Study: Low vitamin D levels persist even in summer in people at high risk

A study of almost 300 people in northern Britain shows that vitamin D levels often remain low throughout the year in those most at risk of deficiency. The findings, published in the European Journal of Clinical Nutrition, contradict the widely held belief that exposure to sunlight during the summer is sufficient to replenish vitamin D stores. The research was carried out by specialists from the Human Nutrition and Exercise Research Centre at Newcastle University and analysed the levels of the vitamin in almost 300 people in the north of the UK.

• Elderly people and ethnic minorities most vulnerable

The study focused on adults aged over 65 and people of all ages from minority ethnic groups. Funding was provided by the British company Better You Ltd, which specializes in nutritional supplements, but the researchers emphasize that the company had no role in conducting the study or interpreting the results. The results showed that vitamin D deficiency is common in both groups analyzed. More than half of the elderly had insufficient levels, and the proportion was even higher among participants from minority ethnic groups.

• Summer did not bring an improvement in vitamin D levels

One of the most surprising findings of the research is that vitamin D levels did not increase even in the summer months, when exposure to sunlight is greater.

"What is striking about these findings is that vitamin D levels did not improve even in the summer months, when we would normally expect them to recover. For those living in areas such as the north of England, this shows that sun exposure is not necessarily sufficient, particularly for older people and those from minority ethnic groups,” said Professor Bernard Corfe, one of the study's coordinators. According to the researcher, people in high-risk groups should not rely solely on time spent outdoors in the warm season to maintain adequate vitamin D levels.

• Essential role in bone and immune health

Vitamin D is essential for bone health and the proper functioning of the body. Insufficient levels have been associated with a higher risk of osteoporosis, rickets and a weakened immune system. Participants in the study were recruited through community-based programmes and online platforms. Each took a simple blood test, which was taken by pricking their finger, and the samples were then analysed in a specialist laboratory.

• Researchers call for better public health strategies

The study authors believe the results highlight the need for more targeted measures. These include clearer recommendations on taking vitamin D, testing levels during medical visits and using supplements when necessary. "The message is simple but important. If you are in a high-risk group, you cannot assume that spending more time outside in the summer will solve the problem. We need to think about more consistent ways, all year round, to maintain healthy vitamin D levels,” said Professor Bernard Corfe. In the next stage, the researchers will look at personalised and culturally adapted ways to improve vitamin D levels, including dietary advice and medical strategies designed to better meet the needs of different communities.