Effect of household cooking on the retention of vitamin D2 and 25-hydroxyvitamin D2 in pulse UV-irradiated, air-dried button mushrooms (Agaricus bisporus)

Vitamin D deficiency has widespread global prevalence. Fresh mushrooms exposed to ultraviolet (UV) radiation generate vitamin D₂ which remains after drying. It is not clear if vitamin D₂ is retained after rehydration and cooking of dried mushrooms. The aim of this study was to determine the true retention of both vitamin D₂ and 25-hydroxyvitamin D₂ (25(OH)D₂) after cooking UV-irradiated, air-dried, then rehydrated button mushrooms (Agaricus bisporus). Mushrooms were exposed to pulsed UV radiation, then air-dried in a convection oven, followed by rehydration in warm water. Samples were cooked in three different ways: frying (5 min), baking (10 min, 200 °C) and boiling (20 min, 90 °C). Compared to rehydrated, uncooked controls, there was a high retention of D vitamers (≥95%) after cooking. Frying and baking resulted in significantly higher vitamin D₂ retention compared to boiling (p < 0.0001). UV-irradiated, dried mushrooms are a valuable source of vitamin D₂ after rehydration and cooking.

Independent Associations of Serum 25-hydroxyvitamin D3 and D2 with Depressive Symptoms in Females

BACKGROUND

The role of vitamin D in depression has been gaining increased research interest. However, little is known about the independent associations of serum 25-hydroxyvitamin D₃ (25(OH)D₃) and D₂ (25(OH)D₂) with depressive symptoms. The goal of this study was to examine the metabolites of vitamin D and their associations with depression.

METHODS

This study was conducted in US females using data from the National Health and Nutrition Examination Survey 2011-2014. Depressive symptoms were assessed using a nine-item Patient Health Questionnaire, and serum 25(OH)D₃ and 25(OH)D₂ levels were measured using liquid chromatography-tandem mass spectrometry. Linear regression and generalized additive models were applied to evaluate the associations between 25(OH)D₃, 25(OH)D₂ and depression.

RESULTS

A negative association between serum 25(OH)D₃ and depressive symptoms was observed in the fully adjusted model. This association was also found among widowed, divorced, separated, and never-married individuals. The association between 25(OH)D₂ and depressive symptoms was not statistically significant, but the dose-response analysis revealed an inverted U-shaped relationship between them with an inflection point at 56.2 nmol/L. To the left of the inflection point, we detected a positive association between 25(OH)D₂ and depressive symptoms, whereas a negative association was observed to the right of the inflection point.

LIMITATIONS

The study used a cross-sectional approach, so causation cannot be determined.

CONCLUSIONS

Our study shows an inverse linear association between serum 25(OH)D₃ and depressive symptoms in US females. The association between 25(OH)D₂ and depression follows an inverted U-shaped curve with the inflection point at 56.2 nmol/L.

An assessment of 25-hydroxyvitamin D measurements in comparability studies conducted by the Vitamin D Metabolites Quality Assurance Program

BACKGROUND

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements, established the first accuracy-based program for improving the comparability of vitamin D metabolite measurements, the Vitamin D Metabolites Quality Assurance Program.

METHODS

The study samples were human serum or plasma Standard Reference Materials (SRMs) with 25-hydroxyvitamin D values that were determined at NIST. Participants evaluated the materials using immunoassay (IA), liquid chromatography (LC) with mass spectrometric detection, and LC with ultraviolet absorbance detection. NIST evaluated the results for concordance within the participant community as well as trueness relative to the NIST value.

RESULTS

For the study materials that contain mostly 25-hydroxyvitamin D3 (25(OH)D3),the coefficient of variation (CV) for the participant results was consistently in the range from 7% to 19%, and the median values were biased high relative to the NIST values. However, for materials that contain significant concentrations of both 25-hydroxyvitamin D2 (25(OH)D2) and 25(OH)D3, the median IA results were biased lower than both the LC and the NIST values, and the CV was as high as 28%. The first interlaboratory comparison results for SRM 972a Vitamin D Metabolites in Human Serum are also reported.

CONCLUSIONS

Relatively large within-lab and between-lab variability hinders conclusive assessments of bias and accuracy.