The Sun & Skin Color
Human skin is an incredibly complex system. It is defined as a sensory organ, home to the somatosensory system, and is an integral part of protecting the rest of the human body from outside dangers, both small and large. The skin hosts a large range of bacteria, roughly about a thousand different species that are vital to keeping more dangerous bacteria out of the skin. The skin is also the organ that comes into most contact with the rays of the sun. This section will introduce the positive and negative effects that sun exposure can have on the skin, ranging from improving mental health to developing skin cancer, as well as discussing possible options to protect from the radiation damage.
Vitamin D Synthesis
When the sun comes into contact with the cells of the skin, a particular molecule known as 7-dehydrocholesterol within skin cells will be converted into previtamin-D due to the photon interaction. Then the liver and kidneys can further process this into vitamin-D, which is an incredibly important vitamin for physical as well as mental human health.
Vitamin D & Mental Health
Further exploring the causes and effects of sunlight exposure, studies show that individuals living in higher latitudes across the globe are more susceptible to suffering from Seasonal Affective Disorder (S.A.D.). These latitudes are known for their longer and colder winters, which result in less sun exposure. This lack of sun exposure would decrease the amount of vitamin D produced within the body due to the light emitted from the sun. Seeing that many researchers would agree that vitamin D is a key defense mechanism against depression, the result is that the less sun exposure, the less vitamin D naturally produced, thus negatively affecting an individual’s mental health. However, there are many foods and supplements that contain vitamin D that can also prevent Seasonal Affective Disorder.
UV Radiation
However, it’s not all sunshine when it comes to the interaction between the light photons of the sun and human skin. The light photons that are emitted by the sun consist of ultraviolet rays, which are capable of penetrating the cells in our skin and even damaging our DNA. The reaction of a sunburn that many individuals may experience after a long exposure to high intensity ultraviolet photons due to the sun is actually the result of an individual’s immune system. The immune system will break down the damaged cells via the lymphatic and circulatory system, and will signal for the healing process to occur. The reddening and inflammation of the affected area is due to this process.
Cell Response
Besides the mutated cells undergoing apoptosis, there are a handful of other responses that can occur due to cell damage. The DNA within these cells can be repaired if possible, or if the damage is so negligible to the effectiveness of the cell it may just be left as it is. However, occasionally a mutated cell can slip through the cracks of the immune system’s repairs as well as avoiding apoptosis, and continue to grow and divide uncontrollably. This process, an ungovernable mutated cell growing rapidly, can lead to the development of skin cancer. Excess sun exposure and UV radiation can also break down folate (also known as Vitamin B-9). Folate is a molecule present in skin that is responsible for assisting in the repair of damaged skin cells. So not only can UV radiation damage skin cells, but it also damages an essential molecule that is capable of repairing the damages.
However, there are multiple defense barriers to protect the skin from this event occurring. Firstly, within the skin there are melanocyte cells, which are responsible for creating eumelanin, which is one of the pigments that gives skin its color. This eumelanin is transported around other skin cells within enveloping cells referred to as melanosomes. This eumelanin plays a key role in protecting the body against harmful synthesis of UV radiation, as it blocks the UV radiation from damaging the DNA.
Defenses Against UV
There are other defenses that individuals can take when it comes to protecting from harmful UV radiation from the sun. The application of sunscreen is another definitive way to protect one’s self from the harmful effects of the sun’s rays, especially for those who don’t produce as much eumelanin and have a lighter skin tone. Sunscreen rests on the surface of the skin, and when hit with UV Radiation, causes the light to ‘bounce’, or scatter from the surface instead of penetrating it and interfering with the DNA within the cells.
The sun is an integral part of human’s capability to survive, however too much exposure can lead to harmful results. On one hand, too little sunlight is shown to play a role in mental health anomalies, Whereas too much sunlight leads to DNA mutations and can ultimately cause skin cancer. There is a fine line between too much and too little exposure to the light from the sun. However, there are defenses one can take to protect themselves from the harmful rays and still be able to reap the benefits sunlight can provide for one’s health; both natural eumelanin and applied sunscreen are important to staying safe on a warm, sunny day.
