Vitamin D and Other Benefits of Sunlight

     The debate on whether the sun is a friend or a foe is ongoing, with more and more people afraid of sun exposure given its ties to skin cancer and premature aging. But don't completely shun the sun, as sun exposure has numerous health benefits that go beyond just vitamin D.
    
     In a study conducted at the University of Caliornia, San Diego, researchers combined data from other surveys of satellite measurements of sunlight and cloud during the winter from 15 countries to estimate the serum level of vitamin D metabolite of people living in 177 countries. The compilation of data revealed a linked between low vitamin D levels and risk of colorectal and breast cancer. According to the researchers, raising the serum levels was found to be ideal for cancer prevention, which means 600,000 cases of breast and colorectal cancer could be prevented each year with sufficient exposure to sunlight.  Dr. Cedric Garland, DrPh, of UC San Diego School of Medicine and Moores Cancer Center and co-author of the study, said, "This could be best achieved with a combination of diet, supplements and short intervals - 10 or 15 minutes a day - in the sun." The Food and Drug Administration's (FDA) recommended levels of daily vitamin D is 1,000 IUs, the equivalent of 10 to 15 minutes of sun exposure.

A Better Night's Sleep

     Your amount of daylight exposure is vital in maintaining a normal circadian rhythm. These rhythms include physical, mental, and behavioral changes that follow a 24-hour cycle and respond to light and darkness in the body's environment, says the National Institute of General Medical Sciences (NIGMS). The sleep-wake cycle is contingent on morning sunlight to help you sleep at night. Natural daylight helps your body clock restart to its active daytime phase. To ensure that your body clock is in sync, be sure to go outside and get some sunlight when you wake up or turn on the lights in your room. This will give your body the signal that it is daytime and not nighttime. To avoid confusing your circadian rhythm, try not to sit in dim settings during the day because your body will associate the bright light with night. The less morning light you expose yourself to, the more difficult it will be for you to fall asleep and wake up at your set time,
 saysDiscovery.com.

     Regular sunlight exposure can naturally increase the serotonin levels in your body, making you more active and alert. In an article published by the National Institutes of Health (NIH), exposure to bright light is seen as an approach to increase serotonin without the use of drugs. The positive correlation between the development of serotonin and the hours of sunlight during the day was seen in healthy volunteers. In a sample size of 101 healthy men, researchers found that turnover of serotonin in the brain was lowest during the winter whereas the production rate of serotonin was highest when the subjects stayed in the sunlight longer.


Enhances Your Mood

     The article therefore suggests that spending time in the summer sun can help you avoid the winter blues. Seasonal affective disorder (SAD), seasonal depression, and mood variation has been linked to sunlight exposure. Dr. Timo Partonen from the University of Helsinki's National Public Health Institute in Finland and researchers found that blood levels of cholecalciferol, also known as vitamin D3, are relatively low in the winter months. Sunlight exposure in the summer can equip your body to stock up on vitamin D3 that can last throughout the fall and yield for the production of more vitamin D, which leads to higher serotonin levels.


Lowers Blood Pressure

     Skin that is exposed to ultraviolet (UV) rays release a compound, nitric oxide, that lowers blood pressure. In a recent study conducted at Edinburgh University, dermatologists studied the blood pressure of 34 volunteers under UV and heat lamps. In one session, the volunteers were exposed to both light sources and in the other session, the UV rays were blocked so only the heat affected the skin. The results of the study showed a significant drop in blood pressure after exposure to UV rays for an hour but not after the heat-only sessions. It is important to note that the volunteers' vitamin D levels were unaffected in both sessions.


Actually Protects From Melanoma

     Yes, safe sun exposure can actually protect you from melanoma. The skin's exposure to ultraviolet radiation of short wavelegnths (UVB) has been linked to a decreased risk of melanoma in outdoor workers compared to their indoor counterparts, which suggests chronic sunlight exposure can have a protective effect, says The Lancet Journal. In astudy, indoor workers were found to have increased rates of melanoma because they were only exposed to UVA light, which is associated with skin damage and skin cancer. These workers were found to get three to nine times less solar UV exposure than outdoor workers and therefore had lower levels of vitamin D. It was reported that the indoor UV breaks down vitamin D3 formed after outdoor UVB exposure, which can result in a vitamin D deficiency and increase the risk of melanoma.


Sufficient Supply of Vitamin D

     The most notable benefit of exposure to sunlight is its ability to boost your body's vitamin D supply. The NIH says at least 1,000 different genes that control every tissue in the body are linked to be regulated by vitamin D3. Vitamin D is produced by the skin's response to UV radiation primarily through sun exposure, which affects 10 percent of the genes in the human body. In a study, researchers did vitamin D screenings on approximately 500 children admitted to a pediatric hospital ward for 12 months. Two in five children were found to have a vitamin D deficiency, which was linked to severe illness and a longer hospital stay. A healthy supply of vitamin D promotes bone growth and prevent illnesses such as breast and colon cancer, inflammation, multiple sclerosis, seasonal disorders, and depression.

Source: Yahoo Health: Healthy Living
Sun Exposure: Vitamin D And Other Health Benefits Of Sunlight
By Lizette Borreli | Jun 4, 2013 01:50 PM EDT