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Ask an expert: How can I stay safe in the sun?


Although the hot summer months give us a welcome boost of vitamin D, too much sun exposure can lead to premature skin ageing and increase the risk of developing skin cancer. Vancouver Coastal Health Research Institute (VCHRI) researcher Dr. Sunil Kalia details why we should all be sun-smart.

Q: I’ve heard that UVA and UVB radiation are both damaging for skin, but in what ways?

A: UVB rays make up only five per cent of UV radiation from the sun, but they are strongly linked with sunburns and skin cancer. This is because of the intensity of the highly energetic photons they emit, which can break the bonds that connect DNA molecules in skin. On the other hand, UVA constitutes 95 per cent of the UV radiation from the sun and is largely linked with skin ageing, such as dark spots and wrinkling. Because of its longer wavelengths, UVA rays can penetrate into deeper layers of skin and damage collagen. They can also cause skin cancer by stimulating the production of skin-damaging reactive oxygen species chemicals.

Q: How much time in the sun is okay for getting a healthy dose of vitamin D? 

A: It depends on the time of the day and the season. During the fall, winter and early spring in British Columbia, you cannot obtain adequate levels of vitamin D from the sun, even after several hours of exposure. During July and August, five to 15 minutes of sun exposure could be sufficient to get all the vitamin D you need. However, research has found that, due to the inability to acquire adequate vitamin D levels with sun exposure during the majority of the year and increased skin cancer risks with UV radiation, it is better to get the recommended amount of vitamin D through oral supplementation or foods that are high in vitamin D.

Q: How much sun exposure should I get based on my skin type and colour? 

A: People with all skin types and colours should minimize their sun exposure to reduce their skin cancer risk, especially when UV radiation levels are highest during the summer months between the hours of 11 a.m. and 3 p.m. 

Read the full Q&A at for more science-based and myth-busting insights on how to protect your skin from the sun.

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