Humans lack a key enzyme found in many animals and plants that reverses severe sun damage. For the first time, researchers have witnessed how this enzyme works at the atomic level to repair sun-damaged DNA.
Scientists were able to observe the enzyme, called photolyase, inject a single electron and proton into an injured strand of DNA. These subatomic particles healed the damage in a fraction of a second.
According to Physorg:
"[Researchers] synthesized DNA in the lab and exposed it to ultraviolet light, producing damage similar to that of sunburn, then added photolyase enzymes. Using ultrafast light pulses, they took a series of 'snapshots' to reveal how the enzyme repaired the DNA at the atomic level."
This is a fantastic example of the miracle of "life" itself – how compounds, such as enzymes, work on the energetic level to heal DNA damage, almost instantaneously!
As described by Physorg, the photolyase enzyme captures photons from the visible light spectrum, which gives it sufficient amounts of energy to inject a single electron and a single proton into the damaged DNA strand. This sets off a complex series of chemical reactions that reorganizes and repairs that DNA, all within a few billionths of a second.
Physorg further explains:
"This study has revealed that photolyase breaks up those errant bonds in just the right spots to cause the atoms in the DNA to move back into their original positions.
The bonds are then arranged in such a way that the electron and proton are automatically ejected out of the DNA helix and back into the photolyase, presumably so it could start the cycle over again and go on to heal other sites."
This discovery may have beneficial applications in preventive remedies or treatments for sunburn and skin cancer in the future. However, although humans are not equipped with this protective enzyme, your body IS designed to protect itself from this type of DNA damage, and you DO possess an ingenious mechanism that can protect you from skin cancer.
It's already well established that exposure to ultraviolet light (UV) can damage your skin and lead to skin cancer. However, more recent findings show that the recommendation to avoid direct sun exposure to prevent skin cancer is all backwards.
How Sun Exposure Causes Skin Cancer
It's true that some skin cancer is caused by skin damage and subsequent DNA mutations, which can occur when you get sunburned. However, contrary to popular belief, appropriate sun exposure actually helps prevent the fatal type of skin cancer, melanoma, and there's plenty of evidence to support this stance.
In fact, research shows that your risk of melanoma decreases with greater sun exposure, and can be increased by sunscreens! In addition, melanoma patients with higher levels of sun exposure have been found to be prone to a less aggressive tumor type, and to live longer than other melanoma patients.
Indoor workers are also more prone to developing melanoma, despite the fact that they receive three to nine times less solar UV exposure than outdoor workers.
Statistics alone will tell you there is a serious flaw in the current recommendations to stay out of the sun to avoid skin cancer, as melanoma rates have increased while, at the same time, sun exposure and vitamin D levels in the general population has significantly decreased.
Fortunately, despite the fact that we lack photolyase to repair sun damaged DNA, your body has a built-in feedback loop that can provide similar protection, but you need to know how to unlock this mechanism.
Not All UV Exposure Causes the Same Chemical Reactions
There are two major factors that help explain why melanoma rates are rising among indoor workers and people who religiously apply sunscreen and rarely expose their skin to the sun.
The first has to do with the type of UV exposure you get. There are two primary types of UV rays from sunlight:
- UVB rays that make your skin produce vitamin-D, and
- UVA rays that cause skin damage
Both UVA and UVB can cause tanning and burning, although UVB does so far more rapidly. UVA, however, penetrates your skin more deeply and are likely a much more important factor in photoaging, wrinkles and skin cancers. In addition, UVA rays can penetrate through window glass, whereas UVB do not, and this may be a significant part of the problem.
A recent study by Dr. Dianne Godar of the U.S. Food and Drug Administration (FDA), indicates that it is the damaging, glass-penetrating UVA light -- not the UVB light that allows your body to produce vitamin D – that causes malignant melanoma.
This brings us to the second factor that influences your risk of melanoma, namely your vitamin D level. Dr. Godar's research also indicates that inadequate vitamin D levels are a factor.
As you probably know, vitamin D is created when your skin is exposed to natural sunlight. Without appropriate amounts of sun exposure, your vitamin D levels decline, which can cause a wide variety of health problems – including an increased risk of skin cancer, as well as at least 16 other types of cancer.
As explained by Dr. John Cannell, one of the leading authorities on vitamin D, when vitamin D is produced in your skin, it goes directly to the genes where it helps prevent the types of abnormalities that ultraviolet light (mainly UVA) causes.
Therefore, when you avoid the sun entirely, or slather on sun block whenever you go out, your skin is not producing any vitamin D, leaving you without this built-in cancer protection.
So, in summary, it's the combination of exposure to damaging UVA rays and vitamin D deficiency that appears to be causing the increased rates of melanoma – not sun exposure in general.
How to Get the Benefits of Vitamin D with Little Risk of Skin Cancer
Please understand that regular sun exposure is absolutely essential for your health. To get a better understanding of the health promoting role vitamin D plays, I recommend reading through this previous article.
However, that doesn't mean I'm an advocate of reckless tanning to the point of getting burned. No, once you're sunburned, you've incurred skin damage, and that's certainly not advisable.
To maximize your vitamin D production while minimizing your risk of melanoma, seek to expose as much skin as possible to the sun during the middle of the day (roughly between 10:00am and 2:00pm).
During this time you need the shortest exposure time to produce vitamin D because UVB rays are most intense at this time. Plus, when the sun goes down toward the horizon, the UVB is filtered out much more than the dangerous UVA.
However, you need to be very mindful about the length of your exposure. You only need enough exposure to have your skin turn the lightest shade of pink. If you have very pale skin, this may only be a few minutes.
Once you reach this point your body will not make any additional vitamin D and any additional exposure will only cause harm and damage to your skin.
Most people with fair skin will max out their vitamin D production in just 10-20 minutes, or, again, when your skin starts turning the lightest shade of pink. Some will need less, others more. The darker your skin, the longer exposure you will need to optimize your vitamin D production.
To learn more about sunlight and vitamin D, including why I recommend getting your levels tested and how to use the sun for cancer prevention, please set aside an hour to watch my free lecture on vitamin D.
So remember, spending a little bit of time out in the sun on a regular basis is well advised, as it will optimize levels of one of your body's own natural defenses against cancer. Just be mindful of your exposure so you don't get burned.