A Review of Mushrooms as a Potential Source of Dietary Vitamin D

When commonly consumed mushroom species are exposed to a source of ultraviolet (UV) radiation, such as sunlight or a UV lamp, they can generate nutritionally relevant amounts of vitamin D. The most common form of vitamin D in mushrooms is D-2, with lesser amounts of vitamins D-3 and D-4, while vitamin D-3 is the most common form in animal foods. Although the levels of vitamin D-2 in UV-exposed mushrooms may decrease with storage and cooking, if they are consumed before the best-before' date, vitamin D-2 level is likely to remain above 10 g/100 g fresh weight, which is higher than the level in most vitamin D-containing foods and similar to the daily requirement of vitamin D recommended internationally. Worldwide mushroom consumption has increased markedly in the past four decades, and mushrooms have the potential to be the only non-animal, unfortified food source of vitamin D that can provide a substantial amount of vitamin D-2 in a single serve. This review examines the current information on the role of UV radiation in enhancing the concentration of vitamin D-2 in mushrooms, the effects of storage and cooking on vitamin D-2 content, and the bioavailability of vitamin D-2 from mushrooms.