Finding the Sun-Powered Source: Which vegan food has the highest vitamin D?

October 6, 2025 •

4 min read

Over one billion people worldwide are vitamin D deficient, and for those following a vegan diet, finding adequate food sources can be challenging. This is why identifying which vegan food has the highest vitamin D is crucial for maintaining bone health and immune function. The answer lies in a fascinating fungal phenomenon: mushrooms exposed to ultraviolet (UV) light.

Quick Summary

UV-exposed mushrooms are the top natural vegan food source for vitamin D, while fortified products like plant-based milks and cereals provide additional support. Supplements are often recommended to ensure consistent intake, especially during winter months.

Key Points

UV-Exposed Mushrooms: Maitake and portobello mushrooms treated with UV light are the most potent natural vegan source of vitamin D, containing hundreds to thousands of IU per serving.
Fortified Plant Milks: Products like soy, almond, and oat milk are commonly fortified, offering a convenient and reliable daily source of vitamin D.
Check Product Labels: The vitamin D content in fortified foods varies significantly by brand, so always read the nutrition facts to confirm its inclusion and amount.
Consider Vegan Supplements: Since dietary sources can be inconsistent, a vegan D2 or lichen-derived D3 supplement is a highly reliable way to ensure adequate vitamin D intake, especially in winter.
Enhance Absorption with Fat: To maximize vitamin D absorption, consume your dietary sources or supplements with a meal containing healthy fats like avocado, nuts, or seeds.
DIY Sun-Exposure: You can easily increase the vitamin D content of store-bought mushrooms at home by leaving them in direct midday sunlight for 15-60 minutes.

Mushrooms: The Natural Vegan Powerhouse of Vitamin D

Mushrooms are unique among plant-based foods because they are fungi, and like humans, they can produce vitamin D when exposed to UV light. A compound called ergosterol in mushrooms is converted into vitamin D2 (ergocalciferol) by UV radiation. While most store-bought mushrooms are grown in dark conditions and have very low vitamin D content, wild mushrooms or those intentionally exposed to UV light can be incredibly rich sources.

Some of the highest natural vegan sources come from these specially prepared mushrooms:

UV-exposed maitake mushrooms: Can contain well over 2,000 IU of vitamin D per 3 oz serving.
UV-exposed raw Portobello mushrooms: May contain as much as 568 IU per 50g.
UV-exposed raw white mushrooms: Can provide around 523 IU per 50g.

You can even boost the vitamin D content of your own mushrooms at home. Simply place them gill-side up in direct sunlight for 15 minutes to an hour. The vitamin D content generated this way is remarkably stable and survives cooking.

Fortified Foods: Reliable Dietary Additions

For consistent and reliable vitamin D intake, fortified foods are a practical option for vegans. These products have vitamin D added during processing, but it is important to check labels as not all brands fortify their products.

Common Fortified Vegan Products

Plant-based milks: Many soy, almond, and oat milks are fortified with vitamin D. A single cup can provide a significant portion of your daily needs, with amounts varying by brand. Be sure to shake the container well before serving, as the vitamin can settle at the bottom.
Breakfast cereals: A wide range of mainstream cereals are fortified with vitamins and minerals, including vitamin D. The amount per serving varies, so reading the nutrition label is key.
Certain tofu products: Some brands of tofu are fortified with vitamin D, along with other essential nutrients like calcium. Look for this information on the packaging.
Fortified orange juice: Not all orange juice contains added vitamin D, but options fortified with both calcium and vitamin D are readily available. As with other fortified products, check the label.

Understanding Vitamin D2 and D3

Vitamin D comes in two major forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is produced by fungi (like mushrooms) and yeast when exposed to UV light, making it a natural vegan source. Vitamin D3 is typically sourced from animals, but vegan-friendly versions derived from lichen are now widely available.

While some studies suggest D3 may be slightly more effective at raising blood levels, both forms are well-absorbed and can effectively increase and maintain vitamin D status, especially when taken consistently. For most vegans, a combination of D2 from mushrooms and fortified foods, supplemented with D3 from lichen if needed, is a robust strategy.

Sunlight: The Ultimate Source

It's important not to forget the most natural and potent source of vitamin D: sunlight. The body produces vitamin D3 when the skin is exposed to UVB rays. For most people, 10–30 minutes of midday sun exposure to the face, arms, hands, and legs a few times a week is sufficient for vitamin D synthesis. However, factors like season, latitude, skin pigmentation, and age can affect the amount of vitamin D produced. Sunscreen, while vital for skin protection, also blocks vitamin D synthesis. Vegans and others with limited sun exposure should focus on dietary sources and consider supplementation.

A Comparison of Vegan Vitamin D Sources


Source	Vitamin D Type	IU per Serving (Approx.)	Notes
UV-Exposed Maitake Mushrooms	D2	>2000 IU (3 oz)	Requires special growing conditions or UV treatment. Highest concentration.
UV-Exposed Portobello Mushrooms	D2	568 IU (50g)	Requires special growing conditions or UV treatment.
Fortified Soy Milk	D2 or D3	116 IU (1 cup)	Varies by brand. Check labels.
Fortified Cereal	D2 or D3	8-120 IU (per serving)	Varies widely by brand. Check labels.
Fortified Tofu	D2 or D3	100 IU (100g)	Varies by brand. Check labels.
Fortified Orange Juice	D2 or D3	100 IU (8 oz)	Only fortified versions contain vitamin D.
Wild Morel Mushrooms	D2	136 IU (1 cup)	Content varies based on natural sun exposure.
Vegan D3 Supplement (Lichen)	D3	Varies widely	Look for lichen-sourced D3. Excellent for consistent, high-dose intake.

The Role of Fat in Absorption

Vitamin D is a fat-soluble vitamin, meaning it is absorbed more effectively when consumed with fat. When incorporating fortified vegan foods or supplements into your diet, consider pairing them with healthy fats to maximize absorption. For example, have fortified plant milk in a smoothie with avocado or nuts, or take your supplement with a meal containing olive oil or seeds.

Conclusion

When it comes to answering the question of which vegan food has the highest vitamin D, the undeniable winner is mushrooms that have been deliberately exposed to ultraviolet light. These fungi, particularly maitake and portobello varieties, can provide a single-serving dose that far surpasses other dietary sources. However, relying solely on natural dietary sources is often insufficient for consistent, optimal vitamin D levels. A holistic strategy for vegans includes embracing UV-exposed mushrooms, choosing a variety of fortified plant-based foods, getting safe sun exposure, and considering a quality vegan supplement derived from lichen or yeast. By combining these approaches, vegans can effectively maintain healthy vitamin D levels for robust bone health and overall well-being. For more information on dietary reference intakes for vitamin D, consult authoritative sources like the National Institutes of Health. [^authoritative-link]

[^authoritative-link]: National Institutes of Health - Vitamin D Fact Sheet for Health Professionals

Frequently Asked Questions

It is very challenging to get sufficient vitamin D from vegan food sources alone due to the limited number of naturally occurring sources. While UV-exposed mushrooms and fortified foods help, most health professionals recommend supplementation, especially during months with limited sun exposure.

No. Most commercially grown mushrooms are cultivated in the dark and contain negligible amounts of vitamin D. Only wild mushrooms or those explicitly exposed to ultraviolet (UV) light contain significant levels.

Vitamin D2 is derived from plants and fungi like yeast and mushrooms, while traditional D3 comes from animal sources. Vegan D3 supplements, however, are sourced from lichen, a plant-like organism. Both forms are effective, but some studies suggest D3 may be more potent.

You must check the nutrition label on the product packaging. The label will list vitamin D if it has been added. Not all plant milks are fortified.

No, studies show that the vitamin D2 in UV-exposed mushrooms is relatively stable during cooking and processing. Retention rates are generally high, although some minor loss may occur depending on the cooking method.

The body can naturally produce vitamin D3 when the skin is exposed to direct sunlight. Vegans can and should utilize safe sun exposure, but it's not a reliable year-round source for everyone due to factors like latitude, season, and skin tone.

It is highly unlikely to get a toxic level of vitamin D from food and sun exposure alone. However, high-dose supplementation can lead to excessive intake, so it is important to follow dosage recommendations and consult a doctor.