Summer sun fails to fix vitamin D gap in at risk groups

Vitamin D levels remain low all year-round in key at-risk groups in England, challenging the belief that summer sunlight is enough to restore them.

A new study, led by experts at Newcastle University's Human Nutrition and Exercise Research Centre, UK, analyzed the vitamin D levels of almost 300 people from across northern Britain.

Findings show that many people could be living with low vitamin D all year round without realizing it. This has implications for bone health, general well-being and longer-term health risks.

The research, published in the European Journal of Clinical Nutrition, focused on adults aged 65 and over, alongside people from minoritized ethnic backgrounds of all ages.

Low vitamin D despite summer sun

Analysis revealed that vitamin D insufficiency was widespread across both groups as more than half of older adults were affected, while rates were even higher among minoritized ethnic participants.

Crucially, vitamin D insufficiency rates did not improve during the summer months, challenging the common belief that increased sunlight alone is enough to restore healthy levels.

Vitamin D plays an essential role in bone health and overall well-being, and low levels are linked to a higher risk of long-term conditions, such as osteoporosis, rickets and weakened immune systems.

Bernard Corfe, Professor of Human Nutrition and Health at Newcastle University, who co-led the research, said, "What's striking about these findings is that vitamin D levels didn't improve, even in the summer months when we would usually expect them to recover.

"For people living in places like the North of England, this shows that sunlight alone may not be enough, particularly for older adults and those from minoritized ethnic backgrounds.

"The message is simple but important. If you are in a higher-risk group, you can't assume that spending more time outdoors in summer will solve the problem.

"We need to be thinking about more consistent, year-round ways to support healthy vitamin D levels."

Call for targeted action

Study participants were recruited locally through community and online approaches. Each completed a simple finger-prick blood test, with samples analyzed by a specialist laboratory.

Data also highlighted the need for more targeted public health action. This could include clearer messaging, brief checks during GP appointments, and, where appropriate, vitamin D supplementation.

It strengthens the evidence base in a relatively underresearched area and provides a clearer understanding of year‑round risk among vulnerable populations.

The next phase of the research will focus on improving vitamin D levels through personalized and culturally appropriate approaches, such as tailored dietary advice and sensitive health care delivery.