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.
Sun exposure reduces risk of heart disease. High cholesterol levels are associated with vascular diseases such as heart disease, ischemic stroke and intermittent claudication (an occlusion of the arteries of the legs that leads to pain and disability). The authors of a recent study compared the effects of vitamin D supplementation with sun exposure to determine which was more effective in reducing risk factors. A group of individuals with insufficient serum vitamin D levels was divided into two groups with different experimental protocols: one was treated with sun exposure to the arms and face between 11 AM and 3 PM and the other was treated with 1,000 IU of vitamin D. A third group had “normal” vitamin D levels and served as a control (no treatment group). Total cholesterol levels and its components of cholesterol, HDL and LDL, were also measured to determine the positive (or negative) effects of the two treatment protocols.
The results were enlightening. Both experimental groups had significant increases in vitamin D. However, the results with cholesterol varied. A significant decrease in total cholesterol was noted in the sun exposure group, and HDL and LDL also decreased in the sun-exposure group. However, in the vitamin D-supplement group, a significant increase was noted in in total cholesterol. HDL also increased significantly, and LDL increased non-significantly.
In other words, vitamin D supplementation could actually lead to an increased risk of vascular diseases by raising total cholesterol, whereas sun exposure is protective against those diseases. So the takeaway is that there is no substitute for the sun when it comes to providing some protection against vascular diseases.
There are those people who worry that melanoma risk may be increased by regular sun exposure. However, we have mentioned many time in this blog that melanoma is much more common among those who work indoors than those who work outdoors. It should also be mentioned that vascular diseases kill far more people than skin cancer. Dr. Richard perhaps said it best:
“Sunlight may have beneficial cardiovascular effects, independently of Vitamin D production. Vitamin D could, in these circumstances, act as a marker for sunlight exposure and its postulated beneficial effects. These recent human data show the physiological relevance of photorelaxation. High blood pressure is the leading cause of disability-adjusted life years lost worldwide and as a risk factor underlies 18% of all deaths.” Weller further noted: “The action spectrum of nitrite release shows ultraviolet B is also involved in nitrite reduction to Nitric Oxide, and thus sunlight may be more effective than a pure UVA source.” He concluded: “the prevalence of cardiovascular and cerebrovascular deaths is around 100 times higher than those from skin cancer. Interventions leading to small changes in the incidence of cardiovascular disease are thus of greater benefit to the health of the public even than large changes in skin cancer incidence.”
Safely embrace the sun and your heart, brain and blood vessels will love you for it!
 Patwardhan VG, Mughal ZM, Padidela R, Chiplonkar SA, Khadilkar VV, Khadilkar AV. Randomized Control Trial Assessing Impact of Increased Sunlight Exposure versus Vitamin D Supplementation on Lipid Profile in Indian Vitamin D Deficient Men. Indian J Endocrinol Metab. 2017 May-Jun;21(3):393-398.
 Weller R. The health benefits of UV radiation exposure through vitamin D production or non-vitamin D
Pathways. Blood pressure and cardiovascular disease. Photochem. Photobiol. Sci. 2016.
Sun exposure and health… by Dr. Marc Sorenson, Sunlight Institute…
Lack of vitamin D, which is produced by sun exposure, leads to rickets, osteoporosis, osteomalacia and other bone diseases. In addition, research well after the first discovery of vitamin D has shown that vitamin D deficiency and sunlight deprivation also lead to many cancers, heart disease and multiple additional maladies. Now, as the world has modernized, the population is moving indoors, and even in the areas that are sunny throughout the year, sunlight exposure and vitamin D deficiency is increasing, both in rural and urban populations. The bones become so weakened without regular sun exposure, that the slightest movement may cause a fracture. As an example, the mother of an acquaintance of mine—a woman who avoided the sun—turned over in bed one night and broke her hip. Osteoporosis often destroys all quality or life for those who suffer it.
The importance of the sun in maintaining and producing strong bones has been known since antiquity. Dr. Richard Hobday, author of The Healing Sun, writes the following comments along with a history in an online article. “Traditionally, sunlight deprivation has been linked with weak or brittle bones. One of the earliest references to this was made more than two thousand years ago by the Greek historian Herodotus (480-425 BC), who noted a marked difference between the remains of the Egyptian and Persian casualties at the site of battle of Pelusium which took place in 525 BC:
‘At the place where this battle was fought I saw a very odd thing, which the natives had told me about. The bones still lay there, those of the Persian dead separate from those of the Egyptian, just as they were originally divided, and I noticed that the skulls of the Persians were so thin that the merest touch with a pebble will pierce them, but those of the Egyptians, on the other hand, are so tough that it is hardly possible to break them with a blow from a stone. I was told, very credibly, that the reason was that the Egyptians shave their heads from childhood, so that the bone of the skull is indurated by the action of the sun — this is why they hardly ever go bald, baldness being rarer in Egypt than anywhere else. This, then, explains the thickness of their skulls; and the thinness of the Persian’s skulls rests upon a similar principle: namely that they have always worn felt skull -caps, to guard their heads from the sun.’
Herodotus, ‘The Histories’”
And here is a perhaps the transcendent study on hip fracture and sun exposure: research in Spain showed that women who were sun seekers had only about one-eleventh the risk of hip fracture as those who stayed indoors (See the chart below).
That is very powerful evidence of the efficacy of sun in preventing weak bones. In stark contrast to this research are studies done on women who completely avoid the sun and suffer from osteomalacia. Osteomalacia is a soft-bone disease known as adult rickets, resulting from severe vitamin D deficiency, which deficiency prevents bone from properly mineralizing. Women who seldom go outdoors, or who are nearly always fully covered with clothing, have an extremely high incidence of osteomalacia at a very young age, even if they live in geographical areas with abundant sunlight.  If one is never exposed to the available sun, the sun will not be able to produce its beneficial effects on the body, so one may as well live at the North Pole.
Sunbed use also is associated with stronger bones and higher vitamin D levels. An excellent study compared 50 people who used sunbeds regularly with 106 who did not. The sunbed group had 90% higher vitamin D, significantly higher bone density and lower PTH levels (high PTH levels are associated with lower bone mass). The users had healthful vitamin D levels of 46 ng/ml [115 nmol/L] compared to only 24 ng/ml [60 nmol/L] for those who did not regularly use sunbeds.
Scientists at one time believed that sunlight and vitamin D were good only for preventing rickets, osteoporosis and other bone weaknesses. That belief has been supplanted by myriad research studies that show the efficacy of both sun exposure and vitamin D repletion on protection against numerous additional diseases. Nevertheless, we should never forget the extraordinary, never-changing value of sun exposure to maintaining a strong skeleton well into old age.
Richard Hobday. The Healing sun: Sunlight, Brittle Bones, and Osteoporosis. http://sunlightenment.com/the-healing-sun-sunlight-brittle-bones-and-osteoporosis/. (accessed February 5, 2016)
 Larrosa M, Casado E, Gómez A, Moreno M, Berlanga E, Ramón J, Gratacós J. Vitamin D deficiency and related factors in patients with osteoporotic hip fracture. Med Clin (BARC) 2008;130:6-9.
 Sahibzada AS, Khan MS, Javed M. Presentation of osteomalacia in Kohistani women. J Ayub Med Coll Abbottabad 2004;16:63-5
 Al-Jurayyan NA, El-Desouki ME, Al-Herbish AS, Al-Mazyad AS, Al-Qhtani MM. Nutritional rickets and osteomalacia in school children and adolescents. Saudi Med J 2002;23:182-85.
 Tangpricha V, Turner A, Spina C, Decastro S, Chen TC, Holick MF. Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density. Am J Clin Nutr. 2004 Dec;80(6):1645-9.
The Vitamin D Society of Canada has just released one of the best articles on the relationship of sun exposure and its potential for vitamin D production. Sun exposure is the natural way to obtain your essential vitamin D, and of course provides other essential photoproducts such as nitric oxide, serotonin, endorphin and BDNF.
Here is the press release from the Vitamin D Society, in full:
For Immediate Distribution
TORONTO, Ont (April 4, 2017) – The daylight hours are getting longer, the sun is getting stronger and summer is just around the corner. Make this the year that you optimize your vitamin D levels through effective sun exposure. Enjoy the health benefits and disease prevention from optimal vitamin D levels and learn to control your risks from sun exposure.
Vitamin D is made naturally in your body when UVB rays from the sun convert cholesterol in your skin to pre-vitamin D3. We make about 90% of our vitamin D from UVB sun exposure. UVB rays are short and only reach the earth when the sun is directly above us. We can’t make vitamin D in the winter in Canada because the sun is at too low of an angle and the UVB rays are absorbed in the atmosphere.
You make vitamin D in Canada between the months of May and October. The best time for exposure is around midday, between 10am and 2pm, when the UV index is above 3 and your shadow is shorter than your height. The further you get from noon, the lower the amount of vitamin D you’ll make. The sun’s visible light may penetrate through glass, but UVB light will not; therefore you will not make vitamin D.
Full body sun exposure at non-burning levels can create between
10,000-25,000 IU of vitamin D in your skin. You can never get too much vitamin D from the sun as your skin self regulates, whereas ingesting vitamin D does not have the same control. In addition, vitamin D that you make from the sun lasts twice as long in your body as vitamin D taken through supplements or food.
Statistics Canada reports that Canadian vitamin D levels have dropped by 10% over the past six years. The root cause of this decrease is lower sun exposure. People are just not getting outside around midday in the summer and making vitamin D, and when they are outside they are using sunscreen, which if applied correctly prevents 95%+ of vitamin D production.
In Canada, 12 million Canadians (35%) have vitamin D blood levels below the recommendations from Health Canada. This puts these people at a higher risk for several diseases, including cardiovascular disease, cancer, osteoporosis, diabetes, multiple sclerosis, Alzheimer’s disease and many more. In fact, a study completed in 2016 reported that if Canadians increased their vitamin D levels to the recommended level of 100 nmol/L, we would save $12.5B in healthcare costs and 23,000 premature deaths annually.
A recent study reported that women who avoided the sun have twice the risk of all cause death. The authors said that “avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking.”
Skin cancer is a concern and risk of sun exposure must be managed and balanced with the benefits from vitamin D and other photoproducts. Research has shown that people with higher sun exposure such as outdoor workers, who have 3-10 times the sun exposure as indoor workers, have a lower incidence of melanoma. The National Cancer Institute reports that
melanoma risk is increased as a result of intermittent acute sun
exposure leading to sunburn. People who are a skin type 1, with white or very pale skin colour, red or blonde hair colour and who always burn and never tan, should severely limit their sun exposure.
The Vitamin D Society offers the following tips:
– Know your own skin and skin type. Don’t burn. Never overexpose yourself.
– Acclimatize or condition your skin for sun exposure by gradually
building or lengthening exposure times as your skin begins to tan to reduce your risk of burning
– Prevent burning and overexposure when required through the use of hats, clothing, shade and sunscreens.
– For vitamin D, get sun exposure at midday, between 10 am and 2 pm, when the UV index is above 3 and your shadow is shorter than your height.
– Expose more skin for a shorter period of time to generate more vitamin D while reducing your risk of overexposure.
It’s important to manage the risk and enjoy the rewards of moderate sun exposure for good health. Cancer Research UK, through the Consensus Vitamin D Position Statement, offers the following recommendation:
“Enjoying the sun safely, while taking care not to burn, can help provide the benefits of vitamin D without unduly raising the risk of skin cancer.”
“This advice may go against what current health organizations
recommend,” says Perry Holman, Executive Director of the Vitamin D Society. “They typically recommend you stay out of the sun at midday and use sunscreen when outdoors. But this would reduce your potential vitamin D production and does not consider the benefits as well as the risks of sun exposure on overall health. You need to have balance.”
About the Vitamin D Society:
The Vitamin D Society is a Canadian non-profit group organized to increase awareness of the many health conditions strongly linked to vitamin D deficiency; encourage people to be proactive in protecting their health and have their vitamin D levels tested annually; and help fund valuable vitamin D research. The Vitamin D Society recommends people achieve and maintain optimal 25(OH)D blood levels between 100 –
150 nmol/L (Can) or 40-60 ng/ml (USA).
To learn more about vitamin D, please visit www.vitamindsociety.org
For more information, please contact:
Melissa Andrade, Enterprise Canada 905-346-1230
THIS PRESS RELEASE CONTAINS MUCH OF WHAT YOU NEED TO KNOW ABOUT VITAMIN D, SUN EXPOSURE AND HEALTH. Please read it carefully, as it could save your life.
A very interesting study has been completed in a remote area of South America.
An indigenous tribe from the remote Bolivian Amazon jungle, known as the Tsimane, has been found to have the world’s healthiest arteries. People there survive on a diet low in saturated fats and high in non-processed foods. One of the researchers stated that “Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied.”
Here are some of the lifestyle habits and facts regarding the Tsimane.
- The diet is fiber rich.
- The diet is approximately 75% non-processed carbohydrates. Isn’t that supposed to make us fat?
- The diet includes rice, plantain (a type of banana), corn, nuts, and a very small amount of animal meat.
- Smoking is almost non-existent.
- Only three per cent of the people had moderate to high heart disease risk; two-thirds of them over 75 years of age had virtually no risk. The article states that only 14% of Americans had no risk, and that half had a moderate or high risk—about 5 times higher than the Tsimane.
- Men spend six to seven hours of their day being physically active, whereas women spend four to six hours. This, of course, means plenty of sun exposure.
During most of my professional career, I have advised people to live on this type of diet, but without the meat or any other animal product. In addition we helped them to exercise several hours daily outside. During that time, my wife and I have observed that people have recovered from diabetes, heart disease, arthritis and other maladies. That is no surprise, considering this new research and many other studies. Vitamin D and nitric oxide, both photoproducts, are exceptionally important to human health, but when it comes to heart disease, nitric oxide is probably the operative photoproduct. Here is a quote from Dr. Richard Weller, a common-sense dermatologist and great researcher:
“Sunlight may have beneficial cardiovascular effects, independently of Vitamin D production. Vitamin D could in these circumstances act as a marker for sunlight exposure and its postulated beneficial effects.” “These recent human data show the physiological relevance of photorelaxation. High blood pressure is the leading cause of disability adjusted life years lost worldwide and as a risk factor underlies 18% of all deaths.” The study noted: “The action spectrum of nitrite release shows that ultraviolet B is also involved in nitrite reduction to Nitric Oxide, and thus sunlight may be more effective than a pure UVA source.” The study concluded: “the prevalence of cardiovascular and cerebrovascular deaths is around 100 times higher than those from skin cancer. Interventions leading to small changes in the incidence of cardiovascular disease are thus of greater benefit to the health of the public even than large changes in skin cancer incidence.”
The Tsimane, therefore, are living (unknowingly) an almost perfect lifestyle for optimal health. To stay well, it is imperative that we do the same, although we don’t need quite that much sun exposure. Remember to build up a tan and be safe in the sun.
 Weller R. The health benefits of UV radiation exposure through vitamin D production or non-vitamin D pathways. Blood pressure and cardiovascular disease. Photochem. Photobiol. Sci. 2016, DOI: 10.1039/C6PP00336B.
According to a new study, people with MS feel better when they spend more time in the sunshine. Not only will they feel better, but they will have lower rates of fatigue, and a slower progression to disability. None of this should be a surprise, since similar results have been reported for decades. For example, in 1922 Dr. Charles Davenport wrote a paper entitled, “Multiple Sclerosis from the standpoint of geographic distribution and race. He analyzed the MS rate of military draftees and compared it to their states of origin. The highest rates were found in men who grew up in Michigan, Wisconsin, and the extreme northwest—all areas with low sun availability. There were few cases of MS among those who grew up in southern states, where sun exposure is abundant. He also noted that those from urban areas, which have lower sun availability than rural areas, had 50% higher MS rates than those from rural areas. Similar studies confirm that relationship. 
Another interesting research paper demonstrated that sun exposure, while obviously being critical in the production of vitamin D, had its own profound influence in lessening the degeneration of nerves (neurodegeneration) in those with MS. By measuring whole brain volume (WBV) and grey-matter volume (GMV) by magnetic resonance imaging (MRI), the scientists determined that greater summer sun exposure predicted greater WBV and GMV in MS patients. Interestingly though, when vitamin D levels were measured, they had no influence on the positive effects of sun exposure with WBV or GMV. The researchers concluded: “Sun exposure may have direct effects on MRI measures of neurodegeneration in MS, independently of vitamin D.”
Be sure that you soak up your share of sunlight, without burning of course. It may indeed save your life!
 Davenport, C. Multiple Sclerosis from the standpoint of geographic distribution and race. Arch Neurol Psychiatry 1922;8:
 Acheson ED, Bachrach CA, Wright FM. Some comments on the relationship of the distribution of multiple sclerosis to altitude, solar radiation and other variables. Acta Psychiat (Scand) 1960;35 (suppl 147):132-47. 51-58
 Norman JE Jr, Kurtzke JF, Beebe GW. Epidemiology of multiple sclerosis in USA veterans: 2. Latitude, climate, and risk of multiple sclerosis. J Chron Dis 1983;36:551-59
 Zivadinov R, Treu CN, Weinstock-Guttman B, Turner C, Bergsland N, O’Connor K, Dwyer MG, Carl E, Ramasamy DP, Qu J, Ramanathan M. Interdependence and contributions of sun exposure and vitamin D to MRI measures in multiple sclerosis. J Neurol Neurosurg Psychiatry. 2013 Oct;84(10):1075-81.
Benegits of sun exposure by Marc Sorenson, EdD…
For those who follow my writings, it should now be obvious that the risk of melanoma is decreased by regular sun exposure, and that the evidence for the health benefits of safe sun becomes clearer by the day. I opine that millions of lives could be saved yearly by regular, non-burning sun exposure for the entire population.
Another benefit of moderate sun exposure, or other ultraviolet radiation (UVR), is that it does not cause sufficient DNA damage to prevent efficient repair. A study published in the British Journal of Dermatology reviewed the impact of repeated low level sunlight exposures on vitamin D status and DNA damage/repair in light and brown skinned individuals. The UVR doses were equivalent to 13-17 minutes of midday exposure in the UK. The study reported that no evidence existed for these low-level exposures leading to accumulated DNA-damage, indicating that any damage was quickly repaired. The research also showed that the exposures led to sufficient vitamin D levels in the participants. In addition, it has been shown that “Regular exposure to UV leads to an almost complete disappearance of DNA damage in the basal and suprabasal layers of the epidermis, where the initiating of skin cancer occurs. It is no wonder that regular sun exposure is associated with less melanoma! Soak up some moderate, non-burning sun!
 Felton SJ, Cooke MS, Kift R, Berry JL, Webb AR, Lam PMW, de Gruijl FR, Vail A, and Rhodes LE. Concurrent beneficial (vitamin D production) and hazardous (cutaneous DNA damage) impact of repeated low-level summer sunlight exposures. Br J Dermatol. 2016 Jul 14. doi: 10.1111/bjd.14863. [Epub ahead of print]
 van der Rhee H, de Vries E, Coomans C, van de Velde P, Jan Willem Coebergh JW. Sunlight: For Better or For Worse? A Review of Positive and Negative Effects of Sun Exposure. Cancer Research Frontiers. 2016 May; 2(2): 156-183.
By Marc Sorenson, EdD, Sunlight Institute, for sensible tanning bed use
The online magazine, Life Science Daily, just posted an article regarding the health benefits of UV light from tanning beds. Surprisingly, they were quoting from research published in the British Journal of Dermatology. I say “surprising,” because so many dermatologists and dermatological organizations are vehemently opposed to a single ray of sunlight touching the skin. And heaven forbid someone should use a tanning bed.
Three times weekly, adult subjects were exposed to a tanning bed that emitted 95% UVA rays and 5% UVB rays, which is approximately the amount of UVA and UVB that midday summer sunlight emits. Each exposure lasted six minutes. Here are some of the salient points reported in the article:
- Any damage caused by the light exposure was repaired by the by the skin.
- One of the positive benefits of the light was the production of nitric oxide, which improves blood flow and reduces blood pressure.
- Another positive benefit was the productions of beta-endorphins, which reduce depression.
- A third benefit, of course, is the production of vitamin D, necessary for growth and bone strength, as well as asthma prevention.
Here is one of the important quotes from the article, from Dr. Michael Holick: “What this study shows is that you can get a reasonable amount of sunlight that would make enough vitamin D in your skin living in the U.K. Yes, the DNA is somewhat damaged, but because the body has adapted to its environment, it has the ability to repair it.” Dr. Holick also suggested that people become educated about the wide range of health benefits from modest sun exposure, which is superior to taking vitamin D supplements.
Step by step, the truth is overcoming the powers of darkness! Seek the sun, and let a tanning bed enhance your health in the winter.
Click here to read the article. https://lifesciencedaily.com/stories/19743-study-shows-health-benefits-non-burning-exposure-uv-light/
Sun exposure and health By Marc Sorenson, EdD, Sunlight Institute…
New research shows that sunlight boosts the effectiveness of T-cells, an integral part of the immune system. T-cells are a type of lymphocyte that recognizes and binds to foreign invaders, thereby rendering them harmless. This is an important new finding, which demonstrates another beneficial effect of sun—one that has no relationship to vitamin D.
The key player in this action is the blue-light spectrum of sunlight that stimulates hydrogen peroxide production. The hydrogen peroxide (HP) causes T-cells to move to the site of infection, and it (HP) is also involved in the killing of noxious bacteria. Dr. Gerard Ahern, one of the primary investigators, stated it in this way: “T cells, whether they are helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response. This study shows that sunlight directly activates key immune cells by increasing their movement.”
Also interesting is the fact that the skin has a large share of the total T-cells in humans, about twice the number circulating in the blood. Think about this magnificent body of ours! It is programmed to immediately respond to any invasions that may occur in the skin, and sun exposure, if we take full advantage of it, immediately accelerates the process. Then, when the t-cells are activated by the blue light, they can move rapidly to other body areas where they can be utilized.
Sun exposure has also been found to have an exceptionally important and positive effect on autoimmune diseases such as lupus, MS, rheumatoid arthritis and others, many of which have been found to associate with low solar radiation and vitamin D. In this case, a different type of T-cell, called a regulatory T-cell, attacks the body’s own tissue, mistaking it for a foreign invader, and causes severe damage. The mechanism of autoimmune disease prevention by sunlight may be the suppression of regulatory T cells, in a manner that impedes the immune system’s attacks on its own tissues. 
Sunlight is one of God’s (or Nature’s) greatest miracles. Be sure to receive your full contingent of wonderful, non-burning sun.
 Thieu X. Phan, Barbara Jaruga, Sandeep C. Pingle, Bidhan C. Bandyopadhyay, Gerard P. Ahern. Intrinsic Photosensitivity Enhances Motility of T Lymphocytes. Scientific Reports, 2016;6:39479
 Schwalfenberg GK. Solar radiation and vitamin D: mitigating environmental factors in autoimmune disease. J Environ Public Health. 2012;2012:619381.
ArtukovićM1, Ikić M, Kustelega J, Artuković IN, Kaliterna DM. Influence of UV radiation on immunological system and occurrence of autoimmune diseases. Coll Antropol. 2010 Apr;34 Suppl 2:175-8.
Marsh-Wakefield F, Byrne SN. Photoimmunology and Multiple Sclerosis. Curr Top Behav Neurosci. 2015;26:117-41.
Sun exposure Information by Marc Sorenson, EdD. Sunlight Institute.
There are 62,700 cases of kidney cancer and 14,240 deaths annually. Kidney cancer incidence has tripled since the early 1980s, and some researchers have felt that environmental factors may have played a part in that worrisome increase. One of those factors may be sun exposure, which may be vital to the prevention of the disease. The newest research measured sun exposure, which was based on the average number of hours per day outdoors in the summer, during different periods of life. The researchers also took into consideration the age of the subjects and adjusted the data for other factors that may associate to kidney cancer.
These were some of the research results:
- Higher summer sun exposure at age 40+ years, but not at younger ages, was associated with a significantly lower risk of thyroid cancer. When comparing the highest quartile (fourth) of sun exposure to the lowest quartile, there was a 44% reduction in risk.
- Average lifetime sun exposure was not associated with thyroid-cancer risk.
- Recent summer sun exposure was closely associated with a decreased risk of thyroid cancer.
One of the salient points, in my mind, is that the best sun exposure is that which is habitual or consistent. In the case of kidney cancer, sun exposure in the past does not indicate that the disease will be avoided in the future. Only recent sun exposure provides protection. However, this is not necessarily true of other diseases; in the case of breast and prostate cancers, childhood sun exposure is associated with a lesser risk of the diseases in adulthood.
Previous research has also confirmed the importance of sun exposure on kidney-cancer prevention. There is a strong inverse correlation between sun exposure and kidney cancer. For example, one study that used NMSC as a measure of sun exposure, determined that sun exposure reduced the risk of several cancers, including kidney cancer, from 35% to 42%. Kidney cancer mortality rates were found to be strongly inversely correlated with solar UVB doses in Dr. William Grant’s 2002 and 2006 ecological studies. 
Recent research by Dr. Sara Karami and colleagues, demonstrates that in women, there is a significant reduction in kidney cancer with high levels of sun exposure. Those women with the highest fourth of sun exposure showed a 33% reduction in risk. Interestingly, the data was adjusted for vitamin D intake, and the results still showed sun exposure to have a stand-alone protective influence on kidney cancer—another indication that sun exposure has protective effects beyond vitamin D production.
Remember that a lifetime habit of non-burning sun exposure will always provide the best health outcomes.
 Rachel D Zamoiski, Elizabeth K. Cahoon, D. Michal Freedman, et al. Prospective study of ultraviolet radiation exposure and thyroid cancer risk in the United States. Cancer Epidemiol Biomarkers Prev Published Online First December 2, 2016.
 Tuohimaa P, Pukkala E, Scélo G, Olsen JH, Brewster DH, Hemminki K, Tracey E, Weiderpass E, Kliewer EV, Pompe-Kirn V, McBride ML, Martos C, Chia KS, Tonita JM, Jonasson JG, Boffetta P, Brennan P. Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin D as a possible explanation. Eur J Cancer 2007;43(11):1701-12
 Grant WB. An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation. Cancer. 2002 Mar 15;94(6):1867-75.
 Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res. 2006 Jul-Aug;26(4A):2687-99.
 Karami S, Colt JS, Stewart PA, Schwartz K, Davis FG, Ruterbusch JJ, Chow WH, Wacholder S, Graubard BI, Purdue MP, MooreLE. Short Report: A case-control study of occupational sun exposure and renal cancer risk. Int J Cancer. 2015 Oct 27.