Potential Hidden Risk in Vitamin D2 Supplements

Select Language:

Credit: Unsplash+

Vitamin D ranks among the most popular dietary supplements worldwide. Many individuals supplement with it to strengthen bones, boost immunity, and promote overall well-being.

This vitamin becomes especially crucial during the winter months when sunlight exposure decreases, and the body’s natural production diminishes.

Our bodies primarily produce vitamin D when UV rays from sunlight hit our skin, triggering a process that generates vitamin D3. This form is often regarded as the most natural and effective because it’s the same type our bodies create naturally.

However, during periods of limited sunlight or when people spend most of their time indoors, vitamin D production may fall short. That’s why doctors frequently recommend supplements, especially in colder seasons.

Recent research indicates that not all vitamin D supplements work equally in the body.

Researchers from the University of Surrey, the John Innes Centre, and the Quadram Institute Bioscience recently examined two common forms: vitamin D2 and vitamin D3.

Both are readily available at pharmacies and health stores. Many assume they are equally effective, but the new study suggests otherwise.

The team analyzed data from multiple clinical trials to see how these supplements influence blood vitamin D levels. They specifically looked at how D2 and D3 affect circulating vitamin D in the bloodstream.

The results were unexpected.

Participants taking vitamin D2 showed a decrease in their blood levels of vitamin D3. This indicates that while the supplement adds D2, it might also suppress the more beneficial D3.

Vitamin D3 is important because it’s the form naturally produced through sunlight exposure and is generally deemed more effective at maintaining optimal vitamin D levels.

In several analyzed trials, individuals taking D2 ended up with lower D3 levels compared to those not taking any vitamin D supplement.

This suggests that D2 might not support vitamin D status as well as D3 does.

Lead researcher Dr. Emily Brown from the University of Surrey explained that vitamin D supplements are especially vital during winter. In countries like the UK, sunlight from October to March is often too weak for our bodies to generate enough vitamin D naturally.

Because of this, health authorities recommend supplementation during these months.

However, the study emphasizes that the kind of supplement matters.

“Our research shows that vitamin D2 supplements can actually lower vitamin D3 levels in the body,” said Dr. Brown. “This implies that vitamin D3 might be the better choice for those looking to boost their vitamin D levels.”

The findings align with earlier research indicating distinct behaviors of D2 and D3 within the body.

In a prior study published in Frontiers in Immunology, scientists at the University of Surrey found that vitamin D3 activates a crucial part of the immune system called the type I interferon signaling pathway.

This immune component helps defend against bacteria and viruses. The study observed that D3 stimulated this response, whereas D2 lacked the same effect.

Having adequate vitamin D levels supports many health areas. It aids calcium absorption necessary for strong bones and teeth, contributes to muscle function, enhances immune responses, and helps reduce inflammation.

Despite its importance, vitamin D deficiency remains widespread, especially during winter when sun exposure drops.

Professor Martin Warren from the Quadram Institute Bioscience highlighted that selecting the most effective form of vitamin D could improve public health outcomes. Proper supplementation may help decrease deficiency rates across populations.

Professor Cathie Martin from the John Innes Centre added that expanding plant-based sources of vitamin D3 could make the vitamin more accessible, especially for vegetarians and vegans.

Although vitamin D3 appears to have advantages, researchers emphasize that further studies are necessary to fully understand the differences between D2 and D3.

Based on current evidence, D3 seems to be the preferable choice for maintaining healthy vitamin D levels.

If you’re interested in nutrition, check out studies explaining why vitamin K is vital for older adults, or learn about a snack that may affect your heart rhythm.

For additional health insights, explore recent research on vitamins that could reduce the risk of type 2 diabetes, or see findings indicating that common food chemicals might influence blood pressure.

This research was published in the journal Nutrition Reviews.