Vitamin D linked to improved fertility in wild animals

High levels of vitamin D improve the fertility and reproductive success of wild sheep.

A study led by Dr Richard Mellanby, Head of Small Animal Medicine at the University of Edinburgh's Royal (Dick) School of Veterinary Studies, adds to growing evidence that vitamin D is associated with reproductive health.

Experts hope that further studies will help to determine the relevance of the results for other mammals, including people.

The study measured concentrations of a marker linked to vitamin D in the blood of an unmanaged population of Soay sheep on the remote Hebridean islands of 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. It can also be found in some foods, including certain types of plants. It is essential for healthy bones and teeth and has been linked to other health benefits.

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.

The research is published in the journal Scientific Reports. It was funded by the Wellcome Trust and the Natural Environment Research Council: Vitamin D status predicts reproductive fitness in a wild sheep population.

Our study is the first to link vitamin D status and reproductive success in a wild animal population.

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.

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