Melanin Melanin by MAD Writer Productions Melanin is important because its the most primitive and universal pigment in living organisms. Melanin is produced in the pineal gland. Abundantly found in primitive organisms such as fungi, as well as advanced primates. Furthermore, within each living organism, melanin appears to be located in the major functional sites. For example, in vertebrates, melanin is not only present in the skin, eyes, ears, central nervous system, it can also be found in the pineal gland, pituitary gland, thyroid gland, thymus gland, adrenal gland, and the barathary gland. Melanin is abundantly present in the viscera, including the heart, liver, arteries, the muscles, and the gastrointestinal tract; thus, within each and every living organ which aids the human body melanin appears. Regardless of what color your skin appears to be all genes in all creatures on this planet are black because they are coated with melanin. The amount of melanin in the skin is one of the most variable of human traits, and many polygenes are involved.

Groups of people or the population of the world were once classified according to the skin shade: Black (Nubians), White (Caucasians), Yellow (Orientals) and Red (Native Americans) etc... We must realize that just because this is the way they have classified people does not mean this is the way it should be. The hues of color of your skin depend on several factors. First is the amount of melanin in the outer layers of the skin. Melanin acts as a filter to prevent damage to the delicate deeper layers of the skin, by penetration of ultraviolet light. There is more than one type of melanin. You have brain melanin, also known as neuromelanin, and you have skin melanin. Neuromelanin does not run parallel with skin melanin. Whether white, red, yellow, black, or brown, neuromelanin plays an important role in functioning of the brain, and nervous system. Melanosomes (small structures within the melanocyte cells where melanin is synthesized) find their way into the hair cells, giving them color. (Two types of melanin, one dark brown and one red, are responsible for all hair shades).

Pigments that contribute to skin color are called carotene, a yellowish hemoglobin, in blood vessels (pink-red), and melanin (black, brown, red). Darker skins are dominated by melanin, which is produced from the amino acid tyrosine, by pigment cells (melanocytes) in the skin. Melanocytes are characterized by long, fixed extensions of the outer cell membrane. In humans, other mammals, and birds, melanin is dispersed permantely throughout each melanocyte, including the extensions, and is also, transported to nearby skin cells. In other words, if you increase the amount of melanin in the skin you become darker and vice versa. So, what is so important about melanin? Melanin controls all mental and physical body activities. Melanin is an extremely stable molecule, and highly resistant to the digestion by most acids and bases, and is one of the hardest molecule to ever be analyzed. If you do not purify your melanin molecule, you will not heal your body of diseases. In parts of Africa, India, and Australia the deposits of melanin in the skin is heaviest because the people have been exposed to the most intense sunlight for generations.

Northern Europeans have the least amount of deposits in their skin are lighter, not to mention their weather is cloudy and cool. The thickness of the outer layer of the skin is also a factor. People with darker skin complexions have thicker layers of skin. And this is a factor alone enhances the skins filtering effect. The thinner the skin the least melanin. When the skin is very thin, the blood vessels show through and give a pinkish color. When an individual adapts to the shifting of the intensity of the sunlight, the skin becomes darker because they are exposed to more sunlight. Thats how you get suntans because its the result of both thickening and increasing the melanin in the skin. Keratin is the substance the nails of the fingers and toes are made of. It also appears in the outer layer of the skin. When keratin deposits are heavy, the skin has a yellowish, brown shade, as in the Mongolian populations. They have adapted along a different pathway to avoid the damaging effects of ultraviolet light. The reddish hue of the Native Americans results from a combination of keratin and melanin deposits. Now, you might be asking yourself what does melanin have to do with ultra-violet light?

Well, the DNA molecules are all covered with melanin. One of the things that melanin does is it actually absorbs ultraviolet radiation. Melanin is constantly reaching out towards the ultraviolet rays of the sun. Ultraviolet radiation has been found to be dangerous to protein. When protein is passed through ultraviolet radiation it actually causes the molecule to blend. Just like you have some of our sisters and brothers who go to hairdressers, killing their ethers just to get their hair done. No offence to those who do this type of activity so dont go off the deep end with me. Im not here to tell you what you should do or not do, because you have your own mind but if you choose to go to hair dressers and get up under these strange lights and you have to wear special kind of glasses with it because of the ultraviolet radiation. When your ethers are exposed to the chemical or protein structure in those perms and tents it causes it to lock into a certain position, then your hair will not change. Thats the same thing that happens to your chromosomes or genes.

When ultraviolet rays are exposed to the chromosomes or the genes, in order for your genes to be able to do what they are suppose to do naturally, they have to be able to change. But when they are exposed to ultraviolet radiation they cant. Thus when the time or need comes for it to change they will not be able to change. This will result in deformities in your body. Melanin can also be toxic. Eating the improper foods or overeating can block your connection with the suns energy. When the suns energy cannot reach the melanin, diseases manifest. Melanin is deranged only when it becomes toxic. Any individual who might have toxic melanin will act in a very similar manner, that which is primitive, animalistic, and barbaric. It is a civilizing chemical when it is not toxic. It has physical properties, and personality traits, which distinguishes it from others. Thats why our bodies are dedicated to making melanin. Vitamin B keeps melanin clean, not to mention good eating habits.

If you want to continue to consume pork, smoke weed, and drink alcohol thats your own business but your body is dedicated to making melanin, thus if you make it toxic, youre only hurting yourself. Melanin is like a superconductor, or like a battery in a car. It always stay charged when it is exposed to things such as light, sound, color, and sun light. It will absorb it to the point where the melanin will actually absorb the additional energy and recharge it- self to a brand new level. Your body has committed itself to creating melanin so you can survive. The melanin in your body is always partial charged. When you look around things like sound, light, sunlight, or colors, the melanin will absorb the additional energy, and recharge itself, taking your body to another level. If youre around sounds that arent good for you your body reacts to it. Your melanin can convert light energy to sound energy, thats why an entertainer like Michael Jackson, who was a big hit back in the days. What he was doing was using his melanin to convert light energy to sound energy.

Now that he is lacking melanin he hasnt been able to really get a big hit like in the past. People with melanin are walking radios and the very dark skinned people are very sensitive to the different types of radio frequency or thought patterns that are in the environment. So everything you do, everything you listen to, everything you eat affects you. It affects your melanin. What is melamine and how does it affect the human body? | eNotes What is melamine and how does it affect the human body? giorgiana1976 | College Teacher | (Level 3) Valedictorian Posted on January 17, 2010 at 11:43 PM Producers and consumers have been alerted that hundreds of tonnes of milk powder produced in China and used as an ingredient in the manufacture of baby milk formulas, but also as an ingredient in various food products for humans or animals contained melamine, added to falsifying chemical protein content from milk . Thus, producers get a "quality"commodity, without costs and their profits were high.

Chemical, melamine, is used in tanning the skin and affect the reproductive and urinary sytems, even in animals, and in this case was used by the chinese company to increase protein amount that the milk powder would have to bear, to pass the quality protein tests. Because the product is the cheapest of the Chinese market, extremely poor consumers are no longer bringing food safety issues. Six people died and more than 300,000 needed hospital treatment after poisoning with melamine. Physio-chemical characteristics of melamine fostering the enter in the urinary system, causing obstruction and preventing the proper disposal of urine, experts explained. Thus, not only urine is not removed properly from the body, nor blood flow within the kidney is not in normal parameters. In adults, ingestion of melamine is not as dangerous, although it is hard to do long-term predictions, just as there are no data to show how each body will react. European Union has set a maximum tolerable daily dose of 0.5 milligrams of melamine per kilogram body weight. In other words, for most adults there are no risk beyond that threshold, however, not all people react the same and it can not be said that is absolutely safe.

like 2 dislike 0 January 17, 2010 at 10:30 PM Melamine is a white, crystallized, organic compound. In manufacturing it is often mixed with formaldehyde to create a resin. It has been used to make dishes, white boards in classrooms, and for many other commercial items. I 2007 concerns about its use in manufacturing dishes became a concern after a large population of dogs became ill and many died as the result of using dog bowls made from melamine. The chemical had absorbed into the food. : Concern about Melamine in food contents in recent years began when the babies in China died from milk that was over laced with melamine content. The producers of the milk products had been adding it to the formula in order to make it appear that the formula had higher protein content. “Harmful if swallowed, inhaled or absorbed through the skin. Chronic exposure may cause cancer or reproductive damage. Eye, skin and respiratory irritant.” January 18, 2010 at 1:56 AM Melanin is a pigment found in human beings, plants and in animals.

In human beings melanin is responsible for skin colour and also found in hair, the pigmented tissue underlying the iris, the medulla and zona reticularis of the adrenal gland, the stria vascularis of the inner ear, and in pigment-bearing neurons within areas of the brain stem, such as the locus ceruleus and the substantia nigra. Dermal melanin is produced by melanocytes, which are found in the stratum basale of the epidermis. Some individual animals and humans have very little or no melanin in their bodies, a condition known as albinism. Both pheomelanin and eumelanin are found in human skin and hair, but eumelanin is the most abundant melanin in humans, as well as the form most likely to be deficient in albinism. like 1 dislike 2 Understanding Genetics Where do different skin colors come from? -A curious adult from California November 6, 2008 Human skin color can vary from almost translucent to almost black. This range of colors comes from the amount and type of a pigment called melanin found in the skin. There are two types of melanin--eumelanin and pheomelanin.

In general, the more eumelanin in your skin, the darker your skin will be. People who make more pheomelanin than eumelanin tend to have lighter skin with freckles. Like many other traits, the amount and kind of pigment in your skin is controlled by genes. The version you have of each of these genes work together to create the final product -- your skin color. To understand how this works, we'll talk about some of the genes that scientists have found that affect human coloring. And how some fish helped us find these genes! It is also interesting to think about why we have different skin colors. Later on, we'll see how vitamins and where your ancestors lived might have influenced what your skin color is. Melanin and Your Skin Melanin is made in special cells called melanocytes. These cells are found in the epidermis of your skin. There are at least three ways people can end up with different skin color. One way is if people make less pigment. Less pigment = lighter skin. Another way is when people have fewer melanocytes. Fewer melanocytes mean less pigment overall and so lighter skin.

The third way is a bit more complicated and has to do with the kind of pigment someone makes. There are two types of melanin. Eumelanin is black or brown pigment and pheomelanin is red or yellow pigment. People who make lots of pheomelanin tend to have lighter skin, often because of freckling. Freckles happen when melanocytes clump together. Melanocytes are usually spread pretty evenly in the skin. So when freckles form, some spots of the skin have lots of melanocytes (freckles) and other spots have few or none. Where there are no melanocytes, the skin is very fair. Skin Color Genes Scientists have figured out that several genes are involved in skin color. One of these genes is the melanocortin 1 receptor (MC1R). When MC1R is working well, it has melanocytes convert pheomelanin into eumelanin. If it's not working well, then pheomelanin builds up. Most people with red hair and/or very fair skin have versions of the MC1R gene that don't work well.

This means they end up with lots of pheomelanin, which leads to lighter skin. (For more information on MC1R and red hair, check this out.) Two other skin color genes were first identified in fish. One gene was found in stickleback fish and the other in zebrafish. Researchers studying the stickleback fish found that the kit ligand gene (kitlg) was different between dark and light stickleback fish. They also found that humans have different versions of this gene too! And that certain versions lead to lighter skin. The kit ligand gene is needed for the survival of melanocytes. So if a person (or a fish) has a version of this gene that doesn't work well, their melanocytes won't survive as well. Fewer melanocytes will mean less pigment. And so lighter skin. Researchers studying zebrafish with light colored stripes found another gene involved in human skin color, SLC24A5. The fish with light colored stripes had a version of this gene that didn't work well. When they looked in people, researchers found that some lighter skinned people also had a poorly working version of this gene.

Unlike the case with kitlg, scientists don't know for sure what SLC24A5 does. Some clues suggest that it may be important for moving calcium into cells. It may be that calcium is important for having more melanin in cells. Scientists have figured out that lighter skinned East Asians get their skin color mostly from a non-working version of kitlg. Northern European people with lighter skin often have a poorly working version of SLC24A5. A small number of pale northern Europeans get their skin color from a non-working MC1R gene. Although these three genes help to account for skin color differences between populations, there are probably other genes that scientists have yet to find. And scientists are hard at work to find the genes that make different people within a population have different colored skin. Think northern and southern Europeans. Or eastern and southern Asians. Why different skin colors may have evolved It is pretty obvious that people whose ancestors come from Northern Europe or Japan tend to have lighter skin than people whose ancestors are from sub-Saharan Africa or Australia. The reason for these differences may have to do with the amount of sunlight in each place. Sunlight can be pretty dangerous stuff because of its ultraviolet (UV) light.

UV light can do things like destroy folic acid or cause changes (mutations) in the DNA of some skin cells. Sometimes, these mutations can lead to skin cancer. So darker skin is helpful when there is a lot of sunlight. But sunlight isn't all bad. Sunlight can help our bodies make vitamin D. Everyone needs vitamin D and you have probably seen it in things like your milk. When we don't have enough vitamin D, it can cause problems with your bones. Vitamin D deficiency can cause things like rickets or osteoporosis. It has even been linked to some types of cancer. When our skin gets UV rays from the sun, our bodies use the UV light to make vitamin D. But melanin in our skin acts like a filter, making it harder for people with more melanin (darker skin) to make vitamin D. This means that the more melanin you have, the more sunshine you need to make enough vitamin D. Imagine you lived somewhere cold and dark. Your skin wouldn't see much sunshine. How would your body get enough sunshine to make all of the vitamin D you needed?

Well, if your skin had less melanin (which would make it lighter colored), then you would need less time in sunshine to make enough vitamin D! So it's possible that lighter skin evolved so that people in darker places were able to get all of the vitamin D they needed to stay healthy (and have kids). So the skin color you have might be a result of how much sun your ancestors got!* Now we know that skin color is just a matter of how much melanin you have. The versions of the skin color genes tell your body how much melanin to make. All of this means that the difference between dark and light skin is only a few changes in DNA! * Of course there are other theories too. Click here to learn more. Jamie Conklin How Does Melanin Affect Your Health? | LIVESTRONG.COM How Does Melanin Affect Your Health? by JOE KING, M.S. Last Updated: Jul 28, 2011 Joe King, M.S. Joe King began writing fitness and nutrition articles in 2001 for the "Journal of Hyperplasia Research" and Champion Nutrition.

As a personal trainer, he has been helping clients reach their fitness goals for more than a decade. King holds a Bachelor of Science in kinesiology from California State University, Hayward, and a Master of Science in exercise physiology from California State University, East Bay. Melanin determines skin tone and has other effects on the body. Photo Credit Ralf Nau/Lifesize/Getty Images Melanin is a compound derived from the amino acid, tyrosine. It provides pigment to most animals, including humans. In people, melanin determines skin color. People with high amounts of melanin tend to have darker skin, whereas people with less melanin have lighter skin. Melanin is also important for many different aspects of human health and has a wide range of effects on your body. Albinism People with little to no melanin in their skin suffer from a condition called albinism and are known as albinos. Albinism results from a deficiency in the enzyme required to produce melanin, causing a lack of pigmentation of the skin, eyes, ears and hair.

According to MayoClinic.com, people with albinism are at an increased risk for skin cancer because melanin acts as a natural sunblock, protecting your skin from the powerful UV rays of the sun. Neuromelanin There are several forms of melanin in your body, including neuromelanin, produced in your brain. Scientists do no fully understand the function of neuromelanin; however, its production appears to increase as you age. According to the European Synchrotron Radiation Facility, or ESRF, one proposed function of neuromelanin is that it helps your body maintain a balance of metals, assuring you do not have too much or too little in your blood stream, which can have negative consequences. Deafness Although not clearly understood, melanin appears to play a role in your ability to hear properly and is important for the overall function of your inner ear canal. According to a 1994 study published in the journal of "Pigment Cell Research," individuals who suffer hearing loss or are deaf lack adequate melanocytes, which are cells found throughout your body that are responsible for producing melanin.

According to the researchers, a lack of melanocytes in the inner ear results in cochlear impairment, or hearing loss, although the reason is not clear. Vitamin Deficiency High levels of melanin in your body increase your risk for developing a vitamin D deficiency, according to Palomar College. You obtain vitamin D primarily through sunlight. When you expose your skin to sunlight, the UV rays from the sun trigger vitamin D production in your body. Melanin blocks UV rays, leaving people with darker skin more susceptible to a vitamin D deficiency. This can cause other conditions such as rickets and osteoporosis. Related Searches Lose Weight. Feel Great Change your life with MyPlate by LIVESTRONG.COM GOAL Gain 2 pounds per week Gain 1.5 pounds per week Gain 1 pound per week Gain 0.5 pound per week Maintain my current weight Lose 0.5 pound per week Lose 1 pound per week Lose 1.5 pounds per week Lose 2 pounds per week GENDER Why do humans have different skin colors? - Healthy Skin - Sharecare Healthy Skin Why do humans have different skin colors? A Dr.

Mehmet Oz, MD , Cardiology (Cardiovascular Disease), answered While all humans have the same number of melanocytes (which produce melanin and determine skin color), those melanocytes produce different amounts of melanin. People who moved to northern climates needed more UV-B rays to make vitamin D so they produce less melanin. And over time that has gotten ingrained into the genome so northerners typically have less dark skin. Within 1,000 years of a population's migration from one climate to another, descendants have the correct color skin to protect and maximize nutrients. If you chart the evolution of skin color of populations living in one area for 500 years, the curve perfectly correlates UV radiation with skin color. The only exception are the Inuit, who have dark skin and hair even though they inhabit northern climates; that's because they eat lots of fatty fish, which provide vitamin D, so they don't need it from the sun. Our ancestors began migrating from northern Africa 250,000 years ago, so there has been lots of time for our skin types to adapt to our climate.

Find out more about this book: Human Biological Adaptability: Skin Color as an Adaptation is essentially unable to tan While skin tanning is often most noticeable on light complexioned people, even those with very dark brown skin can tan as a result of prolonged exposure to the sun. Some Northwest Europeans have substantially lost the ability to tan as a result of relaxed natural selection. Their skin burns and peels rather than tans. This is due to the fact that they produce a defective form of a skin protein Mc1r (melanocortin-1 receptor) which is necessary for the production of melanin. They are at a distinct disadvantage in tropical and subtropical environments. Not only do they suffer the discomfort of readily burning, but they are at a much higher risk for skin cancer. The same is true of albinos . It would be harmful if melanin acted as a complete shield. A certain amount of shortwave ultraviolet radiation (UVB) must penetrate the outer skin layer in order for the body to produce vitamin D. Approximately 90% of this vitamin in people normally is synthesized in their skin and the kidneys from a cholesterol-like precursor chemical with the help of ultraviolet radiation.

The remaining 10% comes from foods such as fatty fish and egg yolks. Simple vitamin D is converted by our bodies into two sequential forms. The last form, commonly referred to as vitamin D3, is needed for the intestines to absorb calcium and phosphorus from food for bone growth and repair. Calcium is also necessary in adults to maintain normal heart action, blood clotting, and a stable nervous system. New evidence suggests that vitamin D may help prevent a wide range of cancers, including those of the colon and breasts. Vitamin D plays an additional important role in promoting the production of cathelicidin, which helps to defend our bodies against fungal, bacterial, and viral infections, including the common flu. Too much ultraviolet radiation penetrating the skin may cause the breakdown of folate in the body, which can cause anemia . Folate is derived from folic acid (one of the B vitamins) in our food. Pregnant women who are deficient in folate are at a higher risk of having miscarriages and babies with neural tube defects . Because folate is needed for DNA replication in dividing cells, its absence can have an effect on many body processes, including the production of sperm cells.

It may be that the ability to produce melanin was selected for in our early human ancestors because it helped preserve the body's supply of folate in addition to reducing the chances of developing skin cancer. People who live in far northern latitudes, where solar radiation is relatively weak most of the year, have an advantage if their skin has little shielding pigmentation. Nature selects for less melanin when ultraviolet radiation is weak. In such an environment, very dark skin is a disadvantage because it can prevent people from producing enough vitamin D, potentially resulting in rickets disease in children and osteoporosis in adults. Contributing to the development of osteoporosis in older people is the fact that their skin generally loses some of its ability to produce vitamin D. Women who had prolonged vitamin D deficiencies as girls have a higher incidence of pelvic deformities that prevent normal delivery of babies. The Inuit people of the American Subarctic are an exception. They have moderately heavy skin pigmentation despite the far northern latitude at which they live. While this is a disadvantage for vitamin D production, they apparently made up for it by eating fish and sea mammal blubber that are high in vitamin D.

In addition, the Inuit have been in the far north for only about 5,000 years. This may not have been enough time for significantly lower melanin production to have been selected for by nature. In the United States and other developed nations, milk is now usually fortified with vitamins D and A in order to prevent developmental problems such as those described above. However, the popularity of carbonated soft drinks and other alternatives to milk along with a decrease in the amount of time spent outdoors has led to a considerable rise in the rate of rickets disease. Not surprisingly, vitamin D deficiency is most acute in the winter in temperate and colder zones, especially among people of African ancestry. There is a growing epidemic of vitamin D deficiency in the United States. The 2007-2008 "National Government Health and Nutrition Examination Survey" found that only 23% of teens and adults had a sufficient amount of this essential vitamin in their blood. It was 45% a decade earlier. The rate for African Americans in particular was far worse. It has dropped from 12% to only 3% having what doctors consider to be an adequate amount of vitamin D for overall good health.

Given this difference, it is not surprising that 15% African American women have pelvis deformities, while the rate among European Americans is only 2%. There is also a strong correlation between the amount of sunlight that children are exposed to and whether or not they will develop multiple sclerosis as adults. Most cases of this degenerative neural disorder are in the temperate regions of the world where the sunlight is rarely intense. Children growing up in tropical and subtropical regions rarely develop MS regardless of where their ancestors came from. This protection apparently continues for those who move to far northern or far southern regions after 16 years of age. What processes are responsible for this protection from MS and its possible relationship to skin color are unknown. New research by Nina Jablonski and George Chaplin has led to the discovery that women generally produce 3-4% less melanin in their skin than do men in all populations of the world. They suggest that this is probably due to the fact that women have far higher calcium requirements during their reproductive years. Mate selection preference and other cultural practices may also be partly responsible for this gender difference in skin coloration.

Nina Jablonski breaks the illusion of skin color --explanation of why humans have a wide variation in skin color around the world. This link takes you to an external website. To return here, you must click the "back" button on your browser program. (length = 14 mins, 46 secs) Skin Color Distribution Around the World Before the mass global migrations of people during the last 500 years, dark skin color was mostly concentrated in the southern hemisphere near the equator and light color progressively increased farther away, as illustrated in the map below. In fact, the majority of dark pigmented people lived within 20� of the equator. Most of the lighter pigmented people lived in the northern hemisphere north of 20� latitude, where ultraviolet radiation is much less intense on average. (Data for native populations collected by R. Biasutti prior to 1940.) Such a non-random distribution pattern of human skin color was predicted by Constantin Wilhelm Lambert Gloger, a 19th century German zoologist. In 1833, he observed that heavily pigmented animals are to be found mostly in hot climates where there is intense sunshine.

Conversely, those in cold climates closer to the poles commonly have light pigmentation. Presumably, the relative intensity of solar radiation is largely responsible for this distribution pattern. There are exceptions to Gloger's rule in the animal kingdom. In some species the survival value of having a camouflaged body can be more important than the selective pressures of ultraviolet radiation. This is the case with arctic hares, which are white like snow in the winter and mottled black, brown, and gray similar to the rocky ground in their region after the snow melts in the summer. These color changes make it more difficult for arctic foxes to prey on them. Among humans, mate selection preferences may counter some of the evolutionary trend in skin color predicted by Gloger. Ultraviolet radiation is also blocked to some degree by hair, clothing, smog, fog, smoke, clouds, and trees. The Inuit case described earlier suggests that diet may additionally be a significant factor in some societies.

NEWS: In the February 2007 issue of the Journal of Nutrition, a research team led by Lisa Bodnar of the University of Pittsburgh School of Public Health reported that among 400 first-time pregnant women from that city who participated in their study, only 16.1% of African Americans and 52.9% of European Americans had sufficient amounts of vitamin D in their blood to be considered healthy at the end of their pregnancies. This was despite the fact that more than 90% of them had regularly taken standard doses of prenatal vitamin supplements. Tests of umbilical cord blood indicated that only 7.6% of the African American infants and 33.9% of the European American ones had adequate amounts of vitamin D at birth. The authors concluded that prenatal vitamins should include higher doses of vitamin D, especially in the northern regions of the U.S. What is Melanin? What is Melanin? By Dr Ananya Mandal, MD Melanin is a complex polymer derived from the amino acid tyrosine. Melanin is responsible for determining skin and hair colour and is present in the skin to varying degrees, depending on how much a population has been exposed to the sun historically.

Melanin synthesis Numerous steps are involved in the biosynthesis of melanin. The first step is catalysis of the chemical L-3,4-dihydroxyphenylalanine by tyrosinase. A lack of tyrosine can lead to albinism. Tyrosine is only found in a specialized cells called melanocytes, inside which tiny granules of melanin pigment are contained in vesicles called melanosomes. These melanosomes leave the melanocytes and move into other cells in the epidermis. Mostly brown or black in colour, melanin deposits determine the skin pigment which varies depending on the number and distribution of the melanosomes. Aside from determining skin colour, the light absorbent melanin protects the DNA against UV radiation from the sun and it is considered a potential candidate in melanoma treatment.

Related Stories Melanin is found in several areas of the human body including: Skin where it provides skin color Hair Pupils or irises of the eyes Stria vascularis of the inner ear Areas of the brain, the substantia nigra and locus coeruleus The medulla and zona reticularis of the adrenal gland Types of melanin Some of the different types of melanin include eumelanin, pheomelanin and neuromelanin. Eumelanin is found in the hair, skin and dark areas around the nipples. It is particularly abundant among black populations and provides black and brown pigment to the hair, skin and eyes. When eumelanin is present only in small amounts, hair may be blonde. Pheomelanin is also found in the hair and skin. This type of melanin provides pink and red colors and is the main pigment found among red-haired individuals. This type of melanin is not as protective against UV- radiation induced cancer as eumelanin. Neuromelanin is a form of melanin found in different areas of the brain and loss of this melanin may cause several neurological disorders. Humans | Causes of Color Never burns, but tans very darkly.

African Americans, Africans, or dark-skinned individuals with heavy pigmentation. Balancing the benefits and the dangers of ultraviolet radiation for differing climates The darkest skin tones are found in tropical latitudes with open grassland, while areas further from the equator that are forested tend to favor lighter skin tones There is a striking correlation between geographic conditions, particularly exposure to sunlight, and skin tone. These differences have evolved to find the balance between the benefits and the dangers of the ultraviolet (UV) radiation we absorb from the sun. Early humankind living in the sun-soaked savannah plains of Africa developed a dark-toned skin, rich in the pigment melanin. Within the skin cells, melanin concentrates above the nucleus, shielding the vital DNA from radiation damage. In an environment where there is little to break the path of sunlight onto the skin, this barrier is a great advantage. There are other benefits to having a high concentration of melanin in the skin and other parts of the body. Melanin boosts the immune system, and darker-skinned groups have been shown to have a lower incidence of a number of serious diseases, including Parkinson’s, multiple sclerosis, and spina bifida.

Darker-skinned individuals also age better, as their skin is better protected from sun damage. Vitamin D and skin color: finding a balance It is the UV component of sunlight that helps the body utilize vitamin D. This vitamin helps promote bone growth, maintaining the right balance between calcium and phosphorus in the body. A deficiency of vitamin D leads to rickets and similar diseases. It seems that, as early peoples migrated away from the equator into areas less exposed to the sun, there was not enough UV radiation to produce sufficient vitamin D to prevent diseases such as rickets. Their bodies compensated by producing less melanin, so that more sunlight would be allowed through. They could then produce sufficient vitamin D with less exposure to sunlight. Light-skinned people visiting sunny locations may not have enough melanin to block the sun sufficiently, and may burn their skin without the protection of sunblock. Dark-skinned people visiting areas where there is less exposure to the sun may apparently not produce enough vitamin D, but can get it from supplements or food sources. Many foods such as milk and bread are now vitamin D fortified. As the distribution map of skin color shows, skin color variation is not deter mined purely by distance from the equator.

For example, people in snow-covered areas often have a dark skin tone. This may be because they are exposed to high levels of reflected UV radiation from the snow, or because their diet with its high proportion of fish is rich in vitamin D. Grains in breads and cereals are often fortified with vitamin D. Fish is a natural source of vitamin D. Light skin becomes darker when exposed to ultraviolet radiation. Tanning: darkening light skin The popularity of tanning seems cyclical, alternately being perceived as a healthy vibrant look and as a worrying reminder of the dangers of sunburn and carcinogenic melanomas. Light skin becomes darker upon exposure to ultraviolet radiation. Sunshine is the primary source of UV radiation, but artificial sources such as tanning beds produce similar effects. Skin is alive, so when melanin is destroyed by UV ra diation, the skin responds to this damage. Skin cells will produce more melanin, replacing what has been lost and increasing the percentage of melanin in the skin. This melanin has two effects, acting as a barrier to protect the skin from further damage, and darkening the natural color of the skin. Ultraviolet light produced in a tanning bed causes the same effect.

Melanogenesis is the name of the process where melanins are produced by specialized pigment cells called melanocytes, in response to UV radiation. Melanin in our skin protects our DNA from damage by UV radiation. This creates a long-lasting tan. A tan effect is also created when existing melanin is oxidized, but this doesn’t last as long. Regular tanning beds use several fluorescent lamps (see light bulbs and lamps ) that have phosphor blends designed to emit UV in a spectrum that is somewhat similar to the sun. The radiation produced is primarily UVA, with some UVB always being emitted, but the combinations of UVA and UVB can vary. Tanning bulbs are long fluorescent tubes, and fall into two main categories: low pressure lamps and high-pressure bulbs. Each bulb typically has a power between 100W and 200W. Alternative designs use high-powered parabolic lamps. The number of bulbs used by tanning beds vary: those designed for the home use 20 to 30 bulbs, commercial beds use 30 to 40 bulbs, and specialist stand-up booths use as many as 60 bulbs.

Tanning bed A tanning bed or sun bed (whether at home or in a salon) is a device emitting ultraviolet radiation used to produce a cosmetic tan. The World Health Organization (WHO) does not recommend the use of UV tanning devices for cosmetic reasons. Overexposure to UV radiation from the sun and artificial sources is of considerable concern for its adverse effects on health. UV radiation plays an important role in the development of skin cancer, cataracts, (see colorblindness ), and other eye conditions. It also suppresses the immune system. Cumulative UV radiation ages the skin prematurely. Tanning lotions An alternative method of darkening the skin is the use of tanning lotions. These lotions use a wide range of active ingredients. One of the original sunless tanning lotions caused streaking and an orange skin tone, which gave the fake tan a bad reputation. Lotions that contain dihydroxyacetone (DHA) as the active ingredient are used in many sunless tanning products. DHA, which is derived from plant sources like sugar beets and sugar cane, is a colorless sugar that interacts with the dead cells located in the stratum corneum of the epidermis.

As the sugar interacts with the dead skin cells, a color change occurs. This change usually lasts about five to seven days from the initial application. Another sunless tanning product is a tanning pill that contains canthaxanthin, most commonly used as a color additive in certain foods (see plants and other organic molecules ). While the FDA has approved the use of canthaxanthin in food, it does not approve its use as a tanning agent. When used as a color additive, only very small amounts of canthaxanthin are necessary. As a tanning agent, however, much larger quantities are involved. Upon taking the tanning pill, canthaxanthin is deposited all over your body, including in your skin, which turns an orange-brown color. Various side effects, including canthaxanthin retinopathy, a condition in which yellow deposits form in the retina of the eye, have been identified. Most tanning accelerators are lotions or pills that contain the amino acid tyrosine. The producers claim that the tyrosine stimulates and increases melanin formation, thereby accelerating the natural tanning process.

However, more scientific data is needed to determine the validity of these claims and to assess the safety of using large amounts of tyrosine. Another popular form of sunless tanning is the bronzer. These powders and moisturizers, once applied, create a tan that can easily be removed with soap and water. More like make-up, these products tint or stain your skin only until they are washed off. Lightening dark skin While some light skinned people tan or use cosmetic means to darken their skin, dark-skinned people may use cosmetic means to lighten their skin. This is an even more controversial process than tanning, as the desire for whiter skin is intertwined with issues of health, self-image, racial inequalities and colonial attitudes. The term skin whitening covers a variety of cosmetic methods used to lighten the skin’s color. Most skin-lightening treatments are aimed at inhibiting tyrosinase, to reduce or halt the production of melanin. Exfoliants such as topical cosmetics or chemical peels may be used, or the skin may be treated with lasers, depending on the response of the individual’s skin to treatment. As with some tanning products, there is some evidence suggesting that there are harmful side effects to skin-lightening products.

Question: In the human body, what does melanin determine?
Answer: Skin colour