By Marc Sorenson, EdD, Sunlight Institute
Often we are told that we are bad parents if we do not protect our children from the sun, and if we follow this heinous advice, we set our children up for a lifetime to compromised physical, mental and emotional health. I recently ran across a paper on sunlight exposure and its influence on children’s risk of non-Hodgkin lymphoma. This research definitely adds another compelling reason to be sure that our children do what is natural for them: play in the sun!
A seven-year investigation in Greece demonstrated that an increment of 15 days of sunbathing at Greek seaside resorts associated to a lower risk of non-Hodgkin lymphoma of 40% but had no affect on Hodgkin lymphoma.[1]
This is important, because extrapolating to 30 days of sunbathing would predict an 80% reduced risk of non-Hodgkin lymphoma in these children.
Our children need to play in the sun and sunbathe optimal health. Good parents will ensure that their children regularly participate safely in those and other sunny activities. And no, they should not use sunscreens. When these children have had enough sun, they should come indoors, seek shade, and cover up with hats and other clothing. They should also develop a good tan as an excellent form of protection against overexposure.
[1] Petridou ET1, Dikalioti SK, Skalkidou A, Andrie E, Dessypris N, Trichopoulos D. Sun exposure, birth weight and childhood lymphomas: a case control study in Greece. Cancer Causes Control. 2007 Nov;18(9):1031-7.
By Marc Sorenson, EdD, Sunlight Institute..
Just when one thinks that there is nothing new that sunlight can do, new research belies that idea. It has now been shown that among children who growth-hormone deficient, and are being treated for that deficiency, growth is more rapid during summer months.[1] In a one-year study using 118 children from 14 countries as subjects, growth was measured and compared to the amount of sunlight received by the children. Those who were exposed to more sunlight had faster growth. The investigators also implicated a role for circadian-clock pathways in influencing growth (see my previous blogs on the importance of sunlight in correctly setting the circadian clock).
Although this research was claimed to be the first to demonstrate an influence of sunlight on accelerated growth among children being treated with growth hormone, another investigation from 2013 came to the same conclusion. [2] Others have also observed that children seem to grow more rapidly in summer. [3] [4] [5]
We want our children to have reasonable rates of growth, and the vitamin D produced by sunlight may produce larger and stronger bones. Or, it may be another factor such as nitric oxide, serotonin, endorphins or other less studied photoproducts. Whatever the mechanism, we now know that sunlight has one more critically important effect on human health, this time for our children.
[1] De Leonibus C, Chatelain P, Knight C, Clayton P, Stevens A. Effect of summer daylight exposure and genetic background on growth in growth hormone-deficient children. Pharmacogenomics J. 2015 Oct 27. [Epub ahead of print].
[2] Dorothy I Shulman, James Frane, and Barbara Lippe. Is there “seasonal” variation in height velocity in children treated with growth hormone? Data from the National Cooperative Growth Study. Int J Pediatr Endocrinol. 2013; 2013(1): 2.
[3] Marshall WA. Evaluation of growth rate in height over periods of less than one year. Arch Dis Child. 1971;46:414–420.
[4] Lee PA. Independence of seasonal variation of growth from temperature change. Growth. 1980;44:54–57.
[5] Joseph Gigante, M.D, Banderbilt Children’s hospital, Nashville, Tennessee. http://www.parenting.com/article/way-kids-grow.
By Marc Sorenson, EdD, Sunlight Institute..
A new article in Tech Times[i] reminded me of the sometimes terrible consequences of chemical sunscreen use. We know that melanoma incidence has paralleled the increase in sun exposure (see my previous blog), meaning that at best sunscreens are a waste of time and money, and at worst they are dangerous.
The dangers of chemical sunscreens are numerous in terms of health: feminization of humans, animals and fish are just a few. However, there is also a terrific environmental impact that has to do with the harm to the environment. A study from the Archives of Environmental Contamination and Toxicology regarding the detrimental effects of Oxybenzone, one of the worst (and most used) of the sunscreen ingredients, stated that Oxybenzone is a photo-toxicant, meaning that its adverse effects are exacerbated in the light.[ii] Does this chemical sound like something you’d like to apply to your skin while out in the sunlight?
The researchers also stated: “Oxybenzone is an emerging contaminant of concern in the marine environment.” The researchers found that a small dollop of sunscreen in six Olympic-sized pools caused a disruption of coral growth. Such disruption leads to a whitening and killing of the marine activity of the coral reefs. This is accomplished by ossification of a free-swimming larva called a planula, which kills it and stops the growth of coral reefs.
Here are a few of the other facts about oxybenzone and other chemical sunscreens:
The Center for Disease Control (CDC) in 2008 released a study showing that 96.8% of Americans at age six are contaminated with oxybenzone and that women were 3.5 times as likely to have high concentrations as men.[iii] The authors suggest that the greater use by women of personal-care products, most of which contain sunscreens, is the reason for their higher degree of contamination; oxybenzone is used in 588 sunscreens and in 567 other personal-care products.[iv] An incredible 9% or more of the applied amount is absorbed through the skin.[v]
Pregnant mothers exposed to oxybenzone gave birth to babies with low birth weights,[vi] which “programs” the developing child for greater risks of heart disease, hypertension, type-2 diabetes and other diseases in adulthood.[vii] Furthermore, sunlight causes the chemical to become a potent allergen[viii] [ix] and to form free radicals.[x]
Other dangers of sunscreen chemicals are their potential “gender-bending” characteristics; they increase estrogen and decrease testosterone in men[xi] [xii] and may be partly responsible for the nearly 50% reduction of sperm count in the last few decades.[xiii] Sunscreen chemicals are also known to cause the feminization of fish,[xiv] 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.[xv]
Sunscreens also increase the absorption of pesticides through the skin.[xvi] [xvii] Think carefully about this information when you next see a sunscreen ad.
Enjoy the sun safely by covering up when you have had enough. Chemical sunscreens are not the answer.
[i] http://www.techtimes.com/articles/98181/20151022/sunscreen-ingredient-threatens-marine-life-heres-how-oxybenzone-kills-coral-reefs.htm
[ii] C. A. Downs , Esti Kramarsky-Winter, Roee Segal, John Fauth, Sean Knutson, Omri Bronstein, Frederic R. Ciner, Rina Jeger, Yona Lichtenfeld et al. Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Archives of Environmental Contamination and Toxicology Oct 20 2015.
[iii] Calafat AM, Wong LY, Ye X, Reidy JA, Needham LL. Concentrations of the Sunscreen Agent, Benzophenone-3, in Residents of the United States: National Health and Nutrition Examination Survey 2003–2004. (available at http://dx.doi.org/).
[iv] Environmental Working Group: Americans Carry Body Burden of Toxic Sunscreen Chemical. March 25, 2008. (available at http://www.ewg.org/node/26212).
[v] Hayden CG, Roberts MS, Benson HA. Systemic absorption of sunscreen after topical application. Lancet 1997:350:863-64.
[vi] Wolff MS, Engel SM, Berkowitz GS, Ye X, Silva MJ, Zhu C, Wetmur J, Calafat AM. Prenatal Phenol and Phthalate Exposures and Birth Outcomes. National Institutes of Health USA Department of Health and Human Services. doi:10.1289/ehp.11007 (available at http://dx.doi.org/)
[vii] Lau C, Rogers JM. 2004. Embryonic and fetal programming of physiological disorders in adulthood. Birth Defects Res C Embryo Today 2004;72:300-12.
[viii] Bryden AM, Moseley H, Ibbotson SH, Chowdhury MM, Beck MH, Bourke J, English J, Farr P, et al. Photopatch testing of 1155 patients: results of the U.K. multicentre photopatch group. The British Journal of Dermatology 155:737-47
[ix] Rodriguez E, Valbuena MC, Rey M, Porras de Quintana L. 2006. Causal agents of photoallergic contact dermatitis diagnosed in the national institute of dermatology of Colombia. Photodermatol Photoimmunol Photomed 2006;22:189-92.
[x] Environmental Working Group: Americans Carry Body Burden of Toxic Sunscreen Chemical. March 25, 2008. (available at http://www.ewg.org/node/26212).
[xi] Environmental Working Group: Americans Carry Body Burden of Toxic Sunscreen Chemical. March 25, 2008. (available at http://www.ewg.org/node/26212).
[xii] 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.
[xiii] Pickart, L. The Chemical Sunscreen Health Disaster 2000-2008. (available at http://www.skinbiology.com/toxicsunscreens.html)
[xiv] 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.
[xv] Pickart, L. The Chemical Sunscreen Health Disaster. 2000-2008. (available at http://www.skinbiology.com/toxicsunscreens.html)
[xvi] 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.
[xvii] 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.
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[1] 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.[2] 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.[3] 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.”[4] Indeed, the American Cancer Society in 2014 reported that one in 50 now contracts the disease.[5] 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,[6] [7] 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.[8] [9] [10]
- The use of sunscreen, which has increased steadily, has not resulted in a decrease in melanoma.[11] 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!”
[1] 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.
[2] 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
[3] 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).
[4] 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.
[5] 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
[6] Godar D. UV doses worldwide. Photochem Photobiol 2005;81:736–49.
[7] 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.
[8] 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.
[9] Rivers, J. Is there more than one road to melanoma? Lancet 2004;363:728-30.
[10] Crombie, I. Racial differences in melanoma incidence. Br J Cancer 1979;40:185-93.
[11] Phillippe Autier. Do high factor Sunscreens offer protection from melanoma? West J Med. 2000 Jul; 173(1): 58.
By Marc Sorenson, EdD, Sunlight Institute
Babies and their mothers need Sunlight! Research published in October, 2015[i] is supremely important and establishes two important facts:
- Children born in summer are more likely to be healthy when they become adults.
- When women get more sunlight during pregnancy, it leads to a higher birth weight for their babies, and later puberty for girls.
Girls born in the months of June, July and August, according to the research, have a higher birthweight and later puberty, which have profound, positive impacts on overall health in women as adults. And girls born in the sunny months are also taller as adults. Later puberty is associated with a lesser risk of breast cancer,[ii] and it is likely that other health problems are associated with early puberty, which is also closely related to the type of food consumed. Soda pop consumption, for example, is associated with early puberty.[iii] Low birthweight babies also have problems such as increased risk of autism, lower cognitive function and increased risk attention-deficit hyperactivity.[iv]
Anything that can reduce the risk of these disorders should be considered critical to the health of the baby and essential to the progression to adulthood. Sunlight exposure for both the pregnant mother and her newborn should be the sine qua non for child’s wellbeing. Coupled with a decent nutrition program, sans soda pop and junk foods, it can assist the child to a healthful and productive life.
[i] http://www.eurekalert.org/pub_releases/2015-10/e-cbi100715.php Accessed October 13, 2015
[ii] Ambrosone CB, Zirpoli G, Hong CC, Yao S, Troester MA, Bandera EV, Schedin P, Bethea TN, Borges V, Park SY, Chandra D, Rosenberg L, Kolonel LN, Olshan AF, Palmer JR. Important Role of Menarche in Development of Estrogen Receptor-Negative Breast Cancer in African American Women. J Natl Cancer Inst. 2015 Jun 17;107(9).
[iii] Carwile JL, Willett WC, Spiegelman D, Hertzmark E, Rich-Edwards J, Frazier AL, Michels KB. Sugar-sweetened beverage consumption and age at menarche in a prospective study of US girls. Hum Reprod 2015 Mar;30(3):675-83.
[iv] Ochiai M, Ichiyama M, Iwayama M, Sakai Y, Yoshida K, Hara T. Longitudinal study of very low birth weight infants until 9years of age; attention deficit hyperactivity and autistic features are correlated with their cognitive functions. Early Hum Dev. 2015 Oct 3. [Epub ahead of print].
By Marc Sorenson, EdD, Sunlight Institute
Although several of my posts on the Sunlight Institute have discussed sunlight and MS, this post will provide the results of the most recent paper that I am aware of, and it reviews some of the most important investigations showing that sunlight exposure is absolutely essential for preventing or mitigating the disease.
MS is a disease in which the myelin sheaths (nerve coverings and insulators) are destroyed, leaving nerves bare and susceptible to “short circuiting.” This process is known as demyelination. New research, which should surprise no one, demonstrates that teenagers who have the greatest exposure to sunlight have a delayed onset of MS as adults.[1] The study involved 1,161 Danish patients with MS who were given questionnaires regarding their sun-exposure habits and body-mass index (BMI) as teenagers. BMI is a measure of obesity (or the lack thereof). Besides sunlight, other vitamin-D predicting measures were also used to determine the probable cause of MS.
Interestingly, only sunlight exposure and lower BMI were associated with later age at the onset of the disease; other serum vitamin D predictors such as fish consumption did not show any association with MS. The authors still seemed to feel that vitamin D was the reason for the extended time before disease onset; however, that is unlikely, since other predictors of higher vitamin D levels showed no association. And, it has been shown that sunlight exposure has profoundly protective effects against MS, independently of vitamin D.[2] Researchers determined to find the mechanism by which sunlight exposure suppressed the disease and found that UV light selectively inhibits spinal cord inflammation and demyelination.[3] In that study, they performed an investigation in which ultraviolet radiation (UVR)—the same radiation that is found in sunlight and tanning beds—was administered to animals who suffered from experimental autoimmune encephalomyelitis (EAE). EAE is MS that has been deliberately induced in animals in a laboratory setting. The researchers found that the UVR treatments stopped inflammation and demyelination of the spinal cord by inhibiting a chemical known as a chemokine, also known as a cytokine. Chemokines are the cause of the inflammation and autoimmune attacks that result in MS. The MS-ameliorating effects in the study were directly initiated by UVR, independent of vitamin D.
Stunningly, another study by some of these same investigators determined that vitamin D was actually necessary for EAE to take place![4] Mice that lacked the vitamin D receptor, which causes vitamin D deficiency, had a markedly lower risk of developing EAE. In those mice that had receptors but were simply vitamin D deficient, the development of EAE was also partially suppressed. I do not look on this research as proving that vitamin D sufficiency leads to MS, but it certainly indicates that sunlight exposure, independent of vitamin D, is absolutely critical to prevent and ameliorate this frightening disease.
The bottom line? Be sure to get plenty of non-burning sun exposure!
[1] Julie Hejgaard Laursen, MD, PhD, Helle Bach Søndergaard, MSc, PhD, Per Soelberg Sørensen, MD, DMSc, Finn Sellebjerg, MD, PhD and Annette Bang Oturai, MD, PhD. Association between age at onset of multiple sclerosis and vitamin D level–related factors. Neurology 2015, Published online before print October 7, 2015.
[2] Becklund BR, Severson KS, Vang SV, DeLuca HF. UV radiation suppresses experimental autoimmune encephalomyelitis independent of vitamin D production. Proc Natl Acad Sci U S A. 2010;107:6418-23.
[3] Wang Y, Marling SJ, Beaver EF, Severson KS, Deluca HF. UV light selectively inhibits spinal cord inflammation and demyelination in experimental autoimmune encephalomyelitis. Arch Biochem Biophys. 2015 Feb 1;567:75-82.
[4] Wang Y, Marling SJ, Zhu JG, Severson KS, DeLuca HF. Development of experimental autoimmune encephalomyelitis (EAE) in mice requires vitamin D and the vitamin D receptor. Proc Natl Acad Sci U S A. 2012 May 29;109(22):8501-4.
By Marc Sorenson, EdD, Sunlight Institute
IM is an acute form of mononucleosis, which is a disease associated with Epstein-Barr virus and characterized by sudden fever and a benign swelling of lymph nodes. It is also known as glandular fever.[i] And is sometimes called the kissing disease, since the virus that causes mono is transmitted through saliva, but though one can contract the disease through kissing, it can also be spread through coughing or sneezing, or by sharing food utensils with someone who has the condition.[ii]
Recent research has shown that in Scotland, the disease is less frequent in summer and peaks in the winter,[iii] indicative of a protective influence of sunlight. And as we have pointed out in posts on multiple sclerosis and MS, there is a strong association between low sunlight exposure and MS. This is an important point, because the two diseases are closely linked.[iv] [v] And in Norway and Italy, the incidence of IM is highest in spring.[vi] This could indicate low vitamin D levels after winter when sunlight exposure is lessened. Whatever the cause, sunlight is an important protective factor.
[i] Dictionary.com, accessed September 17, 2015.
[ii] Mayo Clinic Diseses and Conditions. http://www.mayoclinic.org/diseases-conditions/mononucleosis/basics/definition/con-20021164 Accessed September 19, 2015.
[iii] Visser E1, Milne D, Collacott I, McLernon D, Counsell C, Vickers M. The epidemiology of infectious mononucleosis in Northern Scotland: a decreasing incidence and winter peak. BMC Infect Dis. 2014 Mar 20;14:151.
[iv] Goldacre MJ, Wotton CJ, Seagroatt V, Yeates D. Multiple sclerosis after infectious mononucleosis: record linkage study. J Epidemiol Community Health. 2004 Dec;58(12):1032-5.
[v] Ramagopalan SV, Hoang U, Seagroatt V, Handel A, Ebers GC, Giovannoni G, Goldacre MJ. Geography of hospital admissions for multiple sclerosis in England and comparison with the geography of hospital admissions for infectious mononucleosis: a descriptive study. J Neurol Neurosurg Psychiatry. 2011 Jun;82(6):682-7.
[vi] Lossius A, Riise T, Pugliatti M, Bjørnevik K, Casetta I, Drulovic J, Granieri E, Kampman MT, Landtblom AM, Lauer K, Magalhaes S, Myhr KM, Pekmezovic T, Wesnes K, Wolfson C, Holmøy T. Season of infectious mononucleosis and risk of multiple sclerosis at different latitudes; the EnvIMS Study. Mult Scler. 2014 May;2006:669-74.
By Marc Sorenson, EdD, Sunlight Institute
Sometimes we come across research, conducted many years ago, that carries a great message of health for those who seek the sun. In this case the research was done in 1988 and involved a study on mice that were given a chemical protocol designed to induce skin cancer.[1] Half of the mice were also given ultraviolet B (UVB) irradiation during that protocol. After 20 weeks of cancer a cancer initiation-promotion protocol with two carcinogenic chemicals, there were 75% fewer cancerous tumors per mouse in the mice that were irradiated UVB.
Another 24-week study reported in 1992 showed that 12 weeks of UV radiation, applied either before or after chemical initiation of cancer, resulted in a 61% reduction in the mice that were irradiated before the chemical treatments, and 50% in the mice that were irradiated during the treatments.[2]
The message is this: exposure to UV light from sunlamps or sunshine may be protective against skin cancer development. So what’s new? Many of us have been promulgating that message for many years, and this research simply shows that we were not the first to understand the cancer-preventive influences of sunlight.
[1] Gensler HL Prevention of chemically induced two-stage skin carcinogenesis in mice by systemic effects of ultraviolet irradiation. Carcinogenesis. 1988 May;9(5):767-9.
[2] Gensler HL, Simpson PJ, Powell MB. Inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion in murine skin by systemic effects of ultraviolet irradiation. Photochem Photobiol. 1992 Jul;56(1):25-30.
By Marc Sorenson, EdD
Eczema is an inflammatory condition of the skin characterized by redness, itching, and oozing vesicular lesions which become scaly, crusted, or hardened.[i] Atopic dermatitis is the most common form of the many types of eczema, and UV radiation has been used successfully for decades in its treatment.[ii] An excellent paper by Dr. DJ Palmer mentioned the following regarding the use of UV light as a treatment:
- UV therapy was first used in the 1970s, when UVA radiation was used to treat atopic dermatitis and other skin conditions.[iii] The results were considered poor to fair, but created optimism going forward.
- In the 1980s, a combination of UVA and UVB therapy was used to treat atopic dermatitis, and in one investigation, it was shown that of 107 patients, 93% had good results, and the need for steroidal skin treatments (a typical treatment for the disease) decreased in half of the patients. A second experiment followed, in which 94% of the patients had good results and 85% of them had a decreased need for the steroid treatments.[iv]
- A 12-county European study reported in 2004, found the prevalence of eczema symptoms increased with latitude (indicative of less sunlight exposure).[v]
- In 2009, Italian research showed that seaside holidays led to complete resolution of atopic dermatitis in 91% of patients,[vi] which indicated positive effects of sunlight on the disease. The study also showed that the condition improved during summertime and deteriorated in the other seasons.
- A U.S. study of more than 91,000 children, reported in 2013 found significantly increased prevalence of eczema associated with several measures of lower solar UVB dose.
An investigation in children aged 0-17 years also established that sunlight exposure was associated with lessened prevalence of eczema.[vii] Children in the highest quartile (fourth) of exposure were about 20% less likely to experience eczema. Other research on young people directly assessed sunlight exposure in the first 16 years of life and compared it to the risk of atopic allergic diseases. It demonstrated that high sunlight exposure during summer holidays or weekends was significantly associated with reduced eczema.[viii] However, as the researchers stated, “Increased sun exposure during summer holidays in adolescence was associated with reduced eczema and rhinitis risk, independently of measured vitamin D levels. This is another of the studies that indicates sunlight produces salubrious effects beyond its ability to stimulate vitamin D production.
[i] Palmer DJ. Vitamin D and the Development of Atopic Eczema. J Clin Med. 2015 May 20;4(5):1036-50.
[ii] Palmer DJ. Vitamin D and the Development of Atopic Eczema. J Clin Med. 2015 May 20;4(5):1036-50.
[iii] Lynch WS, Martin JS, Roenigk HH Jr. Clinical results of photochemotherapy. The Cleveland Clinic experience. Cutis. 1977 Oct;20(4):477-80
[iv] Hannuksela M, Karvonen J, Husa M, Jokela R, Katajamäki L, Leppisaari M. Ultraviolet light therapy in atopic dermatitis. Acta Derm Venereol Suppl (Stockh). 1985;114:137-9.
[v] Weiland SK, Husing A, Strachan DP, Rzehak P, Pearce N. Climate and the prevalence of symptoms of asthma, allergic rhinitis, and atopic eczema in children. Occup Environ Med 2004;61:609-15.
[vi] Patrizi A, Savoia F, Giacomini F, Tabanelli M, Gurioli C. The effect of summer holidays and sun exposure on atopic dermatitis. G Ital Dermatol Venereol. 2009 Aug;144(4):463-6
[vii] Silverberg JI, Hanifin J, Simpson EL. Climatic factors are associated with childhood eczema prevalence in the United States. J Invest Dermatol. 2013 Jul;133(7):1752-9
[viii] Kemp AS, Ponsonby AL, Pezic A, Cochrane JA, Dwyer T, Jones G. The influence of sun exposure in childhood and adolescence on atopic disease at adolescence. Pediatr Allergy Immunol. 2013 Aug;24(5):493-500.