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NMU 233 – Vitamin D3 is Superior to Vitamin D2 in Supporting Immune System

Nutrition/Natural Medicine Update No 233 (March 2, 2022)

with Dr. James Meschino


Topic: Vitamin D3 is Superior to Vitamin D2 in Supporting Immune System

Source: Frontiers in Immunology (2022)

Many people don’t realize that there are two forms of vitamin D that are available in the marketplace: vitamin D2 and vitamin D3. Studies over the years have suggested that vitamin D3 is more potent than vitamin D2, and thus more highly beneficial to our health. Many vegans and vegetarians prefer supplements and fortified foods that contain vitamin D2 because vitamin D2 is derived from a non-animal source. With respect to supporting immune health, this may be the one thing that vegans and vegetarians may want to reconsider. I personally am in favor of a more plant-based diet. I follow a program like that myself. But in the case of providing the body with vitamin D, the evidence is quite strong that vitamin D3 is the more beneficial form. Building on previous studies, the February 2022 issue of the journal Frontiers in Immunology, published a paper showing that providing a large group of healthy European and South Asian women with either vitamin D2 or vitamin D3 for 12-weeks through the winter months demonstrated that vitamin D3 increased the secretion of virus and cancer-fighting interferon from immune cells, whereas vitamin D2 did exhibit this effect. Interferon is an important part of your body’s natural defense system against infection, including COVID-19 infection as well as cancer. The interferon your body makes tells your immune system that germs or cancer cells are in your body, which triggers killer immune cells to fight those invaders. Interferon got its name because it “interferes” with viruses and keeps them from multiplying.

In a nutshell, interferon does the following:

  • Alerts your immune system so it can go after the virus or cancer cells.
  • Help your immune system recognize the virus or tumor cells.
  • Tells other immune cells to attack the virus or cancer cells
  • Helps stops the virus and cancer cells from growing and dividing
  • Helps healthy cells fight infection

As the researchers stated regarding vitamin D 3 and COVID-19, “our finding that vitamin D3 appears to stimulate type I interferon signaling could be relevant in the context of its use as a prophylactic treatment “(to help prevent serious COVID-19 complications). It may interest you to know that vitamin D3 found in supplements and many fortified dairy products is synthesized by exposing a component of sheep’s skin (lanolin) to ultra-violet light. This is the same way that the human body makes vitamin D3 when we exposer our skin to UV light from the sun. So, our own body makes vitamin D3, not vitamin D2 – that should be a clue. Vitamin D2 found in certain supplements and some fortified foods, such as some orange juices, cereals, oat milk, etc., is produced by exposing various mushrooms to UV light. This form of vitamin D (vitamin D2) is called ergocalciferol whereas vitamin D3 made in our skin, found in fatty fish, or derived from sheep lanolin is a different molecule known as cholecalciferol. Vitamin D2 is less expensive than vitamin D3, so some companies fortify their products with Vitamin D2 instead of vitamin D3 for this reason.

My preference is to take supplements that contain vitamin D3. There is strong evidence that it is a superior form of vitamin D with respect to immune health as well as possibly being a better form of vitamin D for bone health as well.

I have included the journal reference in the text below.

1. Louise R. Durrant, Giselda Bucca, Andrew Hesketh, Carla Möller-Levet, Laura Tripkovic, Huihai Wu, Kathryn H. Hart, John C. Mathers, Ruan M. Elliott, Susan A. Lanham-New, Colin P. Smith. Vitamins D2 and D3 Have Overlapping But Different Effects on the Human Immune System Revealed Through Analysis of the Blood Transcriptome. Frontiers in Immunology, 2022.

2. Science Daily: Study questioning the role of vitamin D2 in human health but its sibling, vitamin D3, could be important for fighting infections. February 25, 2022


Eat Smart, Live Well, Look great,


Dr. Meschino

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