Nutrition Diet: Understanding Why Vegans Can't Rely on Standard Vitamin D Sources

October 7, 2025 •

4 min read

According to the National Institutes of Health, the highest natural food sources of vitamin D are almost exclusively animal-based, a key reason why can't vegans have vitamin D through diet alone without strategic planning. This necessitates a comprehensive understanding of alternative sources to ensure a nutritionally complete vegan diet.

Quick Summary

This article explores the challenges vegans face in obtaining adequate vitamin D, explaining the natural scarcity of plant-based sources and the differences between vitamin D2 and D3. It details crucial strategies for intake through sunlight, fortified foods, and supplements to maintain optimal levels.

Key Points

Dietary Scarcity: Most natural dietary sources of vitamin D, especially D3, are animal-derived, making it challenging for vegans to obtain it through food alone.
D2 vs. D3: Vitamin D2 is plant-based (from UV-exposed mushrooms and yeast), while most D3 is animal-sourced (sheep's wool lanolin). Vegan D3 from lichen is now available.
Sunlight is Key: UV radiation exposure remains the most effective and natural way for the body to synthesize vitamin D for everyone, but seasonal and skin-tone differences must be considered.
Supplementation and Fortification: Relying on fortified vegan foods (plant milks, cereals) and targeted supplements (especially lichen-based D3) is often necessary for vegans to meet their vitamin D needs.
Label Vigilance: Vegans must carefully check product labels, as some fortified foods and supplements may use non-vegan D3 sources derived from animals.
Enhanced Absorption: Taking vitamin D supplements with fat-containing meals, such as those with nuts, seeds, or avocado, can significantly improve absorption.

The Core Challenge: Dietary Source Limitations

While the phrase "why can't vegans have vitamin D" is a misconception—vegans absolutely can obtain this vital nutrient—it accurately reflects the dietary challenge faced. The primary issue is the natural distribution of vitamin D in the food supply. Most foods that naturally contain substantial amounts of vitamin D are of animal origin. Fatty fish like salmon and mackerel, cod liver oil, and egg yolks are well-known sources, but they are incompatible with a vegan lifestyle. As a result, individuals on a strict plant-based diet must look beyond the standard food groups to meet their needs, requiring a more conscious and proactive approach to nutrition.

The Two Forms of Vitamin D: D2 vs. D3

To understand vegan vitamin D sources, it is essential to distinguish between the two primary forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).

Vitamin D2: The Plant-Based Form

Origin: Vitamin D2 is derived from exposing plants, such as mushrooms, and yeast to ultraviolet (UV) light.
Availability: While mushrooms can be a source, their vitamin D content varies significantly based on their exposure to UV light. Some mushrooms are specifically grown under UV lamps to boost their D2 content.
Fortification: D2 is the most common form of vitamin D used to fortify foods and is often found in vegan-friendly products.

Vitamin D3: Often Animal-Derived

Origin: The body produces D3 when the skin is exposed to sunlight. However, most supplemental and fortified food D3 has traditionally been sourced from animal products, such as lanolin from sheep's wool or fish oils.
Effectiveness: Research suggests that vitamin D3 is more effective than D2 at raising blood vitamin D levels and sustaining them over time, particularly with less frequent dosing.
Vegan Options: Recent innovation has led to the development of vegan-friendly D3 extracted from lichen, a symbiotic fungus-algae organism. This provides vegans with access to the potentially more potent D3 form without compromising their ethical principles.

Key Vegan-Friendly Strategies for Adequate Vitamin D

Harnessing Sunlight

Sunlight exposure remains the most natural and effective way for the body to produce vitamin D, regardless of diet. The amount of exposure needed varies based on factors such as skin pigmentation, latitude, season, and time of day. In summer, 10–30 minutes of midday sun exposure several times a week on bare arms and legs is often sufficient for most people. Those with darker skin require longer exposure times to synthesize the same amount of vitamin D. However, in winter months, especially in higher latitudes, sun synthesis is often inadequate, making other sources necessary.

Choosing Fortified Vegan Foods

Many plant-based products are fortified to help consumers, including vegans, meet their vitamin D needs. These foods can be a convenient part of a daily diet, but it is crucial to check the nutrition labels to ensure the vitamin D source is vegan-friendly.

Commonly Fortified Foods:

Plant Milks and Yogurt Alternatives: Soy, almond, and oat milks are frequently fortified with vitamin D2 or vegan D3.
Breakfast Cereals: Many brands add vitamin D; check the ingredients carefully.
Fortified Orange Juice: Some brands of orange juice are fortified with vitamin D and calcium.
Certain Tofu Products: Some tofu is fortified, providing a dual source of calcium and vitamin D.
UV-Treated Mushrooms: These can be a potent source of vitamin D2; look for products specifically marketed as UV-exposed.

Selecting the Right Supplements

For many vegans, and indeed many non-vegans, supplementation is the most reliable way to ensure consistent vitamin D intake, especially during months with limited sunlight.

Considerations for Vegan Supplements:

Vegan-Certified: Look for supplements explicitly labeled as vegan, confirming that the D3 is derived from lichen rather than lanolin.
D2 vs. D3: While D2 is always vegan, opt for lichen-based D3 for potentially superior absorption, although daily D2 intake can also be effective.
Take with Fat: Vitamin D is a fat-soluble vitamin. Taking a supplement with a meal containing healthy fats, such as nuts, seeds, or avocado, can significantly improve absorption.

Comparison of Vitamin D Sources for Vegans


Source	Type of Vitamin D	Vegan-Friendly?	Notes
Sunlight	D3	Yes	Free, but effectiveness depends on latitude, season, and skin tone.
UV-Treated Mushrooms	D2	Yes	Potent source if exposed to UV light; check product details.
Fortified Plant Milks	D2 or D3	Must Check Label	Many brands are fortified; always read ingredients to ensure vegan D3 is used if present.
Fortified Cereals	D2 or D3	Must Check Label	Varies by brand; can be a good, consistent source.
Fortified Orange Juice	D3	Must Check Label	Often fortified with D3; confirm source is vegan.
Lichen-based D3 Supplement	D3	Yes	Reliable, concentrated source for optimal absorption.
D2 Supplement	D2	Yes	A viable option for daily intake, though potentially less potent than D3.
Fatty Fish (e.g., Salmon)	D3	No	Significant non-vegan source; avoided by vegans.
Egg Yolks	D3	No	Non-vegan source; avoided by vegans.

Conclusion: Thriving on a Vegan Diet with Strategic Vitamin D Planning

The idea that vegans inherently cannot get vitamin D is a myth. The reality is more nuanced; while natural dietary sources are scarce, a well-planned vegan diet, combined with lifestyle considerations, can provide sufficient vitamin D. The key lies in understanding the different forms of vitamin D, recognizing that D3 can now be sourced from vegan lichen, and strategically incorporating fortified foods and reliable supplements. By maximizing sunlight exposure when possible, consuming fortified products, and choosing vegan-certified supplements, vegans can easily meet their vitamin D needs. Regular blood tests can help monitor levels and ensure that any dietary or lifestyle adjustments are effective. In the long run, proactive planning replaces the need for animal-based sources, proving a vegan diet can be nutritionally robust. For more on vitamin D, consult the National Institutes of Health fact sheets on the nutrient.

Frequently Asked Questions

Yes, vegans can struggle to get enough vitamin D from diet alone because the most common natural food sources are animal-based. This requires a more intentional approach to include fortified foods, sunlight, or supplements.

No, not all vitamin D is vegan. Vitamin D2 is always plant-derived, but vitamin D3 is often sourced from animals (e.g., sheep's wool lanolin or fish oil). However, vegan-certified D3 supplements derived from lichen are available.

For vegans, the best approach involves a combination of strategies. This includes regular, safe sun exposure, consuming fortified plant-based foods, and taking a vegan-certified vitamin D supplement, preferably a lichen-derived D3 for better absorption.

Yes, mushrooms exposed to UV light can contain significant amounts of vegan vitamin D2. When purchasing, look for labels that specify the mushrooms were treated with ultraviolet light to maximize their vitamin D content.

As vitamin D is a fat-soluble vitamin, vegans should take their supplements with a meal containing some form of healthy fat, such as avocado, nuts, seeds, or olive oil, to enhance absorption.

While D3 has been shown to be more effective at raising blood levels, both D2 and D3 can help vegans meet their needs. The availability of vegan D3 from lichen means vegans can choose the more effective form if they prefer, though D2 can still be effective with daily dosing.

Many people, including vegans, need to supplement vitamin D, especially during autumn and winter, when sun exposure is limited. Those with darker skin or who spend less time outdoors may need to supplement year-round.