Physiological significance of vitamin D produced in skin compared with oral vitamin D

Low serum 25-Hydroxy-Vitamin D Levels are associated with Metabolic Syndrome in a representative community population from Macau, China

Asians, especially Chinese have an increasingly high prevalence of vitamin D deficiency and insufficiency (serum 25-hydroxy-vitamin D (25OHD) <30 nmol/L and <50 nmol/L, respectively). This population group also has a high prevalence of cardiometabolic risk factors such as Myocardial Infarction (MI), Metabolic Syndrome (MetS) and low blood levels of high-density lipoproteins (HDL) and high blood levels of triglycerides (TG). The aim of this analysis was to investigate these associations in a population from Macau, China. Blood, anthropometric, and physical data were collected from 1410 randomly selected residents of Macau. In this population, (55% female, 19-89 years) 54% were vitamin D insufficient. Results from categorical multivariate regression analyses (adjusted for age, sex, and hours per day of physical activity, sitting and sunlight exposure) indicated significant two-fold associations between vitamin D insufficiency and prevalence of MI, MetS and low HDL and high TG levels. These associations became stronger when investigated with vitamin D deficiency (25OHD < 30 nmol/L). The association between cardiometabolic factors and vitamin D deficiency in those older (≥60yrs) increased markedly to OR MI=9.48 (2.62-34.32), OR MetS=7.82 (3.31-18.46) and OR low HDL=8.68 (1.56-21.16) and OR high TG=2.37 (1.07-5.25). These interesting observational findings suggest high vulnerability to lower 25OHD levels with related health disparities affecting older Asians. Integration of public health measures to detect vitamin D deficiency and insufficiency in Macau is important, and we suggest that routine health screening including serum 25OHD, HDL and TG in China may be protective for those at higher risk for related cardiometabolic conditions.

A Cost-Effective Nonaqueous Reversed-Phase High-Performance Liquid Chromatography Method to Measure Vitamin D3 in Hen's Egg Yolk

The objective of this study is to develop an HPLC-UV method for the cost-effective and quantitative determination of vitamin D3 in food, even in the presence of vitamin D2, with a specific focus on egg yolk. During method development, the performance of three stationary phases in resolving the peak of vitamin D2 from that of vitamin D3 was investigated. The physicochemical properties of these phases differed particularly in the extent of hydrophobicity and silanophilic activity, including a GraceSmart RP C18 column without silanol endcapping, a Robusta RP C18 column with silanol endcapping, and a Waters Xbridge RP C18 column with ethylene-bridged hybrid (BEH) particle technology. The Xbridge C18 stationary phase exhibited the most favorable performance, leading to an RS of 1.6 under the following nonaqueous reversed-phase (NARP) experimental conditions: mobile phase, acetonitrile, methanol, and trifluoroacetic acid in a (99/1/0.1, v/v/v) ratio; column temperature, 15°C. The developed chromatographic method does not require preanalytical purification steps and is also compatible with mass spectrometry. The identity of the vitamin D3 peak observed in the HPLC analysis was verified via GC-MS. The NARP-HPLC-UV method was partially validated, demonstrating satisfactory linearity, precision, accuracy, limit of quantification, and robustness. The HPLC method was then successfully applied to the analysis of real egg yolk samples, revealing average concentrations of vitamin D3 of 4-5 µg/g of wet weight sample.

UV light exposure versus vitamin D supplementation: A comparison of health benefits and vitamin D metabolism in a pig model

There is limited data on the effect of UV light exposure versus orally ingested vitamin D3 on vitamin D metabolism and health. A 4-week study with 16 pigs (as a model for human physiology) was conducted. The pigs were either supplemented with 20 µg/d vitamin D3 or exposed to UV light for 19 min/d to standardize plasma 25-hydroxyvitamin D3 levels. Important differences were higher levels of stored vitamin D3 in skin and subcutaneous fat, higher plasma concentrations of 3-epi-25-hydroxyvitamin D3 and increases of cutaneous lumisterol3 in UV-exposed pigs compared to supplemented pigs. UV light exposure compared to vitamin D3 supplementation resulted in lower hepatic cholesterol, higher circulating plasma nitrite, a marker of the blood pressure-lowering nitric oxide, and a reduction in the release of pro- and anti-inflammatory cytokines from stimulated peripheral blood mononuclear cells. However, plasma metabolome and stool microbiome analyses did not reveal any differences between the two groups. To conclude, the current data show important health relevant differences between oral vitamin D3 supplementation and UV light exposure. The findings may also partly explain the different vitamin D effects on health parameters obtained from association and intervention studies.

Gut aging: A wane from the normal to repercussion and gerotherapeutic strategies

Globally, age-related diseases represent a significant public health concern among the elderly population. In aging, healthy organs and tissues undergo structural and functional changes that put the aged adults at risk of diseases. Some of the age-related diseases include cancer, atherosclerosis, brain disorders, muscle atrophy (sarcopenia), gastrointestinal (GIT) disorders, etc. In organs, a decline in stem cell function is the starting point of many conditions and is extremely important in GIT disorder development. Many studies have established that aging affects stem cells and their surrounding supportive niche components. Although there is a significant advancement in treating intestinal aging, the rising elderly population coupled with a higher occurrence of chronic gut ailments necessitates more effective therapeutic approaches to preserve gut health. Notable therapeutic strategies such as Western medicine, traditional Chinese medicine, and other health-promotion interventions have been reported in several studies to hold promise in mitigating age-related gut disorders. This review highlights findings across various facets of gut aging with a focus on aging-associated changes of intestinal stem cells and their niche components, thus a deviation from the normal to repercussion, as well as essential therapeutic strategies to mitigate intestinal aging.

Vitamin D status among residents of Molidawa Daur Autonomous Banner, Inner Mongolia, North China

OBJECTIVES

To retrospectively analyze the vitamin D (VD) status of residents in northeastern Inner Mongolia and its relationship with the average monthly sunshine hours.

METHODS

Serum 25-hydroxyvitamin D[s-25(OH)D] samples from 4982 outpatients (2092 males) in Moli Dawa Daur Autonomous Banner People's Hospital, Hulunbuir, China from July 2018 to January 2022 were included in this study.

RESULTS

The overall median s-25(OH)D was 53.3 nmol/L, VD deficiency (<30 nmol/L), deficiency (30-50 nmol/L), sufficient (>50-250 nmol/L) and excess (>250 nmol/L) were 16% (796/4982), 30% (1495/4982), 53.4% (2658/4982) and 0.7% (33/4982). There were statistically significant differences in median s-25(OH)D by month, age-groups and gender (p<0.001). Low VD status (LVDS, including VD deficiency and insufficiency) in females was 54.6% and males was 33.9%, and the LVDS composition differed significantly by age-group and month (p<0.05). The changing trend of the median s-25(OH)D level was similar to the monthly average sunshine hours, with a slight lag.

CONCLUSION

Nearly half of residents live in LVDS. LVDS is affected by month, gender, and age.