Vitamin D is often called the “sunshine vitamin” because our bodies make it when our skin is exposed to sunlight.
It plays a very important role in keeping our bones strong and helping the immune system work properly. In many countries, especially in places with long winters and limited sunlight, people are advised to take vitamin D supplements to maintain healthy levels.
In the United Kingdom, for example, the government recommends that people take 10 micrograms of vitamin D each day, particularly between October and March when sunlight is too weak for the body to produce enough vitamin D naturally. Because of this advice, many people turn to supplements to support their health.
However, new research suggests that not all vitamin D supplements work in the same way. Scientists from the University of Surrey, the John Innes Centre, and the Quadram Institute Bioscience have discovered that one common form of vitamin D supplement may actually reduce the level of the body’s most effective form of vitamin D.
The research, published in the scientific journal Nutrition Reviews, looked closely at two types of vitamin D supplements: vitamin D2 and vitamin D3. Both types are widely available and are often used to help people maintain healthy vitamin D levels.
Vitamin D2 usually comes from plant sources and fungi, while vitamin D3 is typically produced from animal sources or made in the body when the skin is exposed to sunlight.
For many years, both forms have been considered acceptable ways to increase vitamin D intake. However, the new study suggests that vitamin D2 may not be as helpful as previously believed.
The researchers analysed data from several randomized controlled trials. These carefully designed studies compare people who receive a treatment with those who do not, allowing scientists to see whether the treatment truly has an effect.
By combining results from multiple studies, the researchers were able to examine how vitamin D2 supplements influence vitamin levels in the body.
Their analysis revealed something unexpected. People who took vitamin D2 supplements often showed a decrease in their levels of vitamin D3, which is the form of vitamin D that the body naturally produces and uses most efficiently.
In some cases, the level of vitamin D3 in people taking vitamin D2 dropped even lower than in people who were not taking any vitamin D supplements at all. This suggests that vitamin D2 may interfere with the body’s natural vitamin D3 levels.
Emily Brown, a PhD Research Fellow and the lead researcher of the study from the University of Surrey’s Nutrition, Exercise, Chronobiology and Sleep research group, explained the importance of the findings.
She said that vitamin D supplements are still very important, especially during months when sunlight is limited and the body cannot produce enough vitamin D naturally. However, the study shows that vitamin D2 may lower vitamin D3 levels in the body, which had not been clearly recognized before.
Because of this effect, the researchers suggest that vitamin D3 supplements may be a better choice for many people, although individual health needs should always be considered.
The study also highlights the growing interest in making plant-based vitamin D3 more widely available. Professor Cathie Martin from the John Innes Centre noted that ensuring access to plant-based vitamin D3 could help people who prefer vegetarian or vegan supplements.
This research also supports earlier findings about differences between vitamin D2 and vitamin D3. A previous study, published in Frontiers in Immunology and led by Professor Colin Smith from the University of Surrey, suggested that the two forms of vitamin D may affect the immune system differently.
In that earlier research, scientists discovered that vitamin D3 appears to activate a key part of the immune system called the type I interferon signalling system. This system plays an important role in the body’s early defense against viruses and bacteria.
The findings suggest that vitamin D3 may help strengthen the body’s ability to fight infections, while vitamin D2 does not appear to produce the same effect.
Because vitamin D plays such a crucial role in overall health, understanding the differences between these two forms of the vitamin is extremely important. Vitamin D deficiency is already considered a major public health concern, particularly in regions with limited sunlight during the winter months.
Professor Martin Warren, Chief Scientific Officer at the Quadram Institute, explained that improving vitamin D levels in the population is an important health priority.
He noted that many people in the UK have low vitamin D levels, especially during the colder months, and finding the most effective ways to provide vitamin D through supplements or fortified foods is essential.
When reviewing the study as a whole, the findings suggest that vitamin D3 may be more effective than vitamin D2 for raising and maintaining healthy vitamin D levels in the body. The research also raises important questions about how different forms of vitamin D interact inside the body and how they affect overall health.
However, scientists emphasize that more research is still needed. Future studies will help clarify exactly how vitamin D2 reduces vitamin D3 levels and determine whether this effect has long-term consequences for health.
Overall, the study provides valuable new insight into vitamin D supplements and suggests that vitamin D3 may offer greater benefits for most people. Understanding these differences will help doctors, nutrition experts, and policymakers make better recommendations about how people can maintain healthy vitamin D levels.
If you care about health, please read studies about the best time to take vitamins to prevent heart disease, and vitamin D supplements strongly reduce cancer death.
For more health information, please see recent studies about plant nutrient that could help reduce high blood pressure, and these antioxidants could help reduce dementia risk.
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