Do we really get enough vitamin D from the sun?

For years, it’s been believed that summer sunshine provides all the vitamin D we need. But new research suggests that for many people living in England, even the brightest months may not be enough.  

Contents:

1. Why is vitamin D important?
2. What are our sources of vitamin D?
3. The study: are we getting enough vitamin D?
4. The summer sun might not be enough
5. The future of vitamin D research

Why is vitamin D important?

Vitamin D is a nutrient that’s essential for life. Our bodies produce active vitamin D after exposure to sunlight, and we get some vitamin D from the food we eat.

Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth, and muscles healthy. If you do not have enough vitamin D, your body doesn’t absorb calcium in food, and instead, the body’s bones become a source of calcium. The body is always seeking the level it needs and takes calcium where it can get it. Without a good external source of vitamin D, bones can become weak and a higher risk of long-term conditions for the whole body, such as osteoporosis, rickets, and weakened immune systems.

What are our sources of vitamin D?

The body creates vitamin D from direct sunlight on the skin when outdoors. This is our primary and most natural source of vitamin D.

It’s been previously thought that most people should be able to make most of the vitamin D they need from sunlight, at least from late March to the end of September. From October to early March, the sun isn’t strong enough in places like the UK to produce vitamin D.

Vitamin D is also found in a number of foods, including oily fish, red meat, egg yolks, liver, and some fortified foods, such as fat spreads and breakfast cereals.

The study: are we getting enough vitamin D?

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

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

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

The summer sun might not be enough

Studies revealed that vitamin D insufficiency was widespread across both target groups. More than half of the older adult participants were affected, while rates were even higher among the minority group participants.

Crucially, the results also showed that the participants were also displaying vitamin D insufficiency during the summer months, during which people are thought to receive the required levels of vitamin D through exposure to sunlight.

'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 minoritised ethnic backgrounds.' – Professor Bernard Corfe, Professor of Human Nutrition and Health at Newcastle University and co-leader of the research

This suggests that residents in England need to be thinking about more consistent, year-round ways to support healthy vitamin D levels.

The future of vitamin D research

Vitamin D insufficiency is a relatively under-researched area, and the study provides clear understanding of year‑round risk among vulnerable populations.

The results 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.

‘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.' – Professor Bernard Corfe, Professor of Human Nutrition and Health at Newcastle University and co-leader of the research

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

The investigations were funded by Better You Ltd, a UK-based health and wellness company. The company wasn’t involved in the study design, delivery, or interpretation of the data, which was carried out entirely by Newcastle University.

You might also like…

• read the press release: ‘Summer sun fails to fix vitamin D gap in at-risk groups’
• read the paper; Goddard, A., Watson, A., Tilbury, R. et al. 'Circannual prevalence of vitamin D insufficiency in older and minoritized ethnic adults in Northern Britain: screening outcomes from a clinical trial' (ISRCTN13778806). Eur J Clin Nutr (2026)
• explore the work of Professor Bernard Corfe, Professor of Human Nutrition and Health at Newcastle University, and co-leader of the research
• discover a world of research into nutrition, public health, physiology and more at Newcastle University’s Human Nutrition and Exercise Research Centre
• read the blog: ‘Cracking techniques for maximising vitamin D in eggs’
• read the blog: ‘How we’re putting the sunshine in sunny side up eggs’
• find out more about Better You Ltd