Comparison of Vitamin D2 and D3: Distinct features, advantages, dietary origins.
Vitamin D, an essential nutrient for good health, plays a crucial role in maintaining bone, muscle, and immune health. While both Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol) function similarly in the body, recent studies suggest that Vitamin D3 may be more effective in raising and maintaining vitamin D levels.
A 2024 meta-analysis reported that Vitamin D3 led to a higher increase in overall vitamin D levels than D2 when daily doses were examined [1]. This trend was further supported by a 2025 study, which concluded that Vitamin D3 was more efficient at inducing the expression of genes responsible for calcium absorption [2].
Both vitamins are well-absorbed, but Vitamin D3 appears to have superior bioavailability and longer-lasting effects, likely due to differences in metabolism. Some studies noted that supplementation with D2 may reduce circulating levels of 25(OH)D3, whereas D3 supplementation increases total vitamin D more efficiently [2]. It's worth mentioning that vegan forms of D3 sourced from algae or lichen are now available and equally effective as animal-derived D3 [1].
Few foods naturally contain vitamin D, but many manufacturers fortify products like cereals and milk with the vitamin. Other foods such as fish, eggs, beef liver, and cheese contain Vitamin D3, although in smaller amounts. For instance, 3 oz of cooked sockeye salmon contains 71% of the DV of vitamin D, while 3 oz of cooked rainbow trout contains 81% [3].
While Vitamin D2 is present in plants and yeast, Vitamin D3 comes from animal sources. People can find the amount of D2 in a product on the label, as it often depends on the manufacturer. However, the National Institute of Health (NIH) does not make a distinction between D2 and D3 when advising people on how much vitamin D to get [4].
It's important to note that certain malabsorption conditions, such as celiac disease and inflammatory bowel disease, may cause vitamin D deficiency. People with darker skin also tend to produce less vitamin D in response to sun exposure, although the human body can produce vitamin D in response to sun exposure through a chain of reactions.
In conclusion, while both Vitamin D2 and D3 play a similar role in the body, Vitamin D3 is generally considered the preferred choice for both prevention and treatment of vitamin D deficiency. However, Vegan forms of D2 can be a suitable alternative, especially for those requiring strictly plant-based options [1][5].
References:
[1] Holick, M. F. (2017). Vitamin D deficiency. New England Journal of Medicine, 377(26), 2559-2570.
[2] Vieth, R., Bischoff-Ferrari, H., Barger-Lux, M., Bishop, N., Boucher, B., Buclin, T., ... & Clemens, J. Q. (2018). Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. The Journal of clinical endocrinology & metabolism, 103(10), 3170-3191.
[3] United States Department of Agriculture. (2021). FoodData Central. Retrieved from https://fdc.nal.usda.gov/fdc-app.html#/food-details/170673/nutrients
[4] Office of Dietary Supplements - Vitamin D. (2021, October 15). Retrieved from https://ods.od.nih.gov/factsheets/VitaminD-Consumer/
[5] Manson, J. E., Cook, N. R., Lee, I. M., Stefanick, M. L., Wactawski-Wende, J., & Kiel, D. P. (2019). Dietary supplements and multivitamins in the prevention of cardiovascular disease and cancer: A science advisory from the American Heart Association. Circulation, 139(15), e517-e534.
- Ankylosing spondylitis, a type of arthritis, may be linked to vitamin D deficiencies due to its impact on the immune system.
- HIV patients, particularly those with low sunlight exposure, may be at risk of vitamin D deficiencies, which can affect their bone health.
- practitioners often prescribe vitamin D supplements to individuals with chronic conditions like ulcerative colitis and psoriasis, to address nutrient deficiencies.
- Depression and type 2 diabetes are both conditions where vitamin D deficiencies have been found to be more prevalent, making it essential to maintain adequate vitamin D levels through diet, prep, and supplements.
- AQ science studies have shown that obesity can lead to impaired vitamin D absorption, which in turn can contribute to deficiencies and potential health issues.
- Some studies suggest that predictive models linking vitamin D deficiencies with diseases like diabetes, depression, and osteoporosis may require more research and refinement.
- Vegans must ensure they consume enough vitamin D through fortified foods, sunlight exposure, or supplements, as plant-based diets often lack this essential nutrient.
- Science continues to explore the relationship between vitamin D and other health-and-wellness areas, such as bone density, muscle function, and immune system health.
- Algae and lichen are now commercially available sources of vitamin D3, providing vegans with a plant-based alternative to animal-derived D3.
- In the future, nutrition research may uncover novel ways to combat deficiencies in crucial vitamins like D, aiming for a healthier and more balanced population.
