Answer: Give it Up for Mushrooms
Excluding fortified foods, mushrooms are the only good plant source of vitamin D. However, mushrooms produce vitamin D2, whereas animals produce vitamin D3. Though vitamin D2 helps raise blood levels of vitamin D, it may not be as effective as vitamin D3. Nonetheless, wild mushrooms are excellent sources of vitamin D2. In fact, some varieties pack up to 2,300 IU per 3.5-ounce (100-gram) serving — nearly three times the DV. Commercially grown mushrooms are often grown in the dark and contain very little D2. However, certain brands are treated with ultraviolet (UV light). These mushrooms can provide 130–450 IU of vitamin D2 per 3.5 ounces (100 grams).