Why Are We Hiding From the Sun?
What recent studies, evolutionary biology, and an ancient Upanishad tell us about our relationship with the sun.
It was June and I was at a beach in the Northeast of the United States with a bunch of other Indians. One of them pulled out a tube of sunscreen and offered it to me. When I declined, she looked at me strangely. I, in turn, looked at all of them strangely as they applied a thick layer of cream on themselves.
I was reminded of this incident when I started reading the book, In Defense of Sunlight by Rowan Jacobsen. Jacobsen has made the case that all of us should seek out more sunshine. I agree with him although I concede that our case is not truly testable.
It is customary to start an article such as this with the admonishment that this is not medical advice and that you should talk to your doctor. But as I type this, I am asking myself what does this even mean?
I don’t have a doctor and I know many others who don’t. The one doctor I have consulted in the last five years is an endocrinologist. I can’t imagine waiting in his anteroom for nearly an hour and then asking him about how much sunlight I should get and whether I should use a sunscreen when I am doing it. If I did ask him, I am pretty sure that he will end his response with asking me to consult a dermatologist and that he could recommend one.
What would the dermatologist say? I am speculating here but there is a good chance that the dermatologist tells me that there are 5.5 million cases of skin cancer each year in the United States. He may tell me that “Patients with metastatic melanoma have a poor prognosis, with a median survival duration of only six to nine months.” and that the American Academy of Dermatology recommends sun protection for people of all skin tones whenever they are outdoors.
If I heard only this, I would order a sunscreen from the dermatologist’s clinic itself. However, there are some other relevant facts. Jacobsen points out,
“Nearly 99 per cent of skin cancer cases are basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). Those are certainly no joke…but they rarely spread beyond the skin or result in serious health issues.”
That is not all. There is also the matter of race. Darker skin has a much greater ability to handle the sun. Jacobsen reports that ‘For melanoma, incidence of new cases per year is about 28 per hundred thousand people in Whites, 5 in Hispanics, and 1 in Blacks and Asians.”
But perhaps, even the 1 in hundred thousand case rate is not a risk worth taking? Why do I need to expose myself to sunlight anyway? To get Vitamin D? I can always supplement with Vitamin D capsules, can’t I?
A full-size book can be written about Vitamin D and thousands of them have been written! A search for “Vitamin D books” on Amazon throws up this
The focus on Vitamin D began when population-wide studies from the 1980s began showing that “people with low Vitamin D levels had a higher incidence of dozens of diseases, including breast cancer, colorectal cancer, high blood pressure, diabetes, heart attack, stroke, dementia, depression, and several autoimmune diseases.”
These studies led to a boom in Vitamin D supplements.
Unfortunately, newer studies show that unless it is to correct a very severe deficiency, these supplements do not have health benefits. It is the exposure to sun that leads to both health benefits and a rise in Vitamin D levels. These studies have got more and more assertive and one Swedish study even concluded,
“Avoidance of sun exposure seems to be a risk factor of a magnitude similar to smoking in life expectancy.”[1]
If the increased level of circulating Vitamin D is not leading to health benefits, then what is? Jacobsen has a few candidates and the most prominent of them is Nitric Oxide. Nitric Oxide is a short-lived gas that helps enlarge our blood vessels. When blood vessels are enlarged, circulation improves. This has been well known in medicine and NO releasing medication forms a part of the tool-kit to deal with a range of diseases such as heart diseases, blood pressure and impotence.
Jacobsen takes us through the mechanism of Nitric Oxide and the sun. We get Nitrates from food — especially Nitrate-rich foods such as leafy greens and Beets. Our body takes these nitrates and deposits them near the skin. When sunlight hits these Nitrate deposits in the skin, they are partly converted to NO which circulates in our blood vessels.
“Not only does it dilate blood vessels — which has led to a wave of new cardio drugs, as well as Viagra — it’s also used by the brain to transmit signals, and by the immune system to kill pathogens. It even improves the efficiency of mitochondria, the tiny structures in our cells that transform nutrients into usable energy.”
Nitric Oxide is not the only mediator between the sun and health benefits. For example, Jacobsen says that Infrared light can reach deep inside our bodies and energize our mitochondria. Another example is that Infra-red rays also help heal the body — a principle behind photobiomodulation therapy, which some dentists use post-procedure to stimulate cellular repair. Jacobsen is convinced that given the low risk of melanomas and the range of benefits, people, especially those with dark skin should not be told to avoid the sun.
“And it’s especially poor advice for people with darker skin, who almost never get sun-induced skin cancer and yet suffer higher rates of many of the other diseases that seem to be alleviated by sunlight.”
It seems we made a mistake when we reduced the interaction between the sun and a complex system such as a human being to a Vitamin pill.
Get Yogesh Upadhyaya’s stories in your inbox
Join Medium for free to get updates from this writer.
Evolutionary logic would support this claim. Just two hundred years ago, my ancestors walked tens of kilometers in the sun on a regular basis. There is a good chance that they did without any cloth on the upper body because textiles were too expensive to be worn on a regular basis. If they were farmers, which is likely, they had to be in the open for large parts of the day. It is likely that my body has evolved to thrive and not just survive under the sun. And it is not just biological evolution, long standing religious and cultural practices also encouraged my ancestors to go out in the sun.
The Surya Upanishad (part of the Atharva Veda) for example, has exhorted us to worship and meditate on the Sun thrice a day — at sunrise, midday, and sunset. It has made this recommendation thousands of years ago. It is very unlikely that such practices would have survived if they were bad for most individuals.
This biological and cultural history suggests that our bodies would have evolved to take advantage of the sun. As Jacobsen says,
“…the human body evolved in an environment of abundant sunlight, and we are designed to make use of that solar energy in various ingenious ways…”
But, those of us who live in big cities, no longer live in the world of our ancestors. It is incredibly difficult to get sun on your skin in Mumbai. The months of April to June are too hot and humid to be out in anything but the early morning sun. In the months of monsoon — July through September — you may not see the sun for weeks on end. October is almost as humid as May. The period Mid-November through mid-January is cool enough to sit out in the sun for a few minutes but these are the peak months for air pollution. As per some accounts, Mumbai has the highest number of skyscrapers under construction in the world! This means that on most days, sunlight will struggle to reach you through all the dust in the air. Mid-January through perhaps mid-March is a brief period when it is pleasant to sit in the sunshine — if you can find it.
If you get sun in your apartment for any meaningful amount of time, you should consider yourself lucky. Most of us do not have the luxury. We have to hunt for an open space in our neighborhood and snatch a few minutes of sunshine on our arms and face. To get sunshine on our back or chest, we would need to go to Goa.
If we do go to Goa to get sun, we may end up applying sunscreen because we are afraid of sun burns. This fear is not baseless, as our skin, unlike that of our habitually topless ancestor, is not used to sun. Just as you cannot run a marathon if the most exercise you have been getting for the last few years is a gentle stroll, you cannot sun bathe for long periods of time if you get sun on your skin only once in a while. Our bodies need to get used to the sun the same way they need to get used to exercise — gradually.
Jacobsen describes many mechanisms by which this ‘getting used to’ happens. Most obviously, our skin darkens. This melanin driven darkening protects you from the worst effects of sunlight. Additionally, the skin thickens with exposure to sunlight and that is protective. Finally, sunlight and sweat on our skin promotes the growth of a layer of bacteria that acts like a sunscreen. (If the idea of bacterial colony on your skin sends you running to take a shower with industrial strength cleaners, remember that the cleaners will merely substitute one type of bacteria with another, like it happens in our guts. Microbiomes are natural on all parts of our body and destroying one type of bacteria would result in another type and the new one could be much worse for us).
Without these protections, all of us need to figure out how we can get more sun in our lives regularly just as we try to figure out how we can get slightly more exercise or slightly better food or slightly better sleep.
But should you try to get more sunlight? The case for better food, exercise and regular sleep seems clear cut. Is the case for sun exposure as good? Assuming your goal is not to have a fair, blemish free skin but is to become healthier, should you try to figure out how to get more sun in your daily life?
I may have been persuasive but I am just a guy on the internet who is quoting a book written by a science journalist. Sure, the science journalist is quoting many doctors but against those doctors are arrayed many others including the formidable sounding American Association of Dermatologists. If we dig deeper in the evolutionary argument, we would discover that my habitually top less ancestor ate differently and lived very differently. Perhaps, he did not live long enough to get cancer? And the Nitric Oxide? Maybe scientists will soon change their tune about it as they have about Vitamin D?
Can you even test whether whichever decision you end up taking is right?
If you increase your sun exposure and notice that your health is improving, is there a causation? First of all, it is very likely that your daily sun exposure would be one factor in many. Perhaps you decided to focus more on health and are eating better, sleeping better and getting some exercise. Could you even isolate the effect of sunlight on you, the individual?
Or if you suffer a negative health event after increasing your sun exposure, how do you know if the sun was actually to blame?
It’s like following the sound advice to walk on the footpath instead of on the main road. However, if you’re walking through Koramangala in Bengaluru during peak traffic and a food-delivery rider zips down the sidewalk to beat his deadline and clips you, was walking on the footpath a bad decision?
This kind of unknowability isn’t unique to sunlight — it is all around us, in health, in parenting and in businesses. Science can give us population averages and physiological mechanisms, but it can’t give us a personal guarantee. We have to make calculated trade-offs based on our skin type, our environment, and our daily routines. Getting a little more sunshine may not be a testable cure-all, but for most of us, stepping out of the shadows is a reasonable place to start.
[1] The American Academy of Dermatology objected to these conclusions, stating “We believe the results of this study may encourage the public, women in particular, to seek the sun and / or use indoor tanning devices, ultimately increasing their risk of cancer.”
Edit: Added the sentence “It seems we made a mistake when we reduced the interaction between the sun and a complex system such as a human being to a Vitamin pill.”
Follow me on medium. Choose the option to get the stories delivered to your Inbox.
You can follow me (@YogeshUpadh) on twitter or on LinkedIn
