"People are hearing many different recommendations, some of which can be misleading," says Dr. Cheryl Rosen, national director of the Canadian Dermatology Association's National Sun Awareness Program. "These include claims by the tanning industry that the use of sun beds promotes vitamin D production in the skin.

"The sun exposure that Canadians receive during their day-to-day activities is generally adequate to maintain vitamin D levels in the spring, summer and fall. If someone is very careful about sun exposure and concerned their vitamin D levels might be low, supplements from food or vitamin pills are excellent ways to obtain enough vitamin D," she adds.

Vitamin D, actually a hormone, maintains the calcium and phosphate levels in our bodies necessary for the development of healthy bones. Without adequate vitamin D, the body begins to 'steal' calcium from our bones, increasing the risk of loss of bone mass and fractures.

"Consumption of fish, such as salmon, can provide a dietary source of vitamin D. Foods, such as milk, may be fortified with vitamin D. However, the daily intake from diet may be insufficient to provide an adequate supply of vitamin D," says Dr. Rosen, a dermatologist at Toronto Western Hospital, University of Toronto.

Vitamin supplements containing vitamin D are a safe way to maintain healthy levels. A dose of 400 IU (international units) a day for adults and 300 to 400 IU a day for children is currently recommended. However, these values are currently being reexamined and are suspected of being on the low side.

"The skin makes vitamin D when exposed to the sun. This process is blocked by sunscreen use. Only brief sun exposure to either the back of the hands, arms, or face, two to three times a week from May to September, is required to maintain sufficient vitamin D levels through production of vitamin D in the skin," she advises.

"Remember that too much sun increases the risk of sunburn, wrinkles, premature aging of the skin, pre-cancerous spots, and skin cancer," she cautions.

"It is important to know that the skin also stops making more Vitamin D when a person is out in the sun for longer periods and it inactivates any excess Vitamin D which is made." Dr. Rosen points out.

During the winter months, oral supplements containing vitamin D can be considered, particularly for the elderly. Canadians living in some parts of the country where there are few hours of sunshine may be severely low in vitamin D if they have an inadequate diet and are not on vitamin D supplements.

Regarding the use of sun beds and claims that exposure to these sources of ultraviolet radiation promotes vitamin D production, Dr. Rosen says: "The major ultraviolet component emitted by the light bulbs used in tanning parlours is ultraviolet A which has no effect on Vitamin D production. Many lamps also emit a smaller amount of ultraviolet B.

"The World Health Organization (WHO) says while sun bed use may increase vitamin D synthesis, incidental sun exposure and dietary sources of vitamin D are generally enough to maintain healthy levels of vitamin D.

"The use of sun beds increases a person's risk of developing skin cancer. Given that organizations such as the WHO and many state governments in the United States and authorities in Europe are recommending that no one under 18 use tanning parlours, we would advise against using sun beds."

The causes of vitamin D deficiency include poor diet, liver disease, kidney disease, fat malabsorption, and living in a place with little sunshine. The skin of elderly people is less able to produce vitamin D.