A popular myth about vitamin D and the sun has been debunked

Scientists from Newcastle University have made an alarming discovery: in older people, vitamin D levels remain critically low throughout the entire year — even in summer, when sunlight is most abundant. The results of the study have been published in the European Journal of Clinical Nutrition (EJCN).

It was long believed that the summer sun could compensate for vitamin D deficiency through the effect of ultraviolet light on the skin. Medical recommendations were built on this assumption: spend more time outdoors — and the problem will resolve itself. However, the new study shatters this myth when it comes to the most vulnerable population groups.

Specialists from the Human Nutrition and Exercise Research Centre at Newcastle University tested vitamin D levels in nearly 300 residents of northern Great Britain. The participants included people over 65, as well as adults from ethnic minority backgrounds across all age categories. Each of them only needed to provide a simple finger-prick blood sample, after which the specimens were sent to a specialised laboratory.

The data obtained surprised even the researchers themselves: vitamin D deficiency turned out to be widespread in both groups and did not subside with the arrival of the warm season. More than half of the older participants demonstrated insufficient levels of this vital vitamin, and among ethnic minority representatives the situation was even worse. The summer months brought no noticeable improvement.

"It is striking that vitamin D levels did not rise even during the summer months, when we would normally expect them to recover. For people living in the north of England, this clearly demonstrates that sunlight may not be enough — especially for older people and those from ethnic minorities. The message is simple but important: if you are in a risk group, you cannot rely on spending more time outdoors to solve the problem," emphasised Bernard Corfe, Professor of Human Nutrition and Health at Newcastle University and one of the study's lead investigators.

The authors of the study insist on a reassessment of public health approaches. They believe that clearer recommendations for at-risk groups are needed, along with rapid vitamin D level assessments during routine doctor's visits and, where necessary, the prescription of supplements. In the next phase, the research team intends to explore ways of increasing vitamin D levels through personalised dietary and culturally adapted strategies.