UVC light may be used as disinfectant to kill viruses and bacteria, but it’s also proven highly cancerous
By the University at Buffalo
Ultraviolet light has the ability to improve immune responses and promote health, but don’t rush out to sunbathe or purchase UV lamps, warns UB light therapy expert Praveen Arany.
A powerful form of radiation, UV light is capable of use as a disinfectant to kill bacteria, viruses and other pathogens. However, prolonged exposure is linked to an increased risk of skin cancer.
“We need to be cautious about UV light,” says Arany, D.D.S., Ph.D., assistant professor in the UB School of Dental Medicine. “There is growing evidence that specific amounts and types of UV light are beneficial to health, but we have to be careful not to mislead the public.”
Arany is president of the World Association for Photobiomodulation Therapy (WALT), which promotes research, education and clinical application of laser photostimulation worldwide. His comments come after President Donald Trump suggested ultraviolet and other forms of light might be used to treat COVID-19 patients.
Costs and Benefits of UV Light
The sun emits three wavelengths of light, UVA, UVB and UVC rays. Each type emits radiation, but there is a delicate relationship between the wavelength’s ability to heal and its role as a skin carcinogen, says Arany.
UVA is the most abundant wavelength in sunlight that is perceived on Earth. Safe in small amounts, it offers the most promise for use in photobiomodulation therapy, a form of low-dose light therapy, says Arany. Although UVA is the weakest carcinogen among the three, prolonged exposure – such as through excessive sunbathing or artificial tanning – poses risks for skin cancer.
In the middle is UVB, of which less than 10% reaches the Earth’s surface, says Arany. This invisible wavelength is the body’s primary tool in the creation of vitamin D, but poses a higher risk for the development of cancer than UVA. Both UVA and UVB are routinely used in dermatological clinics for skin disorders, as well as in tanning beds.
UVC may be used in sterilization, but is a strong carcinogen. This wavelength is only safe when used to disinfect inanimate objects, says Arany. Nearly all UVC in sunlight is absorbed by the Earth’s ozone layer.
Understanding the differences in types of UV is crucial in light of recent news on its potential use in the COVID-19 pandemic. Despite the wide availability of UV lamps, the public should consult a health care professional before the medical use of any UV light. Prolonged exposure to UVA or UVB or any use of UVC can be detrimental to health, says Arany.
Healing in Small Doses
At a high power, light, often in the form of a laser, is used in medicine to cut or destroy tissue. But at low doses, it has the ability to relieve pain and promote healing.
Light therapies have existed for decades, but improvements in the technology have made its therapeutic use more affordable and available, says Arany.
The effectiveness of photobiomodulation in treating pain and stimulating healing has been documented in hundreds of clinical trials and thousands of academic papers. The treatment is used widely across Europe, Canada, Australia and several other nations. However, precise dosing for a broad range of clinical applications are still being investigated, says Arany.
The Arany lab leads numerous studies demonstrating the success of light therapies, including in supportive cancer care, relieving skeletomuscular pain, reducing inflammation, and promoting wound healing and tissue regeneration by harnessing stem cells.
“UV light as a therapeutic has been, unfortunately, somewhat controversial,” says Arany. “It has received bad press because of its excessive use in tanning booths and its connection to skin cancer. While we do need to be cautious with its use, in moderation, light is good for you.”
Arany is an advocate for wider use of photobiomodulation treatments in the U.S. He is chair of the mechanisms of photobiomodulation conference for the Society of Engineers for Optics and Photonics (SPIE).
Arany also took part in the first Congressional briefing on photobiomodulation before the House Science, Space and Technology Committee in Washington, D.C. The briefing, held on Oct. 11, 2018, invited a panel of international experts on the therapy to discuss the potential of photobiomodulation to improve health care and lower dependence on opioids.