By Dr. Mercola
Without the sun there would be no life on this planet, and your body needs sun exposure for optimal health as well. In fact, the sun can be a great healer, providing benefits that go far beyond vitamin D synthesis.
As noted by photobiologist Alexander Wunsch, humans are adapted to sunlight as a complex stimulus that, at the appropriate dosage, helps keep our biological systems running.
When we talk about sun exposure to optimize vitamin D production, we're really only looking at a small portion of the action spectrum of light, because ultraviolet B (UVB) radiation is the only portion able to photosynthesize vitamin D in your skin.
However, sunlight contains many other wavelengths, and we've likely only scratched the surface when it comes to identifying the biological activity influenced by the various portions of the sun's light spectrum.
Your Body Needs the Full Spectrum Light Offered by the Sun
For example, we now know that a whole host of physiological processes are directed by your endogenous circadian rhythm, which is calibrated by exposure to natural sunlight and darkness.
Dr. Auguste Rollier, who has written text books on heliotherapy, emphasizes that the composition of the different parts of the light spectrum are of crucial importance, not only to achieve all of the benefits you can get from the sun, but also to provide protection against potential damage.
For instance, while UVB synthesizes vitamin D in your skin, it can also alter DNA structures, and the ultraviolet A (UVA) rays in sunlight can produce reactive oxygen species in the tissue, leading to damage.
To cope with these side effects, your skin needs other parts in the light spectrum, such as the near-infrared and the red light, which transfers energy to your cells.
Moreover, while on the one hand UVA is associated with tissue damage and wrinkling, UVA also generates nitric oxide (NO) in your skin, which influences your body in a number of beneficial ways.
Most notably, nitric oxide protects your heart by relaxing your blood vessels and lowering your blood pressure. It also stimulates your brain, kills bacteria, and helps defend against tumor cells — so not even UVA can be written off as "all bad," provided it's not excessive.
Nitric oxide is a natural antioxidant that, when occurring in excess, acts as a potent free radical, so too much UVA exposure can be counterproductive and may lead to skin damage.
In short, the full blend of light wavelengths in sunlight enables your body to react in a balanced and beneficial way, which is one of the reasons why I believe regular sun exposure is such an important part of a healthy lifestyle.
This is also why I am passionate about my recommendation that the best way to optimize your vitamin D is through appropriate sun exposure, because you will not only get vitamin D but many other benefits as well.
It is important to remember that if you choose to use sun exposure, you need to expose as much skin as possible. Merely taking a walk during lunch with a shirt and pants on will not give you the amount of exposure you need, even in the summer.
That said, if you can't get enough sun exposure, then taking a vitamin D3 supplement in conjunction with vitamin K2 is certainly advisable as vitamin D deficiency is associated with a wide array of chronic health problems.
Benefits of Red Light and Infrared Laser Therapy
The featured article1 from Dr. Paul Jaminet highlights a number of health benefits associated with various light spectrums. For example, studies have shown that respiratory enzymes are inhibited by blue light and activated by red light.
One of the mechanisms by which red light enhances mitochondrial function is by activating a mitochondrial respiratory enzyme called cytochrome c oxidase (Cox). As explained in the featured article:
"Cox utilizes energetic electrons and protons from opposite sides of the inner mitochondrial membrane to turn one molecule of oxygen (O2) into two molecules of water (H2O), in the process contributing the energy required to form ATP...
[Cox] in mitochondria... absorbs 35 percent or more of red light. If it was so important to let red light reach mitochondria that other human molecules had to evolve transparency in the red, then it is surely important for us to provide our mitochondria with red light."
As far back as 1895, we find research advocating the use of red light for the treatment of smallpox, and sun exposure was the standard treatment for tuberculosis (TB) 100 years ago, long before the advent of antibiotics.
Interestingly, several studies have appeared in the last decade, indicating that vitamin D status is one of the major factors that dictate whether you will actually develop the disease.
These studies have come to the conclusion that vitamin D deficiency sets off the disease if you are a carrier of the bacteria. And, the more severe your vitamin D deficiency, the higher your risk of developing the active form of TB.
In 1910, John Harvey Kellogg published his book, Light Therapeutics,2 recommending light therapy for ailments such as obesity, diabetes, chronic fatigue, insomnia, and even baldness.
By the 1970s, researchers had discovered that red light lasers could help speed up wound healing, and today K-Laser is the leading manufacturer of therapeutic infrared lasers.
Contrary to most Class 3 lasers, which have a penetration depth of only about 1/8 inch, the Class 4 K-laser is able to penetrate much deeper into your body, allowing it to address more deep seated pain.
It also uses three infrared wavelengths rather than just one: 800 nanometers penetrates the deepest, and is at a peak of absorption for the Cox enzyme mentioned earlier; 905 nanometers most efficiently targets the hemoglobin molecule, and 970 nanometers most efficiently stimulates microcirculation.
Using an infrared sauna can provide similar benefits, as discussed in another recent article.
On a side note, ultrasound has also been shown to accelerate tissue healing,3,4 and may offer new hope for those battling chronic wounds, such as diabetics and the elderly, who tend to heal slower. Overall, use of ultrasound decreased healing time by 30 percent, returning the healing rate to more youthful levels.
Other Therapeutic Uses of Red, Blue, and Full Spectrum Light
As noted in the featured article,5 thousands of scientific papers have been published on red or near infrared light therapy over the past several decades, showing that the benefits go far beyond the treatment of pain. Red light has been successfully used to treat a wide spread of ailments, including:
✓ Age-related macular degeneration (the number one cause of blindness in the US)
✓ Cognitive dysfunction following traumatic brain injury
✓ Knee osteoarthritis
✓ Cold sores
✓ Hair loss
Blue light has also been linked to specific health benefits, including the treatment of antibiotic-resistant bacteria such as MRSA. In one 2009 study,7 over 90 percent of community acquired and hospital acquired strains of MRSA were successfully eradicated within mere minutes of exposure to blue light. According to the authors:
"These significant levels of photo-destruction at low dosages indicate that irradiation with 470nm LED light energy may be a practical, inexpensive alternative to treatment with pharmacological agents, particularly in cases involving cutaneous and subcutaneous MRSA infections that are susceptible to non-invasive types of radiation."
Here, the word "radiation" does not refer to ionizing radiation but rather the emission of energy from an LED light source — here within the blue light spectrum, which has a range of 450-495 nanometers (nm). The study in question used 470nm blue light. (Natural sunlight will expose you to the full light spectrum from 415-660nm light, which encompasses the entire spectrum of colors: violet, blue, green, yellow, orange, and red.)
Blue light therapy is also FDA approved for the treatment of severe acne. Many of the blue light treatments for acne use the same wavelengths needed to kill antibiotic-resistant bacteria like MRSA, which means the technology is already commercially available. Meanwhile, full spectrum white light has been found to increase blood flow, increase antibody production, and decrease inflammation by reducing pro-inflammatory cytokines TNF- α, IL-6, interferon-gamma, and interleukin-12, while increasing anti-inflammatory cytokines interleukin-10 and TGF-beta.
As noted in the featured article:
"These anti-inflammatory effects may shed light on the improvements hypothyroid subjects experienced from near infrared phototherapy. TNF-α and IL-6 suppress peripheral thyroid hormone metabolism by decreasing T3 and increasing rT3. Inflammation seems to commonly trigger hypothyroidism, while anti-inflammatory strategies are almost always therapeutic for hypothyroidism."
Your Skin Is Perfectly Adapted to Interact with Sunlight
According to a paper published in the journal Dermato Endocrinology8 in 2012, a large number of molecules (chromophores) found in the different layers of your skin absorb and interact with ultraviolet rays, producing a number of complex and synergistic effects — many of them highly beneficial to your health.
Not surprisingly, a number of skin conditions can be addressed using phototherapy, including psoriasis, atopic dermatitis, and sclerosing skin conditions such as morphea, scleroderma, vitiligo, and mycosis fungoides. But the benefits do not end there. The medical literature shows sun exposure also helps:
✓ Enhance mood and energy through the release of endorphins
✓ Protect against and suppress symptoms of multiple sclerosis (MS)
✓ Protect against melanoma and decreasing mortality from it
✓ Induce nitric oxide (NO), which helps protect your skin against UV damage and offers cardiovascular protection, promotes wound healing through its antimicrobial effect, and has some anti-cancer activity
✓ Melatonin regulation through the "third eye" of the pineal gland photoreceptors
✓ Treat neonatal jaundice
✓ Sterilize your armpits and eliminate the cause of most body odor
✓ Treat Seasonal Affective Disorder (SAD)
✓ Synchronize important biorhythms through sunlight entering your eye and striking your retina
✓ Regulate body temperature
Regarding the benefits and risks associated with specific wavelengths of light, the researchers note:9
"[P]hototherapy can be divided into broadband UVB (290-320 nm), narrow band UVB (310-315 nm), monochromatic UVB (308 nm from an excimer laser), broadband UVA (320-400 nm), and UVA-1 (340-400 nm)... Narrow-band UVB clears psoriasis faster and produces longer remissions than broadband UVB.
Action spectra for UV-induced erythema, DNA damage, photo immunosuppression, squamous cell carcinoma, and vitamin D synthesis are very similar, all in the UVB spectral region of 280-310 nm. Narrowband UVB do not contain the most erythemogenic and carcinogenic wavelengths...." [Emphasis mine]
Overly Restrictive Sun Exposure Warnings Pose Health Risks, Experts Warn
Despite all the proven benefits of sunlight, most dermatologists and organizations such as the World Health Organization's International Agency for Research on Cancer and the US Surgeon General advise strict sun avoidance for the prevention of skin cancer. Unfortunately, such advice may be doing far more harm than good, a recent study10 warns. According to a press release issued by the Vitamin D Society:11
"Following restrictive sun exposure advice in countries with low solar intensity like Canada might in fact be harmful to your health, says the co-author of a new study on sunlight and vitamin D... 'Humans have adapted to sun exposure over many thousands of years and derive numerous physiological benefits from UV exposure, in addition to vitamin D,' said Baggerly, executive director of GrassrootsHealth...
"These benefits are in addition to those derived from vitamin D alone and cannot be replaced by vitamin D supplements and therefore sun avoidance being recommended by the US Surgeon General, the Canadian Cancer Society, the Canadian Dermatology Association, and others, is unnecessarily putting Canadians at risk."
Dr. Reinhold Vieth, Scientific Advisor for the Canadian Vitamin D Consensus and professor at the University of Toronto in the Department of Laboratory Medicine and Pathobiology, also noted that:
"If organizations warn people to stay out of the sun, then they should also let people know that they will not be producing vitamin D. Both the risks and benefits of UV exposure need to be addressed in the best interest of health. Unfortunately, the message Canadians keep hearing lately is that there is no benefit to being in the sun. The paper by Baggerly et al presents a clear case that good overall health does correlate with spending time in the sun."
To Optimize Your Health, Consider Spending More Time in the Sun
Your body is adapted to very specific lighting conditions: bright unfiltered daylight during the day, and low level fire-light in the evening followed by darkness. Notice I said unfiltered. Window glass actually filters UVB from sunlight so you won't be getting any vitamin D behind a window. This rhythm of light and dark is what drives your circadian clock, as discussed in my interview with Dan Pardi. Disregarding the biological adaptation to sunlight that humans clearly have is a recipe for poor health, as so much of your biology is affected and influenced by various wavelengths of light.
Natural sunlight consists of approximately 1500 wavelengths and will expose you to the full light spectrum, which encompasses the entire spectrum of colors: violet, blue, green, yellow, orange, and red. While I've summarized some of the research showing the benefits of red, blue, and full spectrum white light, there are probably benefits to other wavelengths that we still don't know about.
It's also important to recognize that it's virtually impossible to reproduce the full spectrum of sunshine indoors, and research suggests there may even be health risks involved with certain types of indoor lighting,12 particularly blue-only light and "white" LED light, the latter of which tends to peak unnaturally strongly in the blue wavelength. Blue light should also be avoided in the evening to allow melatonin to be produced, which will help you sleep.
Exposing yourself to natural sunlight on a daily basis is all-around ideal, not only for vitamin D synthesis, which needs UVB light, but also for day and nighttime circadian rhythm entrainment (blue during the day and red at night), nitric oxide production (UVA light), and mitochondrial respiration (red and infrared), and much more. Additionally, your pineal gland responds to the contrast of bright sunlight in the day and darkness at night to provide healthy levels of melatonin. If you're interested in this subject, I highly recommend reading Richard J. Wurtman's classic article,13 The Effects of Light on the Human Body. Despite being published 40 years ago, it's as relevant (if not more) today as it was then.