The relationship between vitamin D status and visceral adiposity among older adults remains unclear. This study aimed to investigate the association between serum vitamin D levels and visceral adipose tissue (VAT) among older Iranian adults. This cross-sectional study included older adults aged ≥ 60 years from the Amirkola Health and Aging Project. Serum 25-hydroxyvitamin D levels were measured by enzyme-linked immunosorbent assay. VAT was assessed using dual-energy X-ray absorptiometry. Furthermore, the relationship between vitamin D and VAT was examined through multiple linear regression analysis, adjusting for potential confounders. Of the 600 participants, 345 (57.5%) were males and 255 (42.5%) were females. Their mean age was 68.90 ± 6.97 years, and the mean vitamin D level was 60.50 ± 39.45 ng/mL. Serum vitamin D levels showed a weak negative association with VAT mass (β = −0.062, p = 0.012). In both sexes, VAT mass predictors followed a similar pattern. Body mass index (BMI; β = 0.811, p < 0.001) was identified as a strong predictor, while diabetes status exhibited a positive association with VAT mass (β = 0.078, p = 0.002). Serum vitamin D levels appear to have a weak inverse relationship with visceral adiposity in older Iranian adults. BMI was the most robust predictor of VAT. Further longitudinal research is needed to clarify the causal relationship between vitamin D status and visceral adiposity among older adults.
This study aimed to assess the relationship between serum levels of vitamin D with anthropometric indices, lipid profile and vascular inflammatory factors, in patients who candidate for coronary artery bypass grafting (CABG). This analytical cross-sectional study was conducted in patients who were candidate for CABG. Demographic information, medical records, anthropometric indicators, blood samples, and physical activity of 150 patients were collected. 146 participants with mean ± standard deviation of age: 61.8 ± 10.0 years and body mass index: 26.9 ± 3.7 kg/m2 completed the study. Based on serum levels of vitamin D, patients were divided into 2 groups; groups with sufficient (≥ 30 ng/mL) and insufficient amount of vitamin D (< 30 ng/mL). The 30.14% of the patients had serum vitamin D deficiency. Ejection fraction (EF) % between the 2 groups had significant difference. Unexpectedly the EF% increased 7% in patients with insufficient level of vitamin D (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.03–1.11; p = 0.001). Vitamin D status had a significant inverse association with body weight. The odds of vitamin D deficiency significantly increased by 4% with increasing one kg in weight (OR, 1.04; 95% CI, 1–1.08; p = 0.044). There were no significant association between serum vitamin D level and intra cellular adhesion molecule-1, interleukin-17, fasting blood glucose, and lipid profile (p > 0.05). Considering the inverse association observed between serum vitamin D with EF% and body weight, vitamin D may play a role in modulating of these indices.
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Vitamin D participates in the biological function of the innate and adaptive immune system and inflammation. We aim to specify the effectiveness of the vitamin D supplementation on the side effects BioNTech, Pfizer vaccination, and immunoglobulin G response against severe acute respiratory syndrome coronavirus 2 in subjects tested positive for coronavirus disease 2019 (COVID-19).
In this multi-center randomized clinical trial, 498 people tested positive for COVID-19 were divided into 2 groups, receiving vitamin D capsules or a placebo (1 capsule daily, each containing 600 IU of vitamin D) over 14–16 weeks. Anthropometric indices and biochemical parameters were measured before and after the second dose of vaccination.
Fourteen to 16 weeks after supplementation, the intervention group had an immunoglobulin G (IgG) increase of 10.89 ± 1.2 g/L, while the control group had 8.89 ± 1.3 g/L, and the difference was significant between both groups (p = 0.001). After the second dose of vaccination, the supplement group significantly increased their 25-hydroxy vitamin D from initially 28.73 ± 15.6 ng/mL and increased to 46.48 ± 27.2 ng/mL, and the difference between them was significant. Those with a higher body mass index (BMI) had the most of symptoms, and the difference of side effects according to BMI level was significantly different. In 8 weeks after supplementation obese participants had the lowest IgG levels than overweight or normal subjects. The proportion of all types of side effects on the second dose was significantly diminished compared with the first dose in the intervention group.
Supplementation of 600 IU of vitamin D3 can reduce post-vaccination side effects and increase IgG levels in participants who received BioNTech, Pfizer vaccine.
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Early prevention of sarcopenia can be an important strategy for muscle maintenance, but most studies target subjects at slightly pre-sarcopenic state. Our previous paper describes the effect of protein supplements rich in leucine and vitamin D on muscle condition, and in this paper, we performed a sub-analysis to evaluate who benefitted the most in terms of improvement in muscle health. A 12-week randomized clinical trial of 120 healthy adults (aged 50 to 80) assigned to an intervention group (n = 60) or control group (n = 60) were analyzed. Subjects in the intervention group received, twice per day, a protein supplement containing (per serving) 800 IU of vitamin D, 20 g of protein (3 g of total leucine), 300 mg of calcium, 1.1 g of fat, and 2.5 g of carbohydrate. The subjects were classified into ‘insufficient’ and ‘sufficient’ groups at 25-hydroxyvitamin D (25[OH]D) value of 30 ng/mL. The skeletal muscle mass index normalized to the square of the skeletal muscle mass (SMM) height (kg/m2) increased significantly in the ‘insufficient group’ difference value of change between weeks 0 and 12 (Δ1.07 ± 2.20; p = 0.037). The SMM normalized by body weight (kg/kg, %) was higher, but not significantly, in the insufficient group (Δ0.38 ± 0.69; p = 0.050). For people with insufficient (serum 25[OH]D), supplemental intake of protein and vitamin D, calcium, and leucine and adequate energy intake increases muscle mass in middle-aged and older adults and would be likely to exert a beneficial effect on muscle health.
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Recently several studies have attempted to investigate the association between vitamin D and microbiota. However, studies have reported inconsistent results. This narrative review aimed to investigate the potential association between vitamin D and microbiota population in the gut by pooling together the results from observational studies and clinical trials. We considered animal and human studies in this field. Several studies have shown the correlation of vitamin D deficiency with microbiota. Furthermore, interventional studies were emerging that vitamin D change the microbiota composition in which leads to an increase in beneficial bacteria, such as
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There is a growing body of evidence linking vitamin D and its antiadipogenic activity with body composition. The aim of this study was to investigate the association between vitamin D levels, visceral adiposity index (VAI), and lipid accumulation product index among a group of Iranian people. This cross-sectional study was conducted with 270 Iranian adults. Body composition was measured via bio-impedance analysis. The 25-hydroxyvitamin D [25(OH)D] was also measured using the enzyme-linked immunosorbent assay method. The VAI and lipid accumulation product index were calculated. Multiple linear and logistic regression after controlling for confounder was used to report the results. Multiple linear regression showed that serum 25(OH)D levels were positively correlated with age (crude: β ± standard error [SE] = 0.23 ± 0.06, p ≤ 0.001; model I: β ± SE = 0.18 ± 0.05, p = 0.002) and percent body fat (crude: β ± SE = 0.10 ± 0.04, p = 0.02). Binary logistic regression analysis showed a higher chance of greater percent body fat and lipid accumulation product index in the crude model (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.13–3.72 for percent body fat and OR, 2.07; 95% CI, 1.14–3.76 for lipid accumulation product index), which disappeared after adjusting for covariates. Adults with higher vitamin D levels had higher scores of percent body fat and lipid accumulation product index. More longitudinal studies are needed to confirm these results.
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Non-alcoholic fatty liver disease (NAFLD) is a significant public health problem globally and the most notable chronic liver disease in Asian countries. Various dietary supplements have been assessed as potential methods to alleviate the metabolic damages related to NAFLD, but the results of these works have been equivocal. This study aimed to evaluate the effects of probiotic yogurt fortified with vitamin D (Pro-YFD) on glycemic and anthropometric indices in patients with NAFLD. One hundred and four NAFLD patients of both sexes were randomly allocated to 2 groups: group A (Pro-YFD) and group B (unfortified yogurt). The intervention period was 3 months. Fasting blood samples were obtained for measuring fasting blood sugar (FBS) and insulin level. Food intake was measured using a validated food frequency questionnaire. Body composition was estimated by bio-impedance. Eighty-eight patients completed the study. The mean serum level of 25(OH)D3 was elevated significantly (p < 0.001), while insulin level decreased significantly (p < 0.003) in group A at the end of the study. FBS levels showed no significant differences between the groups at the end of the trial. Also, there were no significant changes in diet caloric intake, physical activity, or anthropometric indices in the 2 groups during the interventions. Pro-YFD in the diets of patients with NAFLD may attenuate insulin resistance and improve serum level of 25(OH)D3.
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This study aimed to utilize structural equation modeling (SEM) techniques to determine the effects of dietary calcium, protein and vitamin D on adiposity and lipidemia and to assess mediatory effects of parathyroid hormone (PTH) and 25-hydroxyvitamin D (25(OH)D) in patients with type 2 diabetes. In this cross-sectional study, a total of 150 diabetic patients (93 females and 57 males) were randomly selected. Anthropometric measures, biochemical analyses, and fat mass percent were recorded. Nutritional data were collected. SEM was performed. Based on the primary hypothesis, adiposity and lipidemia were fitted in a model. The direct effects of dietary calcium (λ = –0.165, p value = 0.002) and PTH (λ = –0.143, p value = 0.011) were significantly associated with lipidemia. There were no significant effects for dietary protein on PTH (λ = –0.270, p value = 0.057), 25(OH)D (λ = –0.071, p value = 0.613), lipidemia (λ = –0.044; p value = 0.638) or adiposity (λ = –0.009, p value = 0.949) as well as for dietary vitamin D on PTH (λ = –0.119, p value = 0.194), 25(OH)D (λ = 0.023, p value = 0.806), lipidemia (λ = 0.034, p value = 0.587) or adiposity (λ = –0.221, p value = 0.118). The correlation between calcium intake and lipidemia, and adiposity are not mediated by 25(OH)D and PTH. There were the direct effects of dietary calcium on adiposity in patients with type 2 diabetes. The model can be tested in future longitudinal and intervention studies to identify the predictors of obesity.
Calcium intake is essential for bone health, but young Korean women have low calcium intakes. Seaweeds have high calcium content, which may affect calcium metabolism. Twenty nine females aged 18–39 years with low calcium intake (< 400 mg/day) participated in a 19-day open-label randomized controlled trial. During the first five days, participants adhered to a controlled-feeding protocol followed by a two-week supplementation period in free-living conditions. The treatment group (n = 14) received an additional 200 mg Ca/day through
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The receptor of vitamin D is expressed in almost all body cells, including vascular endothelial cells and cardiomyocytes. Vitamin D deficiency has been observed widespread amongst heart failure (HF) patients, which could have harmful effects on their health condition. This study aims to investigate the effect of vitamin D supplements on blood pressure (BP) and physical activity of HF patients. Thirty-nine systolic HF patients with low ejection fraction (EF) < 50% and class III of New York Heart Association functional classification were randomly divided into 2 groups including intervention and placebo to enroll in an 8 weeks double-blind clinical trial. During the trial 6-minute walk test (6MWT), 25-hydroxyvitamin D (25[OH]D) level, BP, sodium and potassium intakes were assessed. The mean 25(OH)D level increased to 28.9 ± 11.7 ng/mL (p < 0.001) in the intervention group. There was a poor but non-significant reduction in systolic BP (−0.033 ± 4.71 mmHg, p = 0.531) in the intervention group. The BP also did not change in the placebo group at the end of the trial. A negligible decrease of 6MWT was observed in the intervention group (−6.6 ± 29.2 m) compared to the placebo (−14.1 ± 40.5 m). However, differences between the 2 groups were not statistically significant (p = 0.325). The results solely showed a slight positive correlation between 25(OH)D level and 6MWT. No significant improvements in BP and 6MWT were observed after vitamin D3 supplementation.
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The
objective
s of this study were to investigate the status of vitamin D in Korean adolescents and to determine the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and consumption frequencies of vitamin D food sources by season (June to November and December to May). The subjects were 1,579 adolescents aged 12-18 years participating in the 2008-2009 Korean National Health and Nutrition Examination Survey (KNHANES). Consumption frequencies of vitamin D food sources were estimated by using a qualitative food frequency questionnaire (FFQ). Thirteen food items were selected as vitamin D food sources including beef, egg, mackerel, tuna, yellow corvine, pollack, anchovy, mushroom, milk, yoghurt, ice cream, all fish and dairy products from the FFQ based on previous research. The data was analyzed using proc survey procedures. The deficiency (5.25-12 ng/mL), inadequacy (12-20 ng/mL) and sufficiency (> 20 ng/mL) proportions of serum 25(OH)D from June to November and December to May were 9.9%, 51.4%, 38.7%, and 39.4%, 51.4%, 9.2%, respectively. Mean serum 25(OH)D concentration was positively related to the consumption frequencies of mackerel, anchovy, all fish and milk. These results suggest high proportion (> 61%) of Korean adolescents were vitamin D deficiency or inadequacy, and serum 25(OH)D was associated with the consumption of vitamin D food sources including fish and milk.
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