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Why Do People Have Different Skin Colors

by Lyndon Langley
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Why Do People Have Different Skin Colors

Why Do People Have Different Skin Colors

The skin is our largest organ, covering about two thirds of our body surface area. It’s also one of the most complex tissues in the human body. It has several functions that range from protecting us against ultraviolet (UV) radiation to regulating temperature. In addition, it provides a sense of touch, allows for sensation, helps regulate body fluid balance, and acts as an immune defense system.
Our skin plays such an important role that we often take its appearance for granted. Yet, just like other parts of our bodies, our skin changes over time. For example, while your skin may look healthy now, you can develop age spots or liver spots later on. This happens when cells accumulate damage caused by environmental factors, such as sun exposure, smoking, and poor nutrition. As people get older, they’re more likely to experience these degenerative conditions. However, there are many ways to slow down this process. You can use cosmetics, moisturizers, and sunscreen lotions to improve the health of your skin.
Another thing you might not know is that your skin color doesn’t stay the same throughout life. While some people have light-colored skin with few freckles, others start out dark-skinned but end up having pale skin. Why does this happen? And why do people have different skin colors? To understand this phenomenon, let’s first consider how our skin gets darker.
Melanocytes Produce Melanin
Your skin pigment comes from melanin, a brownish substance made by specialized cells called melanocytes in the outer layer of your skin. Melanocytes contain granules filled with melanosomes, structures that help form melanin. These melanosomes absorb nutrients, including amino acids, vitamins, minerals, and other chemicals, which then combine into melanin. When this chemical reaches certain levels, your melanocytes release the pigment onto the skin’s surface where it becomes visible.
So what determines whether your skin will be lighter or darker? The answer lies in genes, specifically those that control melanocyte activity and melanogenesis, the production of melanin.
Genetics Affect Human Skin Color
In humans, pigmentation isn’t determined solely by environment; genetics play a big part. There are multiple types of genes involved. One type controls the number of melanocytes, another regulates the structure of melanin, and yet another affects the rate at which melanocytes create melanin. So far, scientists have identified 10 genes that affect skin color. Together, they determine the level of melanin produced.
A gene known as MC1R controls how much melanin forms in your melanocytes. If you inherit a mutated version of MC1R, you’ll have dark skin, even if you don’t have any family members who share the trait. Mutations in this gene cause OCA, a disorder characterized by hypopigmentation, or underpigmented patches, all over the body.
Other genes associated with OCA include TYRP1, DCT, MITF, SLC24A5, PDE6B, and GNA11. Mutations in these genes result in oculocutaneous albinism, a condition in which babies are born without enough normal melanin in their skin, hair, and eye color. Children with oculocutaneous albinism typically suffer from poor vision due to cataracts, and they need regular medical treatment for hypertrichosis lanuginosi, excessive growth of coarse black hairs.
Heredity can also affect skin coloration. A gene called ASIP determines whether your skin will become tan or burn after being exposed to UV rays. If you have mutations in ASIP, you could easily burn yourself if you go swimming outdoors during peak sunlight hours.
Besides playing a key role in determining skin color, melanin also contributes to your overall health. Research shows that high levels of melanin protect against cancer and heart disease.
Skin Color Changes Over Time
Although heredity largely dictates how darkly colored your skin will turn, external factors can still influence your skin tone. Exposure to UV radiation, especially from solar radiation, causes melanin to break down. This results in the formation of free radicals, molecules that destroy melanin and lead to wrinkling, aging, and skin cancer. On top of that, the presence of certain hormones, such as estrogen, can increase the risk of developing melanoma, a deadly form of skin cancer.
Sunlight also triggers inflammation in the skin, causing the release of cytokines, chemicals that tell the immune system to bring in white blood cells to fight off infections. The reaction releases oxygen radicals that attack melanin, resulting in a decrease in skin tone.
Smoking increases the production of reactive oxygen species in the lungs, leading to premature aging and lung diseases. Smoking also leads to the loss of collagen fibers and elastin, both components of connective tissue.
And finally, obesity is closely linked to skin discoloration. Excess fat around the waistline can make the skin appear duller and less hydrated. In severe cases, excess weight can even change the shape of the face. Since obese people tend to have higher cholesterol levels, fatty substances can build up in the deeper layers of skin, making them harder to remove through washing alone.
Now that you’ve learned how skin color develops naturally, read on to find out how you can manipulate your skin’s appearance.
You can choose to eat foods rich in antioxidants, which reduce the harmful effects of free radicals. Foods containing vitamin E, selenium, carotenoids, lycopene, lutein, zinc, and beta-carotene offer protection. Antioxidants neutralize free radicals before they inflict harm. They do so by donating electrons, preventing oxidation reactions and restoring cell membranes damaged by free radicals. Examples include broccoli, spinach, green peppers, watermelon, corn, tomatoes, cantaloupe melon, peaches, papayas, mangoes, oranges, pears, and plums.
Dietary Supplements May Help Protect Your Skin From Sun Damage
If you want to keep your skin looking young and healthy, you should try taking dietary supplements that provide antioxidant protection. Many people believe that eating lots of fruits and vegetables can prevent skin problems. But there are also specific foods that research suggests can help shield your skin from the sun’s damaging rays.
Here are five common foods that may provide beneficial amounts of antioxidants.
Vitamin C — Vitamin C reduces the risk of getting wrinkles and skin cancers. It protects DNA from UV radiation and prevents it from breaking down prematurely. Researchers say it also improves collagen synthesis and elastic fiber strength.
Saw Palmetto extract — Saw palmetto berry oil contains compounds that block hormone receptors that signal melanin production. Studies show that saw palmetto extracts lower the amount of melanin produced by melanocytes in laboratory experiments.
Green tea — Green tea contains polyphenols, natural plant compounds that act as powerful antioxidants. Polyphenols react with free radicals that attack your skin and convert them into harmless products. Drinking green tea regularly has been shown to reduce the risk of skin cancer and boost immunity.
Pomegranate juice — Pomegranates contain flavonoids, pigments that give them their red color. Flavonoids are effective scavengers of harmful free radicals, particularly singlet oxygen, which reacts with unsaturated fats in the skin to form peroxides. Peroxide breaks down proteins, lipids, and nucleic acids. Singlet oxygen is responsible for damaging cell walls, killing enzymes, and depleting the supply of ATP in vital organs. Scientists at Harvard Medical School found that drinking a glass of concentrated pomegranate juice improved the flow of blood and oxygen to the brain and prevented cognitive decline among patients suffering from Alzheimer’s disease.
Anthocyanins — Found in blueberries, purple cabbage, eggplant, and potatoes, anthocyanins protect skin from UV rays. They also strengthen capillaries, helping deliver more oxygenated blood to the skin’s deepest layers. Anthocyanins’ protective effect appears to last long after you stop eating them, possibly explaining why wild blueberry consumption lowers the frequency of cardiovascular events.
(Source: National Institutes of Health.)

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