Plant-based Sources of Vitamin D for Cancer

Earlier this year, Nancy Hepp (previous Research Lead at CancerChoices) and I spoke at the Oncology Association of Naturopathic Physicians conference about the important findings of the CancerChoices Vitamin D review. Dr. Lise Alschuler, a naturopathic oncologist, graciously invited us to dig deeper on the topic of vitamin D on her Five to Thrive podcast. In our discussion, I shared food sources of vitamin D, which mostly come from animals, and realized vitamin D supplements are made from animal sources as well. Dr. Lise asked how vegans might get vitamin D, and aside from sunlight, I didn’t have a good answer. 

This is an important question, since many people on a plant-based diet tend to have low blood levels of vitamin D. Having adequate vitamin D levels is vital for health, including helping prevent some cancers. Additionally, based on the evidence, people with cancer with adequate levels of vitamin D are less likely to die from cancer and tend to live longer.  

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This article shares practical tips on how to get vitamin D while on a plant-based, vegan diet. 

Sources of vitamin D

Sun

Safe sun exposure is still one of the best bets for getting vitamin D, naturally. The plants you eat need sunshine and so do you. People with light skin can produce sufficient vitamin D with less than 15 minutes of exposure to the sun around noon on a summer day. The time needed increases among people with darker skin, up to two hours for people with very dark skin. For more information on using the sun as a source of vitamin D, read more in our Vitamin D review. 

Food

Mushrooms and fortified foods are sources of vitamin D2, while the sun and animal products are sources of vitamin D3. Vitamin D3 tends to be more effective and longer lasting than vitamin D2, but D2 can still raise vitamin D levels.¹Cleveland Clinic. Breaking Down Vitamin D, D2 and D3. May 1, 2025. Last viewed August 4, 2025.

1. Fortified foods. Eat foods fortified with vitamin D such as plant milks (i.e. soy, almond, rice), breakfast cereals, and orange juice. Check the label to see if vitamin D has been added, and the quantity added.
2. Mushrooms, especially those exposed to UV light. Look for packages labeled “high vitamin D”  or “vitamin D mushrooms” in the produce department. Read more here.  

Supplements

Up until 2010, almost all vitamin D supplements were produced from an animal product called lanolin (from wool). According to Vegan.com, “Sometime around 2010, supplement companies started producing vegan vitamin D3 from a type of algae called lichen. There are now several vegan vitamin D3 brands on the market.” To see a list of some brands of vegan supplements, go to Vegan Vitamin D Supplement Recommendations.    

Know your vitamin D level

Vegans are more likely to be low in vitamin D than omnivores.²Bakaloudi DR, Halloran A, et al. Intake and adequacy of the vegan diet. A systematic review of the evidence. Clinical Nutrition. 2021;  40(5): 3503-3521. In order to know whether and how much vitamin D supplementation you need, it’s important to know your blood vitamin D levels. 

If you haven’t had your vitamin D levels checked in the last year, or you have just been diagnosed with cancer, ask your doctor for a test to see the level of 25(OH)D in your blood. Vitamin D blood levels between about 20 and 40 ng/mL (50 to 100 nmol/L) appear to be beneficial in terms of lowering cancer risk and improving cancer outcomes, though some experts recommend going no lower than 30 ng/mL. 

Ask your doctor, dietician, or nutritionist for the level to aim for. If your level is low, your doctor may recommend supplementation. See our Vitamin D review to learn about healthy blood levels of vitamin D, including upper limits, as well as what the research says about its benefits for people with cancer.