400-year-old strand of hair unlocks new thinking on Vitamin D and Scotland's weak winter sun

Analysis of the super-rare preserved hair, which came from a skeleton buried at the medieval St Nicholas Kirk in Aberdeen, has shown seasonal lows in vitamin D were an issue in Scotland four centuries ago with massive changes in diet and lifestyle doing little to alleviate the condition over time.

The findings come as archaeologists and nutrition scientists from the University of Aberdeen examine the long-term impact of living in a region with low levels of winter sunlight.

Researchers compared vitamin D levels in the hair of volunteers who have been living in the Aberdeen area for at least two-and-a- half years to the hair taken from the person buried in the 16th or 17th century.

Archaeologist Kate Britton said a clear seasonal variation could be detected in both modern and historical hair samples.

Professor Britton 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 as 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.”

A new method to detect vitamin D in human hair samples was used in the research - the first time it has been applied to archaeological remains.

Researchers in Aberdeen are working with counterparts from Ireland’s Atlantic Technological University and Boise State University (USA) to examine the long-term impact of low levels of sunlight over time and how it relates to vitamin D production.

Vitamin D is essential for healthy skeletal growth, with a shortage of it increasingly recognised for its role in chronic disease development, inflammation and immunity. But 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 supplementation.

The study is a global first in applying a new technique to measure vitamin D using hair in an ancient specimen and it opens a new window into the lives of those living in the past.

Prof Britton said: “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 also suggests that examining vitamin D through hair rather than blood offers potential benefits for understanding health today.

As hair grows around a centimetre each year, scientists can detect changes over multiple months rather than taking a snapshot in time as might be obtained through a blood sample taken in a medical setting.