Skin Types

Skin types are described according to the level of natural
pigment and how it reacts to sunshine. There are six main skin types:

Skin Type I: Always burns and never tans.

This skin type is the most sensitive to ultraviolet radiation
(UVR) and most at risk of sunburn and skin cancers. Persons with this
skin type are unable to develop a tan and usually learn very quickly
how to protect themselves from sunburn. Frequently freckles will
develop when exposed to sunshine which fade during the winter months.
Severe sun damage in this skin type can appear as permanent freckling,
especially on shoulders, face and arms. Red hair and green eyes are
associated with this skin type. Effective sun protection is vital
throughout life, especially babies and young children. Persons with
this skin type should never use a sunbed.

Skin Type II: Frequently burns, sometimes tans

Persons with skin type II are also at risk of sunburn and skin
cancer. Skin cancers are common in this skin type due to individuals
persistently attempting to develop a tan. Sometimes they are successful
but this usually happens after sunburn has occurred. Burning should be
avoided at all costs, therefore sun protection and sunscreens are
important when exposed to sunshine. Fair hair and blue eyes are
associated with this skin type.

Skin Type III: Frequently tans, sometimes burns

This skin type is slightly more tolerant to ultraviolet rays
and tanning is possible. Many people in Britain have a mixture of skin
types II and III, although darker hair and eyes are associated more
with skin type III. Sun protection is required to avoid sunburn and
prevent premature ageing of the skin. Frequent burning occurs during
unexpected bouts of hot weather when the skin is unprepared for the
intensity of sunshine.

Skin Type IV: Always tans, never burns.

Persons with this skin type have tolerant skin when exposed to
sunshine and usually have dark brown hair and eyes. Fortunately burning
is extremely rare which reduces the risk of melanoma skin cancer.
However, prolonged exposure to sunshine rapidly ages the skin and
causes blotches, dryness and wrinkles. Non-melanoma skin cancers may
also develop following years of sun exposure. Therefore it is advisable
to protect skin with clothing, hats and sunscreens.

Skin Type V & VI: Asian and black skin

These skin types are very tolerant to sunshine. However it is
important to remember that burning can still occur if living in
Britain.

Human skin color

Human skin color can range from very dark to nearly colorless (appearing pinkish white due to the blood in the skin) in different people. Skin tone is determined by the amount and type of the pigment melanin in the skin. On average, women have slightly lighter skin than men.

In general, people with ancestors from sunny regions have darker skin than people with ancestors from regions with less sunlight. However, this is complicated by the fact that there are people with ancestors from both sunny and less sunny regions, and whose skin coloring may have any shade of the spectrum of possible tones. Sexual selection also plays a role.

Melanin and genes

Melanin comes in two types: pheomelanin (red) and eumelanin (dark brown to nearly black). Both amount and type are determined by four to six genes which operate under incomplete dominance. One copy of each of those genes is inherited from the father and one from the mother. Each gene comes in several alleles, resulting in a great variety of different skin tones.

Dark skin protects against those skin cancers that are caused by mutations in skin cells induced by ultraviolet light. Light-skinned persons have about a tenfold greater risk of dying from skin cancer under equal sun conditions. Furthermore, dark skin prevents UV-A radiation from destroying the essential B vitamin folate. Folate is needed for the synthesis of DNA in dividing cells and too low levels of folate in pregnant women are associated with birth defects.

While dark skin protects vitamin B, it can lead to a vitamin D deficiency. The advantage of light skin is that it does not block sunlight as effectively, leading to increased production of vitamin D₃, necessary for calcium absorption and bone growth. The lighter skin of women may result from the higher calcium needs of women during pregnancy and lactation.

The evolution of the different skin tones is thought to have occurred as follows: the haired ancestors of humans, like modern great apes, had light skin under their hair. Once the hair was lost, they evolved dark skin, needed to prevent low folate levels since they lived in sun-rich Africa. (The skin cancer connection is probably of secondary importance, since skin cancer usually kills only after the reproductive age and therefore does not exert much evolutionary pressure.) When humans migrated to less sun-intensive regions in the north, low vitamin D₃ levels became a problem and light skin color re-emerged.

Dark-skinned people who live in less sun-intensive regions often lack vitamin D₃, one reason for the fortification of milk with vitamin D in some countries.

The Inuit and Yupik are special cases: even though they live in an extremely sun-poor environment, they have retained their relatively dark skin. This can be explained by the fact that their traditional animal-based diet provides plenty of vitamin D.

Albinism is a condition characterized by the absence of melanin, resulting in very light skin and hair; it is caused by a genetic mutation.

Skin tone has sometimes been used in an (often controversial) attempt to define human races; see also racism. On a cultural level, "Color" terminology for race have evolved based upon genetic variations in human skin tone and changing customs or traditions of what arbitrary criteria and the amount of categories to use.

This article is licensed under the GNU Free Documentation License.
Last updated on Monday May 28, 2007 at 10:51:06 PDT (GMT -0700)

What is Skin?

Skin

Wikipedia, the free encyclopedia - Cite This Source

On zootomy and dermatology, skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs. As the interface with the surroundings, it plays the most important role in protecting (the body) against pathogens. Its other main functions are insulation and temperature regulation, sensation and vitamin D and B synthesis. Skin is one of the most important parts of the body.

Skin has pigmentation, or melanin, provided by melanocytes, which absorb some of the potentially dangerous ultraviolet radiation in sunlight. It also contains DNA repair enzymes which help to reverse UV damage, and people who lack the genes for these enzymes suffer high rates of skin cancer. One form predominantly produced by UV light, malignant melanoma, is particularly invasive, causing it to spread quickly, and can often be deadly. Human skin pigmentation varies among populations in a striking manner. This has sometimes led to the classification of people(s) on the basis of skin color.

Mammalian skin often contains hairs, which in sufficient density is called fur. The hair mainly serves to augment the insulation the skin provides, but can also serve as a secondary sexual characteristic or as camouflage. On some animals the skin is very hard and thick, and can be processed to create leather. Reptiles and fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough β-keratins. Amphibian skin is not a strong barrier to passage of chemicals and is often subject to osmosis. A frog sitting in an anesthetic solution will quickly go to sleep.

The skin is known as "the largest organ of the human body". This applies to exterior surface, as it covers the body, appearing to have the largest surface area of all the organs. Moreover, it applies to weight, as it weighs more than any single internal organ, accounting for about 15 percent of body weight. For the average adult human, the skin has a surface area of between 1.5-2.0 square meters, most of it is between 2-3 mm thick. The average square inch of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than a thousand nerve endings.

The use of natural or synthetic cosmetics to treat the appearance of the face and condition of the skin (such as pore control and black head cleansing) is common.

 

Rising Skin Cancer...

Skin Cancer is on the rise throughout the world, the rising skin cancer rates are more likely to affect wealthy people...

 

Here is a report on Skin Cancer form Science Daily

http://www.sciencedaily.com/releases/2007/06/070611100602.htm

 

Organic Skin Care Tips

 

Organic skin care is becoming big business. When you are choosing skin care, personal care and cosmetic products, you should go for labels. This is the only way to ensure you purchase honest and truly natural and organic skin care products.

 

# 1: Read Product Labels

Be aware of the Rule of Thirds:

The top third of the ingredients label generally lists the ingredients that comprise around 90-98% of the product, most of this is usually water.

 

The middle third generally represents approximately 5-8% of the product.

The bottom third represents around 1-3%.

 

# 2: ‘Natural’ skin care may not always be natural.

There are two definitions of the world natural.

The dictionary definition: “Existing in or, formed by, nature”.

The cosmetic industry definition: “Any ingredient derived from a natural substance”.

Manufacturers may commonly use the word ‘natural’ on labels to deceive consumers.

For example, “Cocamide-DEA derived from coconut oil”.  

Cocamide-DEA may well be from coconut oil, but a synthetic chemical called diethanolamine is used in the extraction process. It is known to cause cancer. An ingredient is not really natural if it has been processed in this way.

 

# 3: Organic doesn’t mean what we think.

An organic certification on a product label is the only way to guarantee the integrity of a product.

The definition of certified organic is as follows:

“An independent third party guarantee of an organic claim”.

Always look for a logo that guarantees the product’s integrity.

 

There are two definitions of organic:

Organic chemistry is concerned with substances that contain carbon. Carbon is present in all living things. Legally, the cosmetics industry is allowed to label any product that contains carbon as ‘organic’. So if it contains petrol, it is organic.

Methylparaben is derived from petrochemicals, which are derived from crude oil, which is derived from living matter. It is a widely used preservative in organic skin care products such as body creams, body wash and deodorants:

So effectively methylparaben can legally be labelled as organic. Now, it is worth noting that a recent study reported traces of methylparaben in human breast cancer tumours.

The second definition of organic is, “The sustainable system of agriculture that uses natural substances & methods to create healthy nutrient rich and fertile soils”

 

# 4: Water quantity in the product

what can actually be meant when companies put ‘73% Organic’ on their labels is that manufacturers can place a few organic teabags in a vat of water and let them infuse into the water.

Because the water constitutes 70+ percent of the overall product, the manufacturer is allowed to claim that the product is 73% organic at the top of the label

 

If you removed the water, the actual organic content of those fancy herbal infusions would probably be less than 0.05% of the total product.

 

# 5: Be aware of inconsistent labelling standards

In some countries, ingredients that are not allowed in certified organic foods ARE allowed in certified organic personal care and cosmetic products. This represents a lack of continuity or consistency in labelling standards.

How can food and cosmetics products have the same certified organic logo when ingredients that are allowed personal care and cosmetics are not allowed in food? Remember that if it’s on your skin, you’re drinking it!

 

# 6: Miracle ingredients don’t exist

Vitamin C, vitamin E, coenzyme Q10, active copper and other ingredients may be touted as miracle ingredients. The fact is that there is no miracle ingredient for the skin or hair, just as there is no magic pill for curing illness and disease.

The quality of the skin is a function of feeding the body and skin high quality nutrients over time and keeping the toxin levels of the body as low as possible.

When you use high quality, certified organic products, ALL the ingredients are active. They are ALL beneficial and they all feed the skin.

 

What is Skin Care?

Healing the skin and keeping it healthy are of primary importance both in preventing further damage and enhancing the patient's quality of life. Developing and following a daily skin care routine is critical to preventing recurrent episodes of symptoms. Key factors are proper bathing and the application of lubricants, such as creams or ointments, within 3 minutes of bathing. People with atopic dermatitis should avoid hot or long (more than 10 to 15 minutes) baths and showers. A lukewarm bath helps to cleanse and moisturize the skin without drying it excessively.