Vitamin D: a critical and essential micronutrient for human health

Evaluation of the vitamin D response index in a Saudi cohort

The concept of the vitamin D response index was developed based on vitamin D intervention studies conducted with Finnish cohorts. In this study, we challenged the concept by performing a single vitamin D3 bolus (80,000 IU) intervention with a cohort of 100 native Saudis. The change of serum levels of the proinflammatory cytokines interleukin 6, interleukin 8 and tumor necrosis factor measured directly before intervention in comparison to samples taken one and thirty days after vitamin D3 supplementation were used as biomarkers for distinguishing low, mid and high responders. Interestingly, we identified 39 % of the study participants as low responders. In contrast, when we used in a subset of 37 study participants whole blood expression changes of seven well-known vitamin D target genes one and thirty days after supplementation as alternative biomarkers, only 9 persons (24 %) were identified as low responders. In conclusion, in Saudi Arabia the rate of low vitamin D responders is equal or even higher than that in Finland. Therefore, similar to Nordic countries also in Saudi Arabia appropriate vitamin D3 supplementation is essential, in order to fulfill the needs of low responders.

Relationship Between Serum 25-Hydroxyvitamin D and Bone Mineral Density, Fracture Risk, and Bone Metabolism in Adults With Osteoporosis/Fractures

OBJECTIVE

To evaluate the association of serum 25-hydroxyvitamin D (25(OH) D) levels with bone mineral density (BMD), fracture risk, and bone metabolism.

METHODS

This multicenter cross-sectional study recruited menopausal females and males greater than or equal to 50 year old with osteoporosis/fractures between September 2016 and September 2021. Assessment included clinical data, 25(OH)D, intact parathyroid hormone (iPTH), procollagen type 1 amino-terminal propeptide (P1NP), carboxy-terminal collagen crosslinks (CTX), lateral thoracolumbar spine x-rays, and BMD.

RESULTS

A total of 3003 individuals were stratified by 25(OH) D levels: 720 individuals (24%) <20 ng/mL, 1338 individuals (44.5%) 20 to 29 ng/mL, and 945 individuals (31.5%) ≥30 ng/mL. In unadjusted and multivariable models, BMD T-score, except spine, was significantly and positively associated with 25(OH)D levels. 25(OH) D levels were inversely associated with Fracture Risk Assessment Tool scores. Patients with 25(OH)D <20 ng/mL had significantly higher iPTH and bone turnover markers (P1NP and CTX) than patients with 25(OH)D ≧20 ng/mL in all models. When analyzing bone-related markers and BMD, total hip and femoral neck BMD T-scores were positively correlated with 25(OH)D concentrations and BMI but negatively correlated with iPTH, P1NP, CTX, and age. In multivariate models with all bone-related markers, only 25(OH)D levels were significantly associated with total hip and femoral neck BMD.

CONCLUSION

Vitamin D deficiency is significantly associated with decreased total hip and femoral neck BMD and increased fracture risk as assessed by Fracture Risk Assessment Tool. In those with osteoporosis/fractures, vitamin D is implicated in the causal relationship between bone remodeling and BMD. Assessing vitamin D status is imperative for those at risk for osteoporosis/fractures.

Prevalence and Risk Factors of Vitamin D, Calcium and Phosphate Deficiency among Apparently Healthy Children Aged 6-24 Months in a Semi-urban Community in Southwest, Nigeria

BACKGROUND

Adequate levels of calcium, phosphate and Vitamin D are essential for bone physiology and growth, as well as preventing some common childhood illnesses. This study aimed to determine the prevalence of the deficiencies of these nutrients and factors affecting their serum levels in Nigerian children.

METHODS

This was a cross-sectional study that involved 220 apparently healthy children aged 6-24 months in Ikenne Local Government Area of Ogun State, Nigeria. Serum calcium and phosphate were assayed using the calorimetric method, while Vitamin D (25-OH Vitamin D) was assayed with ELISA.

RESULTS

The mean (±standard deviation [SD]) serum Vitamin D level was 55.07 ± 16.53 ng/ml, while the mean (±SD) serum calcium and phosphate were 2.27 ± 0.13 mmol/l and 1.28 ± 0.18 mmol/l, respectively. Eleven (5%) of the children had hypovitaminosis D, 23 (10.5%) had hypocalcaemia and 12 (5.5%) had hypophosphataemia. Factors found to be significantly associated with hypovitaminosis D included low consumption of milk and the use of a hijab veil, while malnutrition (both undernutrition and overnutrition) was significantly associated with hypocalcaemia.

CONCLUSION

The prevalence levels of hypovitaminosis D and hypophosphataemia were low, while hypocalcaemia was more common. Low milk consumption and use of a hijab veil were risk factors for hypovitaminosis D, while malnutrition was a risk factor for hypocalcaemia. Malnourished children, especially overnourished ones, should be routinely screened for hypocalcaemia because of its high prevalence among them.

Association between serum vitamin D level and Graves' disease: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis aims to analyze the relationship between serum vitamin D (VD) levels and Graves' disease (GD).

METHODS

We conducted a search for publications on VD and GD in the English language. Our search encompassed databases such as PubMed, Embase, Web of Science, and the Cochrane Library, covering publications available through August 2023. A meta-analysis was performed using Cochrane RevMan 5.4 software. The standardized mean difference (SMD) and 95% confidence interval (CI) were used for outcome calculation. We used R software to test for publication bias.

RESULTS

Twelve studies were selected, comprising 937 (22.4%) cases with GD and 3254 (77.6%) controls. The overall meta-analysis revealed that patients with GD are significantly more likely to have low VD levels (SMD = - 0.66; 95% CI: -1.05, - 0.27; p = 0.001) than those in the control group. Egger's test results indicated no publication bias (p = 0.0791). These studies exhibited a high degree of heterogeneity (chi-square = 205.86, p < 0.00001; I2 = 95%). Subgroup analysis was conducted based on assay method, geographic location, and mean age of the case group to explore the heterogeneity sources. Assay methods and geographic locations were identified as potential heterogeneity sources. Based on the mean age, there were no statistically significant differences found in the subgroup analysis of the included studies.

CONCLUSION

There is promising evidence that low serum VD levels may increase the risk of GD. Further rigorous and long-term trials are needed to explore the role of VD in the onset and treatment of GD.

Supplementation with vitamin D improves the embryo quality in in vitro fertilization (IVF) programs, independently of the patients' basal vitamin D status

PURPOSE

The study aims to demonstrate the effects of Vitamin D (VD) supplementation, prior to oocyte pick-up within IVF protocols, in women with diverse VD status at the enrollment.

METHODS

A total of 204 women eligible for intra-cytoplasmatic sperm injection (ICSI) cycles were included in the study and two homogeneous groups were selected from the database. Both group of patients with normal VD baseline level (> 40 ng/ml) and patients with low VD baseline level (< 20 ng/ml) were divided into control group and treatment group. The control group followed the standard procedure. The treatment group was supplemented with vitamin D3 as cholecalciferol in combination with Myo-Inositol, folic acid, and melatonin 3 months before standard procedure, once a day in the evening.

RESULTS

VD levels significantly increased in the study group of low baseline VD, both in serum and in the follicular fluid compared to controls. The treatment induced a significant improvement of the embryo quality in both group of patients considered.

CONCLUSION

Supplementation of VD in patients undergoing ICSI procedures significantly improved the number of top-quality embryos compared with the control group, either starting from VD normal baseline values or starting from low values.

TRIAL REGISTRATION NUMBER

07/2018.

Two-dimensional Keitz method for the radiant power measurement of planar ultraviolet excilamps

Planar X e B r ∗ and X e C l ∗ excilamps emitting noncoherent narrowband UVB light (280-315 nm) are now widely used to cure psoriasis and vitiligo as well as to improve vitamin D synthesis. The two-dimensional integral formula has been deducted in this study, which is a good method and has great practical significance to calculate the total radiant power and assess the energy efficiency of a planar UV lamp. The measured radiant power of planar white LED lamps through a two-dimensional Keitz formula has been compared to that of gonio-photometer, verifying the applicability of the formula. The optimum measurement distance is dependent on the lamp length (1.5L≤D≤3.5L) for which the derivation from the two methods can be controlled within 10%. The planar X e B r ∗ excilamps have been measured and compared to coaxial excilamps, which show similar patterns of change for the radiant characteristics. Since the planar radiant power formula only needs to measure normal illuminance at a certain distance from the symmetric center of the lamp, it is more convenient to use and is a low-cost method to promote the development of large-sized planar ultraviolet lamps.

Causal association between serum 25-hydroxyvitamin D levels and right ventricular structure and function: A Mendelian randomization study

BACKGROUND AND AIM

Deficient concentrations of vitamin D have been linked to several cardiovascular conditions, but the causal relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and right ventricular structure and function remains unclear. Mendelian randomization (MR) was employed to inspect this association.

METHODS AND RESULTS

Genetic instrumental variables associated with 25(OH)D levels were acquired from genome-wide association studies (GWAS) analyses. Summary statistics for right ventricular structure and function, including right ventricular end diastolic volume, right ventricular end systolic volume, right ventricular stroke volume, and right ventricular ejection fraction, were acquired from publicly available GWAS datasets. For the primary analysis, the inverse variance weighted (IVW) method was utilized in performing the MR analysis. Additionally, secondly analyses were conducted to estimate the robustness and consistency of the attained conclusions. The MR analysis did not reveal a considerable causal association between serum 25(OH)D levels and right ventricular end diastolic volume (β: 0.112, 95% confident interval [CI]: -0.006 to 0.230, p = 0.063), right ventricular end systolic volume (β: 0.102, 95% CI: -0.021 to 0.226, p = 0.105), right ventricular stroke volume (β: 0.095, 95% CI: -0.018 to 0.207, p = 0.099), or right ventricular ejection fraction (β: -0.005, 95% CI: -0.123 to 0.112, p = 0.928).

CONCLUSIONS

Our findings did not reveal any substantial evidence supporting a causal relationship between serum 25(OH)D levels and the structure and function of the right ventricle. These findings suggest that serum 25(OH)D levels may not directly influence right ventricular parameters assessed.

Seasonal Variation in Vitamin D Status Does Not Interfere with Improvements in Aerobic and Muscular Endurance in Conscripts during Basic Military Training

Considering a lack of respective data, the primary objective of this study was to assess whether seasonal variation in vitamin D status (D-status) affects the extent of improvement in physical performance (PP) in conscripts during basic military training (BMT). D-status, PP and several blood parameters were measured repeatedly in conscripts whose 10-week BMT started in July (cohort S-C; n = 96) or in October (cohort A-C; n = 107). D-status during BMT was higher in S-C compared to A-C (overall serum 25(OH)D 61.4 ± 16.1 and 48.5 ± 20.7 nmol/L, respectively; p < 0.0001). Significant (p < 0.05) improvements in both aerobic and muscular endurance occurred in both cohorts during BMT. Pooled data of the two cohorts revealed a highly reliable (p = 0.000) but weak (R2 = 0.038-0.162) positive association between D-status and PP measures both at the beginning and end of BMT. However, further analysis showed that such a relationship occurred only in conscripts with insufficient or deficient D-status, but not in their vitamin D-sufficient companions. Significant (p < 0.05) increases in serum testosterone-to-cortisol ratio and decreases in ferritin levels occurred during BMT. In conclusion, a positive association exists between D-status and PP measures, but seasonal variation in D-status does not influence the extent of improvement in PP in conscripts during BMT.

Vitamin D3 Bioaccessibility from Supplements and Foods-Gastric pH Effect Using a Static In Vitro Gastrointestinal Model

Vitamin D3 deficiency is a global phenomenon, which can be managed with supplementation and food fortification. However, vitamin D3 bioaccessibility may depend on factors such as matrix composition and interactions throughout the gastrointestinal (GI) tract. This research focused on the effect of different matrices on vitamin D3 content during digestion, as well as the effect of pH on its bioaccessibility. The INFOGEST protocol was employed to simulate digestion. Three different types of commercial supplements, two foods naturally rich in vitamin D3, and three fortified foods were investigated. High-Performance Liquid Chromatography was used to determine the initial vitamin D3 content in the supplements and foods, as well as after each digestion stage. The results indicate that the foods exhibited higher bioaccessibility indices compared to the supplements and a higher percentage retention at the end of the gastric phase. The pH study revealed a positive correlation between an increased gastric pH and the corresponding content of vitamin D3. Interestingly, exposing the matrix to a low pH during the gastric phase resulted in an increased intestinal content of D3. Vitamin D3 is more bioaccessible from foods than supplements, and its bioaccessibility is susceptible to changes in gastric pH. Fasting conditions (i.e., gastric pH = 1) enhance the vitamin's bioaccessibility.

Evaluation of the deficiency status of 25-hydroxyvitamin D and associated factors in Southwest China: A hospital-based retrospective cross-sectional analysis of a low-latitude, high-altitude, multiracial region

Vitamin D deficiency is widespread in different populations and regions worldwide and has become a global health issue. The vitamin D status of the population in the Yunnan Province of Southwest China has not been evaluated to date. Therefore, in this study, we evaluated the vitamin D status according to the serum concentrations of 25-hydroxyvitamin D (25(OH)D) in individuals of Yunnan Province, a low-latitude, high-altitude and multiracial region in China. The data on 25(OH)D concentrations from October 2012 to December 2017 were retrospectively collected and assessed using the laboratory information system from 52 950 hospital-based participants (age, 1 day-96 years; females, 73.74%). The serum concentration of 25(OH)D was evaluated using a chemiluminescent immunoassay. The analysis was stratified by sex, age, sampling season, testing year, minority, residential district, latitude, altitude and meteorological factors. Vitamin D status was classified as follows: severe deficiency: <10 ng/mL; deficiency: <20 ng/mL; insufficiency: <30 ng/mL; and sufficiency: ≥30 ng/mL. The results showed that vitamin D deficiency is highly prevalent in Yunnan Province in a hospital-based cohort, with a deficiency and severe deficiency rate of 65.1% and a sufficiency rate of 5.30%. Significantly lower vitamin D levels and sufficiency rates were observed in females than in males (20.13 ± 7.22 ng/mL vs. 17.56 ± 6.66 ng/mL and 8.20% vs. 4.20%; p < 0.01, respectively); in spring and winter (16.93 ± 6.24 ng/mL; 2.97% and 16.38 ± 6.43 ng/mL; 3.06%, respectively) than in summer and autumn (20.23 ± 7.14 ng/mL; 8.02% and 19.10 ± 6.97 ng/mL; 6.61% [p < 0.01], respectively); and in older individuals (0-6 years: 28.29 ± 13.13 ng/mL vs. >60 years: 14.88 ± 8.39 ng/mL; p < 0.01). Relatively higher vitamin D levels were observed in individuals of Yi, Zhuang, Hani, Dai, Miao and Lisu minorities and lower levels in individuals of Hui and Zang minorities compared with those of the Han nationality (p < 0.01). The mean sunlight duration, mean air temperature, maximum ultraviolet value and latitude were significantly correlated with vitamin D levels (r = -0.53, 0.60, 0.31, -0.68, respectively; p < 0.05). These results suggest that vitamin D status is influenced by sex, age, minority, latitude and some meteorological factors in areas with high and low altitudes. Hence, new public health policies, such as advice on sunshine exposure, food fortification and nutrition education, as well as the implementation of vitamin D supplementation programmes must be considered to alleviate vitamin D deficiency in Yunnan province, Southwest China.

Competitive season effects on polyunsaturated fatty acid content in erythrocyte membranes of female football players

BACKGROUND

An optimal and correctly balanced metabolic status is essential to improve sports performance in athletes. Recent advances in omic tools, such as the lipid profile of the mature erythrocyte membranes (LPMEM), allow to have a comprehensive vision of the nutritional and metabolic status of these individuals to provide personalized recommendations for nutrients, specifically, the essential omega-3 and omega-6 fatty acids, individuating deficiencies/unbalances that can arise from both habitual diet and sportive activity. This work aimed to study the LPMEM in professional female football players during the football season for the first time and compare it with those defined as optimal values for the general population and a control group.

METHODS

An observational study was carried out on female football players from the Athletic Club (Bilbao) playing in the first division of the Spanish league. Blood samples were collected at three points: at the beginning, mid-season, and end of the season for three consecutive seasons (2019-2020, 2020-2021, and 2021-2022), providing a total of 160 samples from 40 women. The LPMEM analysis was obtained by GC-FID by published method and correlated to other individual data, such as blood biochemical parameters, body composition, and age.

RESULTS

We observed a significant increase in docosahexaenoic acid (DHA) (p 0.048) and total polyunsaturated fatty acid (PUFA) (p 0.021) in the first season. In the second season, we observed a buildup in the membrane arachidonic acid (AA) (p < .001) and PUFA (p < .001) contents when high training accumulated. In comparison with the benchmark of average population values, 69% of the football players showed lower levels of omega-6 dihomo-γ-linolenic acid (DGLA), whereas 88%, 44%, and 81% of the participants showed increased values of AA, eicosapentaenoic acid (EPA), and the ratio of saturated and monounsaturated fatty acids (SFA/MUFA), respectively. Regarding relationships between blood biochemical parameters, body composition, and age with LPMEM, we observed some mild negative correlations, such as AA and SFA/MUFA ratio with vitamin D levels (coefficient = -0.34 p = .0019 and coefficient = -.25 p = .042); DGLA with urea and cortisol (coefficient = -0.27 p < .006 and coefficient = .28 p < .0028) and AA with age (coefficient = -0.33 p < .001).

CONCLUSION

In conclusion, relevant variations in several fatty acids of the membrane fatty acid profile of elite female football players were observed during the competitive season and, in comparison with the general population, increased PUFA contents were confirmed, as reported in other sportive activities, together with the new aspect of DGLA diminution, an omega-6 involved in immune and anti-inflammatory responses. Our results highlight membrane lipidomics as a tool to ascertain the molecular profile of elite female football players with a potential application for future personalized nutritional strategies (diet and supplementation) to address unbalances created during the competitive season.

Genomic signaling of vitamin D

It took several hundred million years of evolution, in order to develop the endocrine vitamin D signaling system, which is formed by a nuclear receptor, the transcription factor VDR (vitamin D receptor), its ligand, the vitamin D3 metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and several metabolizing enzymes and transport proteins. Even within the nuclear receptor superfamily the affinity of VDR for 1,25(OH)2D3 is outstandingly high (KD = 0.1 nM). The activation of VDR by 1,25(OH)2D3 is the core mechanism of genomic signaling of vitamin D3, which results in the modulation of the epigenome at thousands of promoter and enhancer regions as well as finally in the activation or repression of hundreds of target gene transcription. In addition, rapid non-genomic actions of vitamin D are described, which are mechanistically far less understood. The main function of vitamin D is to keep the human body in homeostasis. This implies the control of calcium levels, which is essential for bone mineralization, as well as for pushing of innate immunity to react sufficiently strong to microbe infection and preventing overreactions of adaptive immunity, i.e., not to cause autoimmune diseases. This review will discuss whether genomic signaling is sufficient for explaining all physiological functions of vitamin D3.

Linking Mechanisms of Vitamin D Signaling with Multiple Sclerosis

Environmental triggers often work via signal transduction cascades that modulate the epigenome and transcriptome of cell types involved in the disease process. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system being characterized by a combination of recurring inflammation, demyelination and progressive loss of axons. The mechanisms of MS onset are not fully understood and genetic variants may explain only some 20% of the disease susceptibility. From the environmental factors being involved in disease development low vitamin D levels have been shown to significantly contribute to MS susceptibility. The pro-hormone vitamin D3 acts via its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) as a high affinity ligand to the transcription factor VDR (vitamin D receptor) and is a potent modulator of the epigenome at thousands of genomic regions and the transcriptome of hundreds of genes. A major target tissue of the effects of 1,25(OH)2D3 and VDR are cells of innate and adaptive immunity, such as monocytes, dendritic cells as well as B and T cells. Vitamin D induces immunological tolerance in T cells and reduces inflammatory reactions of various types of immune cells, all of which are implicated in MS pathogenesis. The immunomodulatory effects of 1,25(OH)2D3 contribute to the prevention of MS. However, the strength of the responses to vitamin D3 supplementation is highly variegated between individuals. This review will relate mechanisms of individual's vitamin D responsiveness to MS susceptibility and discuss the prospect of vitamin D3 supplementation as a way to extinguish the autoimmunity in MS.

The Association between Vitamin D, Interleukin-4, and Interleukin-10 Levels and CD23+ Expression with Bronchial Asthma in Stunted Children

Children with stunted growth have an increased risk of wheezing, and studies have shown that low levels of vitamin D and interleukin (IL)-10, along with increased IL-4 levels and CD23+ expression, are present in stunted and asthmatic children. To date, it is not known whether these factors are related to the incidence of asthma in stunted children. This case-control study investigated the association between vitamin D, IL-4, and IL-10 levels and CD23+ expression with bronchial asthma in stunted children. The study included 99 children aged 24-59 months, i.e., 37 stunted-sthmatic children (cases), 38 stunted children without asthma, and 24 non-stunted children with asthma. All children were tested for their 25(OH)D levels using chemiluminescent immunoassay (CLIA), IL-4 and IL-10 levels were measured through enzyme-linked immunosorbent assay (ELISA) testing, and CD23+ expression was measured through flow cytometry bead testing. The data were analyzed using chi-squared, Kruskal-Wallis, and Mann-Whitney tests. The results showed that stunted asthmatic children had a higher incidence of atopic family members than those without asthma. Additionally, stunted asthmatic children had a higher prevalence of vitamin D deficiency (48.6%) than the control group (44.7% and 20.8%). Furthermore, stunted asthmatic children had significantly lower levels of 25(OH)D [20.55 (16.18-25.55), p = 0.042] and higher levels of IL-4 [1.41 (0.95-2.40), p = 0.038], although there were no significant differences in IL-10 levels and CD23+ expression. The study concluded that low vitamin D and high IL-4 levels are associated with bronchial asthma in stunted children, while IL-10 and CD23+ do not show a significant association.

Intervention Approaches in Studying the Response to Vitamin D3 Supplementation

Vitamin D intervention studies are designed to evaluate the impact of the micronutrient vitamin D3 on health and disease. The appropriate design of studies is essential for their quality, successful execution, and interpretation. Randomized controlled trials (RCTs) are considered the "gold standard" for intervention studies. However, the most recent large-scale (up to 25,000 participants), long-term RCTs involving vitamin D3 did not provide any statistically significant primary results. This may be because they are designed similarly to RCTs of a therapeutic drug but not of a nutritional compound and that only a limited set of parameters per individual were determined. We propose an alternative concept using the segregation of study participants into different groups of responsiveness to vitamin D3 supplementation and in parallel measuring a larger set of genome-wide parameters over multiple time points. This is in accordance with recently developed mechanistic modeling approaches that do not require a large number of study participants, as in the case of statistical modeling of the results of a RCT. Our experience is based on the vitamin D intervention trials VitDmet, VitDbol, and VitDHiD, which allowed us to distinguish the study participants into high, mid, and low vitamin D responders. In particular, investigating the vulnerable group of low vitamin D responders will provide future studies with more conclusive results both on the clinical and molecular benefits of vitamin D3 supplementation. In conclusion, our approach suggests a paradigm shift towards detailed investigations of transcriptome and epigenome-wide parameters of a limited set of individuals, who, due to a longitudinal design, can act as their own controls.

Dietary vitamin D intake and sun exposure are not associated with type 1 diabetic schoolchildren and adolescents: A first report in Algeria

BACKGROUND: A large number of children and adolescents worldwide suffer from physiological vitamin D (VD) deficiency, which has been associated with sun exposure and, consequently, the risk of developing various autoimmune diseases, including type 1 diabetes (T1D). However, the association of the disease with VD intake and sun exposure has yet to be explored. MATERIALS AND METHODS: We conducted a food frequency questionnaire and a 24-hour food recall survey, using “Ciqual table 2016” in 335 type 1 diabetic and age- and gender-matched healthy Algerian school children and adolescents from sunny Saharan and relatively less sunny Northern regions, aged between 5 and 19 years. RESULTS: Both dietary VD intake and VD levels were similar in T1D patients when comparing northern and southern regions (for both comparisons, p > 0.05). Neither sun exposure nor VD intake was associated with the disease (respectively, relative risk [RR] = 1.050, p = 0.680; RR = 1.082, p = 1.000. For Cochran and Mantel-Haenszel analysis; RR = 0.841, p = 0.862). VD intake showed a significant difference between diabetics and non-diabetics in the sunny region (p = 0.022). Additionally, significant differences were found between normal and T1D schoolboys (p = 0.038), and when comparing the two groups according to the dry areas (p = 0.016). Moreover, in contrast to circulating VD levels, which were lower in T1D patients than in healthy controls, those of VD intake were significantly higher (p < 0.05), especially in male patients and in those with balanced diet, low protein or carbohydrate consumption, specific food intolerances, and regular meals (p < 0.05), as well as in patients with a moderate or low consumption of cooked meals or steamed foods (p < 0.01). Conversely, VD intake was markedly lower in type 1 diabetics than in controls for dry and sunny areas, including the region of Adrar, as well as for consumption of low-fat foods and eggs (p < 0.05 for all comparisons). Nevertheless, the relative risk of sun exposure and dietary vitamin D intake according to the World Health Organization (WHO) standard did not show a significant association with T1D (common Mantel-Haenszel estimation, RR = 0.841, 95% CI 0.118–5.973, p > 0.05). CONCLUSIONS: T1D does not appear to be associated with VD intake and sun exposure in the Algerian Sahara region. Therefore, the consumption of VD in T1D patients in the Algerian Sahara would suspect that its association with the disease would be related to its synthesis alteration.

Vitamin D supplementation for depression in older adults: a meta-analysis of randomized controlled trials

Background

In older adults, depression is associated with several other clinical problems such as cognitive impairment and low quality of life. Several studies have evaluated the relationship between vitamin D and depression in older adults; however, the results have been controversial thus far.

Objective

This study aimed to investigate the effects of vitamin D supplementation on depressive symptom improvement among individuals aged ≥60 years with or without a diagnosis of depression or depressive symptoms based on a meta-analysis of randomized controlled trials (RCTs).

Methods

RCTs were identified to analyze the relationship between vitamin D supplementation and depressive symptoms. MEDLINE, CENTRAL, Embase, and PsycINFO were systematically searched for relevant articles published from inception to November 2022. RCTs that evaluated the effect of vitamin D supplementation in participants aged ≥60 years compared to placebo were included. A random effects model was used in this meta-analysis because of the differences between the included RCTs. The quality of the RCTs was assessed using Risk of Bias 2.

Results

Seven trials were included in the analyses. The primary outcome of pre-post score changes included five trials with a total of 752 participants. The secondary outcome of post-intervention score included all seven trials with a total of 4,385 participants. No significant improvement in depressive symptoms in either pre-post score changes [standardized mean difference (SMD) = -0.49; 95% confidence interval (CI) -1.07-0.09; p = 0.10] or post-intervention score (SMD = -0.10; 95% CI -0.28-0.07; p = 0.25) was found.

Conclusion

Vitamin D supplementation in older adults was not associated with an improvement in depressive symptoms. More studies in older adults are needed to evaluate the association between vitamin D supplementation and depression.

Vitamin D: A master example of nutrigenomics

Nutrigenomics attempts to characterize and integrate the relation between dietary molecules and gene expression on a genome-wide level. One of the biologically active nutritional compounds is vitamin D₃, which activates via its metabolite 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) the nuclear receptor VDR (vitamin D receptor). Vitamin D₃ can be synthesized endogenously in our skin, but since we spend long times indoors and often live at higher latitudes where for many winter months UV-B radiation is too low, it became a true vitamin. The ligand-inducible transcription factor VDR is expressed in the majority of human tissues and cell types, where it modulates the epigenome at thousands of genomic sites. In a tissue-specific fashion this results in the up- and downregulation of primary vitamin D target genes, some of which are involved in attenuating oxidative stress. Vitamin D affects a wide range of physiological functions including the control of metabolism, bone formation and immunity. In this review, we will discuss how the epigenome- and transcriptome-wide effects of 1,25(OH)₂D₃ and its receptor VDR serve as a master example in nutrigenomics. In this context, we will outline the basis of a mechanistic understanding for personalized nutrition with vitamin D₃.

Vitamin D in pediatric age: Current evidence, recommendations, and misunderstandings

In recent years vitamin D has been in the spotlight of many researchers for its possible role in various disorders, including autoimmune and infectious diseases. Even if vitamin D deficiency remains a major public health problem, its symptomatic manifestations are less and less common in clinical practice, and pediatric age represents a “gray area” where vitamin D supplementation is often administered in the absence of an effective evaluation of its status. Moreover, a poor knowledge about different definitions of “deficiency,” “insufficiency,” and similar terms is spread among clinicians, while guidelines are not univocal, especially after the first year of life. The aim of this brief opinion paper is to sum up recent evidence about vitamin D status and its supplementation in pediatrics, in order to better clarify a common definition of its deficiency. The aim of this opinion article is to raise awareness on this topic among clinicians and encourage a discussion on the real need for routine 25-hydroxycholecalciferol serum evaluation and its supplementation.

An overview of CYP27B1 enzyme mutation and management: A case report and review of the literature

Vitamin D-dependent rickets type 1 (VDDRIA) is an autosomal recessive disorder caused by mutations in the Cytochrome P450 Family 27 Subfamily B Member 1 (CYP27B1) gene, which encodes for the enzyme 1 alpha-hydroxylase. We report a known case of VDDRIA with hypotonia, growth and developmental disorders and discuss about the mutation and its management.

Vitamin D as a Shield against Aging

Aging can be seen as a physiological progression of biomolecular damage and the accumulation of defective cellular components, which trigger and amplify the process, toward whole-body function weakening. Senescence initiates at the cellular level and consists in an inability to maintain homeostasis, characterized by the overexpression/aberrant expression of inflammatory/immune/stress responses. Aging is associated with significant modifications in immune system cells, toward a decline in immunosurveillance, which, in turn, leads to chronic elevation of inflammation/oxidative stress, increasing the risk of (co)morbidities. Albeit aging is a natural and unavoidable process, it can be regulated by some factors, like lifestyle and diet. Nutrition, indeed, tackles the mechanisms underlying molecular/cellular aging. Many micronutrients, i.e., vitamins and elements, can impact cell function. This review focuses on the role exerted by vitamin D in geroprotection, based on its ability to shape cellular/intracellular processes and drive the immune response toward immune protection against infections and age-related diseases. To this aim, the main biomolecular paths underlying immunosenescence and inflammaging are identified as biotargets of vitamin D. Topics such as heart and skeletal muscle cell function/dysfunction, depending on vitamin D status, are addressed, with comments on hypovitaminosis D correction by food and supplementation. Albeit research has progressed, still limitations exist in translating knowledge into clinical practice, making it necessary to focus attention on the role of vitamin D in aging, especially considering the growing number of older individuals.

Effects of Vitamin D on Satellite Cells: A Systematic Review of In Vivo Studies

The non-classical role of vitamin D has been investigated in recent decades. One of which is related to its role in skeletal muscle. Satellite cells are skeletal muscle stem cells that play a pivotal role in skeletal muscle growth and regeneration. This systematic review aims to investigate the effect of vitamin D on satellite cells. A systematic search was performed in Scopus, MEDLINE, and Google Scholar. In vivo studies assessing the effect of vitamin D on satellite cells, published in English in the last ten years were included. Thirteen in vivo studies were analyzed in this review. Vitamin D increases the proliferation of satellite cells in the early life period. In acute muscle injury, vitamin D deficiency reduces satellite cells differentiation. However, administering high doses of vitamin D impairs skeletal muscle regeneration. Vitamin D may maintain satellite cell quiescence and prevent spontaneous differentiation in aging. Supplementation of vitamin D ameliorates decreased satellite cells' function in chronic disease. Overall, evidence suggests that vitamin D affects satellite cells' function in maintaining skeletal muscle homeostasis. Further research is needed to determine the most appropriate dose of vitamin D supplementation in a specific condition for the optimum satellite cells' function.

25-Hydroxyvitamin D Serum Levels Linked to Single Nucleotide Polymorphisms (SNPs) (rs2228570, rs2282679, rs10741657) in Skeletal Muscle Aging in Institutionalized Elderly Men Not Supplemented with Vitamin D

Sarcopenia (Sp) is the loss of skeletal muscle mass associated with aging that results in an involution of muscle function and strength. Vitamin D deficiency is a common health problem worldwide, especially among the elderly, and hypovitaminosis D leads to musculoskeletal disorders. The aim of this study was to evaluate the impact and presence of a possible linkage between Single Nucleotide Polymorphisms (SNPs) CYP2R1 (rs10741657), GC (rs2282679), and VDR (rs2228570), serum 25-OH/D concentrations and the link with the degree of sarcopenia in 19 institutionalized elderly men not supplemented with vitamin D. Levels of 25-OH vitamin D were quantified with a commercial enzyme-linked immunosorbent assay kit and 3 SNPs were genotyped with KASPar assays. Significant differences in 25-OH/D concentration were determined between the bi-allelic combinations of rs228679 and rs228570. We detected statistically significant weak positive correlations between the AA (rs10741657 and rs228570) and TT (rs228679) and alleles and 25-OH/D and the probability of having higher 25-OH/D concentrations was 2- to 3-fold higher. However, the GG alleles of the 3 SNPs showed that the probability of having optimal 25-0H/D concentrations decreases by 32% for rs10741657, 38% for rs228679, and 74% for rs228570, showing a strong negative correlation between the degree of sarcopenia and 25-OH/D levels. Allelic variations in CYP2R1 (rs10741657), GC (rs2282679), and VDR (rs10741657) affect vitamin D levels and decisively influence the degree of sarcopenia in institutionalized elderly people.

The status of depression literacy and its relationship with quality of life among Iranian public population: a cross sectional study

BACKGROUND

This study was designed and conducted to determine the status of depression literacy (D-Lit) and its relationship with the quality of life across the Iranian population.

METHODS

This cross-sectional study was conducted in 2020 among 1382 participating from the general population in Gonabad, Iran. Participants were selected and recruited using a multistage sampling method. Data were collected using three sets of questionnaires (demographic section, D-Lit scale, and quality of life questionnaire). Data were analyzed by SPSS software version 24 and using independent samples t- test, Chi-square test, One-way ANOVA, and Pearson correlation.

RESULTS

Based on the results, the mean (± standard deviation) of D-Lit and quality of life were 44.14 (± 4.69) and 35.81 (± 5.17), respectively. Based on the results of Pearson correlation coefficient, there was a significant positive correlation between D-Lit and quality of life (r = 0.104, p < 0.001). D-Lit was significantly higher in those who reported having consulted with a psychiatrist compared with those who did not (p < 0.001). Participants with a family history of mental illness and those whose family members were referred to a psychologist for psychological issues had significantly higher levels of D-Lit than others (p < 0.001).

CONCLUSION

Based on the results of this study, some D-Lit projects should be improved. Also, the results revealed that D-Lit is a potential factor that can affect people's mental health status and enhance their quality of life. Therefore, it is necessary to develop appropriate educational programs to enhance D-Lit in the community and ultimately improve the quality of life in the community by reducing mental illness.

Spatial distribution of vitamin A rich foods intake and associated factors among children aged 6-23 months in Ethiopia: spatial and multilevel analysis of 2019 Ethiopian mini demographic and health survey

Background

Inadequate micronutrients in the diet and vitamin A deficiency are worldwide public health problems. In developing regions, many preschool children are undernourished, become blind every year and died before the age of 23 months. This study was aimed to explore the spatial distribution of vitamin A rich foods intake among children aged 6–23 months and identify associated factors in Ethiopia.

Methods

Ethiopian Mini Demographic and Health Survey 2019 dataset with a total 1407 children aged 6–23 months was used. Data management and processing were done using STATA version 15 software and Microsoft Office Excel. ArcMap version 10.7 software was used for mapping and spatial visualization of the distribution. Spatial scan statistics was performed using SaTScan version 9.5 software for Bernoulli-based model. Multilevel mixed effect logistic regression model was employed to identify associated factors.

Results

Overall, 38.99% (95% CI: 36.46–41.62) of children aged 6– 23 months took vitamin A rich foods. Poor intake of vitamin A rich foods was significantly clustered Dire Dawa city, Somali and Harari regions of Ethiopia. Children aged 6–23 months lived in the primary cluster were 70% (RR = 1.70, P-value < 0.001) more likely to intake vitamin A rich foods than children lived outside the window. In the multilevel mixed effect logistic regression analysis, Primary educational status (AOR:1.42, 95% CI: 1.05, 1.93) and higher educational status (AOR:3.0, 95% CI: 1.59, 5.65) of mother, Dire Dawa (AOR:0.49, 95% CI: 0.22, 1.12) city, Afar (AOR: 0.16, 95% CI: 0.07, 0.36), Amhara (AOR: 0.37, 95% CI: 0.19, 0.71) and Somali (AOR: 0.02, 95% CI: 0.003, 0.08) regions of Ethiopia, children aged 13–23 months (AOR: 1.80, 95% CI: 1.28, 2.36), Mothers’ exposure to media (AOR: 1.41, 95% CI: 1.04, 1.92) were statistically significant factors for vitamin A rich foods intake among children aged 6–23 months.

Conclusions

Only 4 out of ten children took vitamin A rich foods which is too low compared to the national target and significantly clustered in Ethiopia. Mother’s educational status, Region, Child age and Mother’s media exposure are significant factors vitamin A rich foods intake. Stakeholders should strengthen mothers’ education status, creating awareness for mothers on child feeding and using locally available natural resource to produce vitamin A rich foods.

Nutritional rickets and vitamin D deficiency: consequences and strategies for treatment and prevention

INTRODUCTION

Rickets is typically characterized by bone deformities due to defective bone mineralization and chondrocyte maturation in growing bones. However, infantile rickets often goes unrecognized, because the skeletal abnormalities are more subtle and often can only be detected radiologically. Nutritional rickets is a major public health concern in several regions worldwide. It is most commonly caused by vitamin D and/or calcium deficiency.

AREA COVERED

We provide an overview of historical perspective, epidemiology, and pathophysiology of nutritional rickets. Additionally, we outline diagnostic approaches and highlight challenges in radiographic diagnosis of rickets. Finally, we present strategies for prevention and treatment of rickets.

EXPERT OPINION

Despite the evidence from clinical databases that rickets is a rare disease, it is likely that rickets is clinically underdiagnosed as studies designed to screen healthy children for radiographic evidence of rickets reported surprisingly much higher prevalence. It has been reported that some of the radiologic features of rickets can be misinterpreted as fractures. To prevent nutritional rickets, most if not all infants and young children, should receive vitamin D from formulas and foods that are fortified with vitamin D or supplementation to achieve a serum 25-hydroxyvitamin D of at least 20 ng/mL as recommended by the Institute of Medicine. It has been recommended by the Endocrine Society that to achieve maximum bone health for children and adults, a serum concentration of 25-hydroxyvitamin D should be at least 30 ng/mL and preferably 40-60 ng/mL. Pregnant women who are unable to obtain an adequate amount of vitamin D from sunlight exposure and natural and fortified diets should take a vitamin D supplement of 1500-2000 IUs daily as recommended by the Endocrine Society since it has been demonstrated that 600 IUs daily will not maintain a circulating 25-hydroxyvitamin D of at least 20 ng/mL and most pregnant women. If lactating women take approximately 6400 IUs of vitamin D daily, they provide enough vitamin D in their milk to satisfy their infant's requirement thereby preventing rickets.

Gene-Regulatory Potential of 25-Hydroxyvitamin D3 and D2

Human peripheral blood mononuclear cells (PBMCs) represent a highly responsive primary tissue that is composed of innate and adaptive immune cells. In this study, we compared modulation of the transcriptome of PBMCs by the vitamin D metabolites 25-hydroxyvitamin D₃ (25(OH)D₃), 25(OH)D₂ and 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃). Saturating concentrations of 1,25(OH)₂D₃, 25(OH)D₃ and 25(OH)D₂ resulted after 24 h stimulation in a comparable number and identity of target genes, but below 250 nM 25(OH)D₃ and 25(OH)D₂ were largely insufficient to affect the transcriptome. The average EC₅₀ values of 206 common target genes were 322 nM for 25(OH)D₃ and 295 nM for 25(OH)D₂ being some 600-fold higher than 0.48 nM for 1,25(OH)₂D₃. The type of target gene, such as primary/secondary, direct/indirect or up-/down-regulated, had no significant effect on vitamin D metabolite sensitivity, but individual genes could be classified into high, mid and lower responders. Since the 1α-hydroxylase CYP27B1 is very low expressed in PBMCs and early (4 and 8 h) transcriptome responses to 25(OH)D₃ and 25(OH)D₂ were as prominent as to 1,25(OH)₂D₃, both vitamin D metabolites may directly control gene expression. In conclusion, at supra-physiological concentrations 25(OH)D₃ and 25(OH)D₂ are equally potent in modulating the transcriptome of PBMCs possibly by directly activating the vitamin D receptor.

Impulsivity and eating disorders: The relationship between serum 25-hydroxyvitamin D and different impulsivity facets in a transdiagnostic sample

OBJECTIVES

Eating disorders (EDs) are severe psychiatric conditions characterised by malnutrition, dysfunctional behaviours, and hypovitaminosis D. In various psychiatric conditions, including EDs, preliminary evidence has correlated impulsivity to a low level of 25-hydroxyvitamin D [25(OH)D]. This study aims to reinforce this evidence by examining different facets, both behavioural and psychological, of the impulsivity construct in patients with ED.

METHODS

A sample of 119 women was evaluated with a validated questionnaire and computerised neuropsychological tasks: the UPPS-P impulsive behaviour scale, a go/no-go task, and the Balloon Analogue Risk Task (BART). A clinical evaluation for EDs and blood sample collection were also performed to assess specific psychopathology and determine the serum level of 25(OH)D.

RESULTS

Significant correlations were found between serum levels of 25(OH)D and BART scores (p = 0.012) and lack of perseverance (p = 0.034). Moreover, regression analyses showed that higher BART scores may be explained by hypovitaminosis D and higher levels of lack of perseverance in patients with EDs.

CONCLUSIONS

The specific aspect of impulsivity linked to goal strategy and behaviours may be explained in patients with EDs by hypovitaminosis D. A possible connection to the brain inflammatory system is also discussed, along with possible directions for future research.

Different Vitamin D Supplementation Strategies in the First Years of Life: A Systematic Review

Vitamin D (VD) is an essential micronutrient with multiple functions for human growth, and adequate intake should be guaranteed throughout life. However, VD insufficiency is observed in infants all over the world. Low VD concentration in the breast milk of non-supplemented mothers and low compliance to VD daily supplementation are the main causes of VD insufficiency, especially in the long term. Furthermore, VD supplementation dosages are still debated and differ by country. We conducted a systematic review to compare the most recent evidence on different postnatal VD supplementation strategies, determining whether supplementation given to the mother is as effective as that administered directly to the child, and whether different dosages and administration schedules differ significantly in terms of efficacy and safety. We identified 18 randomized controlled trials (RCTs) addressing the role of infant (n = 961), maternal (n = 652) or combined infant and maternal VD supplementation (n = 260 pairs). In all studies, similar outcomes emerged in terms of efficacy and safety. According to our findings, alternative approaches of VD supplementation may be adopted, especially in cases where the adherence to daily supplementation strategies is poor. This review shows that different dosages and supplementation strategies result in similar VD sufficiency rates. Therefore, international guidelines may be revised in the future to offer multiple and different options of supplementation for specific settings and ages.

Dietary Intake and Genetic Background Influence Vitamin Needs during Pregnancy

Numerous approaches demonstrate how nutritional intake can be sufficient to ensure the necessary supply of vitamins. However, it is evident that not all vitamins are contained in all foods, so it is necessary either to combine different food groups or to use a vitamin supplement to be well-fed. During pregnancy, deficiencies are often exacerbated due to increased energy and nutritional demands, causing adverse outcomes in mother and child. Micronutrient supplementation could lead to optimal pregnancy outcomes being essential for proper metabolic activities that are involved in tissue growth and functioning in the developing fetus. In order to establish adequate vitamin supplementation, various conditions should be considered, such as metabolism, nutrition and genetic elements. This review accurately evaluated vitamin requirements and possible toxic effects during pregnancy. Much attention was given to investigate the mechanisms of cell response and risk assessment of practical applications to improve quality of life. Importantly, genetic studies suggest that common allelic variants and polymorphisms may play an important role in vitamin metabolism during pregnancy. Changes in gene expression of different proteins involved in micronutrients’ metabolism may influence the physiological needs of the pregnant woman.

Effects of Vitamin D Levels on Cardiovascular Diseases: A Systematic Review

Background:

Cardiovascular diseases (CVDs) are a group of pathologies that involve heart and blood vessel disorders and are considered the main cause of death in the world. Epidemiological studies have shown the association between low vitamin D (VD) levels and CVD. This vitamin, in addition to acting on bone metabolism, plays a role in modulating the cardiovascular system.

Objective:

The present study assesses the effects of VD levels on CVD through a systematic literature review.

Method:

For this purpose, the PICO strategy was used to prepare the guiding question, and articles were searched in the PubMed, Scopus, Science Direct, and Web of Science databases by two authors independently. To guarantee the quality of the evidence of the articles included in the review, the Newcastle-Ottawa scale was used. The literature review followed the PRISMA recommendations.

Results:

In this review, 22,757 articles were identified, but only 10 were considered eligible, of which 70% are prospective cohorts and 30% are retrospective cohorts. The study showed that low 25(OH)D levels correlate with an increased risk of cardiovascular events and death from CVD, including in patients who had preexisting CVD. However, one article did not demonstrate this association.

Conclusion:

As a result, VD correlates with cardiovascular events and the risk of death.

Time-Resolved Gene Expression Analysis Monitors the Regulation of Inflammatory Mediators and Attenuation of Adaptive Immune Response by Vitamin D

Peripheral blood mononuclear cells (PBMCs) belong to the innate and adaptive immune system and are highly sensitive and responsive to changes in their systemic environment. In this study, we focused on the time course of transcriptional changes in freshly isolated human PBMCs 4, 8, 24 and 48 h after onset of stimulation with the active vitamin D metabolite 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃). Taking all four time points together, 662 target genes were identified and segregated either by time of differential gene expression into 179 primary and 483 secondary targets or by driver of expression change into 293 direct and 369 indirect targets. The latter classification revealed that more than 50% of target genes were primarily driven by the cells' response to ex vivo exposure than by the nuclear hormone and largely explained its down-regulatory effect. Functional analysis indicated vitamin D's role in the suppression of the inflammatory and adaptive immune response by down-regulating ten major histocompatibility complex class II genes, five alarmins of the S100 calcium binding protein A family and by affecting six chemokines of the C-X-C motif ligand family. Taken together, studying time-resolved responses allows to better contextualize the effects of vitamin D on the immune system.

Vitamin D and Pigmented Skin

The default supply of vitamin D₃ to humans is its endogenous production in UV-B-exposed skin [...].

Prenatal maternal and cord blood vitamin D concentrations and negative affectivity in infancy

Higher maternal vitamin D concentration during pregnancy is associated with better child mental health. Negative affectivity, an early-emerging temperamental trait, indicates an increased risk of psychopathology. We investigated if maternal early/mid-pregnancy 25-hydroxyvitamin D (25(OH)D) and neonatal cord blood 25(OH)D concentrations are associated with Negative affectivity in infancy. We studied term-born infants from the vitamin D Intervention in Infants study (VIDI, n = 777, follow-up rate 80%, Finland), and the Generation R Study (n = 1505, follow-up rate 40%, Netherlands). We measured maternal serum 25(OH)D at 6-27 weeks (VIDI) or 18-25 weeks (Generation R) of pregnancy, and cord blood 25(OH)D at birth (both cohorts). Caregivers rated infant Negative affectivity at 11.7 months (VIDI) or 6.5 months (Generation R) using the Revised Infant Behavior Questionnaire. Using linear regression, we tested associations between 25(OH)D and Negative affectivity adjusted for infant age, sex, season of 25(OH)D measurement, maternal age, education, smoking, and body-mass-index. Per 10 nmol/l increase in maternal early/mid-pregnancy 25(OH)D, infant Negative affectivity decreased by 0.02 standard deviations (95% confidence interval [CI] - 0.06, - 0.004) in VIDI, and 0.03 standard deviations (95% CI - 0.03, - 0.01) in Generation R. Cord blood 25(OH)D was associated with Negative affectivity in Generation R (- 0.03, 95% CI - 0.05, - 0.01), but not VIDI (0.00, 95% CI - 0.02, 0.02). Lower maternal 25(OH)D concentrations were consistently associated with higher infant Negative affectivity, while associations between cord blood 25(OH)D concentrations and Negative affectivity were less clear. Maternal vitamin D status during early- and mid-pregnancy may be linked with early-emerging differences in offspring behavior.

Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations

Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.

Vitamin D and COVID-19: A review on the role of vitamin D in preventing and reducing the severity of COVID-19 infection

Severe Acute Respiratory Syndrome Coronavirus‐2 (SARS‐CoV‐2) is a pathogenic coronavirus causing COVID‐19 infection. The interaction between the SARS‐CoV‐2 spike protein and the human receptor angiotensin‐converting enzyme 2, both of which contain several cysteine residues, is impacted by the disulfide‐thiol balance in the host cell. The host cell redox status is affected by oxidative stress due to the imbalance between the reactive oxygen/nitrogen species and antioxidants. Recent studies have shown that Vitamin D supplementation could reduce oxidative stress. It has also been proposed that vitamin D at physiological concentration has preventive effects on many viral infections, including COVID‐19. However, the molecular‐level picture of the interplay of vitamin D deficiency, oxidative stress, and the severity of COVID‐19 has remained unclear. Herein, we present a thorough review focusing on the possible molecular mechanism by which vitamin D could alter host cell redox status and block viral entry, thereby preventing COVID‐19 infection or reducing the severity of the disease.

Vitamin D Deficiency, Osteoporosis and Effect on Autoimmune Diseases and Hematopoiesis: A Review

Vitamin D (VD) is essential for bone homeostasis, but it is also involved in pleiotropic effects on various organs and tissues. In adults, VD deficiency can cause or exacerbate osteoporosis and induce osteomalacia. However, every tissue and cell in the body has a VD receptor, including the brain, heart, stomach, pancreas, skin, gonads, and immune cells, and a deficiency may modify the function of these organs. Thus, the wide-ranging actions of VD help to explain why a reduction in VD amount has been correlated with numerous chronic diseases. In fact, VD deficiency increases the risk of osteoporosis and several other diseases and complications characterized by impaired bone metabolisms, such as autoimmune diseases, inflammatory bowel diseases, allergy, endocrinological diseases, hematological malignancies, and bone marrow transplantation. This review aims to investigate the link between VD deficiency, osteoporosis, and its concomitant diseases. Further epidemiological and mechanistic studies are necessary in order to ascertain the real role of hypovitaminosis in causing the reported diseases; however, adequate vitamin supplementation and restoration of metabolic normality could be useful for better management of these pathologies.

Vitamin D and the risk for cancer: A molecular analysis

Uncontrolled overgrowth of cells, such as in cancer, is an unavoidable risk in life that affects nearly every second individual in industrialized countries. However, in part this risk can be controlled through lifestyle adjustments, such as the avoidance of smoking, unhealthy diet, obesity, physical inactivity and other cancer risk factors. A low vitaminD status is a risk in particular for cancers of colon, prostate, breast and leukocytes. VitaminD₃ is produced non-enzymatically, when the cholesterol precursor 7-dehydrocholesterol is exposed to UV-B from sunlight, i.e., all cholesterol synthesizing species, including humans, can make vitaminD₃. VitaminD endocrinology started some 550million years ago, when the metabolite 1α,25-dihydroxyvitaminD₃ and the transcription factor vitaminD receptor teamed up for regulating the expression of hundreds of target genes in a multitude of different tissues and cell types. Initially, these genes were focused on the control of energy homeostasis, which later also involved energy-demanding innate and adaptive immunity. Rapidly growing cells of the immune system as well as those of malignant tumors rely on comparable genes and pathways, some of which are modulated by vitaminD. Accordingly, vitaminD has anti-cancer effects both directly via controling the differentiation, proliferation and apoptosis of neoplastic cells as well as indirectly through regulating immune cells that belong to the microenvironment of malignant tumors. This review discusses effects of vitaminD on the epigenome and transcriptome of stromal and tumor cells, inter-individual variations in vitaminD responsiveness and their relation to the prevention and possible therapy of cancer.

Associations of Vitamin D Levels with Physical Fitness and Motor Performance; A Cross-Sectional Study in Youth Soccer Players from Southern Croatia

Simple Summary

Vitamin D is a fat-soluble prohormone crucial for bone mineralization, muscle contractility, and neurological conductivity. It is theorized that Vitamin D plays an important role in sport performances, especially in young athletes. In this study we examined the associations of levels of 25-hydroxyvitamin D (25(OH)D) with physical fitness and motor-performance achievements in youth soccer players from Southern Croatia. Participants were tested on physical fitness, motor performance and vitamin D at the end of the winter period, when levels of vitamin D are known to be lowest due to low exposure to sunlight. Results showed that deficiency of 25(OH)D was widespread among youth soccer players living in Southern Croatia. Low 25(OH)D levels were associated with lower results in fitness tests (i.e., tests of energetic capacities), but there was no correlation between 25(OH)D levels and the results in motor performance tests (i.e., skill tests). Our results support the theory of the association between vitamin D and energetic capacities of athletes, but there is no evidence on association between vitamin D and skill-based capacities.

Abstract

Vitamin D level is known to be a factor potentially influencing physical fitness, but few studies have examined this phenomenon among youth athletes. We aimed to evaluate the associations of vitamin D levels (as measured by 25-hydroxyvitamin D concentrations—25(OH)D) with various physical fitness and motor performance tests in youth football (soccer) players. This cross-sectional study included a total of 52 youth soccer players (15.98 ± 2.26 years old) from Southern Croatia. The participants were evaluated at the end of the winter period and data were collected of anthropometric measures (body mass and body height), vitamin D status (25(OH)D levels), physical fitness tests (sprints of 10 and 20 m, 20 yards test, the countermovement jump, the reactive strength index (RSI)) and motor performance tests (the soccer-specific CODS, the soccer-specific agility, and static balance). Among the studied players, 54% had 25(OH)D insufficiency/deficiency, showing a lack of 25(OH)D is widespread even in youth athletes living at a southern latitude. The 25(OH)D level was correlated with sprint 20 m, 20 yards tests, and RSI, showing a greater role of 25(OH)D in physical fitness tests where energetic capacity is essential than in sport-related motor performance tests where skills are crucial. Our results support the idea that vitamin D can play a determinant role in physical fitness tests with a clear physiological component, but is not crucial in motor performance tests related to specific sports where skills are a key component. Future studies should investigate the effects of vitamin D supplementation on the performance in physical fitness and motor performance tests among youth athletes.

The association between vitamin D and uveitis: A comprehensive review

Vitamin D plays an important role in both the innate and adaptive immune systems. We review published data on the relationship between uveitis and vitamin D levels or vitamin D-associated gene polymorphisms. A search of the PubMed and Medline databases was conducted to identify relevant articles concerning vitamin D and uveitis. Sixteen studies were included in this review, and the evidence they present, linking low vitamin D levels with uveitis, is compelling. The uveitic entities shown to be modulated by hypovitaminosis D include, but are not limited to, HLA-B27-associated acute anterior uveitis, Vogt-Koyanagi-Harada (VKH) disease, sarcoidosis-associated uveitis, and juvenile idiopathic arthritis-associated uveitis. Specific polymorphisms of vitamin D family genes were found to correlate with uveitis in ankylosing spondylitis, Behçet's disease, VKH, and HLA B27-positive patients. Further understanding of the role of vitamin D, a known regulator of inflammatory processes, in noninfectious uveitis may advance capabilities in the fields of disease prevention and treatment.

Rickets in Children: An Update

Rickets refers to a deficient mineralization of the growth plate cartilage, predominantly affecting longer bones. Despite the fact that preventive measures are available, it is still a common disease worldwide; nutritional rickets, due to vitamin D deficiency or dietary calcium inadequate intake, remains the most common form. Medical history, physical examination, radiologic features and biochemical tests are essential for diagnosis. Although recent studies suggest hypophosphatemia as the leading alteration, rickets is classically divided into two categories: calcipenic rickets and phosphopenic rickets. Knowledge of this categorization and of respective clinical and laboratory features is essential for rapid diagnosis and correct management. The aim of this review is to analyze the epidemiological, pathogenetic, clinical, and therapeutic aspects of the different forms of rickets, describing the novelties on this “long-lived” disease.

Low Vitamin D Level Is Associated with Acute Deep Venous Thrombosis in Patients with Traumatic Brain Injury

Vitamin D and its association with venous thromboembolism (VTE) have been studied in common rehabilitation populations, such as spinal cord injury and ischemic stroke groups. This study explores the relationship between vitamin D levels and acute deep venous thrombosis (DVT) in the traumatic brain injury (TBI) population. This is a retrospective cohort study that analyzes the relationship between vitamin D levels and the prevalence of DVT during acute inpatient rehabilitation. In this population, 62% (117/190) of patients had low vitamin D levels upon admission to acute rehabilitation. Furthermore, 21% (24/117) of patients in the low vitamin D group had acute DVT during admission to acute rehabilitation. In contrast, only 8% (6/73) of patients in the normal vitamin D group had acute DVT during admission to acute rehabilitation. Fisher’s exact tests revealed significant differences between individuals with low and normal vitamin D levels (p = 0.025). In conclusion, a vitamin D level below 30 ng/mL was associated with increased probability of the occurrence of acute DVT in individuals with moderate–severe TBI.

Compartmentalized Reconstitution of Post-squalene Pathway for 7-Dehydrocholesterol Overproduction in Saccharomyces cerevisiae

7-Dehydrocholesterol (7-DHC) is the direct precursor to manufacture vitamin D₃. Our previous study has achieved 7-DHC synthesis in Saccharomyces cerevisiae based on the endogenous post-squalene pathway. However, the distribution of post-squalene enzymes between the endoplasmic reticulum (ER) and lipid bodies (LD) might raise difficulties for ERG proteins to catalyze and deliver sterol intermediates, resulting in unbalanced metabolic flow and low product yield. Herein, we intended to rearrange the subcellular location of post-squalene enzymes to alleviate metabolic bottleneck and boost 7-DHC production. After identifying the location of DHCR24 (C-24 reductase, the only heterologous protein for 7-DHC biosynthesis) on ER, all the ER-located enzymes were grouped into four modules: ERG1/11/24, ERG25/26/27, ERG2/3, and DHCR24. These modules attempted to be overexpressed either on ER or on LDs. As a result, expression of LD-targeted DHCR24 and ER-located ERG1/11/24 could promote the conversion efficiency among the sterol intermediates to 7-DHC, while locating module ERG2/3 into LDs improved the whole metabolic flux of the post-squalene pathway. Coexpressing LD-targeted ERG2/3 and DHCR24 (generating strain SyBE_Sc01250035) improved 7-DHC production from 187.7 to 308.2 mg/L at shake-flask level. Further expressing ER-targeted module ERG1/11/24 in strain SyBE_Sc01250035 dramatically reduced squalene accumulation from 620.2 mg/L to the lowest level (by 93.8%) as well as improved 7-DHC production to the highest level (to 342.2 mg/L). Then targeting module ERG25/26/27 to LDs further increased 7-DHC titer to 360.6 mg/L, which is the highest shake-flask level production for 7-DHC ever reported. Our study not only proposes and further proves the concept of pathway compartmentalized reconstitution to regulate metabolic flux but also provides a promising chassis to produce other steroidal compounds through the post-squalene pathway.