Some types of mushrooms are sources of vitamin D. Vitamin D is more commonly found in dairy products and oily fish. Vegetable-based dishes such as mashed potatoes may contain vitamin D due to the added dairy ingredients.
Portabello mushrooms and white mushrooms tend to have higher levels of vitamin D than other varieties of mushrooms. The human body naturally produces vitamin D when the skin is exposed to ultraviolet light from the sun. Some types of mushrooms are grown under ultraviolet light, and a similar reaction causes them to contain vitamin D.
One cup of raw white mushrooms contains about 12.6 IU of vitamin D, or about 3 percent of an average person's daily required intake. In comparison, 1 cup of diced portabello mushrooms contains about 384 IU of vitamin D, or 64 percent of an average daily required intake. Tofu and other soy-derived foods may also be sources of vitamin D. Three ounces of firm tofu provides as much as 132 IU of vitamin D, or 21 percent of the average daily intake.
Most dairy products are fortified with vitamin D. Fortified semi-skim milk contains around 20 percent of the recommended daily intake. Cod liver oil is one of the most concentrated dietary sources of vitamin D. One tablespoon of the oil contains as much as 1,400 IU, or 233 percent of the average daily amount.