Sunlight, Mushrooms, and Vitamin D

Let’s talk about vitamin D, affectionately nicknamed the sunshine vitamin, and an unusual bedfellow… the mushroom.

Some mushrooms are specially grown to contain vitamin D, perhaps you’ve seen them at your local supermarket. But how?

Here’s what you need to know about your mighty, meaty, magical friend, the mushroom:

• They contain a vitamin D precursor called ergosterol
• When ergosterol is exposed to UV light it is converted to vitamin D (just like in your body – more on that later)
• Wild mushrooms naturally contain vitamin D because they are exposed to the sun 
• Commercial mushrooms are like your unfriendly hoarder neighbor… in the dark, therefore not exposed to sun
• Commercial mushrooms that contain vitamin D do so because they are exposed to UV lamps after harvesting
  • A serve (90g/3oz) of these mushrooms contain ~400IU (international units) of vitamin D
  • For reference, most adults need 600 IU/day

If you don’t buy the vitamin D-enhanced mushrooms, there is a poor man’s solution…! It’s all about letting the sun shine where the sun don’t shine… Take your mushies outside and turn them upside down, gills (called lamellae) facing up, leave for 15 minutes. Benefits of mushroom sunbathing:

• They will produce between 200-800IU of vitamin D
• They may dry out a little or have mild discolouration, but they retain >90% of the vitamin D even after stored and cooked

Some information on vitamin D:

Estimating vitamin D status has some challenges because sun exposure affects vitamin D status, not just food intake. While there are some food sources of vitamin D, it’s not as easy to obtain from food compared to other vitamins and minerals. See the table below for food sources.

How is vitamin D synthesized in the body?

When skin is exposed to UV B radiation, a cholesterol metabolite in the skin produces vitamin D3. But it’s not that simple… Your friendly liver and the kidneys are needed to perform a conversion (called hydroxylation) to produce the biologically active form of vitamin D. Voila.

What did we learn?

• Mushrooms can provide vitamin D
  • If they are grown and exposed to UV light commercially
  • If you expose their lamellae to sunlight (sounds dirty… get it, coz mushroom grow in dirt?)
• Your skin, liver, and kidneys are the players that convert sunlight into vitamin D

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