Joint position statement issued to provide vitamin D clarity
Cancer Research UK has joined with the British Association of Dermatologists, Diabetes UK, the Multiple Sclerosis Society, the National Heart Forum, the National Osteoporosis Society and the Primary Care Dermatology Society to issue a joint position statement on vitamin D.
While it has a number of known benefits, there are still a number of unanswered questions associated with the vitamin.
These include what levels count as "sufficient" or "optimal" and whether vitamin D can help to protect against cancer, heart disease, diabetes, multiple sclerosis and other chronic diseases.
Furthermore, the fact that the sun's rays are people's main source of vitamin D raises questions about the trade-off between under- and overexposure, with the former linked - through vitamin D deficiency - to bone conditions such as rickets in children, and the latter to skin cancer, including melanoma.
As a result, the organisations have presented their unified views in an attempt to provide clarity.
The statement emphasises that while vitamin D is essential for good bone health, the evidence which suggests it can protect against cancer, heart disease, diabetes, multiple sclerosis and other chronic diseases is still inconclusive.
Meanwhile, it is stressed that a standard definition of an 'optimal' level of vitamin D has yet to be established, and that there is no 'one-size-fits-all' answer to the sun exposure question.
Instead, people are urged to enjoy the sun safely and take care not to burn, helping to ensure the benefits of vitamin D can be enjoyed without the risk of skin cancer being raised unnecessarily.
Finally, dietary modifications are recommended during winter time to boost vitamin D levels, although food fortification or widespread vitamin D supplementation for the general population is not advocated at this stage due to a lack of evidence about effectiveness and possible harms.
Ed Yong, head of health information and evidence at Cancer Research UK, said: "This joint consensus statement brings together the latest evidence on vitamin D.
"In representing the unified views of many different organisations, we hope to provide some clarity around this important but controversial issue. It is encouraging that our stance agrees with that of other international organisations, such as the World Health Organisation and the US Institute of Medicine.
"Avoiding sunburn still remains the most important thing people can do to protect themselves against developing skin cancer.
"While some sunshine is good for us and vitamin D is important for good bone health, the evidence suggesting that vitamin D protects against other disease such as cancer or heart disease is inconclusive.
"By enjoying the sun safely, people can make enough vitamin D without increasing their risk of skin cancer."