Attenuative Effect of Grifola frondosa (Maitake Mushroom) on Severe DSS‐Induced Colitis in Vitamin D‐Deficient Mice

Vitamin D deficiency, which has been a global health issue for decades, is involved in gut health and diseases. We examined the health benefits of Grifola frondosa (maitake mushroom), a potent dietary source of fungal vitamin D (D ₂ ), on DSS‐induced colitis in vitamin D‐deficient mice. C57BL/6J mice were fed a control diet, vitamin D ₃ ‐deficient diet (DD), maitake‐fortified DD, or vitamin D ₂ ‐fortified DD for 6 weeks. LC‐MS/MS analysis demonstrated that maitake‐fed mice showed an increased 25(OH)D ₂ alternative to 25(OH)D ₃ in plasma _, as well as the mice fed an equivalent dose of vitamin D ₂ . The mRNA expression profiles of vitamin D‐responsive genes, including renal Cyp24a1 and Cyp27b1 , were normalized in the maitake‐fed mice. Severe DSS‐induced colitis observed in DD mice was attenuated in maitake‐fed mice; the accumulation of immune cells in the colonic mucosa and protein expression of colonic claudin‐2, a target gene of the vitamin D receptor, were comparable to that in control mice. Dietary intake of maitake was effective in improving vitamin D status and biological function, demonstrating a potential attenuative effect on severe DSS‐induced colitis in vitamin D ₃ deficient mice, as well as equivalent doses of vitamin D ₂ .