Which vegetable is a rich source of vitamin D? Debunking myths and finding plant-based options

October 26, 2025 •

3 min read

Globally, millions of people have a vitamin D deficiency, and many assume they can get this vital nutrient from vegetables alone. However, the answer to the question 'Which vegetable is a rich source of vitamin D?' is more specific than most people realize, pointing to one unique food group: mushrooms.

Quick Summary

Examine how mushrooms can naturally become a significant source of vitamin D when exposed to ultraviolet light. Compare this unique plant-based option to other fortified and non-plant dietary sources that are essential for bone health and immune function.

Key Points

Mushrooms are the unique exception: Among common vegetables, mushrooms are the only significant source of vitamin D, but only when exposed to ultraviolet (UV) light.
UV exposure is key: Most commercial mushrooms are grown in the dark and contain very little vitamin D unless they are explicitly treated with UV light.
Boost vitamin D at home: You can increase vitamin D in regular mushrooms by slicing and placing them in direct sunlight for 15-60 minutes.
Fortified foods offer alternatives: For plant-based diets, fortified products like plant-based milks (soy, almond) and cereals provide reliable sources of vitamin D.
Supplements are often necessary: Relying solely on food for vitamin D is difficult, especially during winter or for those with limited sun exposure. Supplements are often recommended.
Vitamin D is vital beyond bones: This nutrient supports immune function, regulates blood sugar, and can influence mood, highlighting its overall importance.

Most common fruits and vegetables contain little to no vitamin D. Humans primarily synthesize vitamin D through sun exposure, and top dietary sources are often animal-based, like fatty fish. However, mushrooms, a type of fungus, are a notable plant-based exception when treated with UV light. This process converts ergosterol in mushrooms into vitamin D2.

The unique case of mushrooms and UV exposure

Mushrooms are unique in the plant kingdom for their ability to produce vitamin D when exposed to UV light. This is due to ergosterol, which becomes vitamin D2 under UV rays. Most commercially grown mushrooms are cultivated in the dark and thus have low vitamin D unless labeled as 'UV-treated'. Wild mushrooms naturally contain higher levels.

Boosting vitamin D in mushrooms at home

Exposing sliced store-bought mushrooms gill-side up to direct sunlight for 15-60 minutes can increase their vitamin D content. They retain a good amount even after cooking.

Other plant-based and dietary sources

Fortified foods and supplements are crucial for vegetarians and vegans. Look for fortified plant milks, cereals, and some tofu, or vegan D3 supplements from lichen. Animal sources include fatty fish and eggs.

Comparison of vitamin D sources

Here's a comparison of approximate vitamin D content:


Source	Vitamin D Content (approximate IU)	Type of Vitamin D	Notes
UV-exposed mushrooms (½ cup white)	~366 IU	Vitamin D2	Excellent plant-based source; requires UV exposure.
Wild maitake mushrooms (½ cup raw)	~562 IU	Vitamin D2	Naturally high content from sun exposure.
Fortified soy milk (1 cup)	100–144 IU	Fortified (often D2)	Reliable, fortified plant-based option.
Wild sockeye salmon (3 oz)	~570 IU	Vitamin D3	One of the best natural animal sources.
Canned tuna (3 oz, drained)	~40 IU	Vitamin D3	Convenient but lower content.
Egg yolk (1 large)	~44 IU	Vitamin D3	Small amount, content depends on hen's diet and sun exposure.

The importance of vitamin D in your diet

Vitamin D is vital for calcium and phosphorus absorption, supporting bone and teeth health. It also aids the immune system, blood sugar regulation, and mood. Deficiency can cause fatigue, bone pain, muscle weakness, and increase the risk of osteoporosis.

Conclusion

Mushrooms are a distinctive plant-based vitamin D source when exposed to UV light. Combining UV-exposed or sun-exposed mushrooms with fortified plant foods and potential supplements helps meet vitamin D needs, especially for those avoiding animal products. Understanding these options is key to maintaining healthy levels.

How can I increase my vitamin D intake on a plant-based diet?

Focus on UV-exposed mushrooms, fortified plant milks and cereals, and consider a vegan D3 supplement.

Is vitamin D from mushrooms different from vitamin D from the sun?

Mushrooms produce vitamin D2 from UV light, while human skin produces D3 from sun exposure. Both are bioavailable, though D3 might be slightly more effective at raising blood levels.

Does cooking destroy the vitamin D in mushrooms?

A significant amount of vitamin D is retained in mushrooms after cooking, with methods like stir-frying showing good retention.

Can I get enough vitamin D from food alone?

Getting sufficient vitamin D from food alone is difficult, particularly with limited sun exposure. Supplements are often recommended.

How much sun exposure is needed to produce vitamin D?

The amount varies by factors like time of day, season, location, and skin tone. Moderate, short periods of sun exposure on skin in sunnier months is often sufficient.

What are the signs of vitamin D deficiency?

Symptoms can include fatigue, bone and muscle pain, muscle weakness, and mood changes.

Can you put regular mushrooms in the sun to increase vitamin D?

Yes, exposing store-bought mushrooms to direct sunlight increases their vitamin D2 content. Slicing them first maximizes UV absorption.

Are mushrooms a good source of vitamin D for everyone?

UV-exposed mushrooms are a valuable D2 source, especially for plant-based diets. Consult a doctor before major dietary changes.

Frequently Asked Questions

Mushrooms are the only vegetable that can be a rich source of vitamin D. Their content, however, depends on whether they have been exposed to ultraviolet (UV) light, as most commercially grown mushrooms are cultivated in the dark.

While UV-exposed mushrooms can contribute significantly to your vitamin D intake, it's difficult to rely on food alone to meet all your needs. Factors like limited sun exposure and cooking loss can impact your levels, so supplements are often still recommended.

Look for labels such as 'UV-treated,' 'enhanced with vitamin D,' or 'high in vitamin D' on the packaging. Wild mushrooms also contain naturally high levels due to sun exposure.

Aside from UV-exposed mushrooms, other plant-based sources are typically fortified foods. These include fortified plant milks (soy, almond, oat), certain cereals, and vegan D3 supplements derived from lichen.

Cooking does not completely destroy the vitamin D in mushrooms. While there may be some loss, studies show that a significant portion is retained, especially with cooking methods like stir-frying.

Mushrooms produce vitamin D2 when exposed to UV light, while the body produces vitamin D3 from sun exposure. Both are usable forms, but some evidence suggests D3 may be more effective at raising blood levels.

Most vegetables do not contain the precursor compound (ergosterol) that mushrooms use to synthesize vitamin D from UV light. This makes mushrooms a unique exception in the plant-based world.