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The Role of UltraViolet Light
The Facts and Bio-Positive effects of UV light
For years, the public has been bombarded with research investigations and published reports claiming that any and all exposure to UV light can cause a multitude of problems. These reports are important because they enable us to get a thorough perspective on the risks of UV energy. There are several problems, however, which have led to a lopsided perception of these risks among the public:
- Many of these studies are flawed and some outdated because of inaccurate measurement equipment and, therefore, do not provide an accurate depiction of how our bodies react to UV light.
- Thus far, most studies have only focused on the downside of excessive UV exposure and have overlooked the potential benefits.
- The overwhelming majority of studies investigating the effects of moderate UV exposure have found no significant adverse effect - yet these studies receive minimal media attention compared to those claiming to find an adverse impact.
While many dermatologists suggest that UV light causes skin cancer and should, therefore be avoided at all costs; others suggest that a moderate amount of sun exposure can ward off a host of deadly and debilitating diseases. Thus far, research has shown that moderate doses of sun exposure increases the amount of Vitamin D in the human body. This increase can prevent diseases and conditions such as osteoporosis, hypertension, diabetes, multiple sclerosis, rheumatoid arthritis, and depression and, more surprisingly, cancers of the colon, prostate, breast. It can actively strengthen the heart and circulation, give the feeling of more vitality and add a positive radiance!
For example, Dr. Michael Holick, Vitamin D expert and professor of Medicine, Dermatology, Physiology, and Biophysics at Boston University Medical Center has claimed that 40-60% of Americans are vitamin D deficient.
How does this impact the study of UV light? We get our Vitamin D from three main sources:
- By eating a diet rich in vitamin D
- By taking vitamin D supplements or
- By receiving a moderate dose of sun exposure
It has become a well-known fact that 'Western World' diets do not provide enough Vitamin D, leaving supplements and moderate sun exposure to make up the difference. Most dermatologists would instinctively suggest supplements versus sun exposure. However, research indicates, oral vitamin D supplements block the squalene process which, it has been proven, results in increased cholesterol in the blood stream.
The third option, sun exposure, may have its consequences - continuous over-exposure and sun-burning has been linked to skin cancer. However, the benefits of moderate exposure to the sun appear to far outweigh the risks. Research shows, and it can be claimed, that Vitamin D produced by the sun may prevent a number of debilitating diseases.
Everyone is exposed to UV radiation from the sun and an increasing number of people are exposed to artificial sources used in industry, commerce and recreation. Emissions from the sun include visible light, heat and UV radiation.
The UV region covers the wavelength range 100-400 nm and is divided into three bands:
- UVA (315-400 nm)
- UVB (280-315 nm)
- UVC (100-280 nm)
As sunlight passes through the atmosphere, all UVC and approximately 90% of UVB radiation is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth's surface is largely composed of UVA with a small UVB component.
Environmental factors that influence the UV level:
- Sun height. The higher the sun in the sky, the higher the UV radiation level. Thus UV radiation varies with time of day and time of year, with maximum levels occurring when the sun is at its maximum elevation, at around midday (solar noon) during the summer months.
- Latitude-the closer the equator, the higher the UV radiation levels.
- Cloud cover- UV radiation levels are highest under cloudless skies. Even with cloud cover, UV radiation levels can be high due to the scattering of UV radiation by water molecules and fine particles in the atmosphere.
- Altitude-at higher altitudes, a thinner atmosphere filters less UV radiation. With every 1000 meters increase in altitude, UV levels increase by 10% to 12%.
- Ozone-ozone absorbs some of the UV radiation that would otherwise reach the Earth's surface. Ozone levels vary over the year and even across the day.
- Ground reflection-UV radiation is reflected or scattered to varying extents by different surfaces, e.g. snow can reflect as much as 80% of UV radiation, dry beach sand about 15%, and sea foam about 25%.
Ozone depletion and UV-related health effects.
Depletion of the ozone layer is likely to aggravate existing health effects caused by exposure to UV radiation, as stratospheric ozone is a particularly effective UV radiation absorber. As the ozone layer becomes thinner, the protective filter provided by the atmosphere is progressively reduced. Consequently, human beings and the environment are exposed to higher UV radiation levels, and especially higher UVB levels that have the greatest impact on human health, animals, marine organisms and plant life.
Computational models predict that a 10% decrease in stratospheric ozone could cause an additional 300,000 non-melanoma and 4500 melanoma skin cancers and between 1.6 and 1.75 million more cases of cataracts worldwide every year.