A recent sunshine article in the UK online newspaper, The Mail, led with the headline, “Sunshine breaks could mean better mental health.” It then went on to describe how many shift workers, as well as other residents of the UK, are deficient in vitamin D. Quoting from research published in the Journal BMC Public Health, the article stated that about 91% of residents are at least insufficient in vitamin D.
Vitamin D deficiency of that extent is a health crisis, of that there is no doubt. It is also a surety that the way to combat vitamin D deficiency is by taking “sunshine breaks.” However, it is misleading to assume it is vitamin D deficiency that is responsible for the entire problem with mental health and other diseases as they relate to sun exposure. Consider the fact that lack of sunshine deficiency also causes problems beyond vitamin D deficiency. For example, the natural 24-hour cycles, called circadian rhythms, are desynchronized by lack of sunshine in the morning. This causes us to feel out of synch and to be more susceptible to many diseases including cancer.
Sunshine is vital to mental and physical health, and that health is not due to vitamin D alone. Take a holistic view of the importance of sunshine.
 Sowah D, Fan X, Dennett L, Hagtvedt R, Straube S. Vitamin D levels and deficiency with different occupations: a systematic review. BMC Public Health. 2017 Jun 22;17(1):519.
 Lambert GW, Reid C, Kaye DM, Jennings GL, Esler MD. Effect of sun and season on serotonin turnover in the brain. Lancet. 2002 Dec 7;360(9348):1840-2.
 Asta Juzeniene and Johan Moan. Beneficial effects of UV radiation other than via vitamin D production: Dermato-End Holick, M. The UV Advantage 2. Ibooks 2003, New York. Ocrinology 2012;4(2):109–117.
 Holick, M. The UV Advantage 2. Ibooks 2003, New York.
 Molendijk ML, Haffmans JP, Bus BA, Spinhoven P, Penninx BW, Prickaerts J, Oude Voshaar RC, Elzinga BM. Serum BDNF concentrations show strong seasonal variation and correlations with the amount of ambient sun. PLoS One. 2012;7(11):e48046.
By Marc Sorenson, EdD, for sun exposure…
A new research paper on sun exposure and cancer has some interesting observations and some errors. It is entitled, Does Sunlight protect us from cancer? Here is the abstract of the article, verbatim.
“The Ultraviolet (UV) radiation contained in sunlight is a powerful mutagen and immune suppressant which partly explains why exposure to solar UV is the biggest risk factor for the development of cutaneous tumors. Evidence is building that sunlight may be protective against some internal malignancies. Because patients with these tumors are often vitamin D deficient, this has led some to propose that vitamin D supplementation will be beneficial in the treatment of these cancers. However, the results from already completed trials have been disappointing which has given weight to the argument that there must be something else about sunlight that explains its cancer-protecting properties.”
The first sentence, of course, is false. The idea, that sun exposure is the biggest risk factor for skin cancer, is erroneous. We have presented materials many times, proving that melanoma is not caused by sun exposure, and that sun exposure is protective against that disease. And as regards common skin cancers, we have shown that high-fat nutrition, lack of antioxidants, meat consumption and alcohol intake are all risk factors. Search the blogs on this site to read the different articles.
The statement is correct, of course, that sunlight is protective against many internal cancers. Dr. Bill Grant and I are finishing our book, Embrace the Sun, where we present nearly all of the research on the protective influence of sun exposure against cancer.
The statement that vitamin D research has been disappointing is both true and false. Randomized controlled studies (RCTs) have shown the vitamin D supplements do have a protective effect against internal cancers, contrary to the statement by the researchers.
Finally, let’s look at the statement that there is something beyond vitamin D that explains the cancer-protecting properties of sun exposure. That is partially true. Beyond vitamin D, the sun causes the production of nitric oxide, serotonin, endorphin and BDNF, all of which are vital to human health, and may have their own cancer-protective properties.
The bottom line? Eat correctly (avoid junk), REGULARLY soak up some sun around midday and get plenty of exercise. That advice will be a boon to your health in myriad ways.
In a new scientific paper, Dr. MS Razzaque shows that there may be some downsides to vitamin D supplementation, including “cardiovascular events and beyond.” He also states that “since hypovitaminosis D status usually reflects reduced sunlight exposure, the obvious primary replacement should be safe sunlight exposure, and not exogenous supplements.”
The paper specifically mentions that avoiding sunlight exposure may influence the initiation and progression of different types of tumors [cancer], high blood pressure, type 1 diabetes and multiple sclerosis. It also points out that there may be some deleterious consequences of vitamin D supplementation, although in my opinion, the dosage would need to by quite high.
As I have indicated in many of my posts on the Sunlight Institute site, sun exposure is the most natural way to obtain vitamin D, and it has no toxicity, since it is self-regulated.
What wasn’t mentioned was the production of health-promoting substances when sun touches the skin, e.g. endorphins and nitric oxide. And of course, the sun helps the brain to produce serotonin and BDNF, which are critical for proper brain function.
So soak up your sunlight but don’t burn.
 Razzaque MS. Sunlight exposure: Do health benefits outweigh harm? J Steroid Biochem Mol Biol. 2016 Sep 16. [Epub ahead of print].
By Marc Sorenson, EdD. Sunlight Institute… promoting safe sun exposure…
It has long been known that vitamin D deficiency is associated with hypertension. But could that association really be a measurement of inadequate sun exposure? A most interesting investigation was carried out this month (July 2016) in which the researchers evaluated over 1100 subjects from an ongoing study called “the Reasons for Racial and Geographic Differences in Stroke.” They measured vitamin D levels and also assessed sun exposure levels, and found that both high vitamin D levels and high sun exposure levels were associated with higher blood pressure.
What makes this research different is that when the data was adjusted for other factors, high sun exposure was even more impressive as a protective factor against high blood pressure. However, adjusting for vitamin D levels had no effect on the association of sun exposure to lower blood pressure; for each increase in sun exposure, there was a corresponding decrease in blood pressure, but the same was not true for increases or decreases in vitamin D levels.
The researchers made this statement: “We conclude that although 25(OH)D concentration is inversely associated with SBP, it did not explain the association of greater sunlight exposure with lower BP.”
To me, this research indicates that sun exposure directly effects lower blood pressure levels, independently of vitamin D. This is not surprising, since clinical trials of vitamin D supplementation have found only small effects on blood pressure.
I hypothesize that nitric oxide (NO), is the mechanism by which sun exerts its impressive effects. NO is a potent vasodilator, and when it is released into the arteries by UVA stimulation, causes increased blood flow and lowers blood pressure.  Dr. Oplander and his colleagues wrote the first paper on the UVA, NO and blood pressure in 2009, and Dr. Richard Weller has been a leader in doing research and granting interviews on NO since that time. He has made two interesting statements: (1) “We suspect that the benefits to heart health of sun will outweigh the risk of skin cancer. The work we have done provides a mechanism that might account for this, and also explains why dietary vitamin D supplements alone will not be able to compensate for lack of sun.” (2) “Although the benefits of sun are often attributed to vitamin D, a gas called nitric oxide is also important. Made when the sun hits our skin, nitric oxide lowers blood pressure when it enters the bloodstream. Although the reduction is small, it could ‘make a big difference.”
A study from China also demonstrates that exposure to sun correlates to a lowered risk of hypertension. In a randomly selected population of Chinese residents from Macau (where the rate of hypertension is very high), the following risk factors for hypertension were assessed: lack of sun exposure, low intake of fish, smoking, obesity and lack of exercise. An average of more than one-half hour of sun exposure per day compared to none predicted a 40% reduced risk for hypertension.
Vitamin D has many marvelous health effects, but sun exposure per se has many more, because not only does the sun stimulate the production on vitamin D, it also produces other vital photoproducts such as NO, endorphins and serotonin. When we avoid the sun and simply take a vitamin D pill, we are short-changing ourselves for the total package of benefits derived from the sun. And in the case of high blood pressure, we may be receiving almost no benefit from vitamin D. Think about it, and enjoy the sun safely.
 Rostand SG, McClure LA, Kent ST, Judd SE, Gutiérrez OM. Associations of blood pressure, sunlight, and vitamin D in community-dwelling adults. J Hypertens. 2016 Jul 1. [Epub ahead of print]
 Beveridge LA, Struthers AD, Khan F, Jorde R, Scragg R, Macdonald HM, Alvarez JA, Boxer RS. Et. al. Effect of Vitamin D Supplementation on Blood Pressure: A Systematic Review and Meta-analysis Incorporating Individual Patient Data. AMA Intern Med. 2015 May;175(5):745-54.
 Liu D, Fernandez BO, Hamilton A, Lang NN, Gallagher JM, Newby DE, Feelisch M, Weller RB. UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase. J Invest Dermatol. 2014 Jul;134(7):1839-46.
 D Liu, BO Fernandez, NN Lang, JM Gallagher, DE Newby, M Feelisch and RB Weller. UVA lowers blood pressure and vasodilates the systemic arterial vasculature by mobilization of cutaneous nitric oxide stores. Photobiology Abstract # 1247 May 2013.
 Opländer C, Volkmar CM, Paunel-Görgülü A, van Faassen EE, Heiss C, Kelm M, Halmer D, Mürtz M, Pallua N, Suschek CV.. Whole body UVA irradiation lowers systemic blood pressure by release of nitric oxide from intracutaneous photolabile nitric oxide derivates. Circ Res. 2009;105:1031–40.
 Quoted on Mercola.com http://articles.mercola.com/sites/articles/archive/2013/07/15/sun-exposure.aspx accessed July 2, 2015.
 Weller, R. Shunning the sun may be killing you in more ways than you think. New Scientist July 2, 2015.
 Ke L, Ho J, Feng J, Mpofu E, Dibley MJ, Feng X, Van F, Leong S, Lau W, Lueng P, Kowk C, Li Y, Mason RS, Brock KE. Modifiable risk factors including sun exposure and fish consumption are associated with risk of hypertension in a large representative population from Macau. J Steroid Biochem Mol Biol 2013 Nov 1 [Epub ahead of print].
By Marc Sorenson, EdD. Sunlight Institute.
Regular sun exposure is one of the best ways to reduce the risk of many cancers. Although the relationship of sun exposure (and vitamin D) to the risk of prostate cancer is controversial, a study from Australia, published in 2011, showed that the less sun exposure, the greater the risk of the cancer. The researchers investigated the relationship between prostate cancer incidence and solar radiation in non-urban Australia and found an inverse association. There are many other studies that indicate a protective effect of sun exposure. One of the earliest was conducted by Dr. Esther John and her colleagues: they compared the lifetime sun exposure of 450 white men with advanced prostate cancer to that of 455 white men who did not have cancer. The men were divided into quintiles according to the amount of exposure they had received. Subjects in the highest fifth of sun exposure had only 51% of the risk of prostate cancer as did those in the lowest quintile.
Another study on cancer that corroborated these observations was entitled: Is prevention of cancer by sun Exposure more than just the effect of vitamin D? A systematic review of epidemiological studies. In their review, the authors noted that regular sun exposure correlated to a reduced risk of colorectal cancer, prostate cancer, breast cancer and non-Hodgkin’s lymphoma (NHL). However, vitamin D levels correlated to a reduced risk of colorectal, and to a lesser extent, breast cancer, but were not correlated to a significant risk reduction in prostate cancer and non-Hodgkin’s lymphoma. The authors concluded with this statement: “Particularly in prostate cancer and NHL, other sun-potentiated and vitamin D-independent pathways, such as modulation of the immune system and the circadian rhythm, and the degradation of folic acid, might play a role in reduced cancer risk as well.” These researchers did well to remind us, that as important as vitamin D is to the human body, other effects of sun exposure may be more important in some diseases. The authors could have also mentioned the effect of sun on vasodilation, mediated by the production of nitric oxide (produced by the skin after sun exposure). They could also have discussed the influence of sun on production of serotonin and endorphins, all of which may have contributed to their observations.
Other research used childhood sunburn as a measure of UVR exposure and determined that men who had sunburned as children had only about one-fifth the risk of contracting prostate cancer as those who had not sunburned. A note of caution! We are not recommending that anyone sunburn in order to prevent prostate or other types of cancer. Sunburn was used in this research to predict higher vitamin D levels, but it is not necessary to achieve those levels, since non-burning sun exposure achieves the same results. This research also demonstrated that men with lowest level of UVR exposure had more than triple the risk of prostate cancer and that onset of the disease was delayed more than four years in those who had the greatest exposure compared to those who had the least exposure. A follow-up to this study, reported that men in the lowest quartile of sunbathing were linked to a 5.33-fold greater risk of prostate cancer than those in the highest quartile. Still other research has indicated that “higher levels of cumulative exposure, adult sunbathing, childhood sunburn and regular holidays in hot climates were each independently and significantly associated with a reduced risk of this [prostate] cancer.
So men, protect your prostate by regular, non-burning sun exposure. Don’t let the Powers of Darkness frighten you away from the sun.
 Loke TW, Seyfi D, Khadra M. Prostate cancer incidence in Australia correlates inversely with solar radiation. BJU Int. 2012 Apr;109 Suppl 3:75.
 John EM, Schwartz GG, Koo J, Van Den Berg D, Ingles SA. Sun exposure, vitamin D receptor gene polymorphisms, and risk of advanced prostate cancer. Cancer Res 2005;65(12):5470-79.
 van der Rhee H, Coebergh JW, de Vries E. Is prevention of cancer by sun exposure more than just the effect of vitamin D? A systematic review of epidemiological studies. Eur J Cancer. 2013 Apr;49(6):1422-36.
 Moon SJ, Fryer AA, Strange RC. Ultraviolet radiation: effects on risks of prostate cancer and other internal cancers. Mutat Res 2005;571(1-2):207-19.
 Bodiwala D, Luscombe CJ, Liu S, Saxby M, French M, Jones PW, Fryer AA, Strange RC.. Prostate cancer risk and exposure to ultraviolet radiation: further support for the protective effect of sun. Cancer Lett 2003;192:145-49.
Nearly every article written on the addictive influences of sun exposure or other UV exposure takes a negative tack. We need to realize that some addictions are very good for us. Some runners are addicted to getting up every morning and going on the morning run. If one wants to be slim and fit, that is certainly a positive addiction. Hugging my wife is also a positive addiction; her touch helps to heal me and fills me with an addictive love. I’m also addicted to hiking in the pines and aspens near my Nevada ranch. There is little more exhilarating than being at 11,000 feet elevation and breathing the clear mountain air during a hike. You probably have your own positive addictions.
Sun exposure can certainly become an addiction, but is that all bad? In my opinion, no. When done habitually, sunning reduces the risk of melanoma and reduced the risk of myriad harmful diseases. It is therefore a positive and salubrious addiction.
A recent study, somewhat negative in tone, demonstrates that UVB light, contained in both sun lamp radiation and sun radiation, triggers the production of beta endorphins, one of the feel-good chemicals, sometimes called a “reward” chemical, that makes us want more.[i] The researchers used 12 healthy volunteers and used a UVB lamp to deliver a dose of narrow-band UVB light. Skin samples were taken before and after the exposure. After 24 hours, the skin samples showed an increase in endorphin levels in 11 of the twelve subjects.
Sun exposure enhances health. A twenty-year study demonstrated that the risk of death among people who were sun-seekers was only half that of those who received little sun.[ii] The researchers made this statement: “In both models the summary sun exposure variables showed a ‘dose-dependent’ inverse relation between sun exposure and all-cause death.”
Obviously, habitual sun exposure produces a positive addiction, and that is good! God (or nature if you prefer) has programmed our bodies to seek the sunlight in order to help provide a healthful and rewarding life. “Habitual” is the operative word here. An occasional blast of sun that causes burning is definitely not recommended. Be careful and enjoy your positive addictions.
[i] Jussila A, Huotari-Orava R, Ylianttila L, Partonen T, Snellman E. Narrow-band ultraviolet B radiation induces the expression of β-endorphin in human skin in vivo. J Photochem Photobiol B. 2016 Feb;155:104-8.
[ii] Pelle G. Lindqvist, Elisabeth Epstein, Mona Landin-Olsson, Christian Ingvar, Kari Nielsen, Magnus Stenbeck & Håkan Olsson. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86.
By Marc Sorenson, EdD, Sunlight Institute…
A recent post by an online paper called The Korea Bizwire talks of research by Dr. Emad Al Duzahiri, in which he concludes that those who are suffering from chronic fatigue may really be suffering from sun deficiency. The article mentions that vitamin D, preferably from sun exposure, is essential for reducing the risk of the disease.
There is at least one additional study indicating that optimization of vitamin D improves the severity of symptoms in those who suffer from fatigue.
Remember that sun exposure is the best way to obtain your vitamin D, because it also comes along with serotonin, nitric oxide, endorphins and perhaps dopamine, and it profoundly improves the mood—just what the doctor ordered for chronic fatigue.
So when your get-up-and-go has gotten up and gone, don’t forget the sun!
 Emad Al Duzahiri. Quoted in The Korea Bizwire, January 19, 2016. http://koreabizwire.com/lack-of-exposure-to-sunlight-may-lead-to-chronic-fatigue/48480 (accessed January 20, 2016)
 Roy S, Sherman A, Monari-Sparks MJ, Schweiker O, Hunter K. Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study). N Am J Med Sci. 2014 Aug;6(8):396-402.
By Marc Sorenson, EdD, Sunlight Institute…..
Before proceeding with the discussion on sunlight addiction, it is important to review the truth about sunlight and melanoma, to understand why sunlight addiction may be a good thing.
A recent report on ultraviolet light and addiction is obviously meant to be a hit piece regarding sunlight exposure and tanning, as seen in the opening statement: “Despite widespread awareness that UV exposure is a major risk factor for all common cutaneous malignancies, skin cancer incidence relentlessly increases by ~3% per year.”
The “all common cutaneous malignancies” portion of this statement, of course, is patently false. Whereas the relatively benign common skin cancers are increased by exposure to sunlight, melanoma is increased by avoiding the sun. If the dramatic increase in melanoma over the past century were due to sunlight exposure, then sunlight exposure must also have increased dramatically during that time. To determine whether that has happened, we analyzed data from the Office of Occupational Statistics and Employment Projections, Bureau of Labor Statistics, (BLS) to determine if there was an increase or decrease in human sunlight exposure during the years from 1910 to 2,000. The statistics showed that indoor occupations such as “professional, managerial, clerical, sales, and service workers grew from one-quarter to three-quarters of total employment between 1910 and 2000.” BLS also stated that during the same period, the outdoor occupation of farming declined from 33% to 1.2% of total employment, a 96% reduction. The data also showed an approximately 66% decline in the occupation of farmers and 50% of the decline in the occupation of farm laborers.
The Environmental Protection Agency also determined that as of 1986, about 5 percent of adult men worked mostly outside, and that about 10 percent worked outside part of the time. The proportion of women who worked outside was thought to be even lower. These data demonstrate a dramatic shift from outdoor, sun-exposed activity to indoor, non-sun-exposed activity during the mid-to-late 20th Century.
Despite these facts, the Melanoma International Foundation (MIF) has stated that melanoma has increased by 30 times (3,000%) just since 1935! Here is the statement by the MIF: “Melanoma is epidemic: rising faster than any other cancer and projected to affect one person in 50 by 2010, currently it affects 1 in 75. In 1935, only one in 1,500 was struck by the disease.” Indeed, the American Cancer Society in 2014 reported that one in 50 now contracts the disease. That exponential increase in melanoma has been accompanied by a profound decrease in sunlight exposure, yet sunlight or other UV exposure is blamed for the melanoma increase—a totally counterintuitive argument! I submit that not only is sunlight not responsible for the exponential increase in melanoma, but that the decrease in sun exposure may be a major cause of that increase.
Here are other facts that belie the idea that melanoma is caused by sunlight exposure:
- Outdoor workers, while receiving 3-9 times the UVR exposure as indoor workers,  have had no increase in melanoma since before 1940, whereas melanoma incidence in indoor workers has increased steadily and exponentially.
- Most melanomas occur on areas of the body that are seldom or never exposed to the sunlight.  
- The use of sunscreen, which has increased steadily, has not resulted in a decrease in melanoma. In fact, melanoma has increased as sunscreen use has become more widespread. Since sunscreens block sunlight, it is evident that at best they are a waste of money and at worst may be contributing to the increase in melanoma.
Now, let’s discuss the research on the aforementioned addiction to sunlight. The researchers conducted various experiments on mice that showed behavior choices, such as desiring lighter rather than darker environments, were increased by regular exposure. These behavior choices were mediated by β-endorphins, peptide hormones which are similar to opiates. So is this all bad? This marvelous product, β-endorphin, is one of the feel-good hormones that decreases pain and increases a sense of well-being. The case the researchers make regarding addiction to sunlight is compelling, and why not? Sunlight exposure causes vitamin D production in the skin, which is essential to human health; it also stimulates the production of nitric oxide, which relaxes our vessels and lowers our blood pressure; it stimulates the production of serotonin in the brain, which is another feel-good hormone necessary for a happy mood and wellbeing. And considering the myriad additional effects of sunlight on health, including the prevention of cancer, the prevention and reversal of bone diseases and the reduction of heart disease, could it not be part of God’s (or Nature’s) master plan to develop a positive addiction to sunlight so than our health could be enhanced? I am a sunlight addict, and expose myself to it regularly for two reasons: (1) It marvelously improves my mood and (2) it protects me from disease and weakness. I am a light-skinned, blue-eyed Caucasian who has spent much of my seven decades on this earth seeking the sun. Yet, there have been no melanomas or even common skin cancer.
Nevertheless, the researchers summarize their paper on sun addiction with the following: “While primordial UV addiction, mediated by the hedonic [pertaining to pleasure] action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in man.”
That summary statement is claptrap, as can be seen by the research on melanoma and sunlight presented above. If sunlight is addictive and helps me to avoid melanoma, heart disease, bone loss and other maladies, I can only say, “hooray for the addiction!”
 Gillian L. Fell, Kathleen C. Robinson, Jianren Mao, Clifford J. Woolf, and David E.
Fisher. Skin β-endorphin mediates addiction to ultraviolet light. Cell. 2014 June 19; 157(7): 1527–1534.
 Ian D. Wyatt and Daniel E. Hecker. Occupational changes in the 20th century. Monthly Labor Review, March 2006 pp 35-57: Office of Occupational Statistics and Employment Projections, Bureau of Labor Statistics
 U.S. Congress, Office of Technology Assessment, Catching Our Breath: Next Steps for Reducing Urban Ozone, OTA-O-412 (Washington, DC: U.S. Government Printing Office, July 1989).
 Melanoma International Foundation, 2007 Facts about melanoma. Sources: National Cancer Institute 2007 SEER Database, American Cancer Society’s 2007 Facts and Figures, The Skin Cancer Foundation, The American Academy of Dermatology.
 American Cancer Society. Melanoma Skin Cancer Overview 9/16/2014. Accessed on 9/23/2014 at http://www.cancer.org/cancer/skincancer-melanoma/overviewguide/melanoma-skin-cancer-overview-key-statistics
 Godar D. UV doses worldwide. Photochem Photobiol 2005;81:736–49.
 Thieden E, Philipsen PA, Sandby-Møller J, Wulf HC. UV radiation exposure related to age, sex, occupation, and sun behavior based on time-stamped personal dosimeter readings. Arch Dermatol 2004;140:197–203.
 Garland FC, White MR, Garland CF, Shaw E, Gorham ED. Occupational sunlight exposure and melanoma in the USA Navy. Arch Environ Health 1990; 45:261-67.
 Rivers, J. Is there more than one road to melanoma? Lancet 2004;363:728-30.
 Crombie, I. Racial differences in melanoma incidence. Br J Cancer 1979;40:185-93.
 Phillippe Autier. Do high factor Sunscreens offer protection from melanoma? West J Med. 2000 Jul; 173(1): 58.
By Marc Sorenson, EdD
Drs. Asta Juzeniene and Johan Moan wrote a paper in 2012 that beautifully summarizes the effects of sunlight beyond the production of vitamin D. Here are the highlights of their paper, as stated in the abstract. They discuss the separate affects of Ultraviolet B light (UVB) and ultraviolet A light (UVA), which are, of course, components of sunlight.
- UVB induces cosmetic tanning (immediate pigment darkening, persistent pigment darkening and delayed tanning).
- UVB-induced, delayed tanning acts as a sunscreen.
- Several human skin diseases, like psoriasis, vitiligo, atopic dermatitis and localized scleroderma, can be treated with sunlight or artificial UV radiation (phototherapy).
- UV exposure can suppresses multiple sclerosis independently of vitamin D synthesis.
- UVA generates nitric oxide (NO), which may reduce blood pressure and generally improve cardiovascular health.
- UVA induced NO may also have antimicrobial effects.
- UVA induced NO may act as a neurotransmitter.
- UV exposure may improve mood through the release of endorphin.
It wasn’t mentioned in the paper, but we now know that sunlight also helps generate serotonin in the brain, which improves mood, and outside the body it is a potent disinfectant (see my recent blogs on those subjects). So those who claim that sunlight is harmful in any amount, must be living on a different planet. Embrace the Sun, but never burn.
 Asta Juzeniene and Johan Moan. Beneficial effects of UV radiation other than via vitamin D production. Dermato-Endocrinology 4:2, 109–117; April/May/June 2012.