Winter fall in Scots’ vitamin D levels same now as 400 years ago – study

Seasonal falls in Scottish vitamin D levels during the winter months are similar today to what they were 400 years ago despite enormous changes in lifestyle and diet, a study has found.

The study, led by researchers at the University of Aberdeen, saw researchers compare hair samples of modern-day residents of Aberdeen with a rare specimen of preserved hair from someone estimated to have lived in city in the 16th or 17th century.

Using a new method of detecting vitamin D in human hair samples – which they applied to archaeological remains for the first time – they detected the same seasonal variations in vitamin D levels across both the modern day and centuries-old samples.

Archaeologist professor Kate Britton, who led the research team, said: “We might expect that with modern methods to enhance our vitamin D intake through diet and supplementation this seasonal variation would be less significant.

“In recent years, there have been wide-spread health promotions around the benefits of supplementing with vitamin D during winter.

“Similarly, we could reasonably expect that the medieval population is likely to have spent a greater proportion outside and that those living in coastal areas like Aberdeen in the past may have consumed a greater proportion of their diet from local sources such a fish.

“But what this unique study has shown is that levels in many of our modern participants were similar to those of our archaeological sample, and that levels were consistently higher in summer and lower in winter in people who lived in the same city 400 years apart.”

Vitamin D is essential for healthy skeletal growth and is increasingly recognised for its role in chronic disease development, inflammation and immunity.

However, the researchers pointed out, in Scotland the sunshine is only strong enough to allow our bodies to produce our own vitamin D between April and September.

In addition to hours spent outside, vitamin D levels can be increased through diet such as oily fish and supplements.

Prof Britton added: “In archaeology, a lack of vitamin D is usually identified through skeletal manifestations such as rickets but that only informs us about the most extreme deficiencies and cannot be quantified.”

“Using hair in this way is a significant step forward in the growing field of metabolomics in archaeological science.

“If we can measure something such as vitamin D then we might also be able to use these state-of-the-art techniques to look at other aspects of health in the past through hair, such as stress levels, or even drug use of previous populations.”

The study, which examines the long-term impact of living in a region with low levels of winter sunlight, is the first to apply a new technique to measure vitamin D using hair in an ancient specimen – in this case a burial that had been previously excavated from St Nicholas Kirk.

The study team said examining vitamin D levels using hair rather than blood could also have benefits for understanding health today, as scientists can use it to spot changes over multiple months.

Prof Baukje de Roos is a nutritional scientist who collected and co-analysed the modern hair samples used in the study, all of which came from people who had been living in the Aberdeen area for at least two and a half years.

“It is important that we gain a greater understanding of how vitamin D in hair compares to vitamin D levels in blood, which is currently used to assess vitamin D deficiency globally,” she said.

“The method to measure vitamin D in hair opens new opportunities to more easily monitor and understand how diet, supplementation or weight loss affects our vitamin D levels across the seasons and in different settings.

“This could help health professionals to provide better guidance and recommendations in the ways we can best support vitamin D and health.”

The study saw archaeologists and nutrition scientists from the University of Aberdeen work with researchers from Ireland’s Atlantic Technological University and Boise State University in the USA.

It was published in the Nature journal Scientific Reports.