嶄忽森逢亅氏
 
 

嶄猟井   
 
Sun Exposure

  Green Leafy Vegetables Decrease Skin Cancer Risk

  Source: chinadaily.com.cn

  Eating plenty of green leafy vegetables such as kale, spinach and collard greens could decrease skin cancer risk says a study. These vegetables are known to contain a variety of vitamins and minerals and other bioactive substances that include lutein, vitamins C and E, flavonoids, folic acid, and fiber, according to the health portal HealthSentinel.

  Researchers studied over 1,000 adults living in Australia over an 11-year period and provided them full-body skin examinations as well as detailed dietary food frequency questionnaire, according to the study published in International Journal of Cancer.

  After adjusting for a variety of factors the researchers found that increasing intakes of green leafy vegetables were associated with a 41 percent decrease risk of skin cancer--which is known medically as Squamous cell carcinoma (SCC). Dark green leafy vegetables are rich in folic acid, which plays a key role in DNA synthesis and repair, the researchers said.

  The researchers also examined diet if any participant previously had skin cancer. They found an even more substantial relationship. People who previously had skin cancer had a 55 percent decrease in SCC with increasing intakes of green leafy vegetables. Conversely, dairy showed a significant 153 percent increased SCC risk. "Increased intake of unmodified dairy products increased SCC risk by more than 2-fold," the researchers observed. "Our findings show that higher intakes of green leafy vegetables may help prevent SCC tumours among people who have prior skin cancers," the researchers claimed. "A high intake of unmodified dairy, such as whole milk, cheese, and yogurt, may increase SCC risk in susceptible individuals," the researchers said.

  Exposure to the ultraviolet (UV) rays from the sun is widely considered to be the most important environmental factor in developing skin cancer. UV radiation causes direct damage to the DNA and to the immune system. UV radiation also causes indirect damage through the formation of free radicals.

  What is SPF?

  SPF stands for Sun Protection Factor. The number is determined experimentally indoors by exposing human subjects to a light spectrum meant to mimic noontime sun. Some subjects wear sunscreen and others do not. The amount of light that induces redness in sunscreen-protected skin, divided by the amount of light that induces redness in unprotected skin is the SPF. It is mainly a measure of UVB protection and ranges from 1 to 45 or above.

  A sunscreen with an SPF of 15 filters 92% of the UVB. Put another way, a sunscreen with an SPF of 15 will delay the onset of a sunburn in a person who would otherwise burn in 10 minutes to burn in 150 minutes. The SPF 15 sunscreen allows a person to stay out in the sun 15 times longer.

  There is currently no uniform measure of UVA absorption. There are broad-spectrum sunscreens that protect against UVA and UVB radiation although it is important to remember that the SPF does not predict UVA protection. The UV Index is a public health education tool reported by meteorologists in 58 U.S. cities. It offers a daily report of UV light levels on a scale from 1-10+.

  The "protectiveness" of clothing can also be measured by SPF. The following are SPF's of various types of clothing:

  • Nylon Stockings - SPF 2

  • Hats - SPF 3-6

  • Summer-weight clothing - SPF 6.5

  • Sun-protective clothing - up to SPF 30

  Copyright @ 2019 China Anti-Cancer Association