Few foods naturally contain vitamin D, but mushrooms are unique for being the only food in the produce aisle with the ability to increase its vitamin D levels through exposure to UV light or sunlight.
The sun is the most common producer of vitamin D as the ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis. Mushroom farmers took note and began exposing their mushrooms to UV light during the growing process, increasing the overall vitamin D content. Some varieties, such as crimini and portabella, contain higher levels of the plant sterol, ergosterol, which converts to vitamin D upon exposure to UV light and, in turn, results in a higher amount of vitamin D.
Why Vitamin D is Important
Although the majority of Americans consume sufficient amounts of most nutrients, vitamin D is consumed by many individuals in amounts below the Estimated Average Requirement.2 The 2020-2025 Dietary Guidelines for Americans identified vitamin D as a nutrient of public health concern because low intakes are associated with health concerns.