Why is it there is always some lucky soul who doesn't get sick when the flu is going around the office? Or why, when chicken pox is sending all the kids home from school, are there a few who remain untouched? Why do only some in a family develop allergies or eczema? Some attribute this phenomenon to simple luck, while others say Ïstrong genes!" The answer is a bit more complex.

It's true that our genes affect our immune system, and we call that influence our natural "constitution." My 84 year-old grandmother, for instance, has an incredibly sharp mind despite the fact that she has been smoking 1-2 packs of cigarettes a day for 60 years. She has a strong constitution. On the other hand, someone who lives with a smoker and develops a chronic cough from second-hand smoke has a weaker constitution. We can't change our genetic makeup, but we can strengthen our constitution and our immune system. Genes can make us predisposed to certain illnesses, or to a certain immune strength, but they are not as definitive as many modern scientists would have us believe. So let's look at some ways to strengthen (or weaken) our constitution and immune strength.

Diet is a Big Deal

Foods can tear us down, or foods can build us up. Specifically, food that is whole and fresh-like fresh fruits, vegetables, and grains-has a very strengthening effect on our immune function. So strong is this correlation, in fact, that the National Institutes of Health have developed a Designer Foods Program to study the cancer-preventing effects of cruciferous vegetables (like broccoli and cauliflower). Fresh foods not only carry a diverse mixture of vitamins and trace minerals absent from most processed foods, they also have vitality. A teacher of mine once told me, "If we eat to live, it is important that the food we eat have life." That "life" is evident when you consider that the grains and beans we eat could just as easily have been sprouted to create new plants. Watch fresh vegetables (that have wilted a bit) perk up with a little water. You see? These foods have life in them, and they give that life to us when we conscientiously consume them.

On the other hand, food can be poison. Foods full of chemical additives and preservatives are a toxic load on your liver. Foods that are not fresh still give you calories and some vitamins (so they do have some value), but some foods have no value. White sugar is one of the biggest offenders. Refined sugar creates a sudden surge of energy as it is absorbed rapidly into the bloodstream. This is short-lived, however, as the body's response to the rush of high blood sugar is to shuttle it quickly into the tissues. This is typically experienced as a sugar "high," and it is followed by the "sugar blues" that persuade us to eat even more sugar in order to feel better. It's a vicious cycle, and it leaves us depleted energetically.

Some studies, and much more clinical data, point to sugar as an immune suppressant. These are common scenarios: a sore throat that develops after bingeing on sweets, or children who have recurrent ear infections or chronic tonsillitis if they consume a lot of candy, sugared beverages, and other treats. Other stimulants-such as coffee and sodas-seem to have a similar result if they are overused. The common theme here is energy: foods that are solid sources of energy and vitality build us up; foods that cause intermittent boosts of artificial energy leave us depleted. Foods that are loaded with chemicals leave us burdened, rather than energized. This concept is quite logical, but many do not consider diet important to wellness, when in fact it is crucial.

Exercise Matters

When we exercise moderately, we actually stimulate our immune function. (This does not mean you should work out at the club when you have a fever of 103 degrees!) Preventively, regular exercise "demarginates" our white cells; that means it puts more of them into circulation. Exercise also causes our blood vessels to dilate so that circulation is increased. More white blood cells (the ones that gobble up germs and deranged cells), circulating to more areas of our body, means a greater ability to fight and prevent disease.

Stress Hurts

Scientists used to believe that the immune system functioned independently of other systems in the body, including the brain. And in a way it does. If you mix white blood cells with bacteria in a test tube, the white cells will kill the bacteria-without any input from the brain/nervous system. They seem to have a mind of their own when it comes to doing their job.

However, in the last 20 years an astounding amount of research has been done on the connection between the mind, the nervous system, and the immune system-hence the name of the new field: psychoneuroimmunology (PNI). These experiments have revealed many links between these systems, indicating that they strongly affect each other. One particularly powerful set of such experiments measured the number of white blood cells in mice chronically exposed to adrenalin, our stress hormone.

Adrenalin is released by the adrenal gland as a "fight or flight" response to stress or fear. It causes our heart to pump harder and faster; it makes our blood pressure rise; it diverts blood to the brain and extremities so that we can think clearly while running faster; and it makes platelets (the cells responsible for blood clotting) more sticky, so that if we were to be injured, we might not bleed to death. This set of reactions would actually be helpful if you were being chased by a saber tooth tiger. The problem is, this reaction happens continuously for many of us who work and live in stressful situations-constantly thinking, moving, acting, using our senses-with no rest. The experiments with the mice showed (as you probably guessed) that white cell numbers decreased proportionally with adrenalin infusion. In other words, chronic stress is an immune suppressant, weakening the ability of the system to respond to infections, cell mutations, and other possible threats to the system's integrity.

Relaxation Helps

The good news is that creating a deep sense of relaxation can have the opposite effect on the immune system. Adrenalin triggers the sympathetic nervous system-that "fight-or-flight" response. Relaxation stimulates the parasympathetic nervous system. While the sympathetic system is designed for protection against an immediate danger, the parasympathetic system is designed for maintenance, repair, and restoration. It slows heart rate, lowers blood pressure, brings more blood flow to the gastrointestinal tract, and increases the number of white blood cells.
Dr. Herbert Benson of Harvard University studied this effect in the early '70s and named it "the relaxation response." He found that simply relaxing the body through deep diaphragmatic breathing in a restful environment had profound effects on the mind as well, resulting in a greater sense of peace and well-being. This state is now clearly linked with a stronger immune system. (Studies with couples who are "in love," for example, showed higher white cell counts than normal.)

For centuries doctors have known of this connection between mind and body, and eventually coined the term "psychosomatic illness." In speaking of a case of lung infection, Sir William Osler, a famous physician practicing at the turn of the century, was once quoted as saying, "The care of the patient depends more on what is in the patient's head than what is in the patient's chest." Today, the field of PNI is proving what was known long ago-not that emotions cause disease, but that immune strength is dependent on the interaction between mind and body.

In a Nutshell

So if you are one of those who "gets every bug that goes around," here are some tips for you:
Eat well. Heap your plate with fresh vegetables, grains, and fruits, and avoid stimulants like caffeine and white sugar that tax your body.

Exercise regularly. Twenty minutes 3-4 times a week of a low-impact sport like walking, swimming, biking, or hatha yoga is enough.

Do something that decreases the stress in your life. Learn a relaxation technique (the easiest is deep breathing), exercise, listen to soothing music, or get a massage. Find something that is relaxing and restorative (this does not mean sleep more!).

Take supplements that help boost your immune system when you feel like you are "coming down with something." Zinc, vitamin C, B-complex, and the herbs echinacea (purple coneflower) and hydrastis (goldenseal) are especially helpful.

The advantages of bolstering your immune system are obvious-you stop catching every flu, or if you do get sick it only lasts days rather than weeks. You have less discomfort, and miss fewer days at work. More important, however, keeping your immune system strong also prevents more serious diseases.

Our immune system is our protection. It is our army, our guardian against outside invaders. If the army is underactive or exhausted, it doesn't notice invaders (viruses or abnormal cells) and allows them to grow, resulting in chronic infections and even cancer. These are signs of immune system weakness and imbalance, and you can prevent them by following a few simple guidelines. Don't count on your genes or luck to see you through. Exercise, pay attention to your diet, your stress level, and your mind, and stay healthy!