Why Sunlight is Good for You
Sunlight is controversial and the conversation around sun exposure is usually around how best to protect yourself from the sun’s rays. We’re not advocating sunbathing for hours, but sunlight has a number of physical and mental health benefits that we may miss out on if we are always covered up. Sun protection is important, but we need to find that responsible middle ground which allows us to reap the benefits of sunlight for our health, while minimizing the risks of too much sun exposure.
Over the years, a positive association between the sun and health has been discovered. There is growing evidence that regular exposure to the sun contributes to the prevention of colon, breast, and prostate cancer, non-Hodgkin lymphoma, multiple sclerosis, hypertension, and diabetes. The health benefits of the sun were at first attributed to the production of vitamin D, but increasingly research shows that it is immunomodulation (modifying the immune response), the production of nitric oxide, melatonin, serotonin, and the effects on circadian rhythms that are also responsible for the health benefits of the sun.
Linda Geddes, science journalist and author of the book, Chasing the Sun, a book about the new science of sunlight, writes, “the circadian clock is far more than a biological curiosity, it has been implicated in pretty much every biological process looked at. There is a strong daily rhythm in body temperature, blood pressure, and the hormone cortisol. Circadian rhythms govern the release of chemicals that regulate mood; the activity of immune cells that fight off disease, and our body’s response to food.” She argues that change in these biological rhythms is associated with poorer sleep and illnesses from depression to dementia to cancer to cardiovascular disease.
Before diving into the benefits of sunlight, getting too much sun can have negative consequences, so it's very important to prevent burns and cover-up and stay in the shade when outside during the peak hours of 11-3 pm.
The Benefits of Sunlight for Physical and Mental Health
Sunlight and vitamin D
Vitamin D is needed for calcium absorption and for bone strength. Also called the “sunshine shine” vitamin, it helps to reduce the risk of some cancers. In one study, researchers in Japan found that overall cancer risk was 22% lower among those with the higher levels of vitamin D, compared to those with the lowest levels. But before you reach for your vitamin D supplement, you may want to go for a walk in the morning sun first. A large study published in the New England Journal of Medicine, showed that supplementation with vitamin D did not result in a lower incidence of cancer or cardiovascular disease.
Sunlight and your microbiome
Studies suggest that sunlight has the ability to change and improve our gut microbiome. In a small study of 21 healthy women, Canadian researchers found a direct link between the effect of UVB light and intestinal microbes. Women who were exposed to UVB light, showed more diverse microbes in the gut and the positive changes in the diversity of the microbiome was also shown to be independent of vitamin D. Although this work is preliminary and more studies are needed, it suggests that the sun has an effect on gut health.
Sunlight and mood
Sunlight and its effects on mood are well documented. Many people at one time or another have been affected by Seasonal Affective Disorder (SAD) during the winter months. A lack of sunlight during the winter months leads to lower serotonin levels which is linked to feeling of depression and anxiety. But, as we spend more time indoors at work and home, staring at screens, it could be that our modern lifestyles are encouraging feeling a form of SAD all year around. One Australian study found that people have higher serotonin levels on bright sunny days, than cloudy ones.
That’s not all, serotonin has been found in keratinocytes (the dominant cell found in the skin), leading researchers to deduct that skin can produce serotonin and while there needs to be a lot more research done in this area, the findings may suggest that it is possible that sunlight and its interaction with skin cells is involved in the production and bioregulation of serotonin.
Sunlight promotes bone growth
Sunlight is crucial for calcium absorption and is essential for bone growth and formation in children and for preventing osteoporosis in adults. If you are pregnant, you now have double the reason to get some sun and supplement with vitamin D because research shows that a mother’s exposure to the sun can give her children larger and healthier bones.
Sunlight strengthens the immune system
Researchers have found that sunlight strengthens the immune system, independent of vitamin D (which already has a wide-reaching impact on immune function). Sunlight energizes T cells and makes them move to the site of infection faster to orchestrate a response.
Sunlight is good for the heart
Studies show that sunlight lowers blood pressure and that the role of nitric oxide in heart health is particularly interesting. UVA light causes nitric oxide to be released from the skin and into the arteries where it acts to dilate blood vessels, increase blood flow and lower blood pressure. While the relationship between sun exposure and heart health has been linked to vitamin D, the positive changes were not associated with a rise in vitamin D levels, suggesting that the release of nitric oxide from sunlight is the cause of this process.
Sunlight regulates metabolism
Another reason to get more sun in our lives is to regulate metabolism. Researchers studying mice discovered that a particular wavelength found in sunlight triggered a gene called OPN3 to prompt fat cells to release fatty acids as fuel for fat burning. They discovered that the mice couldn’t burn fat very well without this light. The type of light triggering OPN3 wasn’t found in other types of light in significant levels, only in sunlight.
Our bodies have evolved over millennia under the sun’s light and our days spent in artificial light does not provide the full spectrum of light we get from the sun. Geddes found that the illuminance in a typical office is between 100 and 300 lux during the daytime, whereas even on the gloomiest, most overcast winter’s day it is at least 10 times brighter outside. This is important because it shows that we don’t need to spend our days sunbathing to reap the health benefits of the sun.
Despite the advantages of sunlight, there is no getting around the fact that it is hard on our skin and can be dangerous if we are exposed to too much. Interestingly, research shows that people who work outdoors have a decreased risk of melanoma compared to indoor workers, suggesting that regular sun exposure can have a protective effect on the skin. Studies in Europe show that the risk of skin cancer is mostly caused by a sporadic pattern of exposure to the sun, while regular exposure grants little risk. For those of us living in northern climates and working in offices, we need to be responsible with our sun use.
There is no getting around the fact that the sun is hard on our skin. While aging is often targeted as the cause of wrinkles, loss of collagen and thinning of the skin, the real root of the problem is the combination of aging and exposure to the sun.
The shorts UVB rays that cause sunburn can also damage DNA and suppress the skin’s immune system, while the longer UVA rays penetrate more deeply and may cause free radical damage which can damage skin membranes and DNA.
Even with all the benefits of the sun, it's important to get the right balance to minimize the harmful effects of too much sun at the wrong time of day. Linda Geddes applies author Michael Pollan’s adage “eat food, not too much, mostly plants” to the sun and it sounds about right:
“Get lots of natural light, not too much direct sun, and avoid blue light at bedtime.”
How to Safely enjoy the sun
Know your genetics and your skin type. People with pale skin who burn easily and don’t tan are more likely to get skin cancer.
Suddenly getting a lot of sun is more dangerous than steady exposure over time. Reports suggest that there are benefits to cumulative sun exposure, but if you are indoors most of the time, your skin is not primed for sun exposure, so cover-up.
To get the benefits of sunlight, get out in the morning light. It will boost your vitamin D and serotonin production and reinforce your body’s natural circadian rhythms.
Stay out of the sun or stay covered up between the hours of 11-3 pm from March to October and take extra care to keep children appropriately protected from the sun.
Sarka Botanicals and its materials are not intended to treat, diagnose, cure or prevent any disease. All material on Sarka Botanicals is provided for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider for any questions you have regarding a medical condition, and before undertaking any diet, exercise or other health-related programs.