Sun - Benefits and Risks
Is the sun good or bad for our health? There’s been some debate about this in recent years. However, it looks as if:
Moderate exposure to the sun is usually beneficial for:
- Producing vitamin D, which is good for bone health – and may be beneficial in helping prevent a number of conditions, including MS, rheumatoid arthritis and prostate cancer (a review of previously published research in the American Journal of Public Health in late 2005 suggested that taking vitamin D pills could substantially reduce the risk for breast, colon, prostate and ovarian cancer; and researchers theorize that vitamin D is crucial to the regulation of Th1 cells, an important group of immune cells).
- Reversing seasonal affective disorder (SAD).
In 2005 the journal Photochemistry and Photobiology estimated that about 50,000-63,000 annual cancer deaths in the U.S. (10% of all cancer deaths) could be prevented if all Americans had sufficient vitamin D – compared with 10,000 deaths from various forms of skin cancer.
The value of the sun is partly also due to the fact that there aren’t many natural food sources of vitamin D - mainly fat-rich fish that thrive in cold water, such as mackerel and salmon.
However, excessive exposure to the sun (and also to sun lamps and tanning beds) is harmful - particularly when you are young, when you are fair skinned, if you have a lot of moles or freckles, if you have been sunburned before or if you have a personal or family history of skin cancer.
- A combination of ageing and sun produces premature photoaeging of the skin, making it look dry and wrinkled. This causes most of the skin changes we tend to think of as a normal part of ageing. So sun damage to the skin may not be obvious when you're young but it will start to show as you get older.
- More serious is the risk of skin cancer. Research presented at the British Association of Dermatologists annual conference in 2011 identified that young people were significantly more likely to let their skin burn, never cover up or wear a hat to protect their skin. This may help explain why rates of malignant melanoma, the most serious form of skin cancer, have tripled among those aged 15 to 34 since the late 1970’s. And in 2007, an international cancer research organization found that people who started indoor tanning before the age of 35 had a 75% greater risk of developing melanoma.
- Exposure to UV rays can also damage your eyes, and can lead to problems such as burning and cataracts. When you’re buying sunglasses, choose a pair that has one of the following: the 'CE Mark' and British Standard (BS EN 1836:1997); a UV 400 label; or a statement that the sunglasses offer 100% UV protection.
So, don’t be afraid of modest exposure to the sun, without sun lotion (about 10 – 20 minutes a day). However, for longer periods and especially between 10 am and 3 pm stay in the shade or put on plenty of sunscreen with a sun protection factor (SPF) of at least 20 (to protect against UVB rays) and at least four stars (to protect against UVA rays).
Sunscreens which protect against both UVB and UVA rays are labelled ‘broad spectrum.’ Make sure you cover all exposed skin, including the tops of feet, ears and the back of the neck. Also make sure the sunscreen isn’t past its expiry date and wear a hat and shirt around midday (a standard cotton T shirt provides around SP5 sun protection). Reapply sun screen if you’ve been swimming and remember that even on cloudy day 80% of the sun’s rays can still get through.
According to Cancer Research UK, people don't apply as much sunscreen as they need to. If you don't apply enough, you won't get the protection that is claimed on the bottle. The label of the sunscreen will indicate the UVA or UVB protection. UVA rays are responsible for the aging effect of the sun; however, overexposure to UVA rays can also cause skin cancer – whilst UVB rays are responsible for sunburns and skin cancer.
Some useful web links, which provide fuller information, are:
Published 06/07/2011, Review date November 2014