The skin reflects a person's general health and well-being. What's good for your health is often good for your skin. And the health benefits of skin care are more than skin deep, since what affects the skin can affect other parts of the body and a person's self-image as well. Our skin is the most visible organ of our bodies, so skin disorders can have a large emotional impact. A healthy life-style can help keep skin healthy, reduce the severity of many dermatological disorders, and slow skin ageing. When skin disorders develop, appropriate medical advice must be accompanied by educated, daily self-care.

The best nutritional recommendation for healthy skin is not magic, just plain good sense. It's the same phrase you've heard a hundred times before: Eat a well-balanced diet. But while true vitamin and mineral deficiencies are associated with skin disorders, getting more than the recommended daily allowance of vitamins and minerals does not make above-average skin. Supplements will improve the skin only if they are correcting an existing deficiency. In fact, too much of some vitamins can actually cause skin problems. For example, too much vitamin A is toxic and can make the skin rough and dry. Niacin can cause flushing and itching. And vitamin E applied topically can cause acne and allergic reactions in some people.

Some skin disorders are linked to food sensitivities. One person in five experiences hives at some time, which may be brought on by many things, including certain foods. Eggs, nuts, beans, chocolate, strawberries, tomatoes, citrus fruit, seafood, corn, and pork are the most common problematic foods. Several food additives may also cause hives. Tartrazine (yellow dye No. 5), the preservative sodium benzoate, and sulphites are common triggers. Salicylates also cause hives in some people. Salicylates are found in all aspirin-containing medications. They also occur naturally in almonds, apples, peaches, potatoes, and other foods.

Some evidence suggests that some foods exacerbate atopic eczema, or dermatitis. In one study of 36 children with eczema, 12 experienced significant improvement when eggs and cow's milk were eliminated from their diets.

It is a commonly held belief that foods such as chocolate, cola drinks, nuts, and dairy products can make acne worse. Most research to date has failed to establish a clear link between diet and acne. However, some acne patients and their physicians claim to have isolated foods that do affect acne severity, so it remains possible that diet, especially one high in fat and refined carbohydrates, may be a contributing factor in some cases.

Why is it that students (and teachers) look so much better in September than in December? Stress may be one of the factors responsible for this difference. Stress tends to worsen many pre-existing skin problems, especially herpes, acne, eczema, hives, psoriasis, and warts. Stress-management techniques, including hypnosis, biofeedback, and other relaxation exercises, have been shown to improve many skin problems. These techniques may work by changing hormone levels and nervous system activity.

Noted scientist Lewis Thomas has written that it's "one of the great mystifications of science: warts can be ordered off the skin by hypnotic suggestion." The skin responds to a person's beliefs. In one study, subjects were told their skin was being exposed to poison ivy, and many broke out even though the poison ivy was only in their imaginations.

A person's behaviour often makes a skin problem worse. Squeezing pimples and scratching irritated skin are two common examples. Relaxation techniques can be used to help lessen the picking and scratching, and also to decrease the itching associated with conditions such as eczema.

People who smoke cigarettes usually show premature ageing of the skin, especially facial wrinkles. Long-time smokers tend to look about 10 years older than non-smokers of the same age. This effect may be related to some of the chemicals in cigarette smoke and to the decrease in peripheral blood flow caused by nicotine, a potent vasoconstrictor.

During exercise, the body shunts blood to the skin to help release excess heat produced by the contracting muscles. This increased blood flow provides the skin with nutrients and gets rid of wastes. One study found that regular exercisers had thicker skin than sedentary individuals. Thicker skin ages more gracefully because it develops wrinkles later than thinner skin.

Protecting skin from the sun's damaging rays will help prevent premature ageing and cancers of the skin, rates of which have been rising rapidly. In the U.S. over 500,000 people per year (that's one in seven Americans) will develop skin cancer during their lifetimes.

The sun's untraviolet rays are the source of skin damage. Until recently, scientists and consumers were concerned only about UV-B rays, since they are the ones that cause sunburn and skin cancer. UV-A rays cause tanning, and were once thought to be harmless. But UV-A rays actually penetrate the skin more deeply and can damage the skin's connective tissue, causing sagging and wrinkling of the skin. UV-A rays seem to increase the cancer-causing effects of UV-B rays.

Skin protection is the way to go outdoors. The most effective skin protection is some form of sun block. Tightly woven clothing (hold it up to a light and see how much shines through) helps keep the sun's rays from reaching the skin, and wide-brimmed hats provide some protection.

When a sun block is not practical, a sunscreen should be used. These do not shield the skin completely, but they do reduce the damaging effects of the ultraviolet rays. The degree of protection is indicated by a numerical rating, the sun protection factor (SPF), on sunscreen products. The SPF is the time a person can stay in the sun without burning when a product is used divided by the time a person could stay in the sun when the product is not used. For example, if your skin burns after 10 minutes in the sun without protection but after 100 minutes with protection: the SPF of your sunscreen is 10. In other words, the sunscreen allows you to stay in the sun 10 times longer before burning. A sunscreen with SPF15 is generally recommended, although people with light skin may need something stronger. Sunscreens and sun blocks should be used conscientiously whenever outdoors, even on cloudy days, since some radiation penetrates cloud cover.