Sun your 'Shrooms!

Have you ever heard of "sunning your shrooms"? It may sound a little quirky, but it's actually a simple, science-backed way to boost the nutritional value of many edible mushrooms.

Just like our skin can produce vitamin D when exposed to sunlight, mushrooms have a natural compound called ergosterol. When mushrooms are placed in direct sunlight or exposed to ultraviolet (UV) light, ergosterol is converted into vitamin D₂. This means a few minutes in the sun can significantly increase the amount of vitamin D found in many fresh mushrooms.

Vitamin D plays an important role in supporting overall health. It helps the body absorb calcium and phosphorus, contributing to healthy bones and teeth. It also supports normal muscle function, immune health, and many other essential processes throughout the body. While vitamin D can be obtained from sunlight, supplements, and certain foods, sun-exposed mushrooms are one of the few natural plant-based sources of vitamin D.

How to Sun Your Mushrooms

It's easy! Before cooking or eating your mushrooms:

• Place them gill-side up in direct sunlight.

• Leave them outside for about 15–60 minutes, depending on the intensity of the sun and the time of day.

• Cook and enjoy them as you normally would.

Even a short amount of sun exposure can substantially increase the vitamin D₂ content of many common mushrooms, including white button, cremini, and portobello varieties.

A Few Things to Know

Sunning mushrooms increases vitamin D₂, which is one of the forms of vitamin D used by the body. Research has shown that vitamin D₂ from UV-exposed mushrooms is bioavailable, meaning it can effectively raise vitamin D levels in people who consume them. While some studies suggest vitamin D₃ may remain in the body longer, vitamin D₂ is still recognized as an effective source of vitamin D and can be especially helpful for those following vegetarian or vegan diets.

As with any nutritional habit, sunning mushrooms should be viewed as one piece of an overall healthy lifestyle. If you have concerns about your vitamin D status or have been diagnosed with a deficiency, it's always a good idea to speak with your healthcare provider about the best approach for your individual needs.

Learn More

If you'd like to explore the research behind sunning mushrooms, these organizations and publications offer reliable information:

• U.S. Department of Agriculture (USDA): Information on vitamin D in UV-exposed mushrooms.

• The Mushroom Council: Educational resources on mushroom nutrition and vitamin D.

• National Institutes of Health (NIH) Office of Dietary Supplements: Vitamin D Fact Sheet for Consumers.

• Simon RR, Phillips KM, Horst RL, Munro IC. Vitamin D mushrooms: Comparison of the composition of button mushrooms treated postharvest with UVB light or sunlight. Journal of Agricultural and Food Chemistry (2011).

• Cardwell G, Bornman JF, James AP, Black LJ. A Review of Mushrooms as a Potential Source of Dietary Vitamin D. Nutrients (2018).