Do Plants Give Off Vitamin D? Understanding Plant-Based Sources in Your Nutrition Diet

October 31, 2025 •

5 min read

While the sun is a primary source of vitamin D for most people, mushrooms are the most notable non-animal source of this nutrient, producing vitamin D2 when exposed to UV light. This raises a key question for anyone on a plant-based nutrition diet: do plants give off vitamin D in the same way? The answer is more complex than a simple yes or no.

Quick Summary

The article explores whether common vegetables and other plants produce vitamin D. It details the distinction between vitamin D2 and D3, highlighting fungi like mushrooms as the primary plant-based source. The guide covers how mushrooms produce vitamin D with UV exposure, examines the crucial role of fortified foods, and touches upon new biofortification research.

Key Points

Mushrooms are the primary plant-based source: Fungi, including wild and UV-treated mushrooms, are the most reliable non-animal dietary source of vitamin D, converting ergosterol to vitamin D2 when exposed to ultraviolet (UV) light.
Most plants contain no significant vitamin D: Despite absorbing sunlight, most common fruits and vegetables contain only negligible amounts of the vitamin and are not considered a reliable source for humans.
Vitamin D has two main forms: Vitamin D2 comes from fungi and fortified foods, while vitamin D3 is primarily from sun exposure and animal products. Vitamin D3 is more bioavailable.
Fortified foods are a crucial supplement: For those on a plant-based diet, consuming fortified products like plant-based milks, cereals, and juices is an effective strategy to increase vitamin D intake.
Biofortification holds future promise: Emerging research is exploring genetically engineering plants, such as tomatoes, to produce and accumulate higher levels of provitamin D3, potentially offering a new route to plant-based vitamin D sufficiency.
Strategic planning is key for plant-based diets: Maintaining adequate vitamin D levels on a vegan or vegetarian diet requires a conscious effort involving sunlight exposure, dietary intake of mushrooms and fortified foods, and often supplementation.

The Vitamin D Dilemma for Plant-Based Eaters

For most people, the skin’s exposure to ultraviolet B (UVB) rays from sunlight is the most significant source of vitamin D. When UVB rays strike the skin, a precursor molecule is converted into vitamin D3 (cholecalciferol). In contrast, the dietary sources of vitamin D are often limited to animal products, leading many following a plant-based diet to question how they can meet their daily requirements. The assumption that plants, which thrive under the sun, are a natural source is a common misconception, but a closer look reveals some interesting exceptions and modern solutions.

The Crucial Distinction: Vitamin D2 vs. D3

To understand the role of plants, it's important to know the difference between the two main forms of vitamin D available in food and supplements:

Vitamin D2 (Ergocalciferol): This form is produced by fungi (like mushrooms) and yeasts when exposed to UV light. Historically, it has been considered the only plant-based form of the vitamin. It can also be added to fortified foods.
Vitamin D3 (Cholecalciferol): This is the form produced by human and animal skin in response to sunlight. It is also found in animal products like fatty fish, fish liver oils, egg yolks, and some cheese. Research has shown that D3 is more bioavailable and raises blood vitamin D levels more effectively than D2.

Mushrooms: The Primary Plant-Based Exception

While most common fruits and vegetables contain negligible amounts of vitamin D, mushrooms are a unique and valuable exception. Mushrooms contain a compound called ergosterol, which is converted into vitamin D2 when exposed to ultraviolet radiation. This process is similar to how human skin produces vitamin D3. The vitamin D content in mushrooms varies greatly depending on their exposure to UV light.

Wild Mushrooms: Wild varieties like morels are naturally excellent sources of vitamin D2 due to their exposure to sunlight in their natural habitats.
UV-Treated Mushrooms: Many commercially grown mushrooms, which typically grow in dark environments, are now intentionally treated with UV light to boost their vitamin D content. A single cup of UV-treated cremini mushrooms can provide a significant amount of the daily recommended value.
DIY Sunlight Exposure: You can increase the vitamin D content of your store-bought mushrooms at home by spreading them on a tray and placing them in direct sunlight for a short period. The vitamin D levels remain stable even after cooking.

The Role of Fortified Foods

For individuals on a plant-based diet, fortified foods are a reliable way to increase vitamin D intake. Many products that don't naturally contain the nutrient have it added during processing.

Some common fortified plant-based foods include:

Plant-Based Milks: Soy, almond, and oat milks are often fortified with vitamin D, providing a dairy-free alternative.
Breakfast Cereals: Many brands of breakfast cereals are enriched with essential vitamins, including vitamin D.
Orange Juice: Some orange juice products are fortified with vitamin D and calcium.
Margarine: Certain brands add vitamin D to margarine spreads.

Comparison of Major Vitamin D Sources


Source	Vitamin D Type	Bioavailability	Reliability	Special Considerations
Sunlight	D3	High	Varies by location, season, and time of day	Risk of skin damage with overexposure
Animal Foods	D3	High	Consistent source	Not suitable for vegan or vegetarian diets
Mushrooms	D2 (some D3)	Moderate	Variable, depends on UV exposure	Wild mushrooms are the best natural source; UV-treated are reliable
Fortified Foods	D2 or D3	Moderate to High	Consistent and controllable	Must check product labels; amounts vary
Supplements	D2 or D3	High	Very reliable	Dosage requires care; D3 may be more effective

Biofortification: The Future of Plant Vitamin D

Recent advances in biotechnology offer new possibilities for increasing the vitamin D content of plants. Biofortification is the process of increasing the nutrient density of food crops through conventional breeding or genetic engineering. For example, scientists have successfully engineered tomatoes to accumulate higher levels of provitamin D3. While these technologies are still under development and not yet widespread, they represent a potential future for creating more vitamin D-rich plant sources.

Conclusion: Strategic Choices for a Vitamin D-Rich Plant-Based Diet

In conclusion, most plants do not naturally provide a significant amount of vitamin D, challenging the assumption that a plant-rich diet guarantees adequate intake. However, reliable plant-based options exist. Fungi, particularly UV-exposed mushrooms, offer a natural source of vitamin D2, and a wide array of fortified plant-based products help fill the nutritional gap. For many people, a combination of sun exposure, dietary sources, and sometimes supplements is the most effective strategy for maintaining sufficient vitamin D levels. The primary takeaway is that a conscious effort is needed to obtain this vital nutrient, especially for those on a strict plant-based diet, rather than relying on plants as a universal source. For personalized advice, a consultation with a healthcare provider is recommended. More information on dietary sources can also be found at the National Institutes of Health.

Are Plants a Reliable Source of Vitamin D?

No, most plants are not a reliable source of vitamin D for human nutrition. While fungi like mushrooms can produce vitamin D2 when exposed to UV light, and some research shows trace amounts of D3 in specific plant leaves, most edible plants contain negligible amounts of this essential nutrient.

What is the difference between vitamin D2 and D3?

Vitamin D2 (ergocalciferol) is the form found in fungi and fortified foods, while vitamin D3 (cholecalciferol) is the form produced in human and animal skin upon sun exposure. Vitamin D3 is also found in animal products like fatty fish and eggs and is generally considered more bioavailable for humans.

Can a vegan or vegetarian get enough vitamin D from diet alone?

It is very difficult for a vegan or vegetarian to get enough vitamin D from diet alone without specific strategies. Relying on UV-exposed mushrooms and a variety of fortified foods is necessary, and supplementation is often required to meet daily needs, especially in months with low sun exposure.

Do plants produce vitamin D when exposed to sunlight?

Only some fungi and microalgae can effectively produce a form of vitamin D when exposed to UV light. Fungi convert ergosterol to vitamin D2, but most common plants do not have this mechanism. The vitamin D found in plants is often an incidental byproduct of UV irradiation.

Can I increase the vitamin D in my mushrooms at home?

Yes, you can increase the vitamin D content of your mushrooms at home. Simply place them with their gills facing up on a baking sheet in direct sunlight for 15-60 minutes before cooking. The UV exposure will increase their vitamin D2 levels.

How does the body process vitamin D from food versus sunlight?

The body processes vitamin D from food and supplements in the same way it processes the vitamin from sun exposure. Both dietary and skin-produced forms must be hydroxylated by the liver and kidneys into the active form, calcitriol, before they can be used by the body.

What are some examples of fortified foods for vitamin D?

Common fortified foods include cow's milk (in some countries), plant-based milks like soy and almond, some breakfast cereals, certain margarines, and orange juice. It is important to check the product label, as not all brands fortify their products.

Are there any vegetables that naturally contain vitamin D?

Most vegetables do not contain a significant amount of vitamin D. While some specific plant families (like Solanaceae) contain very small traces of vitamin D3 in their leaves, the amount is nutritionally insignificant for humans from dietary consumption.

Frequently Asked Questions

No, most plants do not give off vitamin D in a nutritionally significant way for humans. The most notable exception is fungi, such as mushrooms, which produce vitamin D2 when exposed to ultraviolet light, but most common vegetables contain only negligible amounts.

Vitamin D2 (ergocalciferol) is the form produced by fungi and yeasts and is often used to fortify foods. Vitamin D3 (cholecalciferol) is the form produced in the skin of animals and humans via sun exposure and is found in animal products. D3 is generally considered more effective at raising blood vitamin D levels.

It can be challenging to get sufficient vitamin D from a purely plant-based diet without careful planning. Reliable sources include UV-treated mushrooms, fortified plant-based milks and cereals, and supplements. Many people will require supplementation, especially during periods of low sun exposure.

Mushrooms contain a compound called ergosterol in their cell walls. When exposed to ultraviolet (UV) radiation from the sun or UV lamps, this ergosterol is converted into pre-vitamin D2, which then becomes ergocalciferol, or vitamin D2.

Yes, fortified foods are a reliable way for vegans to increase their vitamin D intake. Many plant-based milks (soy, almond, oat), cereals, and orange juices are fortified. It is important to check product labels, as the amount of vitamin D can vary between brands.

No, eating plants that grow in sunlight does not provide a significant source of vitamin D for humans. Unlike animals and fungi, plants do not have the same metabolic pathway for producing and storing the active forms of vitamin D in a way that is beneficial for human consumption.

Biofortification is the process of increasing the nutrient density of food crops, including through genetic engineering. In the context of vitamin D, scientists have engineered crops like tomatoes to produce high levels of provitamin D3, potentially offering a future dietary source of vitamin D from plants.