Many people in the UK who are considered to be at high risk of vitamin D deficiency may not be getting enough nutrients throughout the year, according to new research. The findings cast doubt on the widely held belief that simply spending time in the summer sun can restore healthy vitamin D levels.
Researchers from Newcastle University’s Human Nutrition and Exercise Research Center analyzed vitamin D levels in around 300 people across the north of England. Their results suggest that a significant number of people may be vitamin D deficient year-round without realizing it, which can impact bone health, overall well-being, and long-term health outcomes.
This research European Journal of Clinical Nutritionfocuses on adults aged 65 and over and people of ethnic minority backgrounds of all ages. The funding was provided by Better You Ltd, a UK-based health and wellness company that manufactures and sells nutritional supplements.
Vitamin D deficiency remains high throughout the year
The researchers found that vitamin D deficiency was common in both groups studied. More than half of older adults had insufficient vitamin D levels, and the proportion was even higher among participants from ethnic minority backgrounds.
Perhaps most notable is that vitamin D levels did not improve over the summer. This finding goes against the common assumption that increasing sun exposure in the summer is enough to bring vitamin D levels back into a healthy range.
Vitamin D is essential for maintaining healthy bones and supporting overall health. Insufficient levels have been reported to increase the risk of diseases such as osteoporosis, rickets, and decreased immune function.
Bernard Korff, professor of human nutrition and health at the University of Newcastle and co-leader of the study, said: “What is surprising about these findings is that vitamin D levels did not improve, even during the summer when vitamin D levels would be expected to recover.”
“For people living in places like the north of England, especially older people and people from ethnic minorities, this shows that sunlight alone may not be enough.
“The message is simple but important: If you are in a high-risk group, spending more time outdoors in the summer is unlikely to solve your problem.
“We need to look at more consistent, year-round ways to support healthy vitamin D levels.”
Researchers call for targeted public health measures
Participants were recruited locally through both community engagement and online methods. Each person completed a simple finger prick blood test and the samples were analyzed by a specialized laboratory.
The findings also point to the need for more targeted public health strategies. Researchers suggest that clearer guidance, a simple vitamin D assessment during a GP visit, and vitamin D supplementation when appropriate, could help solve the problem.
This study adds important evidence to an area that has received relatively limited attention and provides a better understanding of annual vitamin D risks in vulnerable populations.
Researchers say the next stage of the project will explore ways to improve vitamin D levels through individualized and culturally appropriate strategies. These may include customized dietary recommendations and healthcare approaches designed to better meet the needs of different communities.
The study’s funder, Better You Ltd, had no role in the design, conduct, or interpretation of the results. All aspects of the research were conducted independently by Newcastle University.
