Photobiology of vitamin D in mushrooms and its bioavailability in humans

Effects of UV-C treatment and ultrafine-grinding on the biotransformation of ergosterol to vitamin D2, physiochemical properties, and antioxidant properties of shiitake and Jew's ear

In the present study, the impact of ultraviolet (UV)-C treatment and ultrafine grinding on the conversion of ergosterol to vitamin D₂, physiochemical properties, and antioxidant properties of shiitake and Jew's ear was assessed. After exposure to UV-C, vitamin D₂ contents of both the mushroom samples has increased significantly (p < 0.05). Whereas, ultrafine grinding along with UV-C treatment has a synergistic effect on bioconversion of ergosterol to vitamin D₂ and this effect is more prominent in low dose UV-C irradiation groups (2 kJ/m²). Ultrafine grinding significantly (p < 0.05) improved the water holding capacity (WHC), water solubility index (WSI) and polysaccharide dissolution rate (PDR). However, UV-C treatment led to insignificant changes in the physiochemical properties of mushroom samples. A significant improvement was also observed in the antioxidant profiles especially tannin contents of mushrooms followed by the ultrafine grinding and UV-C treatment.

A Critical Appraisal of Strategies to Optimize Vitamin D Status in Germany, a Population with a Western Diet

During the last decade, our scientific knowledge of the pleiotropic biological effects of vitamin D metabolites and their relevance to human health has expanded widely. Beyond the well-known key role of vitamin D in calcium homeostasis and bone health, it has been shown that vitamin D deficiency is associated with a broad variety of independent diseases, including several types of cancer, and with increased overall mortality. Moreover, recent findings have demonstrated biological effects of the vitamin D endocrine system that are not mediated via activation of the classical nuclear vitamin D receptor (VDR) by binding with high affinity to its corresponding ligand, the biologically active vitamin D metabolite 1,25-dihydroxyvitamin D (1,25(OH)₂D). In contrast, many of these new biological effects of vitamin D compounds, including regulation of the circadian clock and many metabolic functions, are mediated by other vitamin D metabolites, including 20-hydroxyvitamin D and 20,23-dihydroxyvitamin D, and involve their binding to the aryl hydrocarbon receptor (AhR) and retinoid-orphan receptor (ROR). In most populations, including the German population, UVB-induced cutaneous vitamin D production is the main source for fulfilling the human body’s requirements of vitamin D. However, this causes a dilemma because solar or artificial UVR exposure is associated with skin cancer risk. In addition to UVB-induced vitamin D production in skin, in humans, there are two other possible sources of vitamin D: from diet and supplements. However, only a few natural foods contain substantial amounts of vitamin D, and in most populations, the dietary source of vitamin D cannot fulfill the body´s requirements. Because an increasing body of evidence has convincingly demonstrated that vitamin D deficiency is very common worldwide, it is the aim of this paper to (i) give an update of the vitamin D status in a population with a western diet, namely, the German population, and to (ii) develop strategies to optimize the vitamin D supply that consider both the advantages as well as the disadvantages/risks of different approaches, including increasing vitamin D status by dietary intake, by supplements, or by UVB-induced cutaneous synthesis of vitamin D.

Impact of the natural resource of UVB on the content of vitamin D2 in oyster mushroom (Pleurotus ostreatus) under subtropical settings

Vitamin D deficiency is a pandemic problem. Non-animal source of vitamin D is obtained from edible mushrooms. Oyster mushroom (Pleurotus ostreatus) was sliced into the size of 1 cm3, 4 cm3 and 9 cm3, and treated with the sun as a natural resource of UVB under subtropical settings in Ethiopia. The content of vitamin D was measured by using high-performance liquid chromatography (HPLC). After sun treatment, there was a significant increment in the content of vitamin D2 from nil to 67.4 ± 28.0 µg/g dry weight (DW). Based on the results of the overall pairwise comparisons, 1 cm3 size of slice group had the highest content of vitamin D2. Duration of sun exposure, sizes of mushroom slices and moisture content were identified as determining factors for vitamin D2 synthesis. Exposing slices of oyster mushroom to the sunlight for <30 min provides the amount that satisfies the current recommended dietary allowance (RDA) of vitamin D without any visible change in color and texture. Thus, sun treatment of oyster mushroom is an effective and economically cheap strategy in the fight against vitamin D deficiency.

The prevalence of hypovitaminosis D and its risk factors in pregnant women and their newborns in the Middle East: A systematic review

BACKGROUND

Pregnant women and newborns are at risk for vitamin D deficiency (VDD). Also, poor health outcomes for pregnant women with VDD are reported in the published literature.

OBJECTIVE

The aim of this systematic review was to estimate the prevalence of hypovitaminosis D and the associated risk factors for hypovitaminosis D in Middle Eastern pregnant women and their newborns.

RESULTS

The prevalence of circulating 25-hydroxyvitamin D (25(OH)D) < 50 nmol/L as a marker of vitamin D status in pregnant women and their newborns was between 24.5-98% and 22-100%, respectively. The prevalence of 25(OH) D < 25 nmol/L in pregnant women and their newborns was over a wide range between 16.7-80% and 22-82%, respectively. Predictors for low maternal and neonatal 25(OH)D concentrations included decreased vitamin D synthesis due to reduced exposure to sunlight and decreased nutritional intake of vitamin D. A predictor of low neonatal 25(OH)D concentrations included maternal vitamin D status and the correlation between vitamin D concentrations in maternal and cord blood.

CONCLUSION

The high prevalence of VDD in the pregnant women of the Middle East underscores the necessity of implementing national prevention and intervention strategies. A clear policy for clinicians and healthcare workers is needed for screening and maintaining sufficient vitamin D status during pregnancy.

Development of high yielding strain of Pleurotus tuber-regium: fructification, nutritional and phylogenetic studies

Mushrooms are nutritionally rich, healthy and medicinal. Pleurotus tuber-regium (Fr.) is one of the nutritious medicinal mushroom found in the tropics and subtropics, but with history of slow growth and low sclerotia yield. In this study, mutants were created by mycelia exposure to ultraviolet irradiation (at a wavelength of 254 nm and a distance of 45 cm), for 3 h and sub-cultured at 30 min interval. The DNA from the wild and mutant strains were extracted, PCR amplified and sequenced. A phylogenetic tree was constructed to show the degree of similarity and differences between the wild and the mutant strains. Fructification studies were conducted on Rhodes grass straw and sawdust to determine the viability of the mutant strains and any nutritional improvement. The wild strain of P. tuber-regium and mutant produced at 30 min (Pt30) cultivated on sawdust and Rhodes straw, yielded sclerotia with biological efficiency of 8.8 and 47.6% respectively. Proximate analysis of the sclerotium showed that the mutant, Pt30, had improved nutritional compositions compared to the wild strain with a total non-structural carbohydrate concentration of 2.41 g as against 0.93 g. Conclusively in this study, better strains of P. tuber-regium were produced with faster growth rate, higher mycelia ramification rate on lignocellulosic substrate and a higher sclerotia yield than the wild P. tuber-regium. It was also established that mutagenesis is capable of improving P. tuber-regium for a successful commercial venture in sclerotia production.

A Review of Mushrooms as a Potential Source of Dietary Vitamin D

When commonly consumed mushroom species are exposed to a source of ultraviolet (UV) radiation, such as sunlight or a UV lamp, they can generate nutritionally relevant amounts of vitamin D. The most common form of vitamin D in mushrooms is D₂, with lesser amounts of vitamins D₃ and D₄, while vitamin D₃ is the most common form in animal foods. Although the levels of vitamin D₂ in UV-exposed mushrooms may decrease with storage and cooking, if they are consumed before the ‘best-before’ date, vitamin D₂ level is likely to remain above 10 μg/100 g fresh weight, which is higher than the level in most vitamin D-containing foods and similar to the daily requirement of vitamin D recommended internationally. Worldwide mushroom consumption has increased markedly in the past four decades, and mushrooms have the potential to be the only non-animal, unfortified food source of vitamin D that can provide a substantial amount of vitamin D₂ in a single serve. This review examines the current information on the role of UV radiation in enhancing the concentration of vitamin D₂ in mushrooms, the effects of storage and cooking on vitamin D₂ content, and the bioavailability of vitamin D₂ from mushrooms.

Development of Vitamin D Toxicity from Overcorrection of Vitamin D Deficiency: A Review of Case Reports

Over the past two decades, vitamin D level measurements have become some of the most frequently ordered tests in the laboratory. This increase is due to a growing awareness of widespread vitamin D deficiency and scientific data suggesting the beneficial effects of vitamin D in various diseases. A literature search was carried out in PubMed for cases reporting vitamin D intoxication and overdose. Thirteen articles were included in this review. Intoxication was severe in the reported cases. Patients presented with serum vitamin D concentrations ranging between 150 and 1220 ng/mL and serum calcium concentrations between 11.1 and 23.1 mg/dL. Most of the reported patients showed symptoms of vitamin D toxicity such as vomiting, dehydration, pain, and loss of appetite. The underlying causes included manufacturing errors, overdosing by patients or prescribers, and combinations of these factors. Our literature search highlights the fact that even though vitamin D intoxication is rare, it does occur and therefore patients and prescribers should be more cognizant of the potential dangers of vitamin D overdose.

Vitamin D Content of Australian Native Food Plants and Australian-Grown Edible Seaweed

Vitamin D has previously been quantified in some plants and algae, particularly in leaves of the Solanaceae family. We measured the vitamin D content of Australian native food plants and Australian-grown edible seaweed. Using liquid chromatography with triple quadrupole mass spectrometry, 13 samples (including leaf, fruit, and seed) were analyzed in duplicate for vitamin D₂, vitamin D₃, 25-hydroxyvitamin D₂, and 25-hydroxyvitamin D₃. Five samples contained vitamin D₂: raw wattleseed (Acacia victoriae) (0.03 µg/100 g dry weight (DW)); fresh and dried lemon myrtle (Backhousia citriodora) leaves (0.03 and 0.24 µg/100 g DW, respectively); and dried leaves and berries of Tasmanian mountain pepper (Tasmannia lanceolata) (0.67 and 0.05 µg/100 g DW, respectively). Fresh kombu (Lessonia corrugata) contained vitamin D₃ (0.01 µg/100 g DW). Detected amounts were low; however, it is possible that exposure to ultraviolet radiation may increase the vitamin D content of plants and algae if vitamin D precursors are present.

Italian Association of Clinical Endocrinologists (AME) and Italian Chapter of the American Association of Clinical Endocrinologists (AACE) Position Statement: Clinical Management of Vitamin D Deficiency in Adults

Vitamin D deficiency is very common and prescriptions of both assay and supplementation are increasing more and more. Health expenditure is exponentially increasing, thus it is timely and appropriate to establish rules. The Italian Association of Clinical Endocrinologists appointed a task force to review literature about vitamin D deficiency in adults. Four topics were identified as worthy for the practicing clinicians. For each topic recommendations based on scientific evidence and clinical practice were issued according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) System. (1) What cut-off defines vitamin D deficiency: even though 20 ng/mL (50 nmol/L) can be considered appropriate in the general population, we recommend to maintain levels above 30 ng/mL (75 nmol/L) in categories at risk. (2) Whom, when, and how to perform screening for vitamin D deficiency: categories at risk (patients with bone, liver, kidney diseases, obesity, malabsorption, during pregnancy and lactation, some elderly) but not healthy people should be screened by the 25-hydroxy-vitamin D assay. (3) Whom and how to treat vitamin D deficiency: beyond healthy lifestyle (mostly sun exposure), we recommend oral vitamin D (vitamin D2 or vitamin D3) supplementation in patients treated with bone active drugs and in those with demonstrated deficiency. Dosages, molecules and modalities of administration can be profitably individually tailored. (4) How to monitor the efficacy of treatment with vitamin D: no routine monitoring is suggested during vitamin D treatment due to its large therapeutic index. In particular conditions, 25-hydroxy-vitamin D can be assayed after at least a 6-month treatment. We are confident that this document will help practicing clinicians in their daily clinical practice.

New insights into the role of vitamin D in hepatocellular carcinoma

In addition to being crucial for host immune defense, vitamin D is involved in cell proliferation, apoptosis, differentiation, inflammation, invasion and metastasis, angiogenesis and micro-RNA modulation. To date, clinical studies have demonstrated that vitamin D deficiency is common not only in patients with chronic liver diseases but also in those with hepatocellular carcinoma (HCC). Experimental studies have also demonstrated that vitamin D and its receptors are related to the occurrence of HCC and the prognoses of patients with HCC. Areas covered: In this review, we discuss the potential anti-tumor role of vitamin D in HCC based on current findings from epidemiological studies, basic science, and clinical studies and provide new insights into the pathogenesis and treatment of HCC. Expert commentary: Recent studies have revealed the anti-tumor effects of vitamin D to a certain degree. Vitamin D and its analogs may provide new treatment targets and prognostic factors for HCC that might be essential for the primary or secondary prevention of HCC and the monitoring of its progression.

Factors influencing the absorption of vitamin D in GIT: an overview

Vitamin D refers to a group of secosteroid compounds and recognized as the antirachitic vitamin, as it counters rickets, mineral desorption from fully-grown bones (Osteodistrophy), bone, joint disorders, and fragility of bones. On one hand, there is scarcity of vitamin D rich food while on other hand a number of factors negotiate its absorption efficiency in human gastrointestinal tract (GIT). These factors include variations in the physiochemical state of the vitamin D (molecular forms, potency and their physiological linkages), the complexity of food matrix (the amount and type of fatty acids, dietary fibers and presence/absence of vitamin D enhancer and inhibitor), and its interaction of other fat soluble compounds with vitamin D as well as the host-associated factors (age, disease, surgery, obesity, genetic variation etc.). It is hypothesized that the bioavailability of vitamin D in GIT is compromised if there changes within these factors. Present article is intended to review the contribution of these factors anticipated to be influencing vitamin D absorption in GIT.

Position of the Academy of Nutrition and Dietetics: Vegetarian Diets

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage. Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease. Vegans need reliable sources of vitamin B-12, such as fortified foods or supplements.

The vitamin D deficiency pandemic: Approaches for diagnosis, treatment and prevention

Vitamin D deficiency and insufficiency is a global health issue that afflicts more than one billion children and adults worldwide. The consequences of vitamin D deficiency cannot be under estimated. There has been an association of vitamin D deficiency with a myriad of acute and chronic illnesses including preeclampsia, childhood dental caries, periodontitis, autoimmune disorders, infectious diseases, cardiovascular disease, deadly cancers, type 2 diabetes and neurological disorders. This review is to put into perspective the controversy surrounding the definition for vitamin D deficiency and insufficiency as well as providing guidance for how to treat and prevent vitamin D deficiency.

Vitamin D-fortified chitosan films from mushroom waste

Brown mushroom (Agaricus bisporus) stalk bases from mushroom waste were treated with UV-B light to rapidly increase vitamin D₂ content. Chitin was also recovered from this waste and converted into chitosan by N-deacetylation. FTIR spectra showed that the mushroom chitosan were similar to chitosan from animal sources. Chitosan films were prepared using high molecular weight (HW), low molecular weight (LW) and fungal chitosan. UV-B treated mushroom particles were also incorporated into fungal chitosan films. The fungal chitosan films showed similar density, porosity and water vapor barrier properties to the LW and HW chitosan films. However, fungal chitosan films were more hydrophobic and less flexible than the LW and HW chitosan films. Addition of mushroom particles did not significantly affect mechanical or water barrier properties of the fungal chitosan films.

Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53 J/cm(2) raised the vitamin D2 content to significantly (P < 0.001) higher levels of 67.1 ± 9.9 μg/g dry weight (DW) than sun exposure (3.9 ± 0.8 μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2) = 0.96, P < 0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9 μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.

Optimal vitamin D3 daily intake of 2000IU inferred from modeled solar exposure of ancestral humans in Northern Tanzania

Recently, high serum 25-hydroxyvitamin D concentration (~110nmol/L) was found in the Hadza tribe still keeping ancient hunter-gather life style. This level could serve as optimal vitamin D level that was built during millennia of human evolution. The personal vitamin D3 effective solar exposures of the Hadza adults are estimated using radiative model simulations with input from the satellite observations over lake Eyasi (3.7°S, 35.0°E). The calculations are carried out assuming the Hadza typical clothing habits and specific scenarios of the out-door activity comprising early morning and late afternoon working time in sun and prolonged midday siesta in the shade. The modeled doses received by the Hadza are converted to the vitamin D3 effective daily doses pertaining to the lighter skinned persons. We propose a novel formula to get adequate vitamin D level - exposure of 1/3 MED around local noon to 1/3 part of the whole body during warm sub-period of the year in the low- and mid-latitude regions. Such daily solar exposure is equivalent to ~2000IU of vitamin D3 taken orally. For many contemporary humans with limited out-door activity habit achieving such daily norm requires vitamin D3 supplementation of 2000IU throughout the whole year.

Effect of Ultraviolet Light-Exposed Mushrooms on Vitamin D Status: Liquid Chromatography-Tandem Mass Spectrometry Reanalysis of Biobanked Sera from a Randomized Controlled Trial and a Systematic Review plus Meta-Analysis

BACKGROUND

Randomized controlled trial (RCT) data on the response of serum total 25-hydroxyvitamin D [25(OH)D] in healthy participants consuming UV light-exposed edible mushrooms are limited and mixed.

OBJECTIVE

The objective was to undertake a systematic review and meta-analysis of responses of serum 25(OH)D [and serum 25-hydroxyergocalciferol, 25(OH)D2, and serum 25-hydroxycholecalciferol, 25(OH)D3, if available] to consumption of UV-exposed mushrooms by healthy participants. Biobanked sera from one RCT (originally analyzed by immunoassay) were reanalyzed by LC-MS/MS to generate serum 25(OH)D2 and serum 25(OH)D3 data.

METHODS

Ovid MEDLINE, EMBASE, and Cochrane CENTRAL were searched for RCTs of UV-exposed mushrooms and data on serum 25(OH)D. Studies were screened for eligibility, and relevant data were extracted. Serum 25(OH)D data were re-analyzed by ANOVA and paired t tests.

RESULTS

Our structured search yielded 6 RCTs meeting our inclusion criteria. Meta-analysis of all 6 RCTs showed serum 25(OH)D was not significantly increased (P = 0.12) by UV-exposed mushrooms, but there was high heterogeneity (I(2) = 87%). Including only the 3 European-based RCTs [mean baseline 25(OH)D, 38.6 nmol/L], serum 25(OH)D was increased significantly by UV-exposed mushrooms [weighted mean difference (WMD): 15.2 nmol/L; 95% CI: 1.5, 28.8 nmol/L, P = 0.03, I(2) = 88%], whereas there was no significant effect in the 3 US-based RCTs [P = 0.83; mean baseline 25(OH)D: 81.5 nmol/L]. Analysis of serum 25(OH)D2 and serum 25(OH)D3 (n = 5 RCTs) revealed a statistically significant increase (WMD: 20.6 nmol/L; 95% CI: 8.0, 33.3 nmol/L, P = 0.001, I(2 =) 99%) and decrease (WMD: -13.3 nmol/L; 95% CI: -15.8, -10.7 nmol/L, P < 0.00001, I(2) = 0%) after supplementation with UV-exposed mushrooms.

CONCLUSIONS

Consumption of UV-exposed mushrooms may increase serum 25(OH)D when baseline vitamin D status is low via an increase in 25(OH)D2 (24.2 nmol/L) and despite a concomitant but relatively smaller reduction in 25(OH)D3 (-12.6 nmol/L). When baseline vitamin D status is high, the mean increase in 25(OH)D2 (18.3 nmol/L) and a relatively similar reduction in 25(OH)D3 (-13.6 nmol/L) may explain the lack of effect on serum 25(OH)D.

Intestinal absorption of vitamin D: from the meal to the enterocyte

Vitamin D plays key roles in bone, infectious, inflammatory and metabolic diseases. As most people get inadequate sun exposure for sufficient vitamin D status, they need adequate intake of dietary vitamin D. Many studies see optimizing vitamin D status as a public health priority. It is thus vital to gain deeper insight into vitamin D intestinal absorption. It was long assumed that vitamin D intestinal absorption is a passive process, but new data from our laboratory showed that it is actually far more complex than previously thought. This review describes the fate of vitamin D in the human upper gastrointestinal lumen during digestion and focuses on the proteins involved in the intestinal membrane and cellular transport of vitamin D across the enterocyte. Although recent data significantly improve our understanding of vitamin D intestinal absorption, further studies are still needed to increase our knowledge of the molecular mechanisms underlying this phenomenon.

Dose-Response Effect of Sunlight on Vitamin D2 Production in Agaricus bisporus Mushrooms

The dose response effect of UV-B irradiation from sunlight on vitamin D2 content of sliced Agaricus bisporus (white button mushroom) during the process of sun-drying was investigated.Real-time UV-B and UV-A data were obtained using a high-performance spectroradiometer. During the first hour of sunlight exposure, the vitamin D2 content of the mushrooms increased in a linear manner, with concentrations increasing from 0.1 μg/g up to 3.9 ± 0.8 μg/g dry weight (DW). At the subsequent two measurements one and 3 h later, respectively, a plateau was reached. Two hours of additional exposure triggered a significant decline in vitamin D2 content. After just 15 min of sun exposure and an UV-B dose of 0.13 J/cm(2), the vitamin D2 content increased significantly to 2.2 ± 0.5 μg/g DW (P < 0.0001), which is equivalent to 17.6 μg (704 IU) vitamin D2 per 100 g of fresh mushrooms and comparable to levels found in fatty fish like the Atlantic salmon.

Cytochrome P450 Vitamin D Hydroxylases in Inflammation and Cancer

Vitamin D insufficiency correlates with increased incidence of inflammatory disorders and cancer of the colon, breast, liver, and prostate. Preclinical studies demonstrated that the hormonally active form of vitamin D, 1,25(OH)2D3, has antiproliferative, proapoptotic, anti-inflammatory, and immunomodulatory effects. Tissue levels of 1,25(OH)2D3 are determined by expression and activity of specific vitamin D hydroxylases expressed at renal and extrarenal sites. In order to understand how perturbations in the vitamin D system affect human health, we need to understand the steps involved in the synthesis and catabolism of the active metabolite. This review provides an overview about recent findings on the altered vitamin D metabolism in inflammatory conditions and carcinogenesis. We will summarize existing data on the pathophysiological regulation of vitamin D hydroxylases and outline the role of adequate levels of 1,25(OH)2D3 on tissue homeostasis.

Bioavailability of vitamin D2 from enriched mushrooms in prediabetic adults: a randomized controlled trial

BACKGROUND/OBJECTIVES

Based on the growing evidence of risk reduction from fresh fruit and vegetable consumption and an inverse relationship between serum 25-hydroxyvitamin D (25OHD) and the risk of type 2 diabetes (T2D), we determined the benefits of regularly consuming vitamin D-enriched mushrooms in a prediabetic cohort. Exposing edible mushrooms to ultraviolet B (UVB) light increases vitamin D2 (D2) and raises serum 25OHD2 in healthy young adults; however, their benefit to deficient prediabetics and glucose metabolism remains untested.

SUBJECTS/METHODS

Forty-three prediabetic, D-deficient adults (25OHD≤20 ng/ml), BMI>25 were randomized to four groups consuming daily entrées containing 100 g fresh sliced cooked mushrooms prepared by a chef for 16 weeks. Two groups were fed UVB-treated mushrooms initially containing: 600 IU D2 or 4000 IU D2; each one also received one capsule of placebo daily. Two control groups were fed untreated mushrooms and D3 dietary supplements at two label doses: 600 IU D3 and 4000 IU D3. D2 and D3 content were analyzed in mushrooms, before and after cooking and in over-the-counter supplements.

RESULTS

After 16 weeks, both D2-UVB-mushroom entrée doses, which were significantly lower after cooking, produced modest or no increases in 25OHD2 or total 25OHD relative to the positive control subjects who actually consumed about 1242 and 7320 IU per day of D3 (higher than stated on the label).

CONCLUSIONS

Unanticipated D2 cooking loss from fresh UVB mushrooms and probable low absorption and/or hydroxylation may explain the smaller increase in 25OHD2 in our prediabetic overweight/obese cohort compared with past findings in younger, healthy subjects. Moreover, no dose or vitamin D source was associated with modifying T2D risk factors.

Vitamin B₁₂-containing plant food sources for vegetarians

The usual dietary sources of Vitamin B₁₂ are animal-derived foods, although a few plant-based foods contain substantial amounts of Vitamin B₁₂. To prevent Vitamin B₁₂ deficiency in high-risk populations such as vegetarians, it is necessary to identify plant-derived foods that contain high levels of Vitamin B₁₂. A survey of naturally occurring plant-derived food sources with high Vitamin B₁₂ contents suggested that dried purple laver (nori) is the most suitable Vitamin B₁₂ source presently available for vegetarians. Furthermore, dried purple laver also contains high levels of other nutrients that are lacking in vegetarian diets, such as iron and n-3 polyunsaturated fatty acids. Dried purple laver is a natural plant product and it is suitable for most people in various vegetarian groups.

Vitamin D for health: a global perspective

It is now generally accepted that vitamin D deficiency is a worldwide health problem that affects not only musculoskeletal health but also a wide range of acute and chronic diseases. However, there remains cynicism about the lack of randomized controlled trials to support the association studies regarding the nonskeletal health benefits of vitamin D. This review was obtained by searching English-language studies published up to April 1, 2013, in PubMed, MEDLINE, and the Cochrane Central Register of Controlled Trials (search terms: vitamin D and supplementation) and focuses on recent challenges regarding the definition of vitamin D deficiency and how to achieve optimal serum 25-hydroxyvitamin D concentrations from dietary sources, supplements, and sun exposure. The effect of vitamin D on fetal programming epigenetics and gene regulation could potentially explain why vitamin D has been reported to have such wide-ranging health benefits throughout life. There is potentially a great upside to increasing the vitamin D status of children and adults worldwide for improving musculoskeletal health and reducing the risk of chronic illnesses, including some cancers, autoimmune diseases, infectious diseases, type 2 diabetes mellitus, neurocognitive disorders, and mortality.