How Sunlight Is Good for Our Health: A HealthCentral Explainer

ATsai Editor
  • We all know that too much sun can lead to skin cancer, and and that wearing sunscreen is an important part of keeping our skin healthy.  But sunlight may also offer hidden benefits.  Outside of acting as a mood booster, a source for Vitamin D and the regulator of our body clock, new research suggests there is more to the story.


    Can sunlight prevent allergies and eczema?

    According to new research, increased exposure to sunlight may reduce the risk of food allergies and eczema in kids.  Researchers analyzed data from a study done on children in Australia, and looked for a connection between food allergy, eczema, asthma and sunlight. Australia was chosen for this study, as it spans 3,000 miles from north to south and varies dramatically in climate, day length and sun strength.

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    Researchers found that children living in the south of Australia were twice as likely to develop eczema compared to those living in the northern region of the country, who had more exposure to sunlight. However, researchers say more investigation is needed to determine which factors are important to the connection between sunlight and allergies. such as temperature, infectious disease and Vitamin D.


                [SLIDESHOW: 5 New Discoveries in Allergy Research]


    Can sunlight reduce the risk for rheumatoid arthritis?

    Exposure to ultraviolet B (UVB) rays may reduce the risk of rheumatoid arthritis in women, according to a recent study published in the Annals of Rheumatic Disease. The positive results were seen mostly in older women, which researchers say could be because younger women are more apt to protect themselves from the sun with sunscreen.


    Data was collected through the U.S.  Nurses’ Health Study, which followed the health of 120,000 nurses from 1976 to 2008, with the starting age between 30 and 55. Another 115,000 nurses were followed from 1989 until 2009, with the starting age between 25 and 42.


    Researchers then measured the rates of UVB exposure with the UVB-flux, which calculates UVB radiation, cloud cover, latitude and altitude. During the course of the study, 1,314 women developed RA, and the nurses with the highest rates of UVB exposure were 21 percent less likely to develop RA than those with the lowest rates of exposure.


    How does sunlight affect multiple sclerosis?

    Vitamin D3, which is derived mainly from sunlight exposure, may be an effective treatment for reducing the severity of multiple sclerosis, and may even prevent it, according to new research.  A team of researchers looked at the relationship between the vitamin D3 hormone, immune cells and the risk and severity of MS in an experimental model.


    They looked at the effect of vitamin D3 on T lymphocytes. Some of the T lymphocytes had vitamin D3 receptors and others did not. Researchers found that the protective effect of vitamin D3 was only evident when the receptors were present in the T lymphocytes. They believe that the D3 hormone works directly on the pathogenic T cells to eliminate them. Though more research is needed, the team notes that future vitamin D treatment strategies are important.


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                [SLIDESHOW: 10 Foods that Fight Inflammation]


    Can sunlight reduce the risk of cancer?

    Although too much sunlight and UV rays is definitely a risk factor for skin cancer, it maybe actually cut the risk of developing esophageal and pancreatic cancer.


    For the esophageal cancer study, researchers compared an estimated lifelong dose of UV rays from two groups of people.  They looked at 1,000 people suffering from esophageal cancer compared to a 1,500 person control group without esophageal cancer. The found that the more UV and sunlight exposure a person experienced in their lifetime, and based on where they lived, the less likely they were to develop esophageal cancer.


    The pancreatic cancer study involved 714 Australians who were matched with controls in germs of age and sex. The study took place between 2007 and 2011. Researchers assigned UV radiation levels to each participant’s birth location using NASA’s Total Ozone Mapping Spectrometer. The group was divided into three categories based on radiation levels. They found that those born in the areas with the highest amount of UV radiation had a 24 percent lower risk of developing pancreatic cancer, compared to those born in the areas with the lowest amount of UV radiation. In addition, they found that people with the most sun-sensitive skin cut their risk for pancreatic cancer by 49 percent, compared to those with the least sun-sensitive skin. Lastly, they found that the risk for pancreatic cancer was 40 percent lower in people with a history of skin cancer.



    The Peninsula College of Medicine and Dentistry (2012, February 3). Lower levels of sunlight exposure link to allergy and eczema in children, study suggests. ScienceDaily. Retrieved from


    Fitzgerald, K. (2013, February 5). "Sunshine Reduces Risk of Rheumatoid Arthritis." Medical News Today. Retrieved from


    Wiley. (2011, March 4). "How Sunlight May Reduce The Severity Of Multiple Sclerosis." Medical News Today. Retrieved from


    The Sunlight Research Forum. (2013, February 8). "Sunlight Reduces The Risk Of Esophageal Cancer." Medical News Today. Retrieved from


    Rattue, P. (2012, July 10). "Pancreatic Cancer Risk Lowered By Exposure To Sun." Medical News Today. Retrieved from


Published On: March 11, 2013