (CX3CL1), monocyte chemoattractant protein-1 (MCP-1), and nitric oxide (NO). The measurements were performed with the ELISA method before and after 3-month-long supplementation of 2000 IU of vitamin D orally. The results showed that the therapy did not induce any statistically significant changes in serum levels of MCP-1, IL-6, CX3CL1, and PACAP. The supplementation was related to a significant increase in measurements of NO and AOPP levels, although the correlation analysis between vitamin D concentration after its supplementation and the concentration of the molecular parameters did not show significant relation. In conclusion, our study seems to contradict certain aspects of findings available in the literature regarding the vitamin D's impact.

Salmon peptides limit obesity-associated metabolic disorders by modulating a gut-liver axis in vitamin D-deficient mice

OBJECTIVE

This study investigated the effects of a low-dose salmon peptide fraction (SPF) and vitamin D₃ (VitD₃ ) in obese and VitD₃ -deficient mice at risk of metabolic syndrome (MetS).

METHODS

Obese and VitD₃ -deficient low-density lipoprotein receptor (LDLr)^-/- /apolipoprotein B100 (ApoB)^100/100 mice were treated with high-fat high-sucrose diets, with 25% of dietary proteins replaced by SPF or a nonfish protein mix (MP). The SPF and MP groups received a VitD₃ -deficient diet or a supplementation of 15,000 IU of VitD₃ per kilogram of diet. Glucose homeostasis, atherosclerosis, nonalcoholic fatty liver disease, and gut health were assessed.

RESULTS

VitD₃ supplementation increased plasma 25-hydroxyvitamin D to optimal status whereas the VitD₃ -deficient diet maintained moderate deficiency. SPF-treated groups spent more energy and accumulated less visceral fat in association with an improved adipokine profile. SPF lowered homeostatic model assessment of insulin resistance compared with MP, suggesting that SPF can improve insulin sensitivity. SPF alone blunted hepatic and colonic inflammation, whereas VitD₃ supplementation attenuated ileal inflammation. These effects were associated with changes in gut microbiota such as increased Mogibacterium and Muribaculaceae.

CONCLUSIONS

SPF treatment improves MetS by modulating hepatic and gut inflammation along with gut microbiota, suggesting that SPF operates through a gut-liver axis. VitD₃ supplementation has limited influence on MetS in this model.

Vitamin D supplementation and energy and metabolic homoeostasis in obese and overweight subjects: a protocol for a systematic review

INTRODUCTION

Obesity and vitamin D deficiency are major public health problems. According to the pathophysiological mechanism of obesity as well as the bidirectional relationship between obesity and vitamin D metabolism and storage, vitamin D supplementation in obese and overweight subjects could have beneficial effects on the energy and metabolic homoeostasis. This review will assess the efficacy of vitamin D supplementation on the energy and metabolic homoeostasis in overweight and obese subjects.

METHODS AND ANALYSIS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols, we retrieved the relevant literature from the following electronic bibliographic databases: MEDLINE/PubMed, EMBASE and the Cochrane Central Register of Controlled Trials, from inception to June 2021. A manual search of the reference lists of all the relevant research articles will be performed to identify additional studies. We will include randomised controlled trials (RCTs) published in English that examine the effects of vitamin D supplementation on energy and metabolic homoeostasis in overweight and obese subjects. RCTs with multiple vitamin D groups will also be included. Two reviewers will independently complete the article selection, data extraction and rating. The bias tool from the Cochrane Handbook for Systematic Reviews of Interventions was used to assess the methodological quality of the included studies. A narrative or quantitative synthesis will be performed based on the available data. The planned start and end dates for the study were 1 February 2021 and 1 March 2022.

ETHICS AND DISSEMINATION

Ethical approval will not be required for this review. The results of this review will be disseminated in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021228981.

The effects of vitamin D supplementation on inflammatory biomarkers in patients with abnormal glucose homeostasis: A systematic review and meta-analysis of randomized controlled trials

FINDINGS

on the level of inflammatory cytokines following vitamin D supplementation among individuals with abnormal glucose homeostasis (AGH) are controversial. Therefore, the present study was conducted on AGH patients to assess the impact of vitamin D on inflammatory cytokines such as CRP, TNF-α and IL-6. A systematic search up to September 2020 was performed through PubMed and Scopus databases. All clinical studies which evaluated the effect of oral vitamin D supplementation on inflammation in patients with AGH were included. The random-effects model was applied to obtain pooled results. For dose-response analysis, we used a fractional polynomial model. Overall, 38 studies, with 46 effect sizes, were included in this study. Combining effect sizes, we found that vitamin D considerably decrease serum concentrations of CRP (weight mean difference (WMD): - 0.67 mg/l; 95%CI: - 0.92, - 0.43; P < 0.001), IL-6 (WMD: -1.93 pg/mL; 95%CI: -2.80, -1.07; P < 0.001) and TNF-α (WMD: -0.81 pg/mL; 95%CI: -1.59, -0.03; P = 0.04). In the dose-response analysis, we failed to find any correlation between dosage of supplements and inflammatory biomarkers concentrations. Summarizing earlier studies, we demonstrated that circulating concentrations of inflammatory cytokines such as CRP, TNF-α, and IL-6 might be decreased following vitamin D supplementation among individuals with AGH.

Moderator role of vitamin D concentrations on the association between metabolic syndrome and C-reactive protein among adults

OBJECTIVE

To evaluate the association between MetS, its components and insulin resistance (IR) with 25(OH)D and hsCRP. The moderator role of 25(OH)D in the association of MetS, its diagnostic components and IR with hsCRP were also explored.

METHODS

A cross-sectional study (2014/2015) with a population-based cohort in Southern Brazil (n = 605). Metabolic syndrome (MetS) diagnosis was defined based on the Joint Interim Statement, while the Homeostasis Model Assessment of insulin resistance (IR) (HOMA-IR) was used for determining IR. Serum concentrations of 25-hydroxy vitamin D [25(OH)D] (ng/mL) and high sensitivity C-reactive protein (hsCRP) (mg/L) were evaluated following standard protocols. 25(OH)D was categorized as sufficiency (>30 ng/mL), insufficiency (20-30 ng/mL) or deficiency (<20 ng/mL) to test its moderator role. Multiple linear regression was used to test the associations. The results were adjusted for possible confounders.

RESULTS

Hypertriglyceridemia and IR were associated with lower 25(OH)D concentrations. However, except for systolic blood pressure, other MetS components and IR were associated with higher hsCRP. The association between elevated waist circumference (WC) and hsCRP was moderated by the 25(OH)D concentrations. The hsCRP median concentrations were more than two times higher among those with elevated WC and 25(OH)D insufficiency or deficiency. In this study, inadequate concentrations of 25(OH)D increased the adverse relationship between elevated WC and inflammation. 25(OH)D concentrations could be incorporated into the clinical protocols for monitoring individuals with abdominal obesity to identify those at a higher risk of complications.

Does Evidence Exist to Blunt Inflammatory Response by Nutraceutical Supplementation during COVID-19 Pandemic? An Overview of Systematic Reviews of Vitamin D, Vitamin C, Melatonin, and Zinc

More than one year has passed since the first cases of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome (SARS)-CoV-2 coronavirus were reported in Wuhan (China), rapidly evolving into a global pandemic. This infectious disease has become a major public health challenge in the world. Unfortunately, to date, no specific antivirals have been proven to be effective against COVID-19, and although a few vaccines are available, the mortality rate is not decreasing but is still increasing. One therapeutic strategy has been focused on infection prevention and control measures. In this regard, the use of nutraceutical supports may play a role against some aspect of the infection, particularly the inflammatory state and the immune system function of patients, thus representing a strategy to control the worst outcomes of this pandemic. For this reason, we performed an overview including meta-analyses and systematic reviews to assess the association among melatonin, vitamin C, vitamin D, zinc supplementation and inflammatory markers using three databases, namely, MEDLINE, PubMed Central and the Cochrane Library of Systematic Reviews. According to the evidence available, an intake of 50,000 IU/month of vitamin D showed efficacy in CRP. An amount of 1 to 2 g per day of vitamin C demonstrated efficacy both in CRP and endothelial function, and a dosage of melatonin ranging from 5 to 25 mg /day showed good evidence of efficacy in CRP, TNF and IL6. A dose of 50 mg/day of elemental zinc supplementation showed positive results in CRP. Based on the data reported in this review, the public health system could consider whether it is possible to supplement the current limited preventive measures through targeted nutraceutical large-scale administration.

Effects of a Single Oral Megadose of Vitamin D3 on Inflammation and Oxidative Stress Markers in Overweight and Obese Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

AIM

The study aimed to evaluate the effects of vitamin D3 (VD3) supplementation on inflammation and oxidative stress markers in overweight and obese women with deficiency or insufficiency of vitamin D.

METHODS

Twenty-nine overweight or obese women who had a deficiency or insufficiency of vitamin D were placed into two groups according to VD3 intervention. Patients in the supplemented group received a single oral megadose of VD3 (VD3, n=14). Patients in placebo group received a single oral identical capsule without vitamin D (placebo, n = 15). Anthropometric and biochemical variables were assessed at baseline and after 4-weeks intervention.

RESULTS

Anthropometric variables (waist circumference, waist-hip ratio, waist-height ratio and body mass index) were similar between groups (p > 0.05). VD3 supplementation increased the serum levels of 25-hydroxyvitamin D (p=0.000), malondialdehyde (p=0.021) and C-reactive protein (p=0.043) in overweight and obese women. Additionally, VD3 supplementation reduced the serum levels of aspartate aminotransferase (AST, p=0.035), alanine aminotransferase (ALT, p<0.0001) in overweight and obese women. Despite this, the serum levels of parathyroid hormone (PTH), fasting glucose (FG), and alpha-1- acid glycoprotein (A1GPA), total antioxidant capacity (TAC) were similar between groups.

CONCLUSION

In summary, a single oral megadose of VD3 increased 25-hydroxyvitamin D serum levels but did not improve oxidative stress and inflammation markers.

Effects of Vitamin D Supplementation on Omentin-1 and Spexin Levels, Inflammatory Parameters, Lipid Profile, and Anthropometric Indices in Obese and Overweight Adults with Vitamin D Deficiency under Low-Calorie Diet: A Randomized Placebo Controlled Trial

Background and Aims

Improved vitamin D levels can have a favorable effect on some metabolic variables. The objective of the current study was to determine the effects of vitamin D supplementation during a weight-loss intervention on the levels of omentin-1, spexin, lipid profiles, and inflammatory factors in obese and overweight participants.

Methods and Materials

In this double-blind placebo-controlled randomized clinical trial, 70 overweight and obese participants with vitamin D deficiency (25(OH)D ≤ 20 nmol/L) were assigned into the intervention (a daily dose of 2,000 IU vitamin D + low-calorie diet) and placebo (placebo + low-calorie diet) groups for 8 weeks. Anthropometric parameters, serum levels of 25-hydroxy vitamin D (25(OH)D), lipid profiles, omentin-1 and spexin levels, high-sensitivity C-reactive protein (hs-CRP), and soluble intercellular adhesion molecule-1 (sICAM-1) concentrations were assessed before and after the intervention.

Results

Vitamin D supplementation after the intervention led to a significant decrease in triglycerides (TG) (P = 0.02), very-low-density lipoprotein-cholesterol (VLDL-C) (P = 0.02), and hs-CRP (P = 0.03) concentrations and a significant increase in the serum vitamin D level (P < 0.001). Furthermore, after adjusting for baseline values, age, and baseline BMI, the levels of serum high-density lipoprotein-cholesterol (HDL-C) (P = 0.01) increased significantly, and a significant reduction was observed in the concentration of sICAM-1 (P = 0.01) in the intervention group. However, we did not find any significant difference in serum omentin-1 and spexin concentrations between the groups after intervention.

Conclusions

Vitamin D supplementation along with a low-calorie diet (LCD) program for 8 weeks significantly decreased the inflammatory markers in obese individuals, while it did not alter serum omentin-1 and spexin concentrations.

Vitamin D regulation of adipogenesis and adipose tissue functions

Vitamin D insufficiency is associated with obesity and its related metabolic diseases. Adipose tissues store and metabolize vitamin D and expression levels of vitamin D metabolizing enzymes are known to be altered in obesity. Sequestration of vitamin D in large amount of adipose tissues and low vitamin D metabolism may contribute to the vitamin D inadequacy in obesity. Vitamin D receptor is expressed in adipose tissues and vitamin D regulates multiple aspects of adipose biology including adipogenesis as well as metabolic and endocrine function of adipose tissues that can contribute to the high risk of metabolic diseases in vitamin D insufficiency. We will review current understanding of vitamin D regulation of adipose biology focusing on vitamin D modulation of adiposity and adipose tissue functions as well as the molecular mechanisms through which vitamin D regulates adipose biology. The effects of supplementation or maintenance of vitamin D on obesity and metabolic diseases are also discussed.

Vitamin D and obesity in adults: a pathophysiological and clinical update

Vitamin D deficiency has become an increasing focus of clinical interest, especially in understanding its associations with obesity in adults. The pathological associations linking the two appear to demonstrate complex cellular inflammatory, hormonal and genetic pathways. Enhanced understanding at both microcellular and clinical levels will help clarify the role of obesity in the development of vitamin D deficiency.

Vitamin D, Marine n-3 Fatty Acids, and Primary Prevention of Cardiovascular Disease Current Evidence

Whether marine omega-3 fatty acid (n-3 FA) or vitamin D supplementation can prevent cardiovascular disease (CVD) in general populations at usual risk for this outcome is unknown. A major goal of VITAL (Vitamin D and Omega-3 Trial) was to fill this knowledge gap. In this article, we review the results of VITAL, discuss relevant mechanistic studies regarding n-3 FAs, vitamin D, and vascular disease, and summarize recent meta-analyses of the randomized trial evidence on these agents. VITAL was a nationwide, randomized, placebo-controlled, 2×2 factorial trial of marine n-3 FAs (1 g/d) and vitamin D3 (2000 IU/d) in the primary prevention of CVD and cancer among 25 871 US men aged ≥50 and women aged ≥55 years, including 5106 blacks. Median treatment duration was 5.3 years. Supplemental n-3 FAs did not significantly reduce the primary cardiovascular end point of major CVD events (composite of myocardial infarction, stroke, and CVD mortality; hazard ratio [HR], 0.92 [95% CI, 0.80-1.06]) but were associated with significant reductions in total myocardial infarction (HR, 0.72 [95% CI, 0.59-0.90]), percutaneous coronary intervention (HR, 0.78 [95% CI, 0.63-0.95]), and fatal myocardial infarction (HR, 0.50 [95% CI, 0.26-0.97]) but not stroke or other cardiovascular end points. For major CVD events, a treatment benefit was seen in those with dietary fish intake below the cohort median of 1.5 servings/wk (HR, 0.81 [95% CI, 0.67-0.98]) but not in those above (P interaction=0.045). For myocardial infarction, the greatest risk reductions were in blacks (HR, 0.23 [95% CI, 0.11-0.47]; P interaction by race, 0.001). Vitamin D supplementation did not reduce major CVD events (HR, 0.97 [95% CI, 0.85-1.12]) or other cardiovascular end points. Updated meta-analyses that include VITAL and other recent trials document coronary risk reduction from supplemental marine n-3 FAs but no clear CVD risk reduction from supplemental vitamin D. Additional research is needed to determine which individuals may be most likely to derive net benefit from supplementation. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01169259.

Effects of Vitamin D Supplementation and Seasonality on Circulating Cytokines in Adolescents: Analysis of Data From a Feasibility Trial in Mongolia

Vitamin D deficiency is prevalent in human populations and has been linked to immune dysfunction. Here we explored the effects of cholecalciferol supplementation on circulating cytokines in severely vitamin D deficient [blood 25(OH)D << 30 nmol/L] adolescents aged 12–15 from Mongolia. The study included 28 children receiving 800 IU daily cholecalciferol for 6 months spanning winter and spring, and 30 children receiving placebo during the same period. The levels of 25(OH)D were assessed at baseline, 3 and 6 months. Twenty-one cytokines were measured in serum at baseline and at 6 months. Changes in 25(OH)D and cytokines were assessed using paired parametric tests. The median blood 25(OH)D concentration at baseline was 13.7 nmol/L (IQR = 10.0–21.7). Supplementation tripled blood 25(OH)D levels (p < 0.001) and was associated with elevated interleukin (IL)-6 (p = 0.043). The placebo group had reduced macrophage inflammatory protein (MIP)-1α (p = 0.007) and IL-8 (p = 0.034) at 6 months. Although limited by a small sample size, these findings suggest that cholecalciferol supplementation and seasonality may impact systemic immunity in adolescents, identifying chemokines as potentially important biomarkers of vitamin D status in this Northeast Asian population. Larger clinical trials are warranted to validate these results.

Clinical Trial Registration:www.ClinicalTrial.org, Identifier: NCT01244204.

Free Vitamin D: Relationship to Insulin Sensitivity and Vascular Health in Youth

OBJECTIVE

To evaluate the relationship of free 25 hydroxy vitamin D [free 25(OH)D] or bioavailable vitamin D (BioD) concentrations to insulin sensitivity and cardiovascular disease risk markers in normal weight and overweight youth.

STUDY DESIGN

Cross-sectional study of 79 adolescents 15.4 ± 0.2 years, 18 normal weight, 30 overweight, and 31 overweight with prediabetes who underwent peripheral arterial tonometry, dual-energy x-ray absorptiometry, and hyperinsulinemic-euglycemic clamp in subset (n = 71) for determination of reactive hyperemia index (RHI), body composition, and insulin sensitivity. 25(OH)D and vitamin D binding protein were measured; free 25(OH)D and BioD were calculated.

RESULTS

Across tertiles of free 25(OH)D concentrations (4.0 ± 0.2, 7.5 ± 0.3, and 17.0 ± 2.1 pg/mL, P < .001), the group in the lowest tertile had significantly higher percent body fat (37.8 ± 1.1, 35.2 ± 1.5 and 25.3 ± 2.1%, P < .001), lower insulin sensitivity (4.4 ± 0.4, 6.7 ± 1.2, and 8.2 ± 0.9 mg/kg fat-free mass/minute per μu/mL, P = .03), lower RHI (1.42 ± 0.06, 1.54 ± 0.06, and 1.77 ± 0.09, P = .002), higher high-sensitivity C-reactive protein (3.4 ± 0.6, 1.7 ± 0.3, and 1.6 ± 0.4 mg/L, P = .015) compared with the second and third tertiles, respectively. Free 25(OH)D levels were inversely related to percent body fat and high-sensitivity C-reactive protein, and positively related to RHI and insulin sensitivity. The relationships of free 25(OH)D to RHI and to insulin sensitivity were no longer significant after adjusting for %body fat. Similar relationships were observed for BioD.

CONCLUSIONS

Youth with low free 25(OH)D or BioD concentrations have lower insulin sensitivity and worse endothelial function and inflammatory biomarkers compared with those with more sufficient 25(OH)D. However, the effects of vitamin D on these biomarkers may not be independent of the effect of adiposity.

Vitamin D and Cardio-Metabolic Risk Factors in Overweight Adults: An Overview of the Evidence

BACKGROUND

Several studies have suggested a potential association between low vitamin D serum levels and several pathological conditions apart from the well-known bone disorders. Thus, vitamin D insufficiency has been linked to cardiometabolic risk factors including obesity, insulin resistance, hypertension, dyslipidemia, as well as type 2 diabetes and cardiovascular disease.

OBJECTIVE

This review intends to provide an overview of recent evidence from clinical studies on vitamin D [25- hydroxyvitamin D (25(OH)D)] and cardiometabolic risk factors in overweight adults. Furthermore, we also discussed potential mechanisms and limits of the retrieved results.

METHODS

The search process was based on the selection of publications (RCT) listed in PubMed and Cochrane Library databases.

RESULTS

Vitamin D status evidenced an inversely strong association with subcutaneous adipose tissue and visceral adiposity, but not significantly related to other bodyweight measures (i.e., body mass index). Studies have shown a potential inverse association of hypovitaminosis D with insulin resistance and cardiovascular risk factors.

CONCLUSION

The mechanisms by which vitamin D deficiency enhances adiposity, as well as putative association with metabolic syndrome features, remain still unclear. Further investigation would be required to conclude whether vitamin D has an independent role in preventing cardiometabolic disorders.

Effects of vitamin D supplementation on bone turnover markers and other bone-related substances in subjects with vitamin D deficiency

In observational studies, vitamin D deficiency is a risk factor for low bone density and future fractures, whereas a causal relation has been difficult to show in randomized controlled trials (RCTs). Similarly, vitamin D deficiency has been associated with increased bone turnover, but RCTs with vitamin D have not shown conclusive effects. This could be due to inclusion of vitamin D sufficient subjects and low vitamin D doses. In the present study 399 subjects with mean baseline serum 25-hydroxyvitamin D (25(OH)D) 34.0 nmol/L completed a four months intervention with vitamin D₃ 20,000 IU per week versus placebo. Mean serum 25(OH)D increased to 89.0 nmol/L in the vitamin D group and decreased slightly in the placebo group. A small, but significant, decrease in the bone formation marker procollagen of type 1 amino-terminal propeptide (P1NP) was seen in the vitamin D group as compared to the placebo group (mean delta P1NP -1.2 pg/mL and 1.5 ng/mL, respectively, P < 0.01). No significant effects were seen on serum carboxyl-terminal telopeptide of type 1 collagen (CTX-1), Dickkopf-1, sclerostin, tumor necrosis factor-alpha, osteoprotegerin, receptor activator of nuclear factor ĸB ligand, or leptin. Subgroup analyses on subjects with low baseline serum 25(OH)D did not yield additional, significant results. In subjects with high baseline serum parathyroid hormone (PTH) > 6.5 pmol/L and post-intervention decrease in PTH, the decrease in P1NP was more pronounced, they also exhibited significantly reduced serum CTX-1 and increased serum sclerostin. In conclusion, supplementation with vitamin D appears to suppress bone turnover, possibly mediated by PTH reduction. Our findings need to be confirmed in even larger cohorts with vitamin D insufficient subjects.

Genetic Variations in VDR could Modulate the Efficacy of Vitamin D3 Supplementation on Inflammatory Markers and Total Antioxidant Capacity among Breast Cancer Women: A Randomized Double Blind Controlled Trial

Background:

Low levels of vitamin D are found in a great part of breast cancer women. Study subjects using vitamin D₃ supplement had lower rates of cancers and fewer markers of inflammation. Additionally, recent studies demonstrate the power of vitamin D supplementation to lower inflammation and oxidative stress biomarkers associate with VDR polymorphism to reduce inflammation. This study was aimed to assess the impact of vitamin D₃ supplementation on the serum concentration of inflammatory markers and antioxidant capacity with regard to VDR polymorphism in the VDR gene in breast cancer women.

Methods:

A randomized, double-blind, placebo-controlled trial was conducted on 56 breast cancer women. Participants were assigned to 2 treatment arms: placebo and vitamin D₃ for 2 months intervention. Supplementation group received 50,000 IU of vitamin weekly. Blood samples were collected at baseline and after the intervention to measure the 25(OH) D₃, TNF-α, TGF- β and TAC. Genotyping was performed for FokI, BsmI, ApaI, and TaqI polymorphism.

Results:

After eight weeks supplementation, the intervention group showed a significant increase in the serum concentration of 25(OH) D₃ (28±2.6 to 39±3.5; p=0.004 and TAC (48.9±13.3 to 63.5±13.3; p= 0.017). Changes in TNF-α, TGF- β1 were not significant. Serum TAC levels of participants with the TT/Tt, Ff genotypes were more responsive to supplementation.

Conclusions:

Supplementation with a vitamin D₃ increased the TAC in breast cancer women, although it had no effect on inflammatory markers. Serum TAC in the TT/Tt, Ff were more responsive to vitamin D supplement compared with those with the FF/ff and tt genotypes.

Platelet/lymphocyte ratio is an independent predictor for osteoporosis

Objectives:

To investigate the intercourse between the platelet/lymphocyte (P/L) and neutrophil/lymphocyte ratio (N/L), and vitamin D (Vit-D) levels in low bone mineral density (BMD) of women.

Methods:

Two hundred fifty-two postmenopausal female outpatients who were admitted to the obstetrics and gynecology and physical therapy clinics between July 2016 and December 2017 were retrospectively analyzed. The patients were grouped in relation to their T-score (normal [n=92], osteopenia [n=112], and PMO [n=48]). The serum levels of P/L, N/L, Vit-D, BMD and complete blood count of the patients were retrospectively examined.

Results:

The median P/L was significantly higher and Vit-D levels were significantly lower in the PMO group (130.75 [52.89-385] versus 123.05 [54-232.5], p=0.02 and 15.4 [4-34] versus 20.1 [4-47], p=0.003). While BMD and P/L were negatively correlated, a positive correlation between BMD and Vit-D was found. Vitamin D levels were negatively correlated with P/L (p<0.001) and N/L (p=0.04). Older age (≥65 years), Vit-D deficiency and P/L values >125.06 were found as independent prognostic factors for PMO in regression analysis.

Conclusion:

Higher P/L seems to be a quite simple marker to help predict postmenopausal PMO. As seen in our study, having low levels of Vit-D is crucial for PMO.

Thirteen weeks of supplementation of vitamin D and leucine-enriched whey protein nutritional supplement attenuates chronic low-grade inflammation in sarcopenic older adults: the PROVIDE study

Background

A chronic low-grade inflammatory profile (CLIP) is associated with sarcopenia in older adults. Protein and Vitamin (Vit)D have immune-modulatory potential, but evidence for effects of nutritional supplementation on CLIP is limited.

Aim

To investigate whether 13 weeks of nutritional supplementation of VitD and leucine-enriched whey protein affected CLIP in subjects enrolled in the PROVIDE-study, as a secondary analysis.

Methods

Sarcopenic adults (low skeletal muscle mass) aged ≥ 65 years with mobility limitations (Short Physical Performance Battery 4–9) and a body mass index of 20–30 kg/m² were randomly allocated to two daily servings of active (n = 137, including 20 g of whey protein, 3 g of leucine and 800 IU VitD) or isocaloric control product (n = 151) for a double-blind period of 13 weeks. At baseline and after 13 weeks, circulating interleukin (IL)-8, IL-1 receptor antagonist (RA), soluble tumor-necrosis-factor receptor (sTNFR)1, IL-6, high-sensitivity C-reactive protein, pre-albumin and 25-hydroxyvitamin(OH)D were measured. Data-analysis included repeated measures analysis of covariance (corrected for dietary VitD intake) and linear regression.

Results

IL-6 and IL-1Ra serum levels showed overall increases after 13 weeks (p = 0.006 and p < 0.001, respectively). For IL-6 a significant time × treatment interaction (p = 0.046) was observed, with no significant change over time in the active group (p = 0.155) compared to control (significant increase p = 0.012). IL-8 showed an overall significant decrease (p = 0.03). The change in pre-albumin was a significant predictor for changes in IL-6 after 13 weeks.

Conclusions

We conclude that 13 weeks of nutritional supplementation with VitD and leucine-enriched whey protein may attenuate the progression of CLIP in older sarcopenic persons with mobility limitations.

Electronic supplementary material

The online version of this article (10.1007/s40520-019-01208-4) contains supplementary material, which is available to authorized users.

Clinical Advances in Immunonutrition and Atherosclerosis: A Review

Atherosclerosis is a chronic low-grade inflammatory disease that affects large and medium-sized arteries and is considered to be a major underlying cause of cardiovascular disease (CVD). The high risk of mortality by atherosclerosis has led to the development of new strategies for disease prevention and management, including immunonutrition. Plant-based dietary patterns, functional foods, dietary supplements, and bioactive compounds such as the Mediterranean Diet, berries, polyunsaturated fatty acids, ω-3 and ω-6, vitamins E, A, C, and D, coenzyme Q10, as well as phytochemicals including isoflavones, stilbenes, and sterols have been associated with improvement in atheroma plaque at an inflammatory level. However, many of these correlations have been obtained in vitro and in experimental animals' models. On one hand, the present review focuses on the evidence obtained from epidemiological, dietary intervention and supplementation studies in humans supporting the role of immunonutrient supplementation and its effect on anti-inflammatory response in atherosclerotic disease. On the other hand, this review also analyzes the possible molecular mechanisms underlying the protective action of these supplements, which may lead a novel therapeutic approach to prevent or attenuate diet-related disease, such as atherosclerosis.

The association between dietary antioxidants and adipokines level among obese women

AIM

Adipokines are associated with several oxidative stress-related diseases and pathologic conditions. We aimed to assess the association between antioxidants and adipokines in obese adults.

METHODS AND MATERIALS

In this cross-sectional study, a total of 160 obese women were included. Body composition and anthropometric characteristics were measured. Dietary intakes were assessed by 3-day, 24-h dietary recall. Blood samples were obtained following an overnight fasting. Serum concentrations of adipokines including progranulin, retinol binding protein 4 (RBP4) and Angiopoietin-related growth factor 6 (ANGPTL6) was measured using an enzyme-linked immunosorbent assay. ANCOVA and the linear regression model analysis was performed to assess the relationship between Progranulin, RBP4, AnGPTL6, and antioxidants.

RESULTS

Mean age of included women was 39.31 ± 12.10. Mean and standard deviation for BMI was 35.05 ± 4.26 in this obese population. There was a positive significant association between ANGPTL6 and vitamin D intake (p < 0.001). Also, there was a marginal association between RBP4 and vitamin A (p = 0.063) intake, but after adjustment age, and fat mass, we found a significant association (p = 0.008). However, the associations between dietary antioxidants, progranulin, and ANGPTL6 were not statistically significant.

CONCLUSIONS

ANGPTL6 and RBP4 levels directly associated with dietary vitamins D and A intake, respectively. But, according to the results, the association between ANGPTL6 and vitamin D was bidirectional. The suggested associations probably can be useful in the development of interventional studies for management of chronic diseases.

Vitamin D and probiotic co-supplementation affects mental health, hormonal, inflammatory and oxidative stress parameters in women with polycystic ovary syndrome

Objective

The aim of this study was to determine the effect of vitamin D and probiotic co-administration on mental health, hormonal, inflammatory and oxidative stress parameters in women with polycystic ovary syndrome (PCOS).

Methods

This randomized, double-blinded, placebo-controlled clinical trial was carried out on 60 subjects, aged 18–40 years old. Subjects were randomly allocated to take either 50,000 IU vitamin D every 2 weeks plus 8 × 10⁹ CFU/day probiotic (n = 30) or placebo (n = 30) for 12 weeks.

Results

Vitamin D and probiotic co-supplementation, compared with the placebo, significantly improved beck depression inventory [β (difference in the mean of outcomes measures between treatment groups) − 0.58; 95% CI, − 1.15, − 0.02; P = 0.04], general health questionnaire scores (β − 0.93; 95% CI, − 1.78, − 0.08; P = 0.03) and depression, anxiety and stress scale scores (β − 0.90; 95% CI, − 1.67, − 0.13; P = 0.02). Vitamin D and probiotic co-supplementation was associated with a significant reduction in total testosterone (β − 0.19 ng/mL; 95% CI, − 0.28, − 0.10; P < 0.001), hirsutism (β − 0.95; 95% CI, − 1.39, − 0.51; P < 0.001), high-sensitivity C-reactive protein (hs-CRP) (β − 0.67 mg/L; 95% CI, − 0.97, − 0.38; P < 0.001) and malondialdehyde (MDA) levels (β − 0.25 μmol/L; 95% CI, − 0.40, − 0.10; P = 0.001), and a significant increase in total antioxidant capacity (TAC) (β 82.81 mmol/L; 95% CI, 42.86, 122.75; P < 0.001) and total glutathione (GSH) levels (β 40.42 μmol/L; 95% CI, 4.69, 76.19; P = 0.02), compared with the placebo.

Conclusions

Overall, the co-administration of vitamin D and probiotic for 12 weeks to women with PCOS had beneficial effects on mental health parameters, serum total testosterone, hirsutism, hs-CRP, plasma TAC, GSH and MDA levels.

Trial Registration

This study was retrospectively registered in the Iranian website (www.irct.ir) for registration of clinical trials (IRCT20170513033941N37).

The Role of Vitamin D Oral Supplementation in Insulin Resistance in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate the effect of vitamin D supplementation (alone or with co-supplementation) on insulin resistance in patients with polycystic ovary syndrome (PCOS).

METHODS

We performed a literature search of databases (Medline, Scopus, Web of Knowledge, Cochrane Library) and identified all reports of randomized controlled trials (RCTs) published prior to April 2018. We compared the effects of supplementation with vitamin D alone (dose from 1000 IU/d to 60,000 IU/week) or with co-supplements to the administration of placebos in women diagnosed with PCOS. The systematic review and meta-analysis protocol was registered in the International Prospective Register of Systematic Reviews (Prospero) as number CRD42018090572.

MAIN RESULTS

Eleven of 345 identified studies were included in the analysis; these involved 601women diagnosed with PCOS. Vitamin D as a co-supplement was found to significantly decrease fasting glucose concentrations and the HOMA-IR value. HOMA-IR also declined significantly when vitamin D was supplemented with a dose lower than 4000 IU/d.

CONCLUSIONS

Evidence from RCTs suggests that the supplementation of PCOS patients with continuous low doses of vitamin D (<4000 IU/d) or supplementation with vitamin D as a co-supplement may improve insulin sensitivity in terms of the fasting glucose concentration (supplementation with vitamin D in combination with other micronutrients) and HOMA-IR (supplementation with vitamin D in continuous low daily doses or as co-supplement).

The effects of vitamin D and probiotic co-supplementation on mental health parameters and metabolic status in type 2 diabetic patients with coronary heart disease: A randomized, double-blind, placebo-controlled trial

BACKGROUND

This study was carried out to evaluate the effects of vitamin D and probiotic co-supplementation on mental health parameters and metabolic status in diabetic people with coronary heart disease (CHD).

METHODS

This randomized, double-blind, placebo-controlled trial was carried out among 60 diabetic people with CHD, aged 45-85 years old. Subjects were randomly allocated into two groups to receive either 50,000 IU vitamin D every 2 weeks plus 8 × 10⁹ CFU/g probiotic of Lactocare Zisttakhmir Co (n = 30) or placebo (n = 30) for 12 weeks. Fasting blood samples were obtained at baseline and after the 12-week intervention to determine metabolic profiles.

RESULTS

After the 12-week intervention, compared with the placebo, vitamin D and probiotic co-supplementation resulted in significant improvements in beck depression inventory total score (-2.8 ± 3.8 vs. -0.9 ± 2.1, P = 0.01), beck anxiety inventory scores (-2.1 ± 2.3 vs. -0.8 ± 1.4, P = 0.009) and general health questionnaire scores (-3.9 ± 4.1 vs. -1.1 ± 3.4, P = 0.005). Compared with the placebo, vitamin D and probiotic co-supplementation resulted in significant reductions in serum insulin levels (-2.8 ± 3.8 vs. +0.2 ± 4.9 μIU/mL, P = 0.009), homeostasis model of assessment-estimated insulin resistance (-1.0 ± 1.6 vs. -0.1 ± 1.5, P = 0.02), and a significant increase in serum 25-OH-vitamin D (+11.8 ± 5.9 vs. +0.1 ± 1.4 ng/mL, P < 0.001), the quantitative insulin sensitivity check index (+0.03 ± 0.04 vs. -0.001 ± 0.01, P = 0.003) and serum HDL-cholesterol levels (+2.3 ± 3.5 vs. -0.5 ± 3.8 mg/dL, P = 0.004). In addition, changes in serum high sensitivity C-reactive protein (hs-CRP) (-950.0 ± 1811.2 vs. +260.5 ± 2298.2 ng/mL, P = 0.02), plasma nitric oxide (NO) (+1.7 ± 4.0 vs. -1.4 ± 6.7 μmol/L, P = 0.03) and plasma total antioxidant capacity (TAC) (+12.6 ± 41.6 vs. -116.9 ± 324.2 mmol/L, P = 0.03) in the supplemented group were significantly different from the changes in these indicators in the placebo group.

CONCLUSIONS

Overall, vitamin D and probiotic co-supplementation after 12 weeks among diabetic people with CHD had beneficial effects on mental health parameters, serum hs-CRP, plasma NO, TAC, glycemic control and HDL-cholesterol levels.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir: IRCT2017073033941N4.