title: Vitamin D2 from light-exposed edible mushrooms is safe, bioavailable and effectively supports bone growth in rats.
abstract: 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.
  
  
  BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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. mona.calvo@fda.hhs.gov
authors.forename: M S
authors.initials: MS
authors.lastname: Calvo
authors.forename: U S
authors.initials: US
authors.lastname: Babu
authors.forename: L H
authors.initials: LH
authors.lastname: Garthoff
authors.forename: T O
authors.initials: TO
authors.lastname: Woods
authors.forename: M
authors.initials: M
authors.lastname: Dreher
authors.forename: G
authors.initials: G
authors.lastname: Hill
authors.forename: S
authors.initials: S
authors.lastname: Nagaraja
mesh_terms: D000363:Agaricales / Q000737:chemistry / Q000528:radiation effects*; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D001846:Bone Development / Q000187:drug effects* / Q000502:physiology; D004032:Diet; D004872:Ergocalciferols / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology; D006128:Growth / Q000187:drug effects; D009753:Nutritive Value / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014466:Ultraviolet Rays; D055114:X-Ray Microtomography
chemical_list: D015415:Biomarkers; D004872:Ergocalciferols