Taking vitamin D2 might lower the body’s levels of the more efficient form of vitamin D, vitamin D3, according to new research from the University of Surrey, John Innes Centre and Quadram Institute Bioscience. Many people take vitamin D supplements to support their bone and immune health and meet the UK government recommendation of 10 micrograms (µg) each day, especially during the winter months.
There are two forms of vitamin D supplements available: vitamin D2 and vitamin D3. Researchers have found that taking vitamin D2 supplements can lead to a drop in the body’s concentration of vitamin D3, which is the form our bodies naturally produce from sunlight and use most effectively to raise overall vitamin D levels.
The study, published in Nutrition Reviews, analysed data from randomised controlled trials and found that vitamin D2 supplementation resulted in a reduction in vitamin D3 levels compared to those not taking a vitamin D2 supplement. In many of the studies, the vitamin D3 levels went lower than in the control group.
Emily Brown, PhD Research Fellow and Lead Researcher of the study from the University of Surrey’s Nutrition, Exercise, Chronobiology & Sleep Discipline, said:
“Vitamin D supplements are important, especially between October and March, when our bodies cannot make vitamin D from sunlight in the UK. However, we discovered that vitamin D2 supplements can actually decrease levels of vitamin D3 in the body, which is a previously unknown effect of taking these supplements. This study suggests that subject to personal considerations, vitamin D3 supplements may be more beneficial for most individuals over vitamin D2.”
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Further research into the different functionalities of vitamin D2 and D3 should be a priority in deciding whether vitamin D3 should be the first-line choice of vitamin D supplement, subject to individual requirements.
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Story Source:
Materials provided by University of Surrey. Note: Content may be edited for style and length.
Journal Reference:
- Emily I G Brown, Andrea L Darling, Tracey M Robertson, Kathryn H Hart, Jie Li, Cathie Martin, Martin J Warren, Colin P Smith, Susan A Lanham-New, Ruan M Elliott. Effect of Vitamin D2 Supplementation on 25-Hydroxyvitamin D3 Status: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrition Reviews, 2025; DOI: 10.1093/nutrit/nuaf166
Source: The vitamin D mistake weakening your immunity | ScienceDaily
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