Mighty Mushrooms: The Answer to What Vegetable Gives You the Most Vitamin D?

October 4, 2025 •

4 min read

Despite popular belief, very few plant foods naturally contain vitamin D, but there is one notable exception: mushrooms. If you've been asking yourself, "what vegetable gives you the most vitamin D?", the answer lies in certain fungi that are intentionally exposed to ultraviolet (UV) light.

Quick Summary

Mushrooms, particularly those treated with UV light, are the only significant vegetable source of vitamin D. Other plant-based options often rely on fortification, as this vitamin is predominantly found in animal products.

Key Points

UV-Exposed Mushrooms: The only significant vegetable source of vitamin D are mushrooms that have been exposed to ultraviolet light, naturally or commercially.
D2 vs. D3: Mushrooms provide vitamin D2, which may be less effective at raising blood levels than vitamin D3 from animal sources or sunlight, but is still a valuable dietary source for vegans.
Fortification is Key: Many common plant-based foods, such as soy milk, orange juice, and cereals, derive their vitamin D from fortification, not from the food itself.
Sunlight Remains Primary: For many, sun exposure is the main natural source of vitamin D, and relying on food alone, even the best vegetable sources, can be insufficient.
Supplementation May Be Necessary: Due to limited natural food sources, many people, especially those following a vegan diet or with limited sun exposure, benefit from vitamin D supplements.

The Fungal King: How Mushrooms Provide Vitamin D

While botanically classified as fungi, mushrooms are commonly treated as vegetables in a culinary context. They are the only food item in this category capable of producing nutritionally relevant amounts of vitamin D naturally. This unique ability comes from a compound called ergosterol, which converts to vitamin D2 (ergocalciferol) when exposed to ultraviolet (UV) radiation.

Unlike commercially grown mushrooms, which are typically cultivated in darkness and contain very little vitamin D, wild mushrooms often have significant amounts due to their exposure to sunlight. To ensure a consistent and high yield of vitamin D, some producers now expose their mushrooms to UV lamps post-harvest.

Maximize Vitamin D with UV-Treated Mushrooms

If you are looking to increase your intake of vitamin D from plant sources, seek out mushrooms specifically labeled as being treated with UV light. Some of the most potent options include:

UV-treated Maitake mushrooms: Can contain over 2,000 IU of vitamin D per 3 oz serving.
UV-treated Cremini mushrooms: Can provide over 1,000 IU per cup.
Sun-dried Wild Mushrooms: Wild chanterelles and morels can also be excellent natural sources.

You can even replicate this process at home. By placing sliced mushrooms gill-side up in direct midday sunlight for 15 minutes to two hours, you can significantly increase their vitamin D2 content. The amount produced depends on the time of day, season, and duration of exposure.

Understanding Vitamin D2 vs. D3

It is important to understand the two main forms of vitamin D available from food. Vitamin D2 is produced by fungi and yeast, while vitamin D3 is produced by animals and from human skin exposed to sunlight.

While both forms raise blood vitamin D levels, research indicates that vitamin D3 is more effective and maintains higher levels for longer than vitamin D2. This doesn't negate the value of UV-exposed mushrooms, but it's a key distinction for anyone evaluating their overall vitamin D strategy. For those on a vegan diet, D2 remains a valuable option, alongside supplements derived from lichen.

Fortified Plant-Based Food Sources

Since mushrooms are the only natural, non-animal source of significant vitamin D, vegetarians and vegans often rely on fortified foods. Food manufacturers add vitamin D to a variety of products to boost their nutritional value. Always check the nutrition label to confirm fortification and dosage.

Common fortified plant foods include:

Plant-based milks: Soy, almond, and oat milk are frequently fortified with vitamin D.
Fortified orange juice: Provides a source of vitamin D along with vitamin C.
Fortified breakfast cereals: Many popular cereals are enriched with vitamin D.
Tofu: Some varieties of packaged tofu are fortified and can provide a moderate amount of vitamin D.

Other Sources and Nutritional Considerations

While this article focuses on the best plant-based options, it's beneficial to understand how these compare to other vitamin D sources and to incorporate foods that support its absorption. The best natural food sources of vitamin D are fatty fish (such as salmon and herring) and cod liver oil. Eggs and beef liver also contain smaller amounts.

Additionally, some vegetables, while not sources of vitamin D themselves, contain complementary nutrients. For example, spinach is rich in calcium, while bananas contain magnesium, which helps activate vitamin D in the body.

A Comparison of Vitamin D Sources


Source	Type	Vitamin D Content (approx. per serving)	Note
UV-Treated Mushrooms (Cremini, Maitake)	Fungi	High (e.g., 1000+ IU per cup)	Content varies based on light exposure.
Wild Mushrooms	Fungi	Variable (e.g., 200+ IU per 100g)	Subject to season and sun exposure.
Fortified Soy Milk	Fortified Food	100–144 IU per cup	Added during processing. Check label.
Fortified Orange Juice	Fortified Food	100 IU per cup	Added during processing. Check label.
Atlantic Salmon	Animal Product	570 IU per 3 oz	One of the richest natural sources.
Cod Liver Oil	Animal Product	1,360 IU per tbsp	Highly concentrated source.
Spinach	Vegetable	Negligible	Contains calcium, but not vitamin D.

The Importance of Supplementation

For most people, it is challenging to meet the daily recommended vitamin D intake through diet alone, especially in regions with limited sunlight. The primary and most efficient source for many remains sun exposure, but this must be balanced against the risk of skin cancer. Due to these challenges, supplementation is often recommended, particularly for individuals with specific dietary needs or those living in northern latitudes during winter. It's crucial to consult a healthcare provider to determine the right dosage for you.

Conclusion

While the search for what vegetable gives you the most vitamin D leads directly to mushrooms, the broader picture of acquiring this essential nutrient is more complex. UV-exposed mushrooms offer a powerful, natural plant-based source of vitamin D2, making them invaluable for vegetarians and vegans. However, fortified foods play a significant role in filling dietary gaps, and sunlight remains a potent natural source for many. Ultimately, a multi-pronged approach that includes sun exposure, fortified products, and, if necessary, supplements is often the most reliable way to maintain adequate vitamin D levels for optimal health.

For more information on the importance of vitamin D and comprehensive food sources, you can visit the Office of Dietary Supplements at NIH.

Frequently Asked Questions

Mushrooms that have been exposed to ultraviolet (UV) light are the only significant vegetable source of vitamin D. Their ergosterol is converted to vitamin D2 by the UV rays.

No, most commercially grown mushrooms are cultivated in the dark and contain very little vitamin D. Only wild mushrooms or those specifically treated with UV light are good sources of the vitamin.

Yes, many plant-based foods are fortified with vitamin D, meaning it is added during processing. Examples include fortified soy milk, orange juice, and breakfast cereals.

You can increase the vitamin D in fresh mushrooms by exposing them to midday sunlight for 15 minutes to two hours. This process works best when they are sliced and placed gill-side up.

No, mushrooms produce vitamin D2, while sunlight triggers the production of vitamin D3 in humans. While D2 is bioavailable, some studies suggest D3 may be more effective at raising blood vitamin D levels.

Vitamin D is crucial for maintaining bone health by regulating calcium and phosphate levels. It also plays a vital role in immune function, muscle development, and overall well-being.

No, leafy greens like spinach and kale are not significant sources of vitamin D. While they are rich in other nutrients like calcium, they cannot be relied upon to boost your vitamin D intake.