By Marc Sorenson, EdD.
Metabolic syndrome, first of all, is a combination of disorders existing concurrently in a human or other animal. So what are these disorders? One can usually discern them with a glance at the people walking the American streets. They are abdominal obesity, high blood pressure, high triglyceride levels and low HDL cholesterol levels. And what are the dangers of metabolic syndrome? Most noteworthy are heart disease, stroke and diabetes, as well as obesity itself. Thus, metabolic syndrome is indicative of deteriorating health.
New, fascinating research has shown a link between metabolic syndrome and Lack of sunlight.
According to Medical News Today, animals can detect light in areas other than the eyes. Especially relevant are proteins called opsins, which detect light in the eye’s retinal cells. However, in addition, it is now known that opsins in the skins of mice can react to sunlight and help to reset circadian rhythms. Nevertheless, until now, it was not suspected that opsins could help to reduce metabolic syndrome.
Also of transcendent importance is the fact that opsins exist below the skin surface. They are also found on fat cells. And when sunlight contacts the skin, the light can penetrate deeply enough to stimulate opsin activities in those cells. Thus, opsins are “turned on” and activate the process of lipolysis, whereby fatty acids are released from the fat cell into the blood.
Another process then occurs: the fatty acids are “burned” by the body to produce heat. And the upshot of this progression? It reduces obesity. And, metabolic syndrome lessens. Hence, the person achieves better health! I have almost come to believe that there is no aspect of human health that sun exposure cannot help, when used properly. In this study, blue light appeared to be the most important spectrum of sunlight.
Other research indicative of a positive effect on obesity.
Another scientific paper “sheds more light” on the subject of obesity. This research was conducted on mice with shaved backs that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR) during a three-month experiment. The mice, without the benefit of UVR, would have been expected to gain weight rapidly on that diet, but when they were exposed to UVR, the weight gain was impressively reduced.
The UVR treatment achieved a 30-40% reduction in weight gain, compared to the expected weight gain with the high-fat diet. And, none of these benefits could be accomplished by vitamin D supplementation. However, stimulation of nitric oxide increase in the skin was able to produce some of the benefits of UVR. This also indicate that either sun exposure or sunbeds could help the health (we know that both do exactly that). However, it was not determined whether opsins had any part to play.
Finally, morning sunlight reduces obesity. 
A recent study demonstrates that timing and intensity of light correlate with body mass index (BMI). BMI is a numerical computation comparing height and weight, and is a commonly used method to assess obesity or the lack thereof. A high BMI usually means a person is obese or at least approaching obesity.
After adjusting for confounders such as diet, exercise and timing of sleep, it was determined that very early exposure to morning light correlated remarkably to lower BMI. Even when light intensity was equal at different times of the day, those who received the earliest bright light had lower BMI. In fact, for each hour later in the day when light exposure occurred, BMI increased by 1.3 units. This is exceptionally important, since a person who has a BMI of 25 (upper ideal range) could approach 30 (obesity) by rising later.
Remember that regular, non-burning sun exposure is vital for human health. Happy sunning!
For more information on sunlight and health, visit http://sunlightinstitute.org/ and read the book, Embrace the Sun. The book is available at Amazon.
Obesity in children: Caused by pregnant mom’s sun deprivation? By Marc Sorenson, EdD. 
Obesity in children is linked closely to maternal vitamin D status in pregnancy.[1] And is anyone surprised about this? First of all, everyone should know that vitamin D deficiency is caused by inadequate sun exposure. So, if high vitamin D is associated with less weight, it is because of high sun exposure. That is of course, unless the research involves vitamin D supplementation. Because sunlight produces nitric oxide, endorphin, serotonin, dopamine and other chemicals, only research can determine if vitamin D is protective. Therefore, a supplementation study would be required.
What did the research show regarding obesity?
It seems like sun exposure, which produces all of the photoproducts, would always be the best way to prevent weight gain. Most noteworthy, however, is that we are discussing only the sun deprivation aspects of obesity. That is because being overweight is primarily due to 1. eating junk food and 2. not staying active. This blog, however, deals only with extra weight due to sun deprivation.
So what did this obesity study show? To perform the research, pregnant women were first of all measured for vitamin D levels before birth. In addition, their newborns were followed for 4-6 years and then compared for obesity levels. In conclusion, those whose mothers had the lowest vitamin D levels had children with the greatest obesity problems.
So, we still don’t know if vitamin D was the protective photoproduct against obesity in children. Because of that lack of surety, let’s visit some research on sunlight and obesity.
In addition to the aforementioned research, another scientific paper “sheds more light” on the subject of obesity.[2]
This research was conducted on mice with shaved backs, because the applied light needed to be unimpeded by hair. Also, a second part of the experiment was to put them on a high-fat diet. Finally, they were exposed to non-burning ultraviolet radiation (UVR) during a three-month period. (UVR is the same light they would receive from sunlight). The mice, because of the high-fat diet, would have been expected to gain weight rapidly. But with UVR, the weight gain was consequently (and impressively) reduced. As a result of the treatment the mice achieved 30-40% less weight gain. That is, compared to the expected weight gain.
Blue light for reduced obesity?
Furthermore, a study published in 2017 showed that the blue-light spectrum of sunlight can cause subcutaneous fat to decrease.[3] In other words, it can cause obesity to diminish, much as good nutrition would also cause it to decrease. Thus, the action of sunlight may help one to prevent obesity or even to create slimness. Consequently, blue light from the sun may be a preventer of obesity, and an adjunct to good nutrition and exercise.
Is obesity reduced by morning light?
So—here we have another benefit of sun exposure—morning sun specifically! A recent study from Northwestern Medicine demonstrates that timing and intensity of light correlate with body mass index (BMI).[4] So to understand the research we need to understand BMI. BMI is a numerical computation comparing height and weight. And it is a commonly used method to assess obesity or the lack thereof. So a high BMI usually means a person is obese or at least approaching obesity. Optimal BMI is 18-25. Below 18 is considered underweight, above 25 is overweight, 30 is obese and 40 and above is morbidly obese.
So does sun exposure influence BMI? Is obesity reduced?
This study showed, first of all, that exposure to bright morning light was directly related to BMI. After adjusting for confounders, it was determined that very early exposure to morning light correlated remarkably to lower BMI. Opposite to what one might expect, when light intensity was equal at different times of the day, results were identical. Consequently, those who received the earliest bright light had lower BMI. Furthermore, for each hour later in the day when light exposure occurred, BMI increased by 1.3 units. This fact is exceptionally important, since a person who has a BMI of 25 (upper ideal range) could approach 30 (obesity). And that would be due to the habit of later sun exposure (10:00 AM rather than 6:00 AM).
Does vitamin D supplementation help prevent obesity?
Another scientific paper “sheds more light” on the subject of obesity.[5] This research was conducted on mice with shaved backs that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR) during a three-month experiment. The mice, without the benefit of UVR, would have been expected to gain weight rapidly on that diet, but when they were exposed to UVR, the weight gain was impressively reduced. The UVR treatment achieved a 30-40% reduction in weight gain, compared to the expected weight gain with the high-fat diet.
Interestingly, when vitamin D supplementation was used, it did not help, and actually stopped the positive effects of UVR treatment.
In conclusion, the pandemic of obesity may be exacerbated by sun deprivation. And, it may be due to something other than low vitamin D. Expectant mothers and their children should always obtain plenty of non-burning sun exposure. So should most other members of the human race. Happy sunning! 
Also see: http://sunlightinstitute.org/sun-exposure-reduces-obesity-vitamin-d-not
Read My book, Embrace the Sun, available at
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[1] V. Daraki T. Roumeliotaki G. Chalkiadaki M. Katrinaki M. Karachaliou V. Leventakou M. Vafeiadi K. Sarri M. Vassilaki S. Papavasiliou M. Kogevinas L. Chatzi. Low maternal vitamin D status in pregnancy increases the risk of childhood obesity
[2] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69
[3] Ondrusova K, Fatehi M, Barr A, Czarnecka Z, Long W, K Suzuki K, Campbell S, Philippaert K, Hubert M, Tredget E, Kwan P, Touret N, M Wabitsch M, Lee K, Peter E. Light P. Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis. Scientific Reports 2017 November 27;7:16332
[4] Reid KJ, Santostasi G, Baron KG, Wilson J, Kang J, Zee PC. Timing and intensity of light correlate with body weight in adults. PLoS One 2014;2;9(4)
[5] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69
What is metabolic syndrome?
Metabolic syndrome is a group of physical conditions that are predictors of disease. And, it can also be an indicator that disease is already present. Hence, when someone suffers from metabolic syndrome, they will have many dangerous disorders. High blood pressure, obesity, high cholesterol, high triglycerides, Low HDL, glucose intolerance and insulin resistance. Furthermore, these disorders are linked to increased risk of cardiovascular disease and type 2 diabetes. And, they are often indicative of upcoming health disasters.
How metabolic syndrome is influenced by sunlight.
First of all, how does this tie into the benefits of sunlight? A recent study showed that a program designed to raise vitamin D levels reduced existing metabolic syndrome remarkably.[1] Fifty-nine people with metabolic syndrome participated in the study. It is most noteworthy that these subjects were told to expose themselves regularly to sunlight and eat foods high in vitamin D. Metabolic syndrome, as a result, decreased by about half after one year on this regimen.
Does other research associate metabolic syndrome with sun exposure?
One major aspect of metabolic syndrome is obesity. Hence, research demonstrating a reduction of obesity also indicates a reduction of metabolic syndrome. So, let’s mention another scientific paper that “sheds more light” on the subject of obesity.[2] This research was conducted on mice with shaved backs that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR). UVR is one of the types of light that is produced by sunlight. Especially relevant is that the mice should have gained weight rapidly. But the weight gain was impressively reduced when they were exposed to UVR. The treatment achieved a 30-40% reduction in weight gain, compared to the expected weight gain with the high-fat diet. Therefore, the “sun treatment” reduced the risk of obesity. And, it also reduced metabolic syndrome.
Other metabolic syndrome changes shown in this research
Benefits of these treatments also included: significant reductions in glucose intolerance, insulin resistance and fasting insulin levels (all markers and predictors of diabetes and metabolic syndrome). In addition, nonalcoholic fatty liver disease and high cholesterol were also reduced.
Furthermore, a very interesting finding emerged: Supplementation with vitamin D actually reduced the aforementioned beneficial effects. Dr. Shelley Gorman, The research leader, made the following interesting observations:
- “These findings were independent of circulating vitamin D and could not be mimicked by vitamin D supplementation.”
- “It looked like the presence of vitamin D in mice on the high fat diet prevented the [beneficial] effect of UV radiation on weight gain.”
- Furthermore, Dr. Gorman mentioned that the mechanism of weight loss may be dependent on nitric oxide (NO). NO originates from diet and is mobilized by UV radiation to become bioactive. This conclusion was due to another part of the experiment. Skin induction of nitric oxide (NO)—also a product of skin exposure to the sun—reproduced many of the positive effects of UVR. This was something vitamin D supplements could not do.
In conclusion to this research, the investigators stated their findings. “These studies suggest UVR [sun exposure] may be an effective means of suppressing the development of obesity and MetS, through mechanisms independent of vitamin D but dependent on other UVR-induced mediators such as NO.”
It seems like there is no end to the miracles of regular, non-burning sun exposure. Consequently, do not disregard the sun and its health-giving effects. Just don’t burn. For more information, read my book, Embrace the Sun, available at Amazon. 
[1] Nasser M. Al-Daghria, Khalid M. Alkharfya, Yousef Al-Salehb, Omar S. Al-Attas et al. Modest reversal of metabolic syndrome manifestations with vitamin D status correction: a 12-month prospective study.
[2] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69
What do you know about melanoma?
May is Melanoma Awareness Month, Therefore, we will discuss some truths to be aware of:
- First of all, seventy-five percent of these cancers occur on areas of the body that are seldom or never exposed to sunlight.[1] For example, research has shown that melanomas in women occur primarily on the upper legs, and in men more frequently on the back—areas of little sun exposure.
- Most noteworthy, in the U.S., sun exposure has decreased by about 90% since 1935. In the same time, melanoma incidence has increased by 3,000%! [2] [3] [4]
Dr. Diane Godar furnishes this exceptionally important melanoma information:[5]
- The same as in the US, while sun exposure in Europe has profoundly decreased, there has been a spectacular increase in the disease.
- Men who work outdoors have about half the risk as men who work indoors. Hence, sun exposure could not be the cause.
- in addition, outdoor workers, while receiving 3-9 times the sun exposure as indoor workers, have had no increase in melanoma since before 1940, whereas the incidence in indoor workers has increased steadily and exponentially.
- Especially relevant is that sunscreen invention, along with its steadily increasing use, has not reduced the risk of melanoma. Rather, the disease has increased as sunscreen use has increased.
- Increasing melanoma incidence significantly correlates with decreasing personal annual sunlight exposure.
- Also, outdoor workers get many sunburns but still have dramatically lower risk of contracting the disease.
So, since melanoma increases as sun exposure decreases, should we continue to blame the sun?
Here are more facts you should know about the causes of melanoma:
- First of all, people in the highest quintile (fifth) of alcohol consumption have a 65% increase in risk.[6]
- Weekly meat consumption increases the risk of melanoma by 84% and daily fruit consumption reduces the risk by nearly 50%.[7]
- Furthermore, those with the highest levels of blood PCBs have 7-times the risk compared to those with the lowest levels.[8]
- Recent use of Viagra is associated with an 84% increase in risk, and long-term use of the drug is associated with a 92% risk increase.[9]
- Finally, there is a positive association between melanoma and obesity.[10]
Furthermore, Dr. Adele Green found that the strongest risk factor for both limb and trunk melanoma was moles. The presence of more than 10 moles on the arm predicted a 42-times increased risk.[11]
Therefore, please stop blaming the sun. Safely embrace the non-burning sun and reduce your risk of melanoma.
References:
[1] Crombie IK. Distribution of malignant melanoma on the body surface.Br J Cancer. 1981 Jun;43(6):842-9.
[2] 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.
[3] Ian D. Wyatt and Daniel E. Hecker. Occupational changes in the 20th century. Monthly Labor Review, 2006 pp 35-57: Office of Occupational Statistics and Employment Projections, Bureau of Labor Statistics.
[4] US Congress, Office of Technology Assessment, Catching Our Breath: Next Steps for Reducing Urban Ozone, OTA-O-412 (Washington, DC: US Government Printing Office, July 1989).
[5] Stephen J Merrill, Samira Ashrafi, Madhan Subramanian & Dianne E Godar. Exponentially increasing incidences of cutaneous malignant melanoma in Europe correlate with low personal annual UV doses and suggests 2 major risk Factors. Dermato-endocrinology 2015;7:1
[6] Millen AE, Tucker MA, Hartge P, Halpern A, Elder DE, Guerry D 4th, Holly EA, Sagebiel RW, Potischman N. Diet and melanoma in a case-control study. Cancer Epidemiol Biomarkers Prev. 2004 Jun;13(6):1042-51.
[7] Gould Rothberg BE, Bulloch KJ, Fine JA, Barnhill RL, Berwick M. Red meat and fruit intake is prognostic among patients with localized cutaneous melanomas more than 1 mm thick. Cancer Epidemiol. 2014 Oct;38(5):599-607.
[8] Gallagher RP, Macarthur AC, Lee TK, Weber JP, Leblanc A, Mark Elwood J, Borugian M, Abanto Z, Spinelli JJ. Plasma levels of polychlorinated biphenyls and risk of cutaneous malignant melanoma: a preliminary study. Int J Cancer. 2011 15;128(8):1872-80.
[9] Li WQ, Qureshi AA, Robinson K, Han J. Sildenafil use and increased risk of incident melanoma in US men: a prospective cohort study. JAMA Intern Med. 2014 Jun;174(6):964-70C
[10] Karimi K, Lindgren TH, Koch CA, Brodell RT. Obesity as a risk factor for malignant melanoma and non-melanoma skin cancer. Rev Endocr Metab Disord. 2016 Sep;17(3):389-403.
[11] Green AC, Siskind V. Risk factors for limb melanomas compared with trunk melanomas in Queensland. Melanoma Res. 2012 ;22(1):86-91.
Health benefits of UV by Marc Sorenson, Ed.D.
How important is UV? 
A transcendentally important scientific paper, by Dr. AT Slominski and colleagues, has added significant information about UV (sunlight) for skin. In addition, it explains the intricate connection between sunlight and the immune, endocrine and central nervous systems.[1] The name of the research paper, published in the journal Endocrinology, is How ultraviolet light touches the brain and endocrine system through skin, and why. The authors begin the abstract by stating that “the skin is a self-regulating protective barrier organ that is empowered with sensory and computing capabilities to counteract the environmental stressors to maintain/restore disrupted cutaneous homeostasis.” In other words, the skin has the ability to take on what life deals it and maintain its equilibrium and balance. In addition, the skin communicates bidirectionally with the central nervous, endocrine and immune systems. Thus, it helps to maintain balance for all body systems.
How does UV work?
First of all, ultraviolet energy (UV and UVB light) triggers all of these marvelous processes. UV, of course is available from sunlight, sunbeds or sunlamps. Its electromagnetic energy, through the skin, converts to chemical, hormonal and neural signals. These signals promote positive effects on the immune system, the endocrine system and the brain. Furthermore, endorphins (opioid-like substances) are increased and immune-system proteins are mobilized; consequently, health improves with UV. And, sun exposure regulates the endocrine system, by way of exposure to the skin, to produce or diminish hormones as needed. Especially relevant is that these effects take place independently of vitamin D synthesis.
Health increases with UV due to the magnificent sun, and our magnificent skin. As a result of the above information, it seems like it would be a good idea to soak up some non-burning sun each day when available. And, when it is not, we should find another UV source. In our soon-to-be-published book, Embrace the Sun, we discuss many facts about the healthful effects sun exposure:
A few healthful effects of sun (UV) exposure
- prevents and reverses obesity
- Improves longevity by reducing the risk of death by 50% over 20 years
- reduces the risk of hip fracture by 90% when compared to sun avoidance
- prevents the risk of breast cancer by 90% when compared to sun avoidance
- reduces by 50% the risk of melanoma in outdoor workers compared with indoor workers
- increases heart and vascular strength
- dramatically improves mood
- reduces the risk of multiple sclerosis
- reduces risk of most internal cancers
- cures psoriasis and eczema
- reduces risk of nervous system disorders
- prevents memory loss
- prevents myopia
The above list is not surprising in view of this new research, nor is the list complete. UV has many more healthful effects, which I’m sure the authors of this research acknowledge. Hence, the scientists sum up their research in this manner: “Thus, UV touches the brain and central neuroendocrine system to reset body homeostasis. This invites multiple therapeutic applications of UV radiation, for example in the management of autoimmune and mood disorders, addiction, and obesity.”
In conclusion, this seem like more compelling evidence to safely embrace the sun, no?
[1] Slominski AT, Zmijewski MA, Plonka PM, Szaflarski JP, Paus R. How ultraviolet light touches the brain and endocrine system through skin, and why. Endocrinology. 2018 Mar 12. [Epub ahead of print]
Obesity: Do vitamin D and sunlight have a part? A new study shows that
when vitamin D-deficient pregnant women bear children, the children may become obese.[1] Furthermore, the children had larger waistlines at age 6, compared with children born to women who had sufficient vitamin D levels. The body-fat percentage of those born to vitamin D- deficient women was also significantly higher. Body fat-percentage is a measure of obesity (or lack thereof).
The authors stated that 95% of vitamin D production in the body comes from sun exposure to skin. That is correct. Consequently, the expectant mothers spend too much time indoors. Or, they are frightened into sunscreen use, which can prevent production of 99% of vitamin D by sun exposure. Therefore, this type of obesity is a sun-deprivation disease. The research suggested that vitamin D supplements might be the answer. However, the answer is not supplements when sunlight is available. We should promote safe, non-burning sun exposure to prevent obesity.
Much has been researched lately regarding the importance of sunlight in preventing obesity. In my last blog, I mentioned several of these studies: http://sunlightinstitute.org/staying-slim-sunlight/
Here is a list of the methods by which sun exposure helps to prevent or reverse obesity:
- First of all, because blue-spectrum light causes cells to dump part of their fat load, it helps weight-control
- Secondly, early-morning light, because it resets circadian rhythms, reduces the risk of weight-gain.
- Thirdly, exposure to ultraviolet radiation (one of the spectrums in sun exposure) has been shown to impressively reduce weight gain in mice on a high-fat diet. Especially relevant is the fact that vitamin D levels made no difference in the weight of the animals.
In conclusion, non-burning sun exposure is vitally important to human health. If you would like to have a fat content that is less than others, be sure to obtain your share or sunshine and make weight-control for you and your children much easier!
[1] V. Daraki, T. Roumeliotaki, G. Chalkiadaki, M. Katrinaki, M. Karachaliou , V. Leventakou, M. Vafeiadi, K. Sarri, M. Vassilaki, S. Papavasiliou, M. Kogevinas and L. Chatzi. Low maternal vitamin D status in pregnancy increases the risk of childhood obesity. Pediatric Obesity Pediatr Obes. 2018 Jan 28. doi: 10.1111/ijpo.12267. [Epub ahead of print]
Obesity: Do vitamin D and sunlight have a part? A new study shows that when vitamin D deficient pregnant women bear children, the children may become obese.[1] Furthermore, the children had larger waistlines at age 6, compared with children born to women who had sufficient vitamin D levels. The body-fat percentage of those born to vitamin D- deficient women was also significantly higher. Body fat-percentage is a measure of obesity (or lack thereof).
How is vitamin D produced?
The authors stated that 95% of vitamin D production in the body comes from sun exposure to skin. That is correct. Consequently, the expectant mothers spend too much time indoors. Or, they are frightened into sunscreen use, which can prevent production of 99% of vitamin D by sun exposure. Therefore, this type of obesity is a sun-deprivation disease. The research suggested that vitamin D supplements might be the answer. However, the answer is not supplements when sunlight is available. We should promote safe, non-burning sun exposure to prevent obesity.
Are there other studies regarding sunlight and obesity?
Much has been researched lately regarding the importance of sunlight in preventing obesity. In my last blog, I mentioned several of these studies: http://sunlightinstitute.org/staying-slim-sunlight/
Here is a list of the methods by which sun exposure helps to prevent or reverse obesity:
- First of all, because blue-spectrum light causes cells to dump part of their fat load, it helps weight-control
- Secondly, early-morning light, because it resets circadian rhythms, reduces the risk of weight-gain.
- Thirdly, exposure to ultraviolet radiation (one of the spectrums in sun exposure) has been shown to impressively reduce weight gain in mice on a high-fat diet. Especially relevant is the fact that vitamin D levels made no difference in the weight of the animals.
In conclusion, non-burning sun exposure is vitally important to human health. If you would like to have a fat content that is less than others, be sure to obtain your share or sunshine and make weight-control for you and your children much easier!
[1] V. Daraki, T. Roumeliotaki, G. Chalkiadaki, M. Katrinaki, M. Karachaliou , V. Leventakou, M. Vafeiadi, K. Sarri, M. Vassilaki, S. Papavasiliou, M. Kogevinas and L. Chatzi. Low maternal vitamin D status in pregnancy increases the risk of childhood obesity. Pediatric Obesity Pediatr Obes. 2018 Jan 28. doi: 10.1111/ijpo.12267. [Epub ahead of print]
Stay slim with sun exposure? 
New, never considered research adds a reason to stay active in the sun:[1] The blue-light spectrum of sunlight, a spectrum that can penetrate the skin, can cause subdermal fat tissue to decrease in size. In other words, it can cause fat loss. Thus, the action of sunlight may help one to stay slim or become slim. The researchers showed that daily exposure of differentiated adipocytes [fat cells] to blue light resulted in decreased lipid droplet size and increased basal lipolytic [fat breakdown] rate.
The researchers had been doing research on light and diabetes, and they serendipitously found that the light could be an asset in maintaining (or producing) a slim body. But there are many other studies that show sun exposure is capable of assisting the body in being slim. For example: here is another benefit of sun exposure—morning sun specifically: A recent study from Northwestern Medicine demonstrates that timing and intensity of light correlate with body mass index (BMI).[2] BMI is a numerical computation comparing height and weight, and is a commonly used method to assess obesity or the lack thereof. A high BMI usually means a person is obese or at least approaching obesity, while optimal BMI is 18-25. Below 18 is considered underweight, above 25 is overweight, 30 is obese and 40 and above is morbidly obese. However, BMI does not work for heavily-muscled people, who may have minimal fat, but whose BMI puts them in an obese category—in reality, they are very slim.
This study showed that exposure to bright morning light was directly related to BMI. After adjusting for confounders such as diet, exercise and timing of sleep, it was determined that very early exposure to morning light correlated remarkably to lower BMI—they were slim, or at least slimmer. Even when light intensity was equal at different times of the day, those who received the earliest bright light had lower BMI. Most noteworthy was the fact that for each hour later in the day when light exposure occurred, BMI increased by 1.3 units. This fact is especially relevant, since a person who has a BMI of 25 (upper ideal range) could approach 30 (obesity), over time, due to the habit of receiving sun exposure later in the day, e.g. 10:00 AM rather than 6:00 AM.
The authors suggested that the mechanisms by which early light exposure could influence the “slim” mechanisms, could be the following: (1) resetting the circadian rhythm (internal clock), (2) the greater quantity of blue light in morning sun and (3) effects on melatonin production. Whatever the mechanisms, we now know that early-morning sun is important to being slim. In addition, it may also be important to other health issues. Rather than think of sun exposure as the cure-all for obesity, we must realize that poor nutritional habits and lack of exercise are much more important. Nevertheless, sun exposure can furnish one more arrow in the quiver.
Sun exposure is far superior to vitamin D supplements in preventing weight gain.
Another scientific paper “sheds more light” on the subject of being slim.[3] This research was conducted on mice with shaved backs that were placed on a high-fat diet and then exposed to non-burning ultraviolet radiation (UVR) during a three-month experiment. The mice, without the benefit of UVR, would have been expected to gain weight rapidly, but when they were exposed to UVR, the weight gain was impressively reduced. Furthermore, the UVR treatment achieved 30-40% less weight gain, compared to the expected weight gain with the high-fat diet. So, not only can sun exposure produce slim humans, it can help to produce slim rats.
Other benefits for the rats included: significant reductions in glucose intolerance, insulin resistance and fasting insulin levels (all markers and predictors of diabetes), nonalcoholic fatty liver disease measures and cholesterol. All of these factors, including obesity, are part of a cluster of maladies known as the metabolic syndrome, or MetS, which is indicative of deteriorating health and susceptibility to heart disease and diabetes. Finally, almost all people who have the aforementioned indications of MetS have a large problem maintaining slim bodies. Not a surprise, eh?
Other interesting findings:
Supplementation with vitamin D actually reduced the aforementioned beneficial effects. Dr. Shelley Gorman, one of the authors, made the following three interesting observations:[4]
- “These findings were independent of circulating vitamin D and could not be mimicked by vitamin D supplementation.”
- “It looked like the presence of vitamin D in mice on the high fat diet prevented the [beneficial] effect of UV radiation on weight gain.”
- She also mentioned the mechanism of weight loss may be dependent on nitric oxide (NO), which originates from diet and can be mobilized by UV radiation to become bioactive. This was due to the fact that in another part of the experiment, skin induction of nitric oxide (NO)—also a product of skin exposure to sun—reproduced many of the positive effects of UVR, something vitamin D supplements could not do.
The Authors conclusions:
The authors concluded their research thusly: These studies suggest UVR (sun exposure) may be an effective means of suppressing the development of obesity and MetS, through mechanisms independent of vitamin D but dependent on other UVR-induced mediators such as NO.”
It has been suggested that since low 25(OH)D levels correlate to obesity, those low levels are a possible cause of obesity. However, vitamin D is stored in fat tissue. Therefore, an increase in fat will lower the quantity of 25(OH)D circulating in the blood. Hence, low vitamin D is a consequence of obesity, and not the cause.[5]
Research continues to mount about the positive effects of sun exposure, independent of vitamin D production. This should in no way be construed to diminish the vital importance of vitamin D. Rather, it is to make a point that sun exposure works in many ways, including stimulating the production of vitamin D, NO, serotonin and endorphins. Why should we be satisfied with any one of these marvelous health aids when the sun is available? Because, with sun exposure, we can enjoy the benefits of the entire package.
So, being slim is dependent on a series of choices: avoiding junk food, eating large quantities of vegetables and fruits, taking a daily walk or engaging in other aerobic exercise, weight training and, finally, soaking up some daily, non-burning sunlight.
In conclusion: Stay slim, my friends.
[1] Katarina Ondrusova, Mohammad Fatehi , Amy Barr, Zofa Czarnecka, Wentong Long, Kunimasa Suzuki, Scott Campbell, Koenraad Philippaert, Matthew Hubert, Edward Tredget, Peter Kwan, Nicolas Touret, Martin Wabitsch, Kevin Y. Lee & Peter E. Light. Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis. Scientific Reports November 27;7:16332
[2] Reid KJ, Santostasi G, Baron KG, Wilson J, Kang J, Zee PC. Timing and intensity of light correlate with body weight in adults. PLoS One 2014;2;9(4)
[3] Geldenhuys S, Hart PH, Endersby R, Jacoby P, Feelisch M, Weller RB, Matthews V, Gorman S. Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet. Diabetes. 2014 Nov;63(11):3759-69
[4] Dr. Shelly Gorman, quoted on Science Network Australia article: Sun shines light on obesity challenge. http://www.sciencewa.net.au/topics/health-a-medicine/item/3618-sun-shines-light-on-obesity-challenge (accessed February 4, 2016)
[5] Cândido FG, Bressan J. Vitamin D: link between osteoporosis, obesity, and diabetes? Int J Mol Sci. 2014 Apr 17;15(4):6569-9.
Although liver cancer is generally thought to be related to drinking, other factor such as obesity, HIV infection, smoking, diabetes, socioeconomic factors, drugs and others come into play. A recent study compared sun exposure to liver cancer and adjusted for the aforementioned factors. Sun exposure was shown to be a major factor in reducing the risk of the most prevalent and deadly liver cancer, called hepatocellular carcinoma.[1]
Major finding for liver cancer:
The subjects were divided into five groups, or quintiles, based on their sun exposure. In addition such factors as as outdoor activity, geographical residence, urban or rural settings, etc. were adjusted for.
Most noteworthy, was the fact that for each quintile of increasing sun exposure, there was a 17% decrease in the liver cancer risk.
A disappointment:
The only disappointing part to the study was this: The researchers assumed that the positive influence of sun exposure on liver cancer was due to vitamin D production. And, they may have been correct. Yet the sun causes the body to produce many other photoproducts. Due to the sun’s myriad effects, serotonin, endorphin, BDNF, nitric oxide, and dopamine are all increased. Therefore, it is impossible to know if vitamin D alone was the reason for the reduced risk of liver cancer. However, vitamin D undoubtedly played a large part in the positive results. And, there is a problem with giving vitamin D the credit without knowing for sure. People may believe, due to this research, that they need only to take a vitamin D supplement to receive all benefits of sunlight. Therefore, they can make very bad assumptions.
This is the first study on sun exposure and liver cancer.
Probably, this is the first research to show a link between liver cancer and inadequate sun exposure. However, there are indications that sun exposure is associated with a reduced risk of another liver ailment, called fatty liver disease.[2]
In conclusion, if you are a liver lover, you can love your liver by protecting it from liver cancer. Hence, you should obtain your share of unscreened, direct, non-burning sun exposure. Happy sunning!
[1] Trang VoPham, Kimberly A. Bertrand, Jian-Min Yuan, Rulla M. Tamimi, Jaime E. Hart,
and Francine Laden. Ambient ultraviolet radiation exposure and hepatocellular carcinoma incidence in the United States. Environmental Health (2017) 16:89.
[2] 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.