Vitamin D levels remain low throughout the year among key at-risk groups in England, challenging the widely held belief that summer sunlight alone is enough to restore healthy levels. A new study led by researchers at Newcastle University analysed vitamin D levels in almost 300 people from across northern Britain and found that many participants experienced persistent insufficiency regardless of season. The findings raise concerns about bone health, overall wellbeing, and long-term health risks linked to inadequate vitamin D.
Published in the European Journal of Clinical Nutrition, the study focused on adults aged 65 and older, as well as people from minoritised ethnic backgrounds across all age groups. Researchers found that vitamin D insufficiency was widespread in both groups. More than half of older adults had insufficient levels, while rates were even higher among participants from minoritised ethnic communities. Importantly, vitamin D levels did not significantly improve during the summer months, despite increased sunlight exposure.
Vitamin D plays a critical role in maintaining bone health and supporting overall wellbeing. Low levels are associated with a greater risk of conditions such as osteoporosis, rickets, weakened immune systems, and other chronic health problems. The findings suggest that many individuals living in northern regions may not produce enough vitamin D through sunlight exposure alone, particularly those who are older or have darker skin tones, which can reduce the body’s ability to synthesise vitamin D from sunlight.
Professor Bernard Corfe, who co-led the research, said the results were especially concerning because vitamin D levels failed to recover even during the summer, when they would normally be expected to rise. He noted that for people living in areas such as the North of England, relying on sunlight alone may not be sufficient, particularly for older adults and those from minoritised ethnic backgrounds. He emphasised that individuals in higher-risk groups should not assume that spending more time outdoors in summer will solve the problem and called for more consistent, year-round approaches to maintaining healthy vitamin D levels.
Participants in the study were recruited through the local community and online outreach. Each person completed a simple finger-prick blood test, with samples analysed by a specialist laboratory. The research was funded by BetterYou Ltd, a UK-based health and wellness company that manufactures nutritional supplements. Researchers said the study strengthens evidence in an area that remains relatively under-researched and provides a clearer understanding of year-round vitamin D risk among vulnerable populations.
The findings also highlight the need for more targeted public health measures. Researchers suggest that clearer health messaging, brief vitamin D assessments during GP appointments, and appropriate supplementation could help address ongoing insufficiency among high-risk groups. The next phase of the research will focus on improving vitamin D levels through personalised and culturally appropriate strategies, including tailored dietary advice and more sensitive healthcare delivery approaches designed to meet the needs of diverse communities.
More information: Alice Goddard et al, Circannual prevalence of vitamin D insufficiency in older and minoritized ethnic adults in Northern Britain: screening outcomes from a clinical trial (ISRCTN13778806), European Journal of Clinical Nutrition. DOI: 10.1038/s41430-026-01760-z
Journal information: European Journal of Clinical Nutrition Provided by Newcastle University
