Unlike your heart, brain, and other organs, your skin is constantly renewing itself. As the active living skin cells in the basal layer of the epidermis divide and multiply, the older cells get more and more crowded. They start looking for room to spread out, moving closer and closer to the skin's surface in the process. Along the way they're busy making keratin, a tough- as- nails protein that protects the outermost layers of the skin. But this must be exhausting work, because before those busy, crowded cells ever make it to the surface, they die.
That top layer of dead skin cells, which is what you touch when you touch your skin, is called the stratum corneum, and it's the thickest in accident-prone areas of the body, such as the knees, elbows, and soles of the feet. Because dead skin cells contain little to no water, this top layer is prone to drying out, chapping, and even cracking, particularly in the winter months (which is why your heels may crack and your elbows and knees can look ashy).
As more and more new cells rise to the top of the epidermis, they push off the older dead cells. Th is is your body's natural way of exfoliating. Supporting this process (by using a body scrub or a pumice stone as well as by eating foods that fuel keratin production) will encourage new cells to come in, keeping your skin looking pink and rosy as opposed to dry and crusty.
Did You Know . . .
There are no blood vessels in the epidermis, so the active living cells (the keratinocytes) depend on oxygen and nutrients diffusing up from the blood vessels located in the deeper layers of the skin below. Cigarette smoking and some medications constrict these blood vessels, however, allowing less oxygen and fewer nutrients to fl ow up to the epidermis. The result is skin that looks pale and sallow.
LAYER TWO: The Dermis
The second layer of your skin (which you can think of as the white part of an orange rind, the stuff between the peel and the fleshy meat) is called the dermis, and it contains connective tissue— collagen, elastic tissue, and hyaluronic acid— that gives the skin support and structure.
Collagen functions like the beams in your house or the boning in a couture gown: It gives your skin its support. There are more than twenty types of collagen in multiple organs throughout the body, but the vast majority of collagen in our skin is Type I, which is the strongest. In fact, gram for gram, Type I collagen is stronger than steel.
We're all born with plenty of collagen, and at fi rst our skin cells are busy pumping out more and more of it (which is why children have firm, resilient skin). As time goes by, however, collagen production slows, so our skin gets thinner, less resilient, and more likely to wrinkle. Eating the right collagenboosting foods can help fight this pro cess and keep your skin looking younger and smoother.
Don't Fall for It: COLLAGEN CREAMS
Creams that promise to fill fine lines and wrinkles with collagen are pretty much bogus because the collagen molecule is too large to actually penetrate the skin; instead, it just sits on the surface. (That's why injectable fillers such as Restylane and Juvéderm were created.) Collagen creams can make decent moisturizers, and that's good (dry skin can make fine lines more pronounced), but they won't get rid of your wrinkles.