Can incidental exposure to sunlight produce optimum levels of vitamin D?

"During the summer months most people should be able to achieve adequate vitamin D (blood 25-hydroxyvitamin D) levels through incidental outdoor UV exposure outside peak UV times (2). As an example, someone who burns easily in the sun (skin type 1 or 2 - see Appendix 2) may only need 5 minutes of daily summer sun exposure before 11am and after 4pm (to the face, hands and forearms) to achieve adequate vitamin D levels whereas someone who tans more easily or has darker skin (skin type 5 or 6) will need more time e.g., up to 20 minutes."

Quoted from Cancer Society Position Statement: The Risks and Benefits of Sun Exposure in New ZealandSeptember 2005

Photo: Alama and Jamine Moller: sun exposure according to skin type

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Gary Moller Comments:These guidelines are misleading and have no relationship with reality. They are instrumental in creating an epidemic of vitamin D deficiency-related ailments that are beginning to swamp our health system.

I have been running a campaign since 2001 to highlight the importance of Vitamin D for optimum health and a long and productive life span. I can tell readers that I have not yet had a single person who has consulted me about health or injury problems who has optimum vitamin D levels. Every single person has been either deficient or not far off it. Clinical deficiency begins at 50, optimum is 120-150nmol/l. The lowest level by a client has been 8. Needless to say, she was not feeling well.

Can you obtain optimum levels of vitamin D by "incidental exposure" as advised by the Cancer Society? My answer is a definite "NO!" Take compeititive cyclists for example: They spend long hours out in the sun, but only expose their arms and legs at the most (Usually when sipping lattes outside a cafe!). This exposure can be over several hours and often during peak UV periods of the day. So far, the highest summer time vitamin D levels I have seen produced by a cyclist is just 75.

Sunlight is our only practical source of vitamin D, unless we consume large amount of seal blubber and various animal organs. Normal dietary sources such as eggs and liver and varous supplements like cod liver oil are not sufficient to significantly increase vitamin D levels. They serve only to slow the attrition that normally occurs over winter months. Cod liver oil, for example, can safely deliver only 200-800 iu of vitamin D, per day whereas full body exposure to sunlight can deliver from 10-20,000 iu in a single day.

It is time that the cancer authorities reviewed the latest evidence and altered their sun exposure guidelines accordingly.