A study from the University of Leeds finds that fair-skinned people who burn quickly in the sun may need supplements to ensure they get enough vitamin D.
Researchers suggest that people with very pale skin may be unable to spend enough time in the sun to make the amount of vitamin D the body needs while also avoiding sunburn. The findings suggest that melanoma patients may need vitamin D supplements as well.
"Fair-skinned individuals who burn easily are not able to make enough vitamin D from sunlight and so should take vitamin D supplements. This should be considered for the majority of populations living in a mild climate like the UK and melanoma patients in particular," said the lead author of the study, Professor Julia Newton-Bishop.
Researchers took the vitamin D levels of around 1,200 people and found that around 730 people had a suboptimal level. Those with fair skin had significantly lower levels.
The study defined the optimal amount of vitamin D required by the body as at least 60nmol/L. At present there is no universally agreed standard definition of an optimal level of vitamin D. Researchers chose 60nmol/L in part because there is evidence that levels lower than this are linked to greater risk of heart disease and poorer survival from breast cancer.
However, a consensus of health charities including Cancer Research UK says that levels below 25nmol/L are vitamin D-deficient which means that these levels are associated with poor bone health. But some researchers consider that higher levels, around 60nmol/l, may be desirable for optimal health effects.
"These include people with naturally brown or black skin who need much more sunlight to increase their vitamin D levels, pregnant women and people who don't go outside much," said Sara Hiom, director of health information at Cancer Research.
Meanwhile, researchers also emphasize that sunlight and supplements are not the only factors that can determine the level of vitamin D in a person's body. Some inherited differences in the way human body processes vitamin D into its active form also have a strong effect on levels.