By Dr. Mercola
While discussions about the health benefits from sun exposure typically center around vitamin D, which your skin produces in response to UVB rays, UVB exposure actually has a number of other health effects unrelated to vitamin D production – whether it's from the sun or a tanning bed.
New evidence presented in the April-June issue of Dermato-Endocrinology1 confirms that exposure to the sun in appropriate and measured timeframes has a number of health benefits unrelated to vitamin D production, such as:
Enhancing mood and energy through the release of endorphins Protecting against and suppressing symptoms of multiple sclerosis (MS) Treating skin diseases, such as psoriasis, vitiligo, atopic dermatitis, and scleroderma. UV radiation also enhances skin barrier functions Inducing 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 Relieving fibromyalgia pain Standard treatment for tuberculosis 100 years ago, long before the advent of antibiotics Treating neonatal jaundice Can be used to sterilize your armpits and eliminate the cause of most body odor Treating Seasonal Affective Disorder (SAD) Synchronizing important biorhythms through sunlight entering your eye and striking your retina Regulating body temperature Protecting against melanoma and decreasing mortality from it May be effective in treating T Cell lymphoma
UV Radiation has Long History of Use as Treatment of Disease
According to the featured Dermato-Endocrinology article:2
"Solar ultraviolet (UV) radiation has been used since ancient times to treat various diseases. This has a scientific background in the fact that a large number of molecules (chromophores) in different layers of the skin interacts with and absorbs UV.
...Phototherapy is a valuable option in the treatment of many psoriatic and nonpsoriatic conditions, including atopic dermatitis, sclerosing skin conditions such as morphea, scleroderma, vitiligo, and mycosis fungoides. Phototherapy is the treatment of certain skin disorders with UV radiation which can be produced by the sun, fluorescent lamps, short arc lamps with UV filters and lasers.
Depending on the shape of the spectrum of radiation emitted by the source, phototherapy 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).
...Traditionally, broadband UVB phototherapy has been used to treat psoriasis, which is an inflammatory skin disease, characterized by keratinocyte hyperproliferation with 1-2 percent prevalence in the general population. However, now more often narrowband UVB or monochromatic UVB are used for the clearance of psoriasis. Narrow-band UVB clears psoriasis faster and produces longer remissions than broadband UVB. Action spectra for UV-induced erythema, DNA damage, photoimmunesuppression, 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.
...Sunbathing or tanning beds seem to have a potential to reduce pain in patients with fibromyalgia. Patients with the chronic pain condition fibromyalgia have reported a greater short-term decrease in pain after exposure to UV compared with non-UV radiation exposure..." [Emphasis mine]
Why I Strongly Advise Using the Sun or Tanning Bed
Another article written by Richard J. Wurtman3, while over 40 years old, still contains loads of interesting information about the health benefits of sunlight, and is well worth a read-through. If you have any interest, I strongly recommend you download this classic, superbly written 11-page PDF from the Massachusetts Institute of Technology. This article reveals the benefits of sun exposure and not merely swallowing a vitamin D tablet or capsule.
I am beyond convinced that you are missing the benefits of vitamin D if you merely rely on swallowing pills or capsules. If you are on the fence about this or don't believe me, please read Dr. Wurtman's classic article.
Just as an example, he rightfully points out the role of sunlight on synchronizing the hormonal rhythms of your body. Melatonin, for example, which is synthesized by your pineal gland, is profoundly affected by light and dark, and proper exposure to bright sun during the day is important for maintaining your internal rhythm. Melatonin, as you may recall, is also a potent antioxidant with cancer-fighting properties, so please do not underestimate the importance of daily UV exposure – as well as the avoidance of artificial light after sunset.
Sensible Sun Exposure Actually Protects Against Melanoma
While the sun has gotten a bad rap, being portrayed as little more than a skin cancer-inducing object in the sky to be avoided at all cost, it's important to consider that exposure to UVB light is actually protective against melanoma (the most lethal form of skin cancer). As documented in The Lancet:4
"Paradoxically, outdoor workers have a decreased risk of melanoma compared with indoor workers, suggesting that chronic sunlight exposure can have a protective effect."
Another study in Medical Hypotheses5 suggested that indoor workers may have increased rates of melanoma because they're exposed to sunlight through windows, and only UVA light, unlike UVB, can pass through window glass. (While UVB light gives you that tanned look and causes your skin to produce vitamin D, UVA rays are the ones associated with skin damage and skin cancer.) Since indoor workers, who get three to nine times less solar UV exposure than outdoor workers, are missing out on exposure to the beneficial UVB rays, they will have lower levels of vitamin D and therefore miss out on the "built-in" cancer protection offered by regular exposure to the sun, or a sun lamp.
The study even noted that indoor UV actually breaks down vitamin D3 formed after outdoor UVB exposure, which would therefore make vitamin D3 deficiency and melanoma risk even worse. A number of associations between regular sun exposure and decreased melanoma risk can be found in the medical literature. For example:
- Occupational exposure, such as farmers and fishermen, and regular weekend sun exposure are associated with decreased risk of melanoma
- Sun exposure appears to protect against melanoma on skin sites not exposed to sun light, and melanoma occurring on skin with large UV exposure has the best prognosis
- Patients with the highest blood levels of vitamin D have thinner melanoma and better survival prognosis than those with the lowest vitamin D levels
Vitamin D Deficiency Common in Sick Kids
Still, there's no getting around the fact that vitamin D, produced by your skin in response to UV radiation is a primary health benefit of sun exposure, as vitamin D influences an estimated 10 percent of all the genes in your body. This makes it a profoundly important factor for maintaining optimal health!
Two recent studies of critically ill children found that vitamin D deficiency is very common in sick children, and is associated with worse outcomes and extended hospital stays.6 Earlier studies had already linked vitamin D deficiency with worse outcomes in critically ill adults.
One study7 showed that two out of five children admitted to the study center's pediatric hospital ward were deficient in the vitamin (below 20 ng/ml), and had more severe illness on admission. Children admitted with life-threatening septic shock had a median vitamin D level of just 19.2 ng/ml. The authors concluded:
"We found a high rate of vitamin D deficiency in critically ill children. Given the roles of vitamin D in bone development and immunity, we recommend screening of those critically ill children with risk factors for vitamin D deficiency and implementation of effective repletion strategies."
The other study8, which included children and teenagers, found that nearly 70 percent of the participants were vitamin D deficient, with deficiency independently associated with longer ICU stays and more severe illness.
Low Vitamin D Levels May Raise Death Risk in Older Adults
Similarly, frail seniors with low levels of vitamin D have an increased risk of death, according to data analyzed by Oregon State University researchers. While the study, which was published in the European Journal of Clinical Nutrition9, showed that those with low vitamin D levels had a 30 percent greater risk, researchers said they couldn't determine whether low vitamin D levels contributed to frailty, or if frail people had low vitamin D levels due to health problems.
According to the university's news release10, about 70 percent of Americans and up to one billion people worldwide have insufficient levels of vitamin D. As I previously mentioned, the solution for this is not to inundate the food supply with supplemental vitamin D but merely encourage people to get as much safe sun exposure as possible to increase their vitamin D levels the way they were designed to. This will also help them reap some of the benefits mentioned in the table above.
Research has also found that sunlight exposure and higher vitamin D levels are both associated with decreased knee cartilage loss11 in patients with knee osteoarthritis.
All of these recent findings support previous research showing that vitamin D may lower your risk of dying from ANY cause.12 Truly, the health benefits of vitamin D levels are so numerous, I believe measuring your vitamin D levels may be your most important blood test, and optimizing your vitamin D levels through appropriate sun exposure or use of a tanning bed may be one of the most important things you can do to improve and maintain your health.
What Makes for an Ideal Tanning Session?
While recent media reports are again trying to dissuade you from using tanning beds, the benefits of sunbeds far outweigh the risks, if and when you cannot get sufficient amounts of regular sun exposure. However, there are two primary concerns with tanning beds that you need to be aware of:
- UV dose. The FDA uses a unit called "one erythemal dose" as a means of calibration for the indoor tanning industry – which is just a fancy word for one tanning session. One erythemal dose equates to the amount of time it takes for a tanning device to produce erythema (slight pinkening of the average person's skin), and this erythema indicates you have achieved a optimal dose of UV – which translates to an optimal dose of vitamin D.
However, keep in mind that the erythemal dose can differ for each person based on skin type and strength of lamps – just as an ideal "dose" of sunshine differs for people based on their skin type, geographic location, and time of day. Start with the lowest recommended dose (time) to avoid getting burned, especially if you are light skinned.
The FDA also makes recommendations about how often you should receive a dose, stating you should wait 24-48 hours between tanning sessions. The reason for this is that it takes at least 24 hours for the erythema to go away.
The FDA's exposure schedule can be described as CONTROLLED SUNSHINE, making it an ideal way to receive the benefits of the sun while indoors. Once you have a base tan, you can then enjoy more time in the sun without burning, and in that respect, you receive some protection that you would not otherwise have.
- EMF exposure. Most tanning beds use magnetic ballasts to generate light. These magnetic ballasts are well known sources of EMF fields that can contribute to cancer. If you hear a loud buzzing noise while in a tanning bed, it has a magnetic ballast system. I strongly recommend you avoid these types of beds and restrict your use of tanning beds to those that use electronic ballasts.
What About Vitamin D Supplements?
If neither sun exposure nor a tanning bed are feasible, you're well advised to take an oral supplement. However, you need to make sure you're taking the right kind.
Most people know that D2 – the synthetic version commonly prescribed by doctors – is not as potent as D3. Each microgram of orally consumed 25-hydroxyvitamin D3 is about five times more effective in raising serum 25(OH)D than an equivalent amount of vitamin D2. However, besides being less potent, D2 supplements may actually do more harm than good overall.
A recent meta-analysis by the Cochrane Database13 looked at mortality rates for people who supplemented their diets with D2 versus those who did so with D3, the form naturally produced by your body, highlighting the significant differences between the two. The analysis of 50 randomized controlled trials, which included a total of 94,000 participants, showed:
- A six percent relative risk reduction among those who used vitamin D3, but
- A two percent relative risk increase among those who used D2
Recently, researchers from England and Australia collaborated on another interesting study, published in PLoS ONE, in which they investigated childhood D2 and D3 levels and subsequent psychotic experiences later in life.14 Dr. Anna-Marija Tolppanen and colleagues from the England and Australia, including two of my heroes, John McGrath and William Fraser, simply measured 25(OH)D2 and 25(OH)D3 in 5,346 subjects at age 9 and then assessed for psychotic experience, such as hearing voices or seeing things that are not there, three years later. Such psychotic experiences are associated with a higher risk of developing schizophrenia in later life.
Surprisingly, children with higher 25(OH)D2 levels had more, not fewer, psychotic experiences at age 12, whereas children with higher 25(OH)D3 levels had fewer psychotic experiences in later life. It's well worth noting that the children with higher 25(OH)D3 got it from sun exposure, not supplements. Increasing amounts of evidence suggests that sun exposure simply cannot be adequately replaced by a vitamin D supplement – especially not the synthetic kind.
Is Low Vitamin D the Culprit in Cavities?
Lastly, the Vitamin D Council recently posted an article about vitamin D's impact on dental health in children.15 Dr. John Cannell writes:
"Severe early childhood caries (S-ECC), also known as bottle rot, is a syndrome characterized by severe decay in the teeth of infants or toddlers. S-ECC is commonly caused by a bacterial infection with Streptococcus mutans. Its prevalence is epidemic; in the US, the rate is highest in minorities, at times infecting over 70 percent of minority children. The disease process begins with the transmission of the bacteria to the child, usually from the mother... Subsequent cavities and surgery is common."
More than one study has investigated the potential link between vitamin D and cavities and found correlations between the two. Most recently, researchers at the University of Manitoba, Canada, found that children with S-ECC (severe early childhood caries) had significantly lower vitamin D levels than cavity-free children (20 ng/ml versus 25ng/ml) and were twice as likely to have levels below 30 ng/ml.16
Dr. Cannell also points out that this link was discovered around 90 years ago, when Dr. May Mellanby showed vitamin D supplementation decreased cavities in the 1920's.
"Unfortunately, her work was forgotten. In addition, early work showed sunbeds were more effective in preventing cavities than was D2," Dr. Cannell writes.
"Even more interesting, children with S-ECC had much higher levels of parathyroid hormone (high PTH is a marker for severe vitamin D deficiency) than cavity free children had. In fact, their PTH was more than triple the normal children and eight times more likely to be elevated than cavity free children. As the variation in PTH was greater than the variation in 25(OH)D, it made me think the obvious: that children all have different set points for vitamin D preventing carries. Thus, all children should have natural levels, around 50 ng/ml, to prevent S-ECC, a level where PTH is quite low, like the cavity free children had. This requires 1,000 IU/day/25 pounds of body weight, rounded up."
Last year, William B. Grant also published a paper in the journal Dermato-Endocrinology discussing UVB exposure and vitamin D in reducing risk of dental caries.17 In it, he writes:
"Studies in the 1920s and 1930s noted that vitamin D and ultraviolet-B (UVB) irradiance reduced caries formation, the proposed mechanism being improved calcium absorption and metabolism. This paper reviews the history of studies of dental caries with respect to vitamin D, geographical location and available solar UVB doses...
The mechanism whereby UVB reduces risk of dental caries is likely through production of vitamin D, followed by induction of cathelicidin and defensins, which have antimicrobial properties. Serum 25-hydroxyvitamin D concentrations at or above 30-40 ng/ml should significantly reduce the formation of dental caries. It is unfortunate that the UVB and vitamin D findings were not given more consideration in the 1950s as a way to reduce the risk of dental caries when water fluoridation was being proposed."
Guidelines for Sun Exposure
While sun exposure is your best source for vitamin D, it's important to understand that not all sun exposure will allow for vitamin D production. Sunlight is composed of about 1500 wavelengths, but the only wavelength that makes your body produce vitamin D are UVB-rays, when they hit exposed skin. The UVB-rays from the sun must pass through the atmosphere and reach where you are on the earth in order for this to take place. This obviously does not occur in the winter for many of us in the U.S., but the sun's rays are also impeded during a fair amount of the year for people living in temperate climates.
Due to the physics and wavelength of UVB rays, they will only penetrate the atmosphere when the sun is above an angle of about 50° from the horizon. When the sun is lower than 50°, the ozone layer reflects the UVB-rays but let through the longer UVA-rays.
So how do you know if you have entered into the summer season and into the time of year, for your location, where enough UVB is actually able to penetrate the atmosphere to allow for vitamin D production in your skin?
The first step is to determine the latitude and longitude of your location. You can easily do this on Google Earth, or if you are in the U.S. you can use the TravelMath Latitude Longitude Calculator to find your latitude and longitude. Once you have obtained that you can go to the U.S. Navy site to calculate a table to determine the times and days of the year that the sun is above 50 degrees from the horizon.
Translated to the date and time of some places on the globe, it means for example: In my hometown of Chicago, the UVB rays are not potentially present until March 25, and by September 16th it is not possible to produce any vitamin D from the sun in Chicago. Please understand it is only theoretically possible to get UVB rays during those times. If it happens to be cloudy or raining, the clouds will also block the UVB rays. For a more detailed understanding of this, please view the following video, and/or read through the corresponding article.
Even Easier if You Have Apple System
Alternatively, if you have an iPhone or iPad you can download a free app called "D Minder", which will make all the calculations for you. It was made by an Apple developer who was motivated to simplify the process after he watched the video above.
From a health perspective, it doesn't make much sense to expose your skin to the sun when it is lower than 50 degrees above the horizon because you will not receive any valuable UVB rays, but you will expose yourself to the more dangerous and potentially deadly UVA rays. UVA's have a longer wavelength than UVB and can more easily penetrate the ozone layer and other obstacles (like clouds and pollution) on their way from the sun to the earth. UVA is what radically increases your risk of skin cancer and photoaging of your skin. So while it will give you a tan, unless the companion UVB rays are available you're likely doing more harm than good and should probably stay out of the sun to protect your skin.
During the times of the year when UVB rays are not present where you live you essentially have two options: You can use a tanning bed or oral vitamin D3.