The Vitamin D debate
The risks and benefits of sun exposureThe human body needs vitamin D to regulate calcium levels and to make and maintain healthy muscles and bones. Some recent studies have also suggested possible beneficial effects of sun exposure in the prevention or improved treatment outcome for a number of other diseases including some internal cancers. Most vitamin D is produced in the skin by exposure to UVB from sunlight. It can also be obtained from foods such as oily fish, eggs, meat, fortified foods (such as margarine and some milks), or Vitamin D supplements. A balance is required between getting enough sun exposure to maintain adequate vitamin D levels, and avoiding an increased risk of skin cancer. Unfortunately there is little research available to determine exactly how much sun exposure is needed to maintain adequate vitamin D levels, as this will vary with age, skin colour, location and the time of day and year. In response to confusion over mixed messages about the risks and benefits of sun exposure, a collaboration of The Cancer Council Australia, the Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia and the Australasian College of Dermatologists developed a position statement, the main points of which are summarised below: Most Australians are thought to have enough UVB exposure during typical day-to-day outdoor activities, to ensure adequate vitamin D production. It has been estimated that fair skinned people can achieve adequate vitamin D levels in summer by exposing the face, arms and hands (or the equivalent area of skin) to a few minutes of sunlight on either side of the peak UV periods on most days of the week. In winter, in the southern regions of Australia, 2-3 hours of sunlight exposure to the face, arms and hands (or equivalent area) over a week is thought to be adequate. Some people are at higher risk of vitamin D deficiency. These include naturally dark skinned people, those who cover their skin for religious or cultural reasons, the elderly, babies of vitamin D deficient mothers, and people who are housebound or in institutional care. Naturally dark skinned people do have some natural protection from skin cancer by the pigment in their skin and probably could safely increase their sun exposure. Others in the group, or those with a high risk of skin cancer might benefit from dietary supplementation with vitamin D.