Vitamin D2 from light exposed mushrooms is safe, bioavailable and effectively supports bone growth in rats

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Osteoporosis International (Impact Factor: 4.17). 02/2012; 24(1). DOI: 10.1007/s00198-012-1934-9
Source: PubMed


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.

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