Potentially deadly bacteria and viruses are all over and within our bodies, ready to take advantage of any chink in our defensive armor. Why, then, are we not all dead? Our immune system, which protects us from these enemies, as well as from cancer cells and atherosclerotic plaques, is busy all the time. Diseases like the flu, colds, arthritis, and cancer cannot happen except when our defenses fail. Recent research has discovered much about how our immune system keeps us well and how to help it to do a better job, whether we are sick or healthy.
The immune system is made up of white blood cells (of which there are several types), the thymus gland (behind the breastbone), the spleen, bone marrow, lymph glands, and a variety of large molecules such as antibodies, interferon, and complement. There are two main types of white blood cells: the T-cells, which identify enemies, then kill and eat them; and the B-cells, which make antibodies, generally under instructions from the T-cells.
The thymus gland serves as the master programmer of the T-cells, educating them to kill only certain specified enemies and only when they are told to do so. The thymus is supported by growth hormone, supplied by the pituitary gland in the brain. Without adequate growth hormone, the thymus shrinks and becomes less effective in defending the body.
Immunity begins in childhood with exposure to various organisms, either through contracting the diseases or via vaccination against those diseases. Some parents believe that it is no longer necessary to vaccinate their children against childhood diseases. What they don't realize is that if the child does not develop immunity, he or she may contract a childhood disease as an adult, when it can have much more serious consequences.
For example, when a baby gets polio, the disease is usually like a bad cold; the infant recovers and then has immunity for life. But when an older child or adult gets polio, the risk of paralysis is much higher. The education that a child's immune system receives early in life is very important to his or her later health.
Nobel Prize-winning tumor biologist P.B. Medawar has said that everyone probably gets cancer thousands or perhaps even millions of times in his life. Most of the time, our immune system destroys the cancer before we ourselves can detect it. When our immune system is not working up to par, however, those few cancer cells may escape notice and develop into a tumor.
What impairs the ability of our immune system to do its job? One important factor is mental state. Depressed individuals tend to have depressed immune systems. Depression is associated with depletion in brain stores of the neurotransmitter (a chemical used by nerve cells to communicate with one another) norepinephrine, NE. NE causes the pituitary gland to release growth hormone. It is also an important neurochemical for mood. People who have suffered a severe personal loss contract cancer at far higher than normal rates during several months following the loss.
It is possible to replenish the brain's stores of norepinephrine by taking the nutrient amino acid phenylalanine. In a clinical study, 70 to 80 percent of patients with depressions of several different types (amphetamine abuse, schizophrenic, endogenous, depressive phase of manic-depressive, and others) were entirely alleviated of their depressions by taking 100 to 500 milligrams of phenylalanine per day for two weeks. (Caution: People with high blood pressure should use phenylalanine cautiously and only under a physician's care, since blood pressure elevations may occur in sensitive individuals.)
Another important factor that reduces the effectiveness of our immune system is free radicals—chemically reactive and destructive entities created in our bodies as part of normal metabolism, by the breakdown in our bodies of peroxidized (rancid) fat (see our column in the August issue), by white blood cells as weapons for killing enemies, and by radiation. (Radiation sickness is a pure free radical disease, although, normally, radiation contributes only a very small part of the total free radicals to which we are exposed.)
Although we have special protective enzymes (such as superoxide dismutase, glutathione peroxidase, and catalase) and protective antioxidant nutrients (including vitamins A, C, B-1, B-5, B-6, E, the amino acid cysteine, and the minerals zinc and selenium), protection is not perfect, and, as time passes, damage tends to build up throughout the body. Free radicals are implicated as causative agents in aging, cancer, heart disease, arthritis, and many other abnormal conditions.
When oils and fats in the body, especially polyunsaturated fats, are exposed to oxygen (or chemical oxidizers), they become peroxidized (rancid). These rancid fats directly inhibit immune function and also break down, releasing lots of free radicals, further impairing the performance of our immune system. In one experiment, rabbits were fed a small quantity of rancid oil. Then the activity of the macrophages (a type of white blood cell) in the lungs was measured. The macrophages were greatly inhibited—they didn't move about, actively seeking out and killing enemies, as they should have—because of the presence of the free radicals released in the breakdown of organic peroxides in the rancid oil.
This is one reason why overweight people are so much more susceptible to diseases of all types, including heart disease and cancer, than normal-weight individuals: they are full of peroxidized fat. People of normal weight who eat significant quantities of polyunsaturated oils without also taking large supplements of antioxidant nutrients, such as those mentioned above, also run a serious risk of immune system depression.
What can we do to stimulate the function of our immune system? In next month's column, we'll discuss some simple nutrients that can boost the body's defenses.
A list of scientific literature on this topic is available. Send a stamped, self-addressed envelope to this publication, referring to the date of this issue.
Sandy Shaw and Durk Pearson are consulting scientists, authors, and TV personalities. Copyright © 1981 by Sandy Shaw and Durk Pearson.