Study Finds Vitamin D2 May Lower Vitamin D3 Levels, Weakening Immune Defenses

A study by researchers from the University of Surrey, John Innes Centre, and Quadram Institute Bioscience has found that vitamin D2 supplements may reduce levels of vitamin D3, the body’s more effective form of vitamin D. Published in Nutrition Reviews, the analysis of randomized controlled trials revealed that vitamin D2 intake often led to decreased vitamin D3 concentrations compared to controls. Since vitamin D3, produced naturally from sunlight, is more efficient at supporting bone and immune health, researchers suggest it should be the preferred supplement. Lead author Dr. Emily Brown noted that while supplements are vital during months with limited sunlight, D2 may inadvertently deplete D3. Supporting studies also show vitamin D3 uniquely enhances immune signaling, helping defend against infections. Experts emphasize improving access to plant-based vitamin D3 and prioritizing further research to ensure effective strategies for addressing widespread vitamin D deficiency.

04-10-2025