What Is Vitamin D
Vitamin D is a fat-soluble vitamin that our body makes naturally when exposed to the sun, which supports a healthy immune system and strong bones. We need about 15-20 mcg or 600-800 IU of Vitamin D a day. (1)
Due to our modern, mostly indoor western lifestyles, observational studies suggest about 40% of the American and European populations are deficient in this critical nutrient. (2, 3) A small study recently published in the Journal of Clinical Endocrinology & Metabolism, found that of 216 patients hospitalized for COVID in a Spanish hospital, 80% of them were Vitamin D deficient. (4)
For those who can’t make it outdoors consistently to get adequate amounts, Vitamin D is also found in a small number of foods, mostly animal-based. Fatty fish like wild salmon are a substantial source of Vitamin D. For example, one three-ounce serving of coho salmon provides 14.2 mcg or 570 IU of Vitamin D. For adults under 70, that’s 95% of your daily needs.
While beef and egg yolks do provide some vitamin D, it’s an insignificant amount. One large egg provides 1.1 mcg or 44 IU (6% of recommended daily intake) while a three-ounce serving of ground beef provides just 1.7 IU. (not even 1% of the daily recommended intake). Other sources like cod liver oil and beef liver are more substantial sources, however, are not always easy to get, or get down. (5)
Mushrooms, on the other hand, are incredibly easy to find, inexpensive, flavorful, and bursting with Vitamin D when prepared in the specific way I outline below.
Vitamin D In Mushrooms
All mushrooms contain a small amount of Vitamin D naturally, but, when exposed to sunlight or UV light, they have the unique ability to significantly increase the amount of Vitamin D.
You can now sometimes find “Vitamin D-enhanced” or “UV-treated” mushrooms for sale at your local grocery store, but they’ll cost you about a dollar extra than comparable mushrooms that have not been exposed to UV light. Save your buck, and give your mushrooms a sunbath at home with this easy hack:
How To Increase Vitamin D In Mushrooms
Place your mushrooms gills up on a plate, like I did in the above photos, either in a sunny windowsill, on your balcony, or in your backyard. Let them soak up the sun for at least 1 to 2 hours, and you should get a day’s worth of Vitamin D (about 20 mcg or 800 IU) in about a cup of white button, crimini, or portabello mushrooms.
If you need your mushrooms sooner, slice them first, which will increase the surface area, and speed up the development of Vitamin D. (5)
If you’d like to add more mushrooms to your plate, check out my recent article on the health benefits of mushrooms which includes some of my fave mushroom recipes.