Summer sun may not fix vitamin D shortfalls in higher-risk groups
Newcastle University researchers found low vitamin D levels persisted year-round among many older adults and people from minoritized ethnic backgrounds.
By Tom Brennan · Health & Medicine Correspondent
3 min read
Summer sunlight may not be enough to restore healthy vitamin D levels for many people in England who are already at higher risk of deficiency, according to Newcastle University researchers. The finding matters because low vitamin D is linked to bone health and broader health concerns, and public advice often assumes summer sun exposure helps levels rebound.
The study, published in the European Journal of Clinical Nutrition, examined nearly 300 people living across northern Britain. Newcastle University said the research focused on adults aged 65 and older and people of all ages from minoritized ethnic backgrounds.
Researchers from the university’s Human Nutrition and Exercise Research Centre found vitamin D insufficiency was common in both groups. According to Newcastle University, more than half of older adults in the study had insufficient levels, and the share was higher among participants from minoritized ethnic backgrounds.
The seasonal pattern was the study’s central finding. Newcastle University said participants’ vitamin D levels did not rise significantly in the summer, even though that is the period when sunlight exposure is often expected to improve vitamin D status.
Bernard Corfe, professor of human nutrition and health at Newcastle University and a co-leader of the study, said the results suggest sunlight alone may not address low vitamin D for people in places such as northern England. He said higher-risk groups should not assume that spending more time outdoors in summer will solve the problem.
What the researchers measured
Participants were recruited through local community outreach and online methods, according to Newcastle University. Each person used a finger-prick blood test, and the samples were assessed by a specialist laboratory.
The study is listed under the title “Circannual prevalence of vitamin D insufficiency in older and minoritized ethnic adults in Northern Britain: screening outcomes from a clinical trial.” The journal reference names Alice Goddard, Anthony Watson, Rowena Tilbury, Bernard M. Corfe and Andrea Fairley as authors.
Newcastle University said vitamin D supports healthy bones and wider health. The university said insufficient levels have been associated with increased risk of osteoporosis, rickets and weakened immune function.
Calls for more targeted advice
The researchers said the findings point to the need for more focused public health measures for groups at elevated risk. Newcastle University said possible steps include clearer guidance, brief vitamin D checks during GP appointments and supplementation where appropriate.
The university said the work adds evidence to an area that has had limited attention: whether people in vulnerable groups remain at risk across the full year rather than only in winter. The researchers said the next stage of the project will examine ways to improve vitamin D levels through personalized and culturally appropriate approaches.
Those approaches may include dietary recommendations and healthcare methods better matched to different communities, according to Newcastle University. The university did not report that the study tested those measures as interventions.
Better You Ltd, a UK health and wellness company that sells nutritional supplements, funded the study, according to Newcastle University. The university said the company had no role in the study design, conduct or interpretation, and that Newcastle University carried out the research independently.
This story draws on original reporting from ScienceDaily.