Vitamin D2 from light exposed mushrooms is safe, bioavailable and effectively supports bone growth in rats
Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, 8301 Muirkirk Road, Laurel, MD, 20708, USA, . Osteoporosis International
(Impact Factor: 4.17).
02/2012; 24(1). DOI: 10.1007/s00198-012-1934-9
Widespread poor vitamin D status, a health risk for bone disease, increases the need for new food sources of vitamin D. Light-exposed edible mushrooms synthesize vitamin D-2. Bioavailability, safety, and efficacy of high levels of vitamin D-2 from mushrooms to support bone health was established in chronically fed growing rats. Poor vitamin D status from reduced sun exposure is made worse by limited access to vitamin D-containing foods. Exposing white button mushrooms to ultraviolet B (UVB) light markedly increases their vitamin D-2 content, creating a new food source of vitamin D. We used a growing rat model to determine safety, bioavailability, and efficacy in support of bone growth by vitamin D-2 from UVB-exposed mushrooms. We fed 150 weanling female rats one of five diets for 10 weeks, all formulated on AIN-93 G. Control diets contained no mushrooms either with or without vitamin D-3. Other diets contained 2.5% and 5.0% of UVB-exposed or -unexposed mushrooms. Safety of the high levels of vitamin D-2 from mushrooms was assessed by animal growth and by Von Kossa staining for soft tissue calcification. Bioavailability was determined from changes in circulating levels of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH). Efficacy in support of bone growth was determined from measures of femur bending properties, size, mineralization, and microarchitecture. Diets containing 2.5% and 5.0% light-exposed mushrooms significantly raised 25(OH)D and suppressed PTH levels compared to control-fed rats or rats fed 5.0% mushroom unexposed to light. Microarchitecture and trabecular mineralization were only modestly higher in the light-treated mushroom-fed rats compared to the controls. Von Kossa staining revealed no soft tissue calcification despite very high plasma 25(OH)D. Vitamin D-2 from UVB-exposed mushrooms is bioavailable, safe, and functional in supporting bone growth and mineralization in a growing rat model without evidence of toxicity.
Available from: Enikö Kállay
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ABSTRACT: Vitamin D deficiency and low calcium intake are considered risk factors for several cancers. Vitamin D, synthesized in the skin or ingested through the diet, is transformed through two hydroxylation steps to the active metabolite, 1α,25-dihydroxyvitamin D3 (1,25-D3). 25-hydroxylases in the liver are responsible for the first hydroxylation step. The ultimate activation is performed by the renal 25-hydroxyvitamin D 1α-hydroxylase (CYP27B1), while the 1,25-dihydroxyvitamin D-24-hydroxylase (CYP24A1) in the kidneys degrades the active metabolite. These two renal vitamin D hydroxylases control the endocrine serum 1,25-D3 levels, and are responsible for maintaining mineral homeostasis. In addition, the active vitamin D hormone 1,25-D3 regulates cellular proliferation, differentiation, and apoptosis in multiple tissues in a paracrine/autocrine manner. Interestingly, it is the low serum level of the precursor 25-hydroxyvitamin D3 (25-D3) that predisposes to numerous cancers and other chronic diseases, and not the serum concentration of the active vitamin D hormone. The extrarenal autocrine/paracrine vitamin D system is able to synthesize and degrade locally the active 1,25-D3 necessary to maintain normal cell growth and to counteract mitogenic stimuli. Thus, vitamin D hydroxylases play a prominent role in this process. The present review describes the role of the vitamin D hydroxylases in cancer pathogenesis and the cross-talk between the extra-renal autocrine/paracrine vitamin D system and calcium in cancer prevention.
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ABSTRACT: Widespread poor vitamin D status in all age and gender groups in the United States (USA) and Canada increases the need for new food sources. Currently ∼ 60% of the intake of vitamin D from foods is from fortified foods in these countries. Those groups in greatest need are consuming significantly lower amounts of commonly fortified foods such as milk. Both countries allow voluntary vitamin D fortification of some other foods, although in Canada this practice is only done on a case-by-case basis. Novel approaches to vitamin D fortification of food in both countries now include "bio-addition" in which food staples are fortified through the addition of another vitamin D-rich food to animal feed during production, or manipulation of food post-harvest or pre-processing. These bio-addition approaches provide a wider range of foods containing vitamin D, and thus appeal to differing preferences, cultures and possibly economic status. An example is the post-harvest exposure of edible mushrooms to ultraviolet light. However, further research into safety and efficacy of bio-addition needs to be established in different target populations.
Available from: Katherine M Phillips
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ABSTRACT: The vitamin D2 content of white button mushrooms is relatively low. UV exposure produces vitamin D2 by rapid conversion of ergosterol to ergocalciferol. Commercial-scale UV treatment has been used to produce vitamin D-enhanced mushrooms. The reliability of a consumer-friendly protocol to increase vitamin D2 in mushrooms by a nutritionally meaningful amount using exposure to sunlight was evaluated. Sliced white button mushrooms were
exposed to sunlight for 15, 30, or 60 minutes in 16 experiments at different times of day, seasons, and cloud cover. Vitamin D2 was measured by HPLC with 3H-vitamin D3 internal standard. Change in vitamin D2 per 70 g serving relative to untreated mushrooms was evaluated. Vitamin D2 in all unexposed mushrooms was <30 IU/70 g (<5%DRI) (median, <7 IU/70 g). Regardless of season, treatment for 15 minutes between 9:30 a.m. and 3:30 p.m. under partly cloudy to clear conditions increased vitamin D2 by157-754 IU/70 g (26-126%DRI), and up to 1142 IU/70 g total increase was observed after 30 min. On overcast and mostly cloudy days the gain was 76-178 IU/70 g (13-30%DRI) after 15 minutes, but after one hour the level was comparable to 15 minutes of treatment in clear conditions. Trials by consumers at four different geographic locations resulted in increases of 367-905 IU/70 g. A preliminary trial showed dramatically elevated vitamin D2 contents in other mushroom types exposed 15 minutes under clear conditions. These results demonstrate that vitamin D2 in mushrooms can be reliably enhanced by at least 25% of the DRI (150
IU; 3.75 μg)/70 g serving by exposure to sunlight for as little as 15 minutes on a clear or partly cloudy day between 9:30 a.m. and 3:30 p.m., and >100% (>600 IU) in many cases. Even under conditions of lower UV intensity similar increases can be achieved after 30-60 minutes.
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