Common vitamin D supplement might have an unforeseen impact, experts caution

Vitamin D2 May Affect Vitamin D3 Levels

Vitamin D is crucial for various aspects of health, but recent studies are raising concerns about certain forms of it. Specifically, the more effective and long-lasting form, vitamin D3 (cholecalciferol), which is produced when skin is exposed to sunlight and also found in various animal foods, appears to be affected by vitamin D2 (ergocalciferol). The latter can be sourced from plants or fungi, as noted by the National Institutes of Health.

Research conducted by the University of Surrey in the UK indicates that vitamin D2 might actually lower the levels of vitamin D3 in the body. This finding comes from an analysis of 11 randomized controlled trials involving 655 adults, which revealed that those taking vitamin D2 supplements had lower vitamin D3 levels compared to those who weren’t.

This study was a collaborative effort involving the John Innes Center and the Quadrum Institute for Biosciences in Norwich, and the results were published in the journal Nutrition Reviews.

According to Professor Colin Smith, the study’s lead researcher, “Vitamin D3, but not vitamin D2, seems to stimulate the body’s type I interferon signaling system, which is essential for the immune response against various pathogens.” This suggests that maintaining adequate levels of vitamin D3 could potentially help prevent infections.

Professor Martin Warren, the chief scientific officer at the Quadrum Institute, highlighted the significant public health issue of vitamin D deficiency, especially during winter months. He mentioned that the research aligns with the mission of the Quadrum Institute to promote healthier living through nutritional innovations. “Finding the most effective means of vitamin D supplementation is crucial for public health,” he stated.

While the study indicates important differences between D2 and D3, the researchers emphasized the need for further investigation to explore how these vitamins impact the body differently and what that might mean for medical guidance. They cautioned that the current analysis has its limitations, including the variability in study designs, such as duration, dosage, and outcome measurements, which could introduce bias.

Factors like sunlight exposure and whether individuals are taking supplements or eating fortified foods could also play a role in the findings.

Health experts confirm that vitamin D3 can be found in fatty fish, egg yolks, cod liver oil, fortified dairy products, and other animal products. On the other hand, vitamin D2 sources include mushrooms and various fortified or plant-based supplements.