Why Does The Skin Age?

For some people, the worst part of aging isn’t what it does to their insides, but the way it makes them look. If only there were a way to prevent or reverse all the lines, marks and wrinkles, they wouldn’t mind getting older so much at all. The good news is that over the last few years there have been some great breakthroughs in this area, although you’d never know it from watching certain late-night television commercials, which have about as much scientific credibility as Paris Hilton claiming to be a member of MENSA.





Why does a person appear older with age? In order to understand how to prevent and reverse skin aging, the two primary aging mechanisms need to be understood. These are chronological aging and photo-aging. There are ways of reducing both of them, although photo-aging can be almost entirely avoided if a person takes adequate measures to protect his or her skin from ultraviolet sun damage.

The chronological aging of the skin is part of the general decline of the body with age. As the immune system deteriorates, skin tumours, both benign and malignant, are more likely. Abnormal blood vessels are particularly noticeable over the nose and cheeks. Instead of being renewed every two to three weeks, the skin takes four to six weeks to be replaced, leading to a drier, thinner appearance. Thinner skin receives less nutrients, because the undulating interface between the dermis (the bottom layer of the skin) and the epidermis (top layer) becomes flatter, reducing the surface area between the two. This leads to a reduction in both the exchange of nutrients (and thus the cellular metabolism in the epidermis), and of the removal of waste products from the cells (including free radicals). The reduction of nutrients leads to less collagen being produced, and so a self-perpetuating cycle ensues. Additionally, gravity exerts pressure on the extra-cellular matrix, causing stress on the mitochondria and leading to the production of superoxide radicals that damage collagen. And intercellular adhesion molecules under the top layer of the skin lead to the production of collagenase, an enzyme that breaks down collagen.

A reduction in collagen, the fibre that supports the skin, leads to lines, wrinkles, and sagging. It is gradually replaced by glycosaminoglycans (CAGs), which are macromolecules that only support the collagen itself in young skin, but act as the primary support when it is gone. The gel-like structure they form is not as strong as collagen, and therefore sags from the weight of gravity, as well as producing less flexible and thinner skin. It is also partly replaced by elastin, which tends to be calcified and to have an excess of lipids. The collagen that remains becomes stiffened and sinewed as it is crosslinked through the process of glycation. All of this leads to a person appearing older, and tends to accelerate from the 40s onward.

Photo-aging is a caused by exposure of the skin to ultraviolet solar rays, leading to oxidation of the collagen and elastin fibres of the skin. UVA rays cause wrinkling and melanoma (as well as tanning, which is why a tan is not a good sign if one wishes to maintain young-looking skin) and UVB rays cause basal and squamous cell cancer, as well as sunburn. The fact that ultraviolet light can produce enzymes that break down collagen means that if you want to avoid wrinkles, you obviously need to wear a good sunscreen and avoid prolonged periods of exposure to the sun, something that few people do.