A new study conducted by researchers at the Newcastle University Human Nutrition and Exercise Research Centre and published in the European Journal of Clinical Nutrition has found that vitamin D deficiency remains common throughout the year among key at-risk groups in England, including older adults and members of ethnic minority communities.

The findings challenge the widespread assumption that increased exposure to summer sunlight is sufficient to restore healthy vitamin D levels.

The study included nearly 300 participants from northern regions of the United Kingdom. Researchers assessed vitamin D status using dried blood spot samples collected through both local and online recruitment efforts. The study population included adults over the age of 65 as well as participants from ethnic minority groups across all age categories.

The results revealed that vitamin D insufficiency was highly prevalent in both groups. More than half of the older participants had below-optimal vitamin D levels, while the prevalence was even higher among individuals from ethnic minority backgrounds.

Perhaps the most notable finding was the absence of the expected seasonal improvement. Even during the summer months, vitamin D levels did not increase substantially.

This observation contradicts the common belief that greater sun exposure during summer can compensate for deficiencies accumulated during winter. According to the researchers, sunlight alone may be insufficient for people living at northern latitudes, such as northern England, particularly among populations already at elevated risk.

Vitamin D plays an essential role in bone metabolism, immune function, and overall health. Deficiency has been linked to an increased risk of conditions including osteoporosis, rickets, and a range of chronic diseases.

Against this backdrop, persistently low vitamin D levels in a significant portion of the population are viewed as an important public health concern.

The researchers argue that more targeted interventions may be necessary. These could include improved public awareness campaigns, the incorporation of rapid vitamin D screening into routine healthcare visits, and broader use of vitamin D supplementation among high-risk groups.

According to the authors, prevention strategies should not focus solely on winter months but should instead be maintained throughout the year, particularly for individuals who are less likely to achieve adequate vitamin D levels through sunlight exposure alone.