The Good, the Bad and the Ugly

[RAISE HAND] Who here feels more ENERGIZED when the SUN is out? Don’t we all enjoy soaking in the sun? Don’t we feel happy when the sun is out? Today I will be talking about the sunlight which travels MILLIONS OF MILES and puts a BIG SMILE on our faces. Bright light from the sun makes everything look more vibrant and energetic. Warmth from the sun gives us comfort. But there is a part of the sunlight that we don’t see or feel, the part of the sunlight that is invisible to us, THE ULTRA VIOLET LIGHT.

Today I am going to talk about this Ultra Violet light and how it INTERACTS WITH OUR BODIES. Ultra Violet light or the UV light has three types of rays: UVA, UVB and UVC. [Show the diagram]

·         UVC rays have the shortest wavelength and highest frequency of all the UV rays. They have the most energy and they are the deadliest. But the good news is that they are completely blocked by the Ozone layer and the atmosphere. Therefore, we don’t have to worry about the UVC rays.

·         UVB rays have the medium wavelength and most of the UVB rays are blocked by the Ozone layer and the atmosphere. Only a small percentage (about 5%) reaches the surface of the earth.

·         UVA rays have the longest wavelength and are not blocked by the atmosphere and the Ozone layer. 95% of the total UV radiation reaching earth’s surface consists of UVA rays.

HOW DOES THIS UV RADIATION INTERACT WITH OUR BODIES? Before I get into that, let me ask you a question. How many of you have heard this or said this to someone? “I AM OUT IN THE SUN MAKING VITAMIN-D”.

Yes, our bodies can make Vitamin-D from the sunlight. That’s why Vitamin D is called the SUNSHINE VITAMIN. UVB RAYS are the ones that catalyze the production of this Vitamin.

HOW DO OUR BODIES CREATE THIS VITAMIN?

[Show the diagram of Vitamin D creation and explain]

Let’s say we are outside and we have our bare skin exposed to the sun. What happens UVB ray from the sun strikes our bare skin, it interacts with an enzyme 7-dehydrocholesterol in the skin to form Vitamin-D3 (Cholecalciferol). So, the type of Vitamin D made by our skin from the sun is Vitamin D3.

IT’S MADE IN THE EPIDERMIS, THE LAYER OF THE SKIN JUST BELOW THE SURFACE.

This Vitamin D3 travels down to the liver through the blood stream where it gets converted to 25-Hydroxyvitamin D3. Then this travels down to the kidney via blood stream where it gets converted to an active form called 1,25 Dihydroxyvitamin D3. This is the active or hormonal form of Vitamin D that maintains calcium balance in the body which promotes healthy bones and teeth.

PAUSE… DRINK WATER

People commonly think that if they are out in the sun they are getting Vitamin D. But that’s not always the case. There are many factors which can affect our skin’s ability to make Vitamin D.

·         Cloud cover

·         Glass

·         Clothing

·         Pollution

·         Sunblock

·         Altitude of the sun

ON A CLEAR SUNNY DAY WHEN YOU ARE OUTSIDE, ALTITUDE OF THE SUN IS THE DECIDING FACTOR. Altitude is the angle of the sun measured above the horizon. 90% altitude means that the sun is directly overhead. This altitude needs to be 50 degrees or greater to make Vitamin D creation possible.

Ideally, the sun should be as close to overhead as possible; the closer to overhead it is, the greater its potential for producing Vitamin D. If your shadow is short than how tall you are that means sun’s angle is right for Vitamin D creation!

In winter in much of North America altitude of the sun never becomes more than 50 degrees so it’s impossible to make Vitamin D during any time of the day because the sun is not high enough in the sky.

If your body is producing Vitamin D in the sun you don’t make an endless amount of it. Our bodies know when to stop making it when sufficient amount has been made.

So, this is the good part: Your body makes Vitamin D from UVB rays.

BUT WITH ALL GOOD COMES BAD!

The same UVB rays which makes this COOL VITAMIN also DOES DREADFUL DAMAGE TO OUR DNA. UVB rays penetrate the outer layers of our skin and are responsible for skin burns and EVEN SKIN CANCER.

UVA RAYS also contribute to the DAMAGE. UVA rays are not blocked by the atmosphere. They even penetrate through glass and clothing.  They penetrate the deepest layers of the skin and gives our skin an instant tan.  These UVA rays contribute to skin ageing and wrinkling which makes us look OLD AND UGLY!

I hope you have a better understanding now of different types of Ultra Violet radiation from the sun and how they interact with our bodies in good, bad and ugly ways.