A study, carried out on wild sheep living on a remote island off the shores of Scotland, found that high levels of vitamin D are linked to improved fertility and reproductive success. Experts hope that further studies will help to determine the relevance of the results for other mammals, including people.
Researchers led by the University of Edinburgh measured concentrations of a marker linked to vitamin D in the blood of an unmanaged population of Soay sheep, on St Kilda. Scientists found that sheep with higher levels of vitamin D in their blood at the end of the summer went on to have more lambs in the following spring.
The study offers the first evidence that an animal’s vitamin D status is associated with an evolutionary advantage.
Vitamin D is produced in the skin of sheep and other animals, including people, after exposure to sunlight. Many studies in the lab have linked vitamin D to reproductive health in animals and humans. This is the first evidence of the link in wild animals.
“Examining the non-skeletal health benefits of vitamin D in humans is challenging because people are exposed to different amounts of sunlight each day. Studying the relationship between skin and dietary sources of vitamin D – and long term health outcomes – is more straightforward in sheep living on a small island.”