Few foods contain ergocalciferol or cholecalciferol. Treatment of mushrooms with UV light increases ergocalciferol content and could provide a dietary source of vitamin D. We evaluated the impact of consuming UV-treated white button mushrooms (Agaricus bisporus) on the vitamin D status of healthy adults. Thirty-eight volunteers were randomized to 4 treatments consumed with a standard meal for 6 wk: the control (C) group received untreated mushrooms providing 0.85 μg/d ergocalciferol (n = 10); groups M1 and M2 received UV-treated mushrooms providing 8.8 (n = 10) and 17.1 μg/d (n = 9), respectively; and the supplement (S) group received purified ergocalciferol plus untreated mushrooms, providing a total of 28.2 μg/d (n = 9). Serum total 25-hydroxyvitamin D [25(OH)D] and 25-hydroxyergocalciferol [25(OH)D2] were 83 ± 38 and 2.4 ± 2.0 nmol/L, respectively, at baseline (mean ± SD). At wk 6, 25(OH)D2 had increased and was higher in all treatment groups than in the C group, whereas 25-hydroxycholecalciferol [25(OH)D3] had decreased and was lower in the M2 and S groups than in the C group. Increases in 25(OH)D2 for groups C, M1, M2, and S were 1.2 ± 5.2, 13.8 ± 7.3, 12.7 ± 3.7, and 32.8 ± 3.3 nmol/L and decreases in 25(OH)D3 were -3.9 ± 16.3, -10.4 ± 6.4, -20.6 ± 14.6, and -29.5 ± 15.9 nmol/L, respectively. Concentrations did not change in group C. In summary, ergocalciferol was absorbed and metabolized to 25(OH)D2 but did not affect vitamin D status, because 25(OH)D3 decreased proportionally.
"In agreement with other studies, supplementation with vitamin D2 increased serum 25(OH)D2 but decreased serum 25(OH)D3 [30,31,32]. Little information is available on potential functional consequences of this metabolic response, but findings from the current study showing that muscle damage was heightened after eccentric exercise in the vitamin D2 supplemented NASCAR pit crew athletes indicate further research on functional outcomes is needed. "
[Show abstract][Hide abstract] ABSTRACT: This study determined if 6-weeks vitamin D2 supplementation (vitD2, 3800 IU/day) had an influence on muscle function, eccentric exercise-induced muscle damage (EIMD), and delayed onset of muscle soreness (DOMS) in National Association for Stock Car Auto Racing (NASCAR) NASCAR pit crew athletes. Subjects were randomized to vitD2 (n = 13) and placebo (n = 15), and ingested supplements (double-blind) for six weeks. Blood samples were collected and muscle function tests conducted pre- and post-study (leg-back and hand grip dynamometer strength tests, body weight bench press to exhaustion, vertical jump, 30-s Wingate test). Post-study, subjects engaged in 90 min eccentric-based exercise, with blood samples and DOMS ratings obtained immediately after and 1- and 2-days post-exercise. Six weeks vitD2 increased serum 25(OH)D2 456% and decreased 25(OH)D3 21% versus placebo (p < 0.001, p = 0.036, respectively), with no influence on muscle function test scores. The post-study eccentric exercise bout induced EIMD and DOMS, with higher muscle damage biomarkers measured in vitD2 compared to placebo (myoglobin 252%, 122% increase, respectively, p = 0.001; creatine phosphokinase 24 h post-exercise, 169%, 32%, p < 0.001), with no differences for DOMS. In summary, 6-weeks vitD2 (3800 IU/day) significantly increased 25(OH)D2 and decreased 25(OH)D3, had no effect on muscle function tests, and amplified muscle damage markers in NASCAR pit crew athletes following eccentric exercise.
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