THE BODY'S LARGEST ORGAN
Although many of us don't think of it as such, the skin is actually an organ, the body's largest. In a typical adult, the skin covers about 2 square meters (or 22 square feet) and weighs 4.5 kg to 5 kg (10 to 11 lb.).
Among the body's organs, none is more visible or exposed to infection, disease and injury than the skin. It reflects our emotions and some aspects of normal physiology, as evidenced by frowning, blushing and sweating. Changes in skin color may indicate homeostatic imbalances in the body; for example, a bluish skin tone is one sign of heart failure. Abnormal skin eruptions or rashes such as chickenpox, cold sores or measles, reveal systemic infections or diseases. Other disorders may involve just the skin itself, such as warts, age spots and pimples. The skin is vulnerable to damage from trauma, sunlight, microbes and pollutants in the environment.
Structurally, the skin has an outer, thinner epithelial portion called the epidermis, which is anchored to an inner, thicker, connective tissue part called the dermis. Beneath the dermis is the subcutaneous layer, which contains primarily fat to cushion the body, and regulate heat loss. Fibers from the dermis anchor the skin to the subcutaneous layer, which in turn attaches to underlying tissues and organs. It is from within the deepest layers that new skin cells are formed. As they mature, the new cells move outward through each layer, replacing skin cells as they are shed or lost to abrasion.
FUNCTIONS OF SKIN
The skin is not just a covering that keeps the body intact; it also performs several essential functions, including:
Physical protection, sensation and immunity. Certain epidermal cells also provide a barrier to invading antigens.
Synthesis of vitamin D – In actuality, vitamin D is a group of closely related compounds. Synthesis of vitamin D begins with activation of a precursor molecule in the skin by UV rays in sunlight. Enzymes in the liver and kidneys then modify the molecule, finally producing calcitriol, the most active form of vitamin D.
Blood reservoir – The dermis contains extensive networks of blood vessels that carry 8 to 10 percent of the total blood flow in a resting adult. During moderate exercise, skin blood flow may increase, which helps dissipate heat from the body.
Regulation of body temperature – The skin and its structures regulate body temperature in two ways. The first is through fluctuations in the amount of blood flowing through the skin. The second is through the production and release of perspiration. Increased sweat production and its evaporation from the skin cool the body.
Excretion – Intertwined with its role in regulating body temperature is perspiration's function in removing body waste, or toxins. Wastes removed from the body's interior can become food for the millions of microbes living on the skin's surface. When the wastes are laden with impurities from the diet, these microbes can flourish, allowing pores to clog. One result is acne.
HEALTHY DIET = CLEANER BODY = OPEN PORES
The body's detoxification system is always working. Once ingested, inhaled or absorbed, toxins and impurities are carried by the blood to the liver, the main organ of detoxification in the body. Once "processed" by the liver, these substances are again transported by the blood as waste to the organs of elimination-the lungs, kidneys, intestines and skin. Of these, the skin is the largest.
It's easy to see, then, why skin health is dependent on good nutrition all the way around. Ingesting a cleaner, healthier diet and ample clean water means less toxins and impurities. It also means that more of the nutrients ingested can go to fuel the body's routine maintenance and rebuilding phases, including production of new skin cells.