In part 1 – we got to know the UV index and how it works. In this part 2 of the Sun Smart Series, we continue with learning about our skin and how it reacts to the UV radiation from the sun.
In this series we will be exploring first the basics of our skin and how the famous melanin pigment works in darkening our skin as a protection against the sun. After this we will look at the dangers of tanning and burning in terms of skin cancers. Finally we will also be examining the link between our skin and Vitamin D production.
Part 2 – Get to Know your Skin
Our skin is the largest organ of our body and is part of the system of organs called the integumentary system. First and foremost it acts as a protective cover for our body offering protection against things like microorganisms and harmful substances. Amongst its many other jobs our skin also produces for us the very critical vitamin D.
The skin is made up of 2 layers: the outer and thinner epidermis, and the inner and thicker dermis. New skin cells are made from the inner layer and hence older cells are pushed further out and eventually die and get sloughed off through our normal everyday activities. In healthy individuals, production of new cells is closely balanced with the loss of lost dead cells.
The epidermis itself is composed of five layers. These are from the outer one to the inner one: i) Stratum corneum, ii) Stratum lucidum, iii) Stratum granulosum, iv) Stratum spinosum and v) Stratum basale.
The epidermis also contains special cells called melanocytes that produce the dark pigment we all associate with skin color called melanin. Melanocytes can be found in the deepest layer of our epidermis the basal layer (Stratum basale) as well as in the deeper dermis.
The task of melanin is to absorb the UV radiation from sunlight and thus preventing it from causing mutations in the DNA of skin cells. There is an increased level of melanin released as our exposure to the sun increases and this is what we came to know as the “sun tan”.
How does a Sun Tan and Sun Burn Work?
The more time we spend in the sun and the more prolonged each exposure is the more our body adapts to protect us from the harmful UV radiation. Hence increased time in the sun leads to a darker skin (a tan) as more melanin is produced.
Increased time in the sun also thickens our outermost epidermal layer that is first to have contact with the sun. If the tanning is continuous, constant or done over many years it leads to a leathery texture of the skin and wrinkling as skin loses its elasticity.
If our sun exposure is extreme (i.e. spending a long time in direct sunlight or a short time in a high UV index condition) a sun burn may result.
A sun burn is an inflammatory reaction of the skin after excessive UV exposure. It leaves the skin red, swollen and painful to the touch.
To try and overcome this stressful situation, after a few days the skin may peel. This is one of the body’s automatic defense reactions to help itself. Skin peeling ensures that the damaged cells are lost so that the mutations they incurred do not spread and cause cancer.
Depending on the severity of the sun burn the skin may not heal properly for a few weeks, months or in some cases years and have permanent damage.
Sun burns heavily damage our skin but they may also result in a wide array of other unpleasant symptoms.
How does Skin Cancer Form?
Cancer is a mutation in the DNA of cells that cause them to reproduce at uncontrolled rates. These mutations can be induced by many substances and conditions, one of them being the UV radiation from the sun.
Both sun tans and sun burns can lead to skin cancers. Where it was once the “in” thing in society to be as white as possible, it is now and has been for the past few decades where the “in” thing is not to have “white” skin but to be “tanned”. This trend is however quickly collapsing as more and more people are facing the horrible truths of sun damage and skin cancer.
Generally speaking the lighter ones skin color is, the more that individual has to be careful with the sun as they have a higher than average risk of skin cancer (i.e. darker people have more of the protective melanin to begin with than white, fair skinned people).
Since our skin is exposed to UV light almost on a daily basis, there are always mutations happening but at a low rate. Under these conditions our body, thanks to many of its amazing reactions fixes these mistakes and mutations. However, when we undergo excessive or continuous mutations, the body cannot keep up with all the repairs and hence a cancer may result.
Types of Skin Cancers
Skin cancers that originate from epithelial cells are called Cutaneous Carcinoma (Basal Cell Carcinoma or Squamous Cell Carcinoma. Cutaneous cancers are the most common type of skin cancer. They occur most often in light skinned people in their later years of adulthood (i.e. 40′s) who have undergone regular exposure to the sun. These cancers are usually the less serious ones as they are localized (noninvasive), slow growing and are usually able to be removed using surgery or radiation.
Skin cancers that originate from melanocyte cells are called Cutaneous Melanoma or Malignant Melanoma. This is the more serious type of skin cancer as it can spread and grows faster. People of any age can develop this type of skin cancer and the risk increases greatly from short, intermittent, high intensity sun exposure. Thus risk of this increases in people who generally stay indoors and endure sun burns.
This cancer can be removed surgically if caught early. Otherwise it spreads deeper and offers a low survival rate to its patients.
Melanoma has been on the rise worldwide now for the past 20 years. Hence the best practice is to visit a dermatologist annually for a skin/mole check as early detection can save your life.
What about Vitamin D?
One of our skin’s many functions is to produce the fat soluble vitamin D. This vitamin is necessary for proper bone and tooth development among many other things and has got a lot of attention in the media in the past few years as being linked to the prevention of several cancers, including breast, colon and lung cancers and other ailments like arthritis.
In our body vitamin D is produced from a substance called dehydrocholesterol (provitamin D) that is synthesized by cells in our digestive system. When this compound reaches the skin by means of our blood stream and is exposed to UV light from the sun, it is changed into vitamin D through a series of biochemical reactions.
Thus, by reducing our exposure to the sun or by constantly covering up our bodies with sunblock when outside we are preventing this critical set of reactions from taking place.
And sure one can try to get their vitamin D in through their diet, but this is not always easily attainable as synthetic sources are not absorbed as efficiently by our system and often people are not aware of which foods have what amounts of vitamin D to cover their requirements.
Helpful Links & Stats
- Skin cancer is the most common cancer in Canada
- The occurrence of skin cancer in Canada has been steadily increasing over the past 30 years
Canadian Dermatology Association
Canadian Skin Cancer Foundation
Health Canada – Skin Cancer Prevention
- Skin cancer is the most common cancer in the United States
American Academy of Dermatology
- Worldwide 1 out of every 3 cancers diagnosed is skin cancer
Conclusion
There are 2 challenges hence that face the average citizen today:
- Not spending enough time out in the sun each day (i.e. at least 15 minutes to get the vitamin D necessary
- Weighing the risks and benefits between spending time in the sun for vitamin D production and at the same time not sustaining skin damage or getting skin cancer
By the end of the week we will address these challenges as we get the whole story on the sun and you! For now, regardless of your age or skin color, but especially if you have never had a skin exam or sustained sun damage, I highly recommend booking an appointment to get a general idea about the health of your skin. In today’s times it may turn out to be a matter of life and death.
In the next article we will be looking getting to know the sun and why you have to take sun exposure today very seriously versus how it was some years or decades ago.
5 Part Sun Smart Series
Part 1 – Get to know the UV index
Part 2 – Get to know Your Skin
Part 4 – Get to know Sunscreen
Part 5 – Summary: Maximize the Benefits, Minimize the Risks
*Photograph provided by freebird4
About the author:Evita Ochel, B.Sc., B.Ed., CHN - is a certified holistic nutritionist, biologist, educator, writer, researcher and speaker in the areas of health, science and holistic wellness. She is a nutritional science expert and her teaching and writing focus on natural, wholesome, plant-based and organic nutrition to achieve optimal health and longevity. Learn more about Evita Ochel or Follow Evita Ochel on Twitter.
