Vitamin D from Sun, Supplements or Mushrooms?

Years ago, it was shown that vitamin D isn’t just the sunshine vitamin for us, but for mushrooms as well. You take some mushrooms, put them under a sun lamp for an hour, and they’ll make vitamin D just like we do lounging at the pool.

Now most mushrooms you buy at the store don’t have any vitamin D because they’re grown in the dark, but now there are sun-bathed varieties on the market that boast significant levels. Some mushrooms grown out in the wild have vitamin D as well, but only about 12% of one’s recommended daily allowance per cup.

But is the vitamin D in mushrooms bioavailable? In 2008 there was a case report of a dark skinned individual living in England in the winter who–like the other 9 out of 10 South Asians living in the UK–was vitamin D deficient. His physician prescribed a vitamin D supplement, but after doing his own research this patient decided to self-treat. He bought a UV bulb from a local hardware shop and proceeded to shine this directly onto 2 cups of regular mushrooms a day before stir-frying and consuming them. He repeated this on a daily basis for 3 months, and indeed his vitamin D levels shot up and he was cured.á So it’s reasonable to assume that such mushrooms may be able to provide a source of vitamin D for those at risk for deficiency. This was just one person though, so further studies were necessary, and finally those studies have been done.

In the above video I profile a study entitled “Bioavailability of Vitamin D from Ultraviolet Light Irradiated Button Mushrooms in Healthy Adults Deficient in Serum 25-Hydroxyvitamin D: A Randomized Controlled Trial.” They compared the mushrooms to vitamin D supplements and placebo, and both the mushrooms and the supplements were equally effective in raising vitamin D levels compared to the placebo.

The type of D made by mushrooms is vitamin D2, which is typically derived from yeast and is the form traditionally prescribed by doctors to cure D deficiency. Most supplements, though, are D3, which is the type found in plants and animals, typically derived from sheep’s wool. Back in 2008 it was established that vitamin D2 was as effective as D3 in maintaining one’s vitamin D levels at standard daily dosing levels. As you can see in the video, whether folks were given D3, D2, or a combo of half D3 and D2, it didn’t seem to matter much in terms of improving vitamin D levels in the bloodstream. But that was 5 years ago–what’s the update? Is vitamin D2 better than vitamin D3? It depends how you take it and what your starting levels are. Watch the video for the latest details.

Here are my vitamin D recommendations for those in the Northern Hemisphere:

  • Below approximately 30░ latitude (south of Los Angeles/Dallas/Atlanta/Cairo)
    • 15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
    • or 2,000 IU supplemental vitamin D daily
  • Between 30░ latitude (sample cities above) & 40░ latitude Portland/Chicago/Boston/Rome/Beijing)
    • From February through November
      • 15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
      • or 2,000 IU supplemental vitamin D daily
    • From December through January
      • 2,000 IU supplemental vitamin D daily
  • Between 40░ latitude (sample cities above) & 50░ latitude (Edmonton/London/Berlin/Moscow)
    • From March through October
      • 15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
      • or 2,000 IU supplemental vitamin D daily
    • From November through February
      • 2,000 IU supplemental vitamin D daily
  • Above approximately 50░ latitude (north of Edmonton/London/Berlin/Moscow)
    • From April through September (or even briefer above 60░ latitude (Anchorage/Stockholm)
      • 15-30 minutes of midday sun (15 for those with lighter skin; 30 for those with darker skin)
      • or 2,000 IU supplemental vitamin D daily
    • From October through March (or even longer above 60░ latitude (Anchorage/Stockholm)
      • 2,000 IU supplemental vitamin D daily

That’s not what the Institute of Medicine says though. I justify my recommendation in this video series:

What about tanning beds? See Vitamin D Pills vs. Tanning Beds.

I also recommend to Take Vitamin D Supplements With Meals.

I still think people should eat mushrooms though! For starters, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 year-in-review presentation Uprooting the Leading Causes of Death.

Image credit: bark, Jim of JimOnLight, chimothy27, and eyesore9 via Flickr; Evan-Amos andáBen Mills via Wikimedia Commons

Many Supplements Worse Than Useless
Are Bioidentical Hormones Safe?
Mushrooms For Breast Cancer Prevention


Dale O.

I live in a cold climate, so I will take a combination from all three. Thankfully, I just love mushrooms of all kinds.

Anne F.
Anne F3 years ago

interesting, but confusing - is he saying that summer sun at 60 degrees N (or S) will cause the development of vitamin D

Duane B.
.3 years ago

Thank you for sharing.

Debbie Crowe
Debbie Crowe3 years ago

In the summer, I get my Vitamin D by being in the garden or weeding! In the winter, I get it through supplements!
I did not know the mushroom had anything to do with it before. I eat them in a lot of foods, but I don't think they have enough Vitamin D in them!

Angela B.
Angela B3 years ago

So interesting, thank you! :)

Nancy Gregg
Nancy Gregg3 years ago


tiffany t.
tiffany t3 years ago

thank you Definitely need Vitamin D, prob should add some calcium as well

Natasha Salgado
natasha s3 years ago

Very interesting,thank you!!!

Kelly Davis-steel
Kelly d3 years ago


E. J.
Past Member 3 years ago