Sunlight Is a Natural Immune Booster
By. Joseph Mercola
T细胞的光谱敏感性在紫外A (UVA)范围的~350纳米(nm)和蓝色光谱的~470纳米(nm)达到峰值。后者(470 nm光)以前曾被证明可以在体外杀死耐甲氧西林金黄色葡萄球菌(MRSA)。
Most recently, researchers at Georgetown University Medical Center (GUMC) published a laboratory study using cells in petri dishes, showing that exposure to blue and ultraviolet (UV) light increases T cell activity — white blood cells involved in immune function and fighting infections.
This is thought to be the first study showing an impact of light on this particular type of immune cell, so more research is needed to verify the results. However, there's plenty of evidence in the medical literature confirming that sunlight has immune-boosting properties.
In this study, light was found to stimulate the production of hydrogen peroxide, which boosted the activity of T lymphocytes. As little as five to 10 minutes of sun exposure were needed to boost immune cell activity. As noted in one news report:
"Given the large surface area of human skin, all of the T cells present in skin could potentially benefit from this phenomenon through exposure to blue light, the researchers suggest.
Note that vitamin D is only produced in the body via exposure to UVB rays, which can be harmful in cases of prolonged sun exposure.
If blue light from the sun's rays is capable of energizing infection-fighting T cells, it could be a potential means of treatment for boosting immunity in many patients, the researchers conclude."
While the researchers appear hopeful that blue light alone might be a valuable immune-boosting treatment, it's important to realize that the biological effects of light can be very complex, and it's important to get it right.
As explained by Dr. Alexander Wunsch, a world class expert on photobiology, excessive exposure to blue light — such as that from LED lighting, which is primarily blue and devoid of near-infrared found in sunlight and incandescent lighting — can be quite harmful, and may be a significant risk factor for age-related macular degeneration (AMD).
The healthiest blue light is from the sun, as it is balanced by near-infrared radiation, which has many important biological functions. Importantly, near-infrared radiation will activate cytochrome C oxidase in your mitochondria and help to optimize ATP production.
Sensible sun exposure has many health benefits. Many are the result of vitamin D production, which occurs when your skin is exposed to UV light, but many others are unrelated to vitamin D
Recent research shows both blue light and UVA light boosts the activity of T lymphocytes. As little as five to 10 minutes of sun exposure was needed to boost immune cell activity
The healthiest blue light is from the sun, as it is balanced by near-infrared radiation, which activates cytochrome C oxidase in your mitochondria and helps optimize ATP production
T Cells Are Intrinsically Photosensitive
For a long time, it was believed mammals only had photosensitive cells in the eye. We're now finding photosensitive cells in many other areas of the human body.
As noted by the authors, this study demonstrates that "T lymphocytes possess intrinsic photosensitivity and this property may enhance their motility on skin." In other words, T cells sense and respond to light.
Blue light specifically triggers the production of hydrogen peroxide (H2O2) in T cells, which triggers a chemical cascade that results in increased T cell motility. The increased motility or activity, in turn, allows the immune cells to function better.
Interestingly, once the T cells are activated they also alter their antioxidant capacity — an effect that appears to allow for greater H2O2 production in response to light.
The spectral sensitivity of T cells peaked at both ~350 nanometers (nm), which is in the ultraviolet A (UVA) range, and ~470 nm, which is in the blue spectrum. The latter (470 nm light) has previously been shown to kill methicillin-resistant Staphylococcus aureus (MRSA) in vitro.
Lowering high blood pressure and reducing risk for heart disease and cancer
Research has shown that when sunlight strikes your skin, nitric oxide (NO) is released into your bloodstream.26 NO is a powerful blood pressure lowering compound that helps protect your cardiovascular system, cutting your risk for both heart attacks and stroke.
UVB light lowers blood pressure by dilating blood vessels specifically the capillaries in your skin. This directs about 60 percent of your blood flow there. This then allows the sun's rays to easily penetrate into your blood.
Sunlight has UV rays known to be germicidal and can help kill infections in your blood. This aspect of sunlight was used to treat tuberculosis in the late 19th and early 20th centuries, even awarding a Nobel prize to Finsen in 1903 for this work.
According to one 2013 study,27,28 for every single skin cancer death, 60 to 100 people die from stroke or heart disease related to hypertension. So your risk of dying from heart disease or stroke is on average 80 times greater than your risk of dying from skin cancer.
While higher vitamin D levels correlate with lower rates of cardiovascular disease, oral vitamin D supplements do not appear to benefit blood pressure, and the fact that supplements do not increase nitric oxide may be the reason for this.
Preventing infectious diseases
Both UV light itself and the vitamin D produced when your skin is exposed to it have potent antimicrobial effects.
While vitamin D increases production of naturally occurring antimicrobial peptides that destroy the cell walls of viruses and bacteria, UV light also increases blood levels of infection-destroying lymphocytes (white blood cells).
Besides boosting rates of cardiovascular disease, widespread sun avoidance may also be responsible for the reemergence of tuberculosis (TB), which now kills about 4,100 people every single day.
In 2014, there were 1.5 million TB-related deaths worldwide, making it the No. 1 infectious disease out there. Compare that to the 55,100 who die from melanoma each year (worldwide).
UV light, especially blue light, also acts as a potent disinfectant of your environment. Research has found UV light can reduce the spread of tuberculosis in hospital wards and waiting rooms by 70 percent, and helps kill 90 percent of drug-resistant bacteria in hospital rooms.
Data suggests UV light at 254 nm can kill drug-resistant strains of S. aureus and E. faecalis in as little as five seconds.
How Sun Exposure Improves Your Immune Function https://articles.mercola.com/sites/articles/archive/2017/01/23/how-sun-exposure-improves-immune-function.aspx