Scientists from the University of Ulster are to explore if we are getting enough vitamin D - vital for the formation of healthy bones and which may also help prevent diseases such as diabetes, cancers, rheumatoid arthritis and multiple sclerosis.
The main source of vitamin D is exposure to ultra-violet radiation in sunlight, which produces vitamin D in the skin. A small amount of vitamin D can also be obtained from the diet.
The researchers from the Northern Ireland Centre for Food and Health are to embark on a three year project in collaboration with colleagues from University College Cork to investigate what level of dietary vitamin D is needed to maintain good vitamin D status in the winter time.
Dr Julie Wallace, a senior research fellow at UU, said: "For six months of the year - roughly from the end of September until mid-March - we cannot make vitamin D through exposure to sunlight - even if we were out all day every day, because the sun is too low in the sky. Our summertime levels will last for part of the year, but by the end of winter we know from our own research that those stores are low. "Traditionally the lack of Vitamin D was thought to be a problem for institutionalised elderly people who did not get exposure to sunlight, but more and more we are realising that it is a problem for the whole population."
She said that the use of sun creams and moisturisers with a sun protection factor also reduces UV absorption and so vitamin D production. "While we only need five or 10 minutes a day exposure of sun on our face and arms during the summer time to obtain the required daily amount of Vitamin D, the risk of skin cancer has meant that people are rightly cautious about sun exposure. Also our lifestyles have changed, we spend more time in front of the TV or computer; traditionally we may have spent more time outdoors".