D3 which comes from oily fish and egg yolks as well as being made in our skin from sunlight is more Immune supportive than D2 from vegatbles. Read your supplement labels carefully.
Professor Colin Smith explained: “We have shown that vitamin D3, but not vitamin D2, appears to stimulate the type I interferon signaling system in the body – a key part of the immune system that provides a first line of defence against bacteria and viruses. Thus, a healthy vitamin D3 status may help prevent viruses and bacteria from gaining a foothold in the body.”
New research from researchers at the University of Surrey in the UK, the John Innes Centre, and Quadram Institute Bioscience is raising questions about a common choice in supplements and food fortification: vitamin D2 (ergocalciferol) versus vitamin D3 (cholecalciferol). Their findings suggest the two forms may not be interchangeable and, in some cases, one could even work against the other.
Vitamin D3 is produced naturally in the skin after sun exposure and is also found in foods like oily fish and egg yolks. Vitamin D2 typically comes from plant sources such as mushrooms exposed to ultraviolet light (from fungal and yeast sterols, especially ergosterol) and has long been considered a suitable alternative as a supplement. As such, vitamin D2 is often added to fortified foods like plant-based milks and cereals. This is because it is inexpensive, reasonably stable in processed foods, and sourced from fungi/yeast rather than animals, making it suitable for vegetarian and vegan products.
However, the new study, published in Nutrition Reviews, found that taking vitamin D2 may actually lower the body’s levels of vitamin D3. Researchers reviewed data from randomised controlled trials and observed that people taking D2 supplements often had reduced D3 levels, in some cases dropping below those seen in people taking no supplement at all.
Experimental work published in Frontiers in Immunology reported that D3, but not D2, enhanced activation of genes involved in type I interferon signaling. This suggests the two forms of vitamin D are not functionally identical at the immunological level, despite both being classified as vitamin D. The implication is that D3 may engage vitamin D receptor-dependent immune pathways more effectively or more durably, potentially helping support antiviral readiness, mucosal defense and immune coordination. The clinical significance in humans is still being clarified, but the findings add to broader evidence that D3 is generally more potent and physiologically active than D2 in multiple systems, including immunity.
In the context of use of vegan forms of vitamin D, Professor Cathie Martin of the John Innes Centre emphasised: “This meta-analysis highlights the importance of ensuring plant-based vitamin D3 is accessible in the UK”, and indeed elsewhere.
For more information see: https://scitechdaily.com/popular-vitamin-d-supplement…/