Bioavailability of vitamin D from wild edible mushrooms (Cantharellus tubaeformis) as measured with a human bioassay.

BACKGROUND The bioavailability of vitamin D from mushrooms in humans is unknown. OBJECTIVE We investigated the bioavailability of vitamin D from wild edible mushrooms (Cantharellus tubaeformis) using the increase in serum 25-hydroxyvitamin D concentrations as a measure of vitamin D bioavailability. DESIGN Twenty-seven volunteers with serum 25-hydroxyvitamin D concentrations <60 nmol/L (mean : 38.5 nmol/L; range: 15-60 nmol/L) were randomly divided into 3 groups of 9 persons each. For 3 wk, excluding Saturdays and Sundays, group 1 received mushrooms (C. tubaeformis) providing 14 microg ergocalciferol/d with their lunch, group 2 (control) received an ergocalciferol supplement providing 14 microg/d, and group 3 (also a control) received no supplementation. RESULTS At the beginning of the study, mean serum 25-hydroxyvitamin D concentrations did not differ significantly among the groups (P = 0.280). When all 3 groups were considered, serum 25-hydroxyvitamin D concentrations showed different time-related changes among the groups during the study: group (P = 0.388), time (P = 0.000), and group x time (P = 0.001). When groups 1 and 2 were compared with group 3, serum 25-hydroxyvitamin D concentrations at 3 wk differed significantly between groups 1 and 3 (P = 0.032) as well as between groups 2 and 3 (P = 0.004). Serum 25-hydroxyvitamin D concentrations at 3 wk did not differ significantly between groups 1 and 2 (P = 0.317). CONCLUSIONS We showed for the first time that ergocalciferol was well absorbed from lyophilized and homogenized mushrooms in humans and that vitamin D bioavailability can be studied in humans with such an experimental protocol.