For years, vitamin D has been known as the ultimate ‘sunshine vitamin,’ the one supplement you can’t skip, especially during the winters. It’s believed to lift your mood, strengthen bones, and boost immunity. But new research suggests that not all vitamin D supplements deliver the same benefits. In fact, one form of it might even be working against your immune system. Yes you read that right! So are you taking it the wrong way?
Are you taking the wrong kind of vitamin D?
A new study from the University of Surrey, published in Nutrition Reviews, has found that vitamin D2, the form found in many supplements and fortified foods, could actually lower the body’s natural levels of vitamin D3, the version most beneficial for immunity.
Lead researcher Emily Brown explained, “Vitamin D supplements are important, especially between October and March. But we found that vitamin D2 can decrease levels of D3, which was previously unknown. For most individuals, D3 may be the better choice.”
The finding challenges the long-held belief that D2 and D3 are equally effective. D3 (cholecalciferol), which your body produces when exposed to sunlight, is better absorbed and retained, while D2 (ergocalciferol), typically derived from plants or fungi, appears to interfere with the body’s natural vitamin D balance.
Why does Vitamin D3 matter for immunity?
The difference between the two forms goes beyond absorption. Additional research published in Frontiers in Immunology shows that vitamin D3, but not D2, activates the type I interferon system, a crucial part of the immune response that helps the body fight viruses and bacteria.
Professor Colin Smith, co-author of the study, noted, “Vitamin D3, but not D2, activates this crucial defence system. A healthy D3 status could help prevent infections from gaining a foothold.”
That means taking D2 might not just be less effective, it could be working against your natural defences by lowering the body’s D3 reserves, leaving you more vulnerable during cold and flu season.
Time to check your supplement label
Most over-the-counter vitamin D supplements are labeled simply as ‘vitamin D,’ making it hard to know which form you’re actually taking. If the ingredients list says ergocalciferol, that’s D2. If it says cholecalciferol, that’s D3, the form your body prefers.
As winter approaches, experts recommend checking your supplement labels and, if needed, switching to D3-based formulas. It’s a simple change that could make a big difference in how your body fights off infections. Because when it comes to vitamin D, the right kind matters more than ever.