Vitamin D and biomarkers of inflammation and oxidative stress among pregnant women: a systematic review of observational studies.

OBJECTIVE: This systematic review aimed to map the evidence evaluated the relationship between vitamin D and redox and inflammatory status during gestation. METHODS: Three databases (PubMed/MEDLINE, Scopus, and Web of Science (WoS)) and reference list of included documents were searched for related observational studies published until 2nd October 2023. To determine the quality of the selected observational studies, the Newcastle-Ottawa Scale (NOS) was used. RESULTS: After a primary search of three databases, 19492records were appeared. When duplicates and irrelevant documents were removed, 14 articles were found to have eligible criteria. The design of the identified studies was cross-sectional, case-control and cohort. Evidence showed an adverse association between 25(OH)D and the biomarkers of inflammation, such as high-sensitivity C-reactive protein (hs-CRP), Interleukin-1beta (IL-1ß), Interleukin-6 (IL-6), and tumor necrosis factor- alfa (TNF-α) during pregnancy. On the contrary, some studies represented that 25(OH)D positively correlated with hs-CRP in the cord blood. One study suggested a direct association between serum concentrations of 25(OH)D and Interleukin-8 (IL-8), macrophage inflammatory protein (MIP), and TNF-α levels in mothers with gestational diabetes mellitus (GDM). A case-control study showed that lower serum concentration of 25(OH)D positively correlated with total antioxidant capacity (TAC) levels in participants. CONCLUSIONS: Evidence confirmed the supposition of the direct relationship between vitamin D levels and biomarkers with anti-inflammatory and anti-oxidative properties. However, the Existence of inconsistent evidence confirms the need for further studies in mothers with GDM and hypertensive disorders. PROSPERO REGISTRATION CODE: CRD42020202600.

Factors related to hypermetabolism in individuals with type 2 diabetes mellitus and non-alcoholic fatty liver disease.

Considering the progressive prevalence and co-occurrence of type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD), as well as the current evidence suggesting the elevated levels of basal metabolic rate (BMR) among these individuals, the present study aimed to identify factors determining hypermetabolism in such subjects. This cross sectional study was conducted in 30 to 53-year-old individuals with concurrent T2DM and NAFLD (controlled attenuation parameter score ≥ 260 dB/m). Resting energy expenditure (REE) was determined by an indirect calorimetry device. Hypermetabolism was defined as an elevated measured REE > 110% of the predicted REE. The multivariate logistic regression test was used for detecting factors associated with hypermetabolism. Between September, 2017, and March, 2018, a total of 95 eligible participants (64.40% male) with both T2DM and NAFLD were included, while 32.63% of them were classified as hypermetabolic. Overall, the mean recruitment age ± standard deviation and median (interquartile range) body mass index were 44.69 ± 5.47 years and 30.20 (27.80-33.30) kg/m2, respectively. Demographic, anthropometric and biochemical variables did not vary significantly across two groups except for total body water, low-density lipoprotein cholesterol and dipeptidyl peptidase 4 (DPP-4) inhibitors (p < 0.05). According to the results of multivariable logistic regression analyses, hypermetabolism had a positive association with adiponectin (odds ratio [OR] 1.167, 95% confidence interval [CI] 1.015-1.342, p = 0.030), physical activity (OR 1.134, 95% CI 1.002-1.284, p = 0.046), alanine transaminase (OR 1.062, 95% CI 1.006-1.122, p = 0.031) and diastolic blood pressure (OR 1.067, 95% CI 1.010-1.127, p = 0.021). However, fat free mass was inversely related to hypermetabolism (OR 0.935, 95% CI 0.883-0.991, p = 0.023). Adiponectin, alanine transaminase, physical activity, diastolic blood pressure and fat free mass were independently associated with hypermetabolism in subjects with NAFLD and T2DM.

The effect of vitamin D supplementation on oxidative stress and inflammatory biomarkers in pregnant women: a systematic review and meta-analysis of clinical trials.

BACKGROUND: Vitamin D deficiency, a common problem among pregnant women, is linked with maternal inflammation, oxidative stress and consequent adverse pregnancy outcomes. The aim of this systematic review was to evaluate the effect of vitamin D supplementation on oxidative stress and inflammatory biomarkers in pregnant women according to the PRISMA guidance. METHODS: Four databases including PubMed/MEDLINE, Scopus, Web of Science and Cochrane were used for searching papers published until 25th July 2022. Clinical trials that assessed 25-Hydroxyvitamin D (25(OH)D), inflammatory markers (including high sensitivity C-reactive protein (hs-CRP) and certain cytokines) and oxidative stress markers (including malondialdehyde (MDA), total antioxidant capacity (TAC) and glutathione (GSH)) in pregnant women, were included in this review. The primary search of three databases displayed 21571 records. After removing duplicates and irrelevant articles, 17 eligible RCTs included for more evaluation. Random effect model and Der Simonian-Laird method were used to pool the data of studies. Risk of bias assessed according to version 2 of the Cochrane risk-of-bias tool for randomized trials. RESULTS: According to the meta-analysis result, vitamin D supplementation caused a significant increase in the maternal circulating concentrations of 25(OH)D (SMD 2.07; 95%, CI 1.51, 2.63; p < 0.001), TAC (SMD 2.13, 95% CI 1.04 to 3.23, p < 0.001) and GSH (SMD 4.37, 95% CI 2.9 to 5.74, p < 0.001) as well as a significant decrease in the levels of MDA (SMD -0.46, 95% CI -0.87 to -0.05, p = 0.02). However, it had no significant impact on hs-CRP concentrations (SMD 0.24; 95% CI, -0.55, 1.03; p = 0.50). CONCLUSION: In the present study, vitamin D supplementation led to increased levels of 25(OH)D, TAC and GSH and also decreased concentration of MDA. Nevertheless, because of low certainty of evidence, these findings have to be declared conservatively. TRIAL REGISTRATION: Registration code in PROSPERO website: CRD42020202600.

Evaluation of the efficacy of two doses of vitamin D supplementation on glycemic, lipidemic and oxidative stress biomarkers during pregnancy: a randomized clinical trial.

BACKGROUND: Vitamin D deficiency during pregnancy is common and is likely to be associated with metabolic complications in the mother. The aim of this study was to assess the efficacy of two doses of vitamin D supplementation during pregnancy on maternal and cord blood vitamin D status and metabolic and oxidative stress biomarkers. METHODS: The eligible pregnant women (n = 84) invited to participate in the study and randomly allocated to one of the two supplementation groups (1000 IU/d vitamin D and 2000 IU/d). Biochemical assessments of mothers including serum concentrations of 25(OH)D, calcium, phosphate, iPTH, fasting serum sugar (FBS), insulin, triglyceride, total cholesterol, LDL-C, HDL-C, malondialdehyde (MDA) and total antioxidant capacity (TAC) were done at the beginning and 34 weeks of gestation. Cord blood serum concentrations of 25(OH)D, iPTH, MDA and TAC were assessed at delivery as well. To determine the effects of vitamin D supplementation on metabolic markers 1-factor repeated-measures analysis of variance (ANOVA) was used. Between groups comparisons was done by using Independent-samples Student's t-test or Mann-Whitney test. P < 0.05 was considered as significant. RESULTS: Supplementation with 1000 IU/d and 2000 IU/d vitamin D resulted in significant changes in vitamin D status over pregnancy (24.01 ± 21.7, P < 0.001 in 1000 IU/d group and 46.7 ± 30.6 nmol/L, P < 0.001 in 2000 IU/d group). Daily intake of 2000 compared with 1000 IU/d tended to increase the serum concentration of HDL-C (10 ± 8.37, P < 0.001 in 1000 IU/d group and 9.52 ± 11.39 mg/dL, P < 0.001 in 2000 IU/d group). A significant decrement in serum concentration of iPTH observed in both groups (- 4.18 ± 7.5, P = 0.002 in 1000 IU/d group and - 8.36 ± 14.17, P = 0.002 in 2000 IU/d group). CONCLUSIONS: Supplementation with 2000 IU/d vitamin D as compared with 1000 IU/d, is more effective in promoting vitamin D status and HDL-C serum concentration and in decreasing iPTH over pregnancy. TRIAL REGISTRATION: This trial is registered at clinicaltrials.gov ( NCT03308487 ). Registered 12 October 2017 'retrospectively registered'.

Macronutrient intake and physical activity levels in individuals with and without metabolic syndrome: An observational study in an urban population.

BACKGROUND: We aimed to compare dietary macronutrient intake and physical activity level (PAL) between community-based samples of Iranian adults with metabolic syndrome (MetS+) and without metabolic syndrome (MetS-). METHODS: This cross-sectional study was conducted among 3800 men and women aged 35-65 years. The International Diabetes Federation (IDF) criteria were used to define MetS. A 24-hour recall was used to evaluate dietary intake. The James and Schofield human energy requirements equations were used to calculate PAL and questions were categorized into time spent on activities during work (including housework), during non-work time, and in bed. RESULTS: The mean ± standard deviation (SD)age of the MetS+ and MetS- subjects was, respectively, 48.8 ± 7.8 years (521 men and 1178 women) and 47.6 ± 7.5 years (714 men and 1222 women) (P = 0.930). The mean energy intake was higher in the MetS+ men compared with MetS- men (1977.4 ± 26.6 vs. 1812.7 ± 21.7 Kcal; P < 0.001). Crude and energy-adjusted intake from total fat was lower in MetS+ women compared with MetS- women (both P < 0.010). PALs were lower in MetS+ compared with MetS- participants (P < 0.001). After adjusting for confounders, no significant association was observed between the intake of individual macronutrients and MetS. In contrast, PAL was inversely associated with the incidence of MetS [OR = 0.34 (95% CI: 0.17-0.57); P < 0.001]. CONCLUSION: In the current study, there was an inverse relationship between PAL and the risk of MetS, but no association between individual dietary macronutrients intake and the incidence of MetS.

Efficacy of two different doses of oral vitamin D supplementation on inflammatory biomarkers and maternal and neonatal outcomes.

Hypovitaminosis D during pregnancy is suggested to have a link with complications in both mother and infant. We aimed to evaluate the efficacy of two doses of vitamin D3 supplementation during pregnancy on maternal and cord blood vitamin D status, inflammatory biomarkers, and maternal and neonatal outcomes. A total of 84 pregnant women (gestational age of <12 weeks) were randomly allocated to one of two groups: (a) 1,000-IU/d vitamin D and (b) 2,000 IU/d. Biochemical assessments (25-hydroxycalciferol (25(OH)D), hs-CRP, and cell-culture supernatant concentrations of IL-1ß, IL-6, and TNF-α) of mothers were performed at the beginning and 34 weeks of gestation. Assessments of infants at delivery comprised cord blood serum concentrations of 25(OH)D, hs-CRP, IL-1ß, IL-6, TNF-α, birth sizes, and Apgar score. Circulating concentrations of 25(OH)D increased in both intervention groups with more increment in 2,000 IU/d than in 1,000 IU/d (46.7 ± 30.7 vs. 24.0 ± 21.07 nmol L-1 , P = .001). Concentrations of TNF-α decreased significantly in group 2,000 (-913.1 ± 1261.3 ng L-1 , P = .01). The cord blood concentration of IL-6 in group 2,000 IU/d, compared with 1,000 IU/d, was significantly lower (25.9 ± 32.0 vs. 4.6 ± 1.4 ng L-1 , P = .03). The birth sizes including weight, length, and head circumference of the infants of group 2,000 IU/d were significantly higher than the infants' of group 1,000 IU/d. Supplementation with 2,000-IU/d vitamin D3 is more effective than 1,000 IU/d in pregnant women in terms of increasing circulating 25(OH)D, ameliorating pro-inflammatory markers notably TNF-α in mother and IL-6 in cord blood, and improving neonatal outcomes including the birth sizes.

Micronutrient intake and the presence of the metabolic syndrome.

BACKGROUND: Dietary micronutrients have been proposed to protect against oxidative damage and related clinical complications. AIMS: We aimed to compare the micronutrient intake between individuals with and without metabolic syndrome (MS). MATERIALS AND METHODS: This cross-sectional study included 3800 men and women who were aged between 35 and 65 years. The diagnosis of the MS was based on International Diabetes Federation criteria. Dietary intake of participants was assessed using a questionnaire for 24 h dietary recall. Student's t-test and Mann-Whitney U-tests were used for comparing the micronutrient intake of subjects with or without the MS and the odds ratio for the presence of the MS was calculated for each micronutrient by control for total energy intake adjusted by the residue method. RESULTS: The mean age of MS subjects and the control group was 48.8 ± 7.9 years and 47.6 ± 7.6 years, respectively. Energy-adjusted intake of vitamin E (P < 0.05), B2 (P < 0.01), and B12 (P < 0.05) was higher in normal women compared with women with MS. Energy-adjusted intake of vitamin B1 was significantly higher in women with MS. After logistic regression analysis, no significant association between micronutrient intake and MS was shown. CONCLUSION: We found no significant association between micronutrient intake and MS.