⬇️ Prefer to listen instead? ⬇️
- 🍄 UV-exposed mushrooms can provide over 46,000 IU of vitamin D2 per 100g of dried shiitake.
- ☀️ Mushrooms use UV-B light to convert ergosterol into vitamin D2 naturally, like human skin produces D3.
- 🥗 Vitamin D2 from mushrooms is effective in raising blood levels of vitamin D despite its shorter half-life.
- 🔬 White button, portabella, shiitake, and maitake mushrooms are the most responsive to UV-B light.
- 🧪 Cooking retains up to 80% of vitamin D2, making UV-treated mushrooms a reliable dietary source.
Vitamin D deficiency is a global concern. This is especially true for people living in places with less sun, those who spend little time outdoors, or people who avoid animal-derived foods. Vitamins in pill form are popular, but people are starting to see mushrooms as a natural, plant-based source of vitamin D. This only happens with a little help from UV-B light. Even home cultivators growing mushrooms in Mushroom Grow Bags or Monotubs can boost vitamin D content by briefly exposing their harvests to UV light after fruiting. Understanding how mushrooms make vitamin D helps both buyers and growers improve this process—a big step toward better nutrition in a natural way.
Vitamin D2 vs. D3: What You Need to Know
There are two main types of vitamin D that help people stay healthy: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both do important jobs. They help keep calcium balanced, bones healthy, and the immune system working, among other things. But they come from different places, last differently, and work differently.
- Vitamin D3 is mainly found in animal foods. These include fatty fish, egg yolks, and liver. Or it is made in a lab for supplements. People think it is easier for the body to use. And it stays in the blood longer.
- Vitamin D2, on the other hand, is only naturally in fungi. This makes it good for people who eat vegetarian or vegan.
An important thing to know is how well D2 from mushrooms works. Studies, like one by Biancuzzo et al. (2010), show that vitamin D2 from UV-exposed mushrooms clearly raises blood levels of 25(OH)D. This is the usual way to check vitamin D status.
And while D3 is stronger per gram and stays in the blood longer, vitamin D2 from mushrooms still offers many good, trustworthy benefits. And for people who avoid animal products or want whole foods, this is big news.
How Mushrooms Naturally Produce Vitamin D
Mushrooms have a special thing plant foods don't have. They can make vitamin D when they get UV-B light. This works because they have a compound called ergosterol. It works like cholesterol does in people. When conditions are right, ergosterol changes into ergocalciferol (vitamin D2) when hit by UV-B light from the sun or lamps.
The Biochemistry of Conversion:
- Ergosterol (in mushroom cell membranes) + UV-B (290–315 nm wavelength) ➝ Ergocalciferol (Vitamin D2)
This chemical reaction needs no additives, preservatives, or added vitamins. Instead, it is a simple, natural change. People can use it by giving mushrooms time in the sun.
And what is more, this change can happen after they are picked. Most other produce does not do this. But mushrooms still react to UV-B light after picking. So, it is easy for people to make their mushrooms better at home.
UV-B and Mushrooms: Making Vitamin D With Light
The specific type of light needed to change ergosterol into vitamin D2 is UV-B (ultraviolet B). This light is in the 290 to 315 nanometer range. It is the same part of the ultraviolet light that makes skin produce vitamin D3.
Guidelines for UV Exposure:
- Time of Day: Sunlight is richest in UV-B between 10 AM and 2 PM.
- Seasonality: In winter or in places far from the equator, sunlight may not have enough UV-B. So, UV-B lamps are a good option then.
- Duration: Giving mushrooms light for just 15 minutes can increase vitamin D. A full 60 minutes gives the best results.
-
Mushroom Positioning:
- Place mushrooms gill-side up for best results. The gills contain the highest concentrations of ergosterol.
- Sliced mushrooms show more surface area to light. This lets more UV light get in and makes a lot more vitamin D.
- Post-Harvest Light: Mushrooms have the most ergosterol and react best to UV light after they are picked, not while growing.
So, if you buy mushrooms at the store or grow them at home, this knowledge helps you improve your food’s nutrients. All you need is light exposure you control.
Which Mushrooms Work Best?
All mushrooms have some ergosterol. But some types are very good at making a lot of vitamin D2 when given UV-B light. Here are the best ones for this change:
Most Responsive Mushroom Varieties:
- White Button (Agaricus bisporus): This is the easiest to find and cheapest type. They are small, but they make a lot of vitamin D when they get UV light.
- Portabella: These are older white button mushrooms. They have bigger tops, which are good for taking in UV light.
- Shiitake (Lentinula edodes): These are popular in Asian cooking and with special growers. Shiitakes have a lot of ergosterol.
- Maitake (Grifola frondosa): You can often find maitakes in health food stores. They react well to UV light. And they have other good polysaccharides too.
Also, wild mushrooms grown in sunlight naturally have more vitamin D than those grown in the dark. If you grow mushrooms at home, pick these types. This means you get the most from using UV-B methods.
Home Cultivation: Take Control of Vitamin D Boosting
Adding mushroom vitamin D to your daily life is especially easy if you grow them yourself. Home kits and counter-top growing systems make it possible for families and people who like hobbies to grow mushrooms without high costs or fancy gear.
Vitamin D Boosting Tips for Home Growers:
- Sunlight Use: After you pick your mushrooms, place them gill-side up. Put them in a sunny windowsill or outside on a clear day for 30 to 60 minutes.
- Artificial UV Light: UV-B lamps made for reptiles or skin treatment can act like natural sunlight. Always follow safety instructions from the maker.
- Slice Before Light: Flat or sliced pieces make sure more tissue with ergosterol gets UV rays. This gets the most vitamin D.
- Rotate or Flip: If mushrooms aren’t sliced, flip them halfway during the light time to treat both sides evenly.
Using these practices turns your mushrooms from simple nice food to healthy superfoods.
How Much Vitamin D Can Mushrooms Provide?
Mushrooms have a very surprising ability to produce vitamin D2. This is especially true when given the right UV-B light. Data from many studies show how much this change can be:
- In a main study by Jasinghe et al. (2005), shiitake mushrooms given UV radiation went from just 100 IU of vitamin D2 per 100 grams dry weight to over 46,000 IU after one hour.
- For context, the Recommended Dietary Allowance (RDA) for vitamin D in adults is:
- 600 IU/day for individuals under 70
- 800 IU/day for those over 70
And if eaten fresh, 100 grams of mushrooms treated well with UV light can easily provide 2,000 to 4,000 IU. This makes them a great help for managing your own nutrition. This is true especially in places without much sun.
Is Vitamin D2 from Mushrooms Effective?
There is some talk among doctors and nutrition experts about how well D2 works compared to D3. But vitamin D2 from mushrooms has shown it can truly help raise blood 25(OH)D levels.
Supporting Evidence:
- Biancuzzo et al. (2010) showed that foods with D2 added (like mushrooms) were just as good as foods with D3 at keeping blood vitamin D levels high enough.
- And while D2 might not be as strong and stays in the blood for less time, eating it often makes up for these things.
- For plant-based eaters or anyone avoiding animal-based supplements, UV-treated mushrooms give a real and important source of vitamin D.
So, when eaten as part of a good diet, vitamin D2 from mushrooms can definitely help you get and keep enough vitamin D in your blood.
Does Cooking or Storing Change Vitamin D Levels?
Heat and storage can change how good nutrients are. But vitamin D2 stays quite stable in mushrooms.
Stability Summary:
- Boiling, baking, and sautéing retain around 80–88% of vitamin D2 content.
- Grilling might keep a bit less D2. This depends on how long they are cooked and if they burn.
- Sun drying is an old way to save mushrooms. It does two good things. It saves mushrooms, and it makes more vitamin D as they dry.
-
Storage Best Practices:
- Keep dried, UV-exposed mushrooms in airtight, opaque containers.
- Store in a cool, dark place. This will keep them from getting worse because of light or heat.
- Vitamin D2 in dried mushrooms remains highly stable for at least 6–12 months.
And these things make mushrooms a great food to keep in your pantry for future nutrition.
Can You Rely Solely on Mushrooms for Vitamin D?
Mushrooms are a strong source of vitamin D2. But they should not be your only source if you are likely to be very low in it. Here is why:
- D2 vs. D3 Limits: D2 stays in the body for less time. So you might need to eat it more often to keep blood levels steady.
- How well your body uses it: Things like gut health, how your body works, and your overall diet change how much vitamin D your body takes in.
- How often you eat it: Not many people eat 100 grams of mushrooms every day. Eating different foods and what is available in different seasons can mean you eat less D2 each day.
Still, mushrooms can realistically make up a big part of the vitamin D you need each day. This is especially true when you eat them with foods that have added vitamins or other natural sources.
Best Practices for Getting the Most Vitamin D from Mushrooms
To turn your mushrooms into a big source of vitamin D, you need to be consistent and do it right.
Practical Tips for Everyday Use:
- Slice before putting them in sunlight to get the most UV-B light.
- Give mushrooms light after picking. This is when they have the most ergosterol.
- Time it right: Try for late morning to early afternoon. This is when UV-B light is strongest.
- Other light sources: Use a UV-B lamp for about 30–60 minutes. Make sure to follow all safety rules.
- Add to meals often — 50–100g servings a few times per week can give a steady push of nutrients.
So, following these strategies makes sure you make the best of every batch of mushrooms for better health benefits.
Zombie Mushrooms: UV Boosting for Hobby Growers
At Zombie Mushrooms, our goal is simple. We help everyday people grow mushrooms full of nutrients at home. Our kits are made so you can easily use UV-B light.
How to Improve Your Zombie Kit Yield:
- Follow growing instructions to produce fresh mushrooms.
- After harvesting, put mushrooms in UV-B light or natural sunlight for 30–60 minutes.
- Slice before giving them light for even more vitamin D.
- Use or store mushrooms in an airtight container afterward.
And with a Zombie Mushrooms kit, you are not just growing fungi. You are creating healthy superfoods that make their own vitamins right from your kitchen counter.
Mushrooms: Your DIY Superfood for Vitamin D
There is a good connection between UV-B and mushrooms. This is a natural wonder. By using the natural ability of mushrooms to make vitamin D2, we get an easy, plant-based way to fight widespread lack of vitamin D. Home growing is easy, and sun exposure is simple. And with these things, mushrooms become a truly easy way to get better health.
So, maybe you want to make your diet better, use nutrition that lasts, or just grow them better. Giving your mushrooms time in the sun might be the healthiest thing you can do today.
Citations
Biancuzzo, R. M., Young, A., Bibuld, D., Cai, M. H., Winter, M. R., Klein, E. K., ... & Holick, M. F. (2010). Fortification of orange juice with vitamin D2 or vitamin D3 is as effective as an oral supplement in maintaining vitamin D status in adults. The American Journal of Clinical Nutrition, 91(6), 1621–1626. https://doi.org/10.3945/ajcn.2009.27972
Jasinghe, V. J., Perera, C. O., & Barlow, P. J. (2005). Bioavailability of vitamin D2 from irradiated mushrooms: preliminary studies. Journal of Nutritional Science and Vitaminology, 51(5), 362–365.
Phillips, K. M., Horst, R. L., Koszewski, N. J., & Simon, R. R. (2012). Vitamin D4 in mushrooms. PLOS ONE, 7(8), e40702. https://doi.org/10.1371/journal.pone.0040702
