Facts You Need to Know About Sunlight and Skin Cancer

Noted expert Dr. John J. Cannell discusses the powerful benefits of vitamin D. Safe sun exposure may be the best thing for your skin, no matter what you may have heard! 


Vitamin D Dose Recommendations
Age Dosage
Below 5 35 units per pound per day
Age 5 - 10 2500 units
Adults 5000 units
Pregnant Women 5000 units
There is no way to know if the above recommendations are correct. The ONLY way to know is to test your blood. You might need 4-5 times the amount recommended above. Ideally your blood level of 25 OH D should be 60ng/ml.
Dr. Mercola's Comments:

In this video, Dr. John Cannell -- one of the leading authorities on vitamin D and founder and Executive Director of the Vitamin D Council -- sheds additional light on what several studies have already confirmed: that appropriate sun exposure actually helps prevent skin cancer. In fact, melanoma occurrence has been found to decrease with greater sun exposure, and can be increased by sunscreens.

One such study discovered that melanoma patients with higher levels of sun exposure were less likely to die than other melanoma patients, and patients who already had melanoma and got a lot of sun exposure were prone to a less aggressive tumor type.

How can this be? Experts are still recommending caution when going out in the sun, and the science still points to the fact that skin cancer is caused by sun exposure. 

As Dr. Cannell explains, the sun does increase genetic damage in your skin and can cause skin cancer, but nature has designed a clever system to obviate this risk. And by staying out of the sun entirely, you avoid the system nature created to help prevent skin cancer.  

As you probably know by now, vitamin D is formed in your skin from exposure to sunlight. The vitamin D then goes directly to the genes in your skin where it helps prevent the types of abnormalities that ultraviolet light causes. Hence, when you avoid the sun entirely, or slather on sun block whenever you go out, your skin is not making any vitamin D, and you’re left without this built-in cancer protection.

But you’re not only raising your risk of skin cancer by shunning the sun.

Optimizing your vitamin D levels can help you to prevent as many as 16 different types of cancer including pancreatic, lung, breast, ovarian, prostate, and colon cancers. And vitamin D does not have just a slight impact on your cancer risk. It can cut your risk by as much as 60 percent!

Its protective effect against cancer works in several ways, including: 

  • Increasing the self-destruction of mutated cells (which, if allowed to replicate, could lead to cancer)
  • Reducing the spread and reproduction of cancer cells
  • Causing cells to become differentiated (cancer cells often lack differentiation)
  • Reducing the growth of new blood vessels from pre-existing ones, which is a step in the transition of dormant tumors turning cancerous 

To Prevent Skin Damage You Have to Protect Against the Most Damaging Rays

Ultraviolet light from the sun comes in two main wavelengths – UVA and UVB.  The difference between them is part of the equation, so it’s important for you to understand the difference between the two.

UVB can be considered the ‘good guy’ that helps your skin produce vitamin D.

UVA is considered the ‘bad guy’ because it penetrates your skin more deeply and causes more damage.  Not only that, but UVA rays are quite constant during ALL hours of daylight, throughout the entire year -- unlike UVB, which are low in morning and evening, and high at midday.

If you’ve ever gotten sunburned on a cloudy day, you now understand why; it’s from the deeply penetrating UVA!

The exposure you’re looking for is the exposure to UVB’s, which are at their greatest during midday, when the sun is at its highest in the sky. This is what Dr. Cannell refers to in this interview when he says you need to expose your skin to the high-noon sun -- which is contrary to conventional advice, which says to avoid tanning during “peak” hours.

You also need to be aware that you need far less sun exposure than you might think to reap its beneficial effects.

Most people with fair skin will max out their vitamin D production in just 10-20 minutes, or 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.

For more detailed guidelines on safe and appropriate sun exposure, please see my previous article, Vitamin D in Your Skin.