Schoolboy, Ryan McLaughlin, tirelessly campaigned on this issue and petitioned the Scottish Parliament to produce new guidelines on vitamin D supplements for children and pregnant women. His efforts have been successful. See BBC News report.
Because Scotland gets less sunshine than the more southerly regions of Britain, it is inevitably more difficult to get sufficient Vitamin D, the 'sunshine vitamin.' Inadequate levels of this vitamin result in many health problems, including more fragile bones, excess weight, muscle weakness and many more. (Click on the Vitamin D label just beneath this post if you would like more information about Vitamin D.) Possibly the most important of Vitamin D's contributions to health is protection from infections. - If you have enough Vitamin D you are far less likely to catch colds and flu, etc.
If getting out into the sun is a problem for you and you decide to take supplements of the sunshine vitamin, the best version is Vitamin D3. Vitamin D is also essential to metabolise calcium. Read about dairy calcium, fat retention and vitamin D on my webpage here.