Researchers from the University of Surrey have discovered that vitamin D2 supplements may actually reduce the body’s levels of vitamin D3, a previously unknown effect, according to a study published in *Nutrition Reviews*. The study, which analyzed 11 randomized controlled trials involving 655 adults, found that individuals taking vitamin D2 had lower vitamin D3 levels than those who did not take D2 supplements. This finding challenges the assumption that the two forms of vitamin D are interchangeable and suggests that D3 may be more beneficial for most individuals.
Vitamin D3, the form naturally produced by the body when exposed to sunlight, is also found in animal products such as fatty fish, egg yolks, and fortified dairy foods, according to health sources. In contrast, vitamin D2 comes from plant or fungal sources and is commonly added to fortified foods and supplements. The study’s lead researcher, Emily Brown, emphasized that the results highlight the importance of choosing the right form of vitamin D for optimal health.
Previous research has shown that vitamin D3 is more effective at boosting the immune system and protecting against viral and bacterial infections, as explained by Professor Colin Smith, who led a related study on the subject. The findings suggest that maintaining adequate levels of D3 could help the body defend against pathogens. However, the researchers caution that more studies are needed to determine whether these findings could influence medical recommendations for vitamin D supplementation.
The study also acknowledges several limitations, including the small number of trials and differences in study design, such as varying durations, dosing schedules, and methods of measurement. Additionally, factors such as sunlight exposure and dietary intake of vitamin D-rich foods may have influenced the results. Despite these limitations, the research underscores the need for greater awareness about the distinctions between D2 and D3 and the potential implications for public health, particularly during periods of reduced sunlight exposure in the winter months.