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.”[1]
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.
[1] 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… sun exposure
If only those who suffer from MS had known the truth when they were younger! Getting plenty of sun exposure might have saved them from the ravages of this horrible disease. Much has been written about the influence of vitamin D on MS, and in this blog, I have pointed out that sun exposure may be more important than vitamin D. A new study conducted in Australia, and presented at the 32nd Congress of the European Committee for Treatment and in MS in Research in London, England, is interesting in the way it was conducted.[1]
By questionnaire, the researchers used past and present sun exposure as a surrogate for vitamin D levels and concluded that historical, but not current, vitamin D levels protect against MS.
This was an erroneous procedure to measure the influence of vitamin D levels on MS. It has already been established that sun exposure per se may be the operative habit that protects against MS. And in my opinion, vitamin D levels may only be surrogates for sun exposure, not vice versa. And, sun exposure probably mitigates MS, independent of vitamin D.
One of the most compelling papers on sun and MS was produced by Dr. Robyn Lucas and colleagues.[2] Here are the salient points in their report called Ultraviolet radiation, vitamin D and multiple sclerosis:
- There is strong evidence from observational studies that low past sun exposure is associated with an increased risk of developing multiple sclerosis (MS).
- Lower sun exposure or lower vitamin D status have been linked to more severe MS, that is, more frequent relapses and more rapid progression to disability.
- Vitamin D supplementation trials for people with MS have shown improvement in immunological and MRI parameters, but with little convincing evidence of clinical benefit.
- Higher levels of sun exposure may have benefits for MS-related immune parameters through both vitamin D and non-vitamin D pathways.
- Exposure to ultraviolet radiation may result in immune tolerance that is beneficial for MS through upregulation of T and B regulatory cells, enhanced levels of cis-urocanic acid, alterations in dendritic cell trafficking as well as release of a range of other cytokines and chemokines.
To elucidate the last paragraph it is necessary to understand the vocabulary used. T cells are an integral part of the immune system that help rid the body of invading microorganisms. The regulatory T cells (or suppressor T cells) are a subpopulation of T cells which modulate the immune system and help prevent the body from attacking itself.[3] MS is another autoimmune disease in which the body is attacked its own immune system, which in the case of MS, destroys the myelin sheath. The regulatory, or T suppressor cells suppress these attacks, thereby preventing, abrogating or ameliorating the disease. B regulatory cells are also a part of the immune system and can, through their suppressive functions decrease inflammation, possibly through the production of anti-inflammatory cytokines.[4] Cis-urocanic acid is a chemical that is significantly lower in MS patients, and when stimulated by sun exposure, significantly reduces many indicators of MS.[5] [6] Dendritic cells are also messenger T cells that are essential in assisting sun exposure to decrease the immune response that effects autoimmune diseases.[7]
So let’s hear it for sun exposure as the very best therapy for MS. Be safe and don’t burn, and don’t use sunscreens, which can negate 99% of the sun’s vitamin D production.
[1] http://www.hcplive.com/conference-coverage/ectrims-2016/current-vitamin-d-doesnt-impact-ms-but-historical-exposure-does#sthash.ZF3nz3IN.dpuf
[2] Robyn M Lucas, Scott N Byrne, Jorge Correale, Susanne Ilschner & Prue H Hart. Ultraviolet radiation, vitamin D and multiple sclerosis. Neurodegener. Dis. Manag 2015 (epub ahead of print).
[3]https://en.wikipedia.org/wiki/Regulatory_T_cell (accessed November 24, 2015.)
[4] Min Yang, Ke Rui, Shengjun Wang and Liwei Lu. Regulatory B cells in autoimmune diseases. Cellular & Molecular Immunology (2013) 10, 122–132. Cellular & Molecular Immunology (2013) 10, 122–132.
[5] Jorge Correale and Mauricio Farez.S60 Multiple Sclerosis: Biomarkers: Clinical Phenotype Immune System Modulation in Multiple Sclerosis as a Result of Sun exposure: Role of cis-Urocanic Acid. Neurology April 6, 2012. (names s
[6] Correale J, Farez MF. Modulation of multiple sclerosis by sun exposure: role of cis-urocanic acid. J Neuroimmunol. 2013 Aug 15;261(1-2):134-40.
[7] Breuer J, Schwab N, Schneider-Hohendorf T, Marziniak M, Mohan H, Bhatia U, Gross CC, Clausen BE, Weishaupt C, Luger TA, Meuth SG, Loser K, Wiendl H. Ultraviolet B light attenuates the systemic immune response in central nervous system autoimmunity. Ann Neurol. 2014 May;75(5):739-58.
By Marc Sorenson, EdD Sunlight Institute… Sunscreen dangers..
Sperm count in men has dropped by more than half since 1950, possibly due to powerful chemicals that are finding their way into the water supply.[1] Now, the sperm that are still viable may have another problem, according to recent research: sunscreen chemicals are absorbed into the blood and carried into the sperm, which can render the sperm infertile.[2] [3] One investigation showed that an incredible 9% or more of the applied amount is absorbed through the skin.[4] Sunscreen chemicals also have potential “gender-bending” characteristics; they increase estrogen and decrease testosterone in men,[5] [6] and are also known to cause the feminization of fish. [7]And environmental pollution by these and similarly-structured chemicals are now thought to cause feminization in alligators and the gradual extinction of Florida panthers due to failure to breed.[8] Sunscreens also increase the absorption of pesticides through the skin. [9] [10] There are many more sunscreen dangers, but time and space will not permit us to discuss them all.
How does the system work to cause infertility? Many of the chemicals that filter out UV radiation can induce calcium signals in human sperm cells and mimic the effect of progesterone. This can render the sperm infertile. The aforementioned study that showed the influence of sunscreen chemicals was a lab study or “in vitro” investigation, using collected human sperm. It is not known if the same would happen in living human subjects, but it is likely.
These chemicals are known as endocrine disruptors, and with sperm count going down and many cancers increasing, they are not something I would recommend for public consumption.
Nature intends for us to cover up or seek the shade when we have had enough sun exposure. Nature also intends that we seek the sun to reap the benefit of it marvelous healthful benefits. Soak up the sun, but be sure not to burn. And don’t’ use sunscreens. There are too many sunscreen dangers, and they stop vitamin D production on the skin they cover.
[1] https://www.lifesitenews.com/news/study-finds-male-sperm-count-falling-dramatically-due-to-pollutants-in-wate.
[2] http://www.cnn.com/2016/04/14/health/sunscreen-sperm-male-fertility/index.html
[3] Rehfeld A, Dissing S, Skakkebæk NE
[4] Hayden CG, Roberts MS, Benson HA. Systemic absorption of sunscreen after topical application. Lancet 1997:350:863-64.
[5] Environmental Working Group: Americans Carry Body Burden of Toxic Sunscreen Chemical. March 25, 2008. (available at http://www.ewg.org/node/26212).
[6] Ma R, Cotton B, Lichtensteiger W, Schlumpf M. UV Filters with Antagonistic Action at Androgen Receptors in the MDA-kb2 Cell Transcriptional-Activation Assay. Toxicological Sciences 2003;74:43-50.
[7] Kunz PY, Galicia HF, Fent K. Comparison of in vitro and in vivo estrogenic activity of UV filters in fish. Toxicol Sci 2006:90:349-61.
[8] Pickart, L. The Chemical Sunscreen Health Disaster. 2000-2008. (available at http://www.skinbiology.com/toxicsunscreens.html)
[9] Brand RM, Pike J, Wilson RM, Charron AR. Sunscreens containing physical UV blockers can increase transdermal absorption of pesticides. Toxicol Ind Health. 2003;19:9-16
[10] Pont AR, Charron AR, Brand RM. Active ingredients in sunscreens act as topical penetration enhancers for the herbicide 2,4 dichlorophenoxyacetic acid. Toxicol Appl Pharmacol. 2004;195:348-54.
Sun Exposure by Marc Sorenson, EdD, Sunlight Institute…
A recent study from Canada produced some intriguing information regarding the influence sun exposure may have on prostate cancer (PC). A total of 1,638 men with prostate cancer and 1,697 without, were assessed between 1994 and 1997 to determine the amount of time each spent outdoors exposed to ultraviolet light (UV).[1] The men were a mixture of Indians, Asians, and Caucasians.
The men were assessed for their sun habits by determining how many hours per day they spent in the sun, whether sun exposure was moderate (2-6 hours per day) or high (>6 hours per day). Interestingly, men who were in the highest level of sun exposure had a reduced risk of PC of about 32% compared to unexposed men (the control group). There was no difference when moderate levels of sun exposure were compared to risk of PC. This would indicate that more sun is better, at least in this single study
The men who were of Asian and Indian descent started out with a profoundly reduced risk of PC, having only a 17% risk or 25% risk of PC, respectively. I opine that because those two ethnic groups consume much higher levels of vegetation than Caucasians, they are more protected.
There are probably 20 studies that show a protective effect of sun exposure on PC. Early research by Dr. Esther John and here colleagues is only one of many that reported a dramatic protective influence of sun exposure on prostate cancer. 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.[2] The men were divided into quintiles (fifths) 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.
So, most research shows an impressive association between higher sun exposure and lower risk of prostate cancer. Men, remember to be safe as you soak up that glorious sun. Don’t burn, and be sure to develop a good tan if you can. If you don’t tan, then a very short time in the sun is sufficient, after which you should wear a big hat and long-sleeved shirt. And please don’t use cancer-causing sunscreens.
[1] Peters CE, Demers PA, Kalia S, Hystad P, Villeneuve PJ, Nicol AM, Kreiger N, Koehoorn MW. Occupational exposure to solar ultraviolet radiation and the risk of prostate cancer. Occup Environ Med. 2016 Jul 27. [Epub ahead of print]
[2] 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.
By Marc Sorenson, EdD. Sunlight institute. Embracing the sun.
Heart disease is our number-one killer. It is caused primarily by consumption of animal products and lack vegetables, fruits, whole grains, and legumes. However, sun exposure and vitamin D may also have profound effects on the disease.
Italian research shows that vitamin D deficiency is closely associated with heart attacks.[1] The researchers measured vitamin D levels in 478 heart attack patients and discovered an average level of 14.5 ng/ml, which is very deficient. Obviously, there had not been enough sunbathing among this group, and the researchers noted that the risk of heart attack was lower during summer season. Nevertheless, vitamin D levels were still far too low.
The study recommended that “exposure to sunlight may be a cost-saving therapeutic strategy for the management of vitamin D deficiency.”
It is wonderful to see such advice from medical or nutritional experts. However, I opine that low vitamin D may not be the primary photoproduct of sun exposure that exerts a protective influence against heart attacks. Nitric oxide, also produced by sun exposure of the skin, has the ability to impressively lower blood pressure. High blood pressure (hypertension) is a major risk factor for heart disease and heart attacks. See one of my previous posts on blood pressure at http://sunlightinstitute.org/high-blood-pressure-hypertension-caused-low-vitamin-d-levels-sun-deprivation/.
For someone who wishes to stop heart disease in its tracks, don’t eat the food that causes the disease. In addition get a few minutes of midday sun without sunscreen as often as possible. It could help to save your life! Remember not to burn. At the first sign of redness, seek shade or cover up.
[1] Aleksova A, Belfiore R, Carriere C, Kassem S, La Carrubba S, Barbati G, Sinagra G. Vitamin D Deficiency in Patients with Acute Myocardial Infarction: An Italian Single-Center Study. Int J Vitam Nutr Res. 2015;85(1-2):23-30.
By Marc Sorenson, EdD. Sunlight Institute…
Acne is a plague among teenagers, and many who are older also suffer. Can sunlight and vitamin D play a role in preventing it? Perhaps so. A new (August 25) study shows that vitamin D deficiency was detected in 48% of patients with acne, but in only 22.5% of healthy controls (no acne).[1] This would indicate that sun exposure has a prophylactic effect on acne. The level of vitamin D was also inversely associated with the severity of the disease, meaning that it was probably the mechanism, perhaps by strengthening the immune system, by which the disease was thwarted. Improvement in the inflammatory lesions caused by the acne was also noted with a vitamin D supplementation program.
This reminds me of a young man, with terrible acne, who attended our health institute in Sunny Southern Utah. Our area is blessed with about 300 days per year of sunlight. After three months, his acne disappeared. Sunlight is known to cure psoriasis, eczema and other skin diseases. Why not acne? Of course, our nutrition program may also have helped him.
One more reason to safely embrace the sun.
[1] Lim SK, Ha JM, Lee YH, Lee Y, Seo YJ, Kim CD, Lee JH, Im M. Comparison of Vitamin D Levels in Patients with and without Acne: A Case-Control Study Combined with a Randomized Controlled Trial. PLoS One. 2016 Aug 25;11(8):e0161162.
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.[1]
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.[2]
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.[3] [4] Dr. Oplander and his colleagues wrote the first paper on the UVA, NO and blood pressure in 2009,[5] 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.”[6] (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.”[7]
A study from China also demonstrates that exposure to sun correlates to a lowered risk of hypertension.[8] 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.
[1] 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]
[2] 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.
[3] 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.
[4] 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.
[5] 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.
[6] Quoted on Mercola.com http://articles.mercola.com/sites/articles/archive/2013/07/15/sun-exposure.aspx accessed July 2, 2015.
[7] Weller, R. Shunning the sun may be killing you in more ways than you think. New Scientist July 2, 2015.
[8] 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…
Let’s face it. We humans love the sun exposure. If it weren’t for feelings of guilt, brought about by those who would rob us of our sun exposure, most of us would be soaking up much more sun. Nothing could be more natural than sun exposure, and a recent study from the scientific Journal PLOS ONE, helps us to understand that our natural inclinations lead us to the sunlight.[1]
The researchers analyzed data from 444 employees from both India and the US, and assessed them for job satisfaction and organizational commitment. Their goal was to investigate the effects of natural elements and sunlight on their performance. They found that natural elements such as plants, nature scenes and flowers improved mood and mental health. However, sun exposure had a considerably stronger effect than natural elements on mental health and was also positively related to job satisfaction and organizational commitment,[2] both of which are important to productivity.
Direct sunlight, or the lack thereof, was a dominant predictor of anxiety, whereas indirect sunlight, or the lack thereof was a dominant predictor of depressed mood, job satisfaction, and organizational commitment.
Many previous studies have also demonstrated that sun enhances mood. One of the most interesting was from the United Arab Emirates. Twenty people with depressive symptoms were split into two groups; one group was asked to spend more time in the sun, and another group was asked to see a doctor. The experiment lasted for seven weeks and showed that those who spent more time in the sun had fewer symptoms of depression than those who visited a doctor.[3]
Obviously, sun exposure has a wonderful influence on the brain. Keep your sunny side up!
[1] An M, Colarelli S, O’Brien K, Boyajian M. Why We Need More Nature at Work: Effects of Natural Elements and Sunlight on Employee Mental Health and Work Attitudes. PLoS One. 2016 May 23;11(5):e0155614.
[2] Chad Brooks, Open the Shades! Exposure to Outdoors Improves productivity. Business News Daily. July 22, 2016.
[3] http://www.huffingtonpost.com/2013/10/06/sunshine-happiness-behavior-mood_n_4014477.html?ir=Sciences
By Marc Sorenson, EdD. Sunlight Institute…
A 2016 paper in the British Journal of Dermatology showed that NMSC (also known as common skin cancer) had a positive association with cancers such as breast cancer, lung cancer and lymphoma.[1] Since NMSC is also associated with increased sun exposure, one might be inclined to say that these cancers are caused by such exposure. This is troubling, as many research papers have showed a reduced risk of most internal cancer with greater sun exposure. For example, breast cancer was the second type of cancer for which an inverse correlation between mortality rates and sun exposure was identified in the United States.[2] And, when assessing sun-exposure habits in a study of 5,000 women, scientists determined that those who lived in the sunniest areas, and who also had the highest sun exposure, had a 33% reduction in breast cancer rates compared to those who had the least exposure.[3] A subsequent study by the same group found “that a high sun exposure index was associated with reduced risk of advanced breast cancer among women with light skin pigmentation.”[4] The reduced risk was 47%. Numerous additional studies have demonstrated a reduction of the risk breast cancer among women who are regularly exposed to the sun. A discussion or these studies will me available in the book, Embrace the Sun, which should be available before the end of the 2016.
As for lung cancer, a geographical study in China demonstrated that lung cancer mortality showed a strong inverse correlation of risk with sun exposure, with an estimated 12% fall per each 10 milliwatts per meter squared per nanometer (a measurement of sun intensity) increase in UVB irradiance (sun exposure) even if adjusted for smoking.[5]
Now let’s consider lymphoma. The most recent research shows that there is an inverse correlation between Hodgkin lymphoma (HL) and the highest vs. lowest lifetime, childhood and adulthood factors: sun exposure, sun-lamp exposure, and sunburn. [1] The pooled analysis showed an odds ratio of .56, or in other words, a 44% reduced risk of contracting the disease.[6] Two items particularly stand out in this research: (1) Sun-lamp use correlated to a reduced risk of the disease—a positive result for the much maligned tanning industry—and (2) sunburn also correlated to a reduced risk. Of course, no one would recommend sun-burning—it simply serves a surrogate measurement for a high degree of sun exposure. Sun exposure can easily be used in high quantities—without burning—by moving out of the sun when the skin begins to redden, and then coming back later, after the skin has adjusted and started to tan.
Therefore, there is an interesting dichotomy between the idea that sun exposure may contribute to the three mentioned cancers, and the fact that all of these cancers have been shown to associate with low sun exposure, and be protected against by higher sun exposure.
So what is the answer? Dr. Bill Grant has found it. When people contract NMSC, they are advised to avoid the sun, thus setting themselves up for increased cancer risk.[7] Thanks again to Dr. Grant for his immediate solution to this dilemma.
There is more than sufficient research to show conclusively that most major cancers are prevented by plenty of sun exposure. Don’t be misled. Be sure to obtain some safe sun exposure whenever possible.
[1] Ransohoff KJ, Stefanick ML, Li S, et al. Association of non-melanoma skin cancer with second non-cutaneous malignancy in the Women’s Health Initiative. Br J Dermatol. 2016 May 26. [Epub ahead of print]
[2] Garland FC, Garland CF, Gorham ED, Young JF. Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Prev Med. 1990 Nov;19(6):614-22.
[3] John EM, Schwartz GG, Dreon DM, Koo J. Vitamin D and breast cancer risk: The HANES 1 epidemiologic follow-up study, 1971-1975 to 1992. Cancer Epidemiology Biomarkers and Prevention 1999;8:399-406.
[4] John EM, Schwartz GG, Koo J, Wang W, Ingles SA. Sun exposure, vitamin D receptor gene polymorphisms, and breast cancer risk in a multiethnic population. Am J Epidemiol. 2007 Dec 15;166(12):1409-19.
[5] Chen W, Clements M, Rahman B, Zhang S, Qiao Y, Armstrong BK. Relationship between cancer mortality/incidence and ambient ultraviolet B irradiance in China. Cancer Causes Control. 2010 Oct;21(10):1701-9.
[6] Monnereau A, Glaser SL, Schupp CW, Ekström Smedby K, de Sanjosé S, Kane E, Melbye M, Forétova L, Maynadié M, Staines A, Becker N, Nieters et al. Exposure to UV radiation and risk of Hodgkin lymphoma: a pooled analysis. Blood 2013;122(20):3492-9.
[7] Grant WB. Increased risk of non-cutaneous malignancy after diagnosis of non-melanoma skin cancer may be due to sun avoidance. Br J Dermatol. 2016 Jul 15. [Epub ahead of print].
Another important research paper on sun exposure and the risk of cancer was completed in March of 2016.[1] In it, the researchers showed once again that areas of greater sun exposure have lower rates of most cancers than areas of lesser sun exposure. To make their assessment, the investigators first obtained data from the North America Land Data Assimilation System daily average sunlight for the continental United States. They then compared that data to cancer incidence and mortality from the Centers for Disease Control.
They found that cancer incidence for all invasive cancers was significantly decreased with increasing solar radiation (sun exposure). Invasive cancer is cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues.[2] The same was true for 11 of 22 leading cancers. Interestingly, however, there was no correlation with mortality with increasing solar radiation when the invasive cancers were considered, although mortality from 7 of 22 leading cancers, including cancers of the uterus, leukemias, lung, ovary and urinary bladder did significantly decrease with increasing solar radiation. Liver cancer increased both in incidence and mortality with increasing sun exposure, and cervical cancer increased in incidence but not mortality. However, the adverse effect on liver cancer may be balanced by the very positive effects of sun exposure in decreasing liver inflammation.[3]
All-in-all, this research is very positive in presenting the anti-cancer effects of sun exposure on most cancers. Be sure to obtain your share of safe, non-burning sun exposure.
[1] Fleischer A, Fleischer S, Solar radiation and the incidence and mortality of leading invasive cancers in the
United States Dermatoendocrinol. 2016 Mar 28;8(1):e1162366
[2] http://www.cancer.gov/publications/dictionaries/cancer-terms?CdrID=45741
[3] Gorman S, Black LJ, Feelisch M, Hart PH, Weller R. Can skin exposure to sun prevent liver inflammation? Nutrients 2015 May 5;7(5):3219-39.