Sunlight Breakthrough: Solar rays can boost your immunity year-round

For decades we’ve been warned about the hazards of getting too much sun. But what we really should have been worrying about was not getting enough sun.

It has become glaringly obvious that people aren’t getting enough vitamin D, which comes from healthy sun exposure. In fact, thanks to the photophobic mythology of modern medicine, there is actually an epidemic of vitamin D deficiency, which is associated with virtually every chronic disease.

But it turns out vitamin D synthesis isn’t sunlight’s only essential function in the human body. An exciting new study shows that solar rays actually help the body fight off infections better and faster.

I’ll tell you more about this important breakthrough in a moment. But first, since winter is over and the sun is now at an angle where even people who live in the northernmost climes can produce their own vitamin D from sunlight, you might consider reading this article outside.

Pull up a chair in a sunny spot, roll up your sleeves and pant legs, and don’t put on any sunscreen. Don’t worry…as you’re about to discover, there’s nothing to be afraid of.

How the science of sunlight got clouded over for so long

Despite the resounding evidence for the benefits of healthy sun exposure, we still remain concerned that too much sun will lead to melanoma.

Of course, melanoma is the one true deadly form of skin cancer, but it’s important to note that it accounts for less than 10% of all skin cancers.

And, often, it’s not even caused by natural sun exposure.

Despite the blanket recommendations for everyone to avoid sunshine in order to prevent melanoma, evidence has been piling up that like all “risk factors,” sun exposure recommendations really need to be targeted to the people who need them most (but then again, what would happen to the lucrative mass-market sunscreen industry if that happened?).

So who are those people? Well, first of all, research shows that excess ultraviolet light exposure (which can come from sun or artificial lights) during adolescence and young adulthood is the real risk factor for developing melanoma later in life.

But the bigger problem is not spending time on the beach, but rather racking up hours in unnatural, unhealthy tanning beds.

In fact, the Melanoma Research Foundation reports that using tanning beds that have artificial lights before age 30 increases the chance of developing melanoma by an astounding 75%.1 The FDA has finally placed restrictions on the use of tanning beds, appropriately enough.

Another study suggests that recommendations about avoiding sun should be targeted particularly to light-skinned, red-haired people, as they are the most likely to get melanoma.2

But, as I wrote in a March 2 Daily Dispatch (“Melanoma caused by mistaken medical beliefs”), the biggest breakthrough of all when it comes to melanoma is new research from France that shows the modern increase in this deadly skin cancer does not result from too much sun exposure at all.

Instead, it’s due to an antiquated, early 20th century medical practice that has now caught up with unfortunate older generations.

This practice, which involved exposing children to extensive artificial ultraviolet radiation for supposed health benefits, caused the spike in melanoma rates we now see in people over age 60.

Fortunately, by the 1950s, this barbaric practice began to fall out of favor. Instead, during the 1960s, ’70s, and ‘80s—before the misguided dermatologists and government bureaucrats began erroneously telling us to cover up—“sun worshipping” became popular.

People of all ages, but especially the younger generations, began to get more and more natural sun exposure on more and more parts of their bodies (especially for women).

And melanoma deaths are now plunging in middle-aged people who got more sunshine, but no ultraviolet medical treatments when they were children.

In fact, the French analysis shows that melanoma rates are now dropping as the scantily clad, sun-worshipping generations get older.3

The other kind of disease-fighting sunlight

So the benefits of natural sunlight exposure appear stronger than ever, while the rationale for avoiding the sun is vanishing evermore into the shadows of antiquated medical practice.

And, as I mentioned earlier, new evidence out of Georgetown University (in the same Department of Physiology and Pharmacology where I serve as adjunct professor) suggests that sun exposure—even in the dead of winter—can increase your immunity and reduce the duration of colds.4

How? Well, it has to do with the solar light spectrum.

When we talk about sun exposure, most people think about ultraviolet B (UVB) wavelengths. UVB light, which is invisible to the human eye, activates vitamin D production in the skin.

But for this study, researchers looked at blue light, which comes from the visible part of the spectrum of solar radiation.

Blue light differs from UVB rays in another key way. As I’ve told you before, UVB rays only penetrate the atmosphere when the sun is high enough, from April through October, in most parts of the U.S. But blue light reaches the Earth whenever the sun is shining—all 12 months of the year.

So, in essence, you can benefit from blue light rays year-round, wherever you are, simply by going out in the sun. And the Georgetown researchers found that blue light can actually penetrate the top layer of your skin and activate T-cells in your immune system, telling them to move throughout the body.

Essentially, blue light increases synthesis of hydrogen peroxide in your body. This synthesis activates a signaling pathway, increasing T-cell movements. White blood cells in your immune system also release hydrogen peroxide, which “calls” T-cells and other immune cells to the site of an infection to mount a full immune response.

Could sunlight be a cure-all?

Another major new global study shows that vitamin D protects against cold and flu viruses.5 So maybe the cold and flu season has something to do with not getting enough of the sun’s blue light and UVB rays on your skin during the winter?

I’m also intrigued by a new study that shows that blue light mobilizes calcium and a number of other cellular mechanisms.6

So is lack of sun a contributing factor to osteoporosis? It wouldn’t surprise me.

After all, the Georgetown study revealed that many different kinds of cells in the body respond to the energy of sunlight—not just the skin and the retina of the eye.

Blue light is key because its wavelengths are best able to penetrate into biological tissues. It is not just plant cells that use photosynthesis (relying on quantum effects, according to the latest research) but mammalian cells as well.

So it may very well be that blue light, and sunlight in general, have even more health benefits that haven’t been discovered yet.

The best way to get the right amount of sunshine

Researchers published the Georgetown study last December 20, just in time for the winter solstice—the day when we get the least amount of sunlight per year.

Now, with the summer approaching, here is a practical way to put their findings to use.

The main reason to avoid getting too much sun is to prevent a painful—and skin-damaging—sunburn.

So to develop a healthy, vitamin D-boosting tan, spend 15 minutes in the sun without sunscreen. There are natural tanning oils, such as coconut oil and cocoa butter, and even natural vegetable-oil sunscreens if you wish to use them

(Learn more in my April 25, 2015 Daily Dispatch “Try these 4 tips for safe sun exposure.”)

As you develop a light tan, you can gradually add more time in the sun each day if your skin can tolerate it without burning. But if you’re fair-skinned, 15 minutes of sunshine a day—with at least part of your legs and arms uncovered—is all you need to manufacture you own healthy dose of D.



2“Development and External Validation of a Melanoma Risk Prediction Model Based on Self-assessed Risk Factors,” JAMA Dermatology 2016 Jun 8.

3“Current Melanoma Epidemic Caused by Old Medical Beliefs,” European Cancer Organization (ECCO) Congress 2017. Abstract 1201. Poster presented January 28, 2017; oral abstract 1144 presented January 29, 2017.

4“Intrinsic Photosensitivity Enhances Motility of T Lymphocytes,” Scientific Reports 12/20/2016; 6: 39479

5“Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data.” BMJ 2017;356:i6583.

6“Blue light-dependent changes in loosely bound calcium in Arabidopsis mesophyll cells: an X-ray microanalysis study.” J Exp Bot 2016; 67 (13): 3953-3964.