Vitamin D2 may “harm health” by interfering with D3’s role, warns study

25 Feb 2022 --- Vitamin D2 has a questionable role on human health, while vitamin D3 may help with fighting viral infections, a collaborative UK study by the Universities of Surrey and Brighton has revealed.

“The main implication of this study is that dietary intake of vitamin D2 should not substitute for vitamin D3. Although this may sound controversial, it is possible that vitamin D2 could harm health by interfering with the physiological roles of vitamin D3,” Colin Smith, lead author of the study and professor at the University of Surrey, tells NutritionInsight.

“The food industry should only add vitamin D3 to its products, avoiding vitamin D2. Health policy should be specific about the type of vitamin D that should be taken, vitamin D3.”

The level of exposure to the sun to stimulate vitamin D3 synthesis by the skin will depend on many factors such as latitude and skin pigmentation.Harming health?
The impact of vitamin D2 was found to have a “questionable” impact on human health, while D3 appears to balance people’s immune systems. It could also help strengthen defenses against viral infections such as COVID-19, the researchers note. 

“Consumers should use vitamin D3 supplements and vitamin D3-fortified foods and, where possible, get into the sun for 30 minutes a day,” Smith says.

According to Smith, individuals on vegan or vegetarian diets tend to use vitamin D2 because vitamin D3 is often sourced from animal products.

“They should switch to a vegan-friendly source of vitamin D3. These do exist,” he highlights. Tapping into the demand, Lycored last year unveiled a vegetarian multivitamin D3, delivering 1 million IU per gram of vitamin D3.

Industry groups have been calling on the European Commission to classify vitamin D3 as a chemical entity, as opposed to a Product of Animal Origin and therefore not be subject to import tests.

Link to immunity
Researchers found evidence that vitamin D3 had a modifying effect on the immune system that could fortify the body against viral and bacterial diseases. The study investigated the impact of vitamin D supplements – D2 and D3 – taken daily over a 12-week period on the activity of genes in people’s blood.

“We have shown that vitamin D3 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 defense against bacteria and viruses. Thus, a healthy vitamin D3 status may help prevent viruses and bacteria from gaining a foothold in the body,” Smith adds. 

“Our study suggests that it is important that people take a vitamin D3 supplement, or suitably fortified foods, especially in the winter months.”Researchers say vitamin D3 should be the favored form for fortified foods and supplement. 

“While we found that vitamin D2 and vitamin D3 do not have the same effect on gene activity within humans, the lack of impact we found when looking at vitamin D2 means that a larger study is urgently required to clarify the differences in the effects,” adds Susan Lanham-New, co-author of the study and head of the department of nutritional sciences at the University of Surrey. 

Although some foods are fortified with vitamin D, like some breakfast cereals, yogurts, and bread, few naturally contain the vitamin. Vitamin D3 is produced naturally in the skin from exposure to sunlight or artificial ultraviolet UVB light, while some plants and fungi produce vitamin D2.  

A study previously revealed that vitamin D3 may reduce the risk of developing advanced cancer among adults over the age of 50 without a diagnosis of cancer at baseline.

By Andria Kades