There are two ways to get vitamin D. You can sit in the sun (sans sunscreen for a few minutes) and soak up the UVB rays, which our skin cells use to make the vitamin. Or you can get it from food. Unfortunately, few foods are rich in D: fatty fish, such as mackerel, sardines and salmon; egg yolks; and D-fortified foods including milk and cereals. We can now add one more food—mushrooms—to the list of vitamin-D-rich foods.
“Mushrooms contain a compound called ergosterol that gets converted to vitamin D when exposed to UVB light,” explains Tara McHugh, Ph.D., research leader at the Western Regional Research Center of the Agricultural Research Service. This conversion is similar to the one that creates vitamin D in our skin. Mushrooms grow in the dark, so theoretically you could force them to make vitamin D by exposing them to sunlight, but it would take a long time. Instead a new technique exposes mushrooms to high-intensity artificial UV rays for a few minutes (think tanning bed).
McHugh helped to develop the process for Monterey Mushrooms, which launched its Sun Bella brand this fall. Dole Food Company, Inc. employs a similar method to create its vitamin-D-rich portobello mushrooms, which have been on the market since June. A single 3-ounce serving of Sun Bella or Dole mushrooms has 100 percent of the recommended daily intake for vitamin D.