A new study has linked low vitamin D levels with a significantly increased risk of dementia, prompting UK supplement brand Supp to call for greater public awareness as winter deficiency rates climb. As the country enters its darkest months, Supp warns that the findings highlight vitamin D as a crucial yet often overlooked part of preventative health.
Although Public Health England already advises daily vitamin D supplementation during autumn and winter, this large-scale study of over 269,000 adults adds renewed urgency. Researchers suggest that maintaining healthy vitamin D levels may benefit not only bone health, but long-term cognitive function as well.
Researchers analysed UK Biobank data from adults aged 55 to 69, following participants for up to 14 years. They found that individuals with vitamin D deficiency – defined as less than 30 nanomoles per litre of blood – were around 25% more likely to develop dementia of any kind compared with people whose levels were in the healthy range. The increased risk applied across multiple types of dementia, including Alzheimer’s disease and vascular dementia.
The study also noted potential benefits associated with supplementation. Participants who took regular vitamin D supplements were found to have a 17% lower risk of developing Alzheimer’s disease over the study period. Those who used multivitamins saw a 14% lower risk of vascular dementia. Although the study does not prove causation, the authors note that the relationship between vitamin D status and cognitive decline appears increasingly difficult to ignore.
Registered Associate Nutritionist Georgina Taylor, who works with supplement brand Supp, said, “Vitamin D has long been known for its role in supporting immunity and bone strength, but this study adds another layer to the picture. There’s growing evidence that low vitamin D status may have a wider impact on cognitive health as we age. While more research is needed to understand exactly why, it’s a timely reminder to stay mindful of our vitamin D levels through the darker months.”
Supp co-founder Olivia Buckley added, “We’re passionate about helping people make informed, evidence-based choices. Studies like this show how something as simple as ensuring you’re getting enough vitamin D can have far-reaching effects. It’s about small, consistent steps that support overall wellbeing. The science keeps evolving, and we want to help people keep pace with it in a clear, accessible way.”
