Lead author Julia Newton-Bishop of the Cancer Research U.K. Centre at the University of Leeds also suggested melanoma patients might also need vitamin D supplements as well.
The study, published in Cancer Causes and Control, defined the optimal amount of vitamin D required by the body as at least 60 nanomoles per liter. However, there is no current universally agreed standard definition of an optimal level of vitamin D, Newton-Bishop said.
Researchers chose 60nmol/L as the optimal vitamin D level in part because there is evidence that levels lower than this may be linked to greater risk of heart disease and poorer survival from breast cancer, Newton-Bishop said.
"Fair-skinned individuals who burn easily are not able to make enough vitamin D from sunlight and so may need to take vitamin D supplements," Newton-Bishop said in a statement. "This should be considered for fair-skinned people living in a mild climate like Britain and melanoma patients in particular."
The researchers took the vitamin D levels of some 1,200 people and found that about 730 people had a sub-optimal level and those with fair-skin had significantly lower levels.