Any condition that harms the body, breaks down, or causes the death of cells is defined as stress. If the diet is adequate, repair quickly occurs, but when rebuilding fails to keep pace with destruction, illness is produced. Disease results from multiple stresses such as anxiety, overwork, perhaps bacterial or viral attack, and inadequate diet, sleep, and exercise. Unfortunately, it usually brings on numerous other stresses: poor appetite, nausea, vomiting, faulty absorption, fever, pain, diarrhea, dehydration, high urinary losses of many nutrients, exposure to x-rays, and the use of drugs.

In the same way that it requires more material for the repair of a damaged house than for the upkeep of one in good condition, every nutrient is needed in larger amounts to repair a body damaged by the multiple stresses that cause disease and result from it. For example, the stress-or damage-caused by x-raying an animal or by giving it anyone of many commonly used drugs increases the need for protein, linoleic acid, several minerals, and vitamins A, C, and all the B vitamins. Presumably the same is true of humans.

Regardless of the forms of stress, the body immediately tries to repair damage done, but it cannot unless all nutrients are generously supplied. The nutritional needs increase tremendously at the very time eating is most difficult; and a diet adequate for a healthy individual becomes markedly inadequate for an ill one.

The body's reaction to stress. The great medical genius Dr. Hans Selye, of the University of Montreal, revolutionized medical thinking with his theory, now confirmed by thousands of scientific studies, that the body reacts to every variety of stress in the same way. At the onset of stress, a tiny gland at the base of the brain, the pituitary-the boss, of the repair crew-starts protective action by secreting chemical messengers, or hormones, ACTH and STH. These hormones, carried in the blood to two small glands above the kidneys, the adrenals, cause the outside border of these glands, or cortex, to produce cortisone and other messengers. Although the center of these glands manufactures adrenaline, the adrenal hormones referred to throughout this book are those made by the cortex. These adrenal cortex hormones quickly prepare the body to meet the emergency: proteins, at first drawn from the thymus and lymph glands, are broken down to form sugar necessary for immediate energy; the blood sugar soars and the remaining sugar is stored in the liver in the form of body starch, or glycogen, which can be instantly converted into sugar if needed; the blood pressure increases, minerals are drawn from the bones, fat is mobilized from storage depots, an abnormal amount of salt is retained, and many other changes take place which prepare the body for "fight or flight." These changes also make it possible to repair vital tissues by a process of robbing Peter to pay Paul. This stage, called the "alarm reaction," varies in intensity with the degree of stress.

The first two stages of stress are characterized by constant damage and repair; most illnesses fall in stage three, which is reached when repair fails. Intense stress, such as drastic surgery, a serious car accident or severe burn may cause a person to pass through all three stages-alarm, resistance, and exhaustion-in a single day. More often we experience repeated "alarm reactions" and live through hundreds of "stages of resistance," one piled on top of the other, before pituitary and adrenal exhaustion threatens our lives. During every illness, however, we are in one of these three stages of stress, and to regain our health our diets must be planned accordingly.

If stress is prolonged after the thymus and lymph glands, whose proteins are purposely destroyed, have shriveled, proteins from the blood plasma, liver, kidneys, and other parts of the body are used. Stomach ulcers may occur not only because of increased production of hydrochloric acid, but also because proteins are stolen from the stomach walls. In ulcerative colitis, the destruction of protein brought about by prolonged stress literally eats away the lining of the intestine. During a single day of severe stress, the urinary loss of nitrogen has shown that the amount of body protein destroyed equals that supplied by 4 quarts of milk. Yet if such a tremendous quantity of protein can be eaten during that day, the tissues are unharmed. In the same way that the body suffers when its proteins are necessarily stolen and not replaced, so are the bones weakened by the theft of calcium. Dozens of other destructive changes similarly occur. Increased blood pressure alone may become dangerous. It is extremely important, therefore, for each of us to learn how to protect ourselves from the ravages of stress.