Eating mushrooms for Vitamin D? Think again!

Do mushrooms contain vitamin D? Can mushrooms increase your vitamin D levels?

Every winter, I see a number of nutritionists recommend eating mushrooms to support vitamin D levels. However, this doesn’t necessarily make sense and the answer to the questions above is a bit more nuanced, so I wanted to weigh in on the discussion.

So do mushrooms contain vitamin D and can they increase your vitamin D levels? The answer is yes but also no. Let me explain…

Mushrooms CAN contain vitamin D but they don’t make a great source for two reasons:

1. Yes, mushrooms can contain a solid amount of vitamin D, but only when exposed to UV-B light. Without UV-B light, the vitamin D amount is negligible. You’ll either have to find mushrooms that have been exposed to plenty of sunlight or grown under UV-B lamps, or put your store bought mushrooms in the sun (or under a UV-B lamp) and they’ll convert that sunlight into vitamin D, just like humans do - pretty cool, no?!

   Note: contrary to popular belief though, this little hack does NOT work if you put them in your window sill since windows block out most of the UV-B rays.

2. Mushrooms can only generate vitamin D2, which is a far less superior form of vitamin D than vitamin D3. D2 (mostly found in mushrooms and supplements) is less effective at raising vitamin D levels than D3 (mostly found in animal products and supplements). This doesn’t mean D2 doesn’t work - it just means you have to consume far more of it to get the same effect you would from consuming D3.

If you’re still keen to consume mushrooms for vitamin D, try these hacks:

• Leave in direct sunlight for a while or - in the unlikely case you own one - under a UV-B lamp

• Opt for oyster mushrooms. Research shows oyster mushrooms generate more than twice the amount of vitamin D2 than shiitake or other types at the same UV exposure level

• Slice before placing them in the sunlight. Research shows that mushrooms generate even more D2 when sliced before being exposed to UV-B light.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213178/#:~:text=Whole%20oyster%20mushrooms%20have%20been,46%2C51%2C52%5D.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213178/#:~:text=Vitamin%20D%2Denhanced%20mushrooms%20are,D%20for%20vegans%20and%20vegetarians.