NEW RESEARCH

For the past fifteen years, extensive research has deepened our understanding of immunity, particularly through the enormous number of studies on cancer and AIDS. Science has made great strides in the exploration of how the immune system works and how to enhance its function. As a result, the American public has a greater appreciation for the importance of immunity.

There is also a large body of medical literature that documents the role of lifestyle factors in immunity. This research reflects the impact on our health of the things we do every day. It also provides information we can use to modify our lifestyle, in order to enhance health and immune function.

LIFESTYLE AND IMMUNITY

To explore the effects of lifestyle on immunity, consider the example of the common cold. Our vulnerability depends on the balance between the strength of our immunity and the strength of the threatening virus. Once exposed, we only get sick if our immune defenses are inadequate. When our reserve defenses are depleted, they can no longer prevent the virus from invading our cells. We all know that when our defenses are strong, we almost never get sick.

Yet many of us tend to overestimate our ability to resist illness, and in the process we neglect our health. Most of us don’t get enough rest. We often eat on the run. We may be exposed to a variety of germs and toxins daily. And, for most of us, stress has become a way of life. We frequently take better care of our cars than of our bodies. It doesn’t take a research scientist to figure out why we sometimes get sick. Consider the effects of lifestyle on our susceptibility to illness. The factors that may increase our vulnerability to disease can also be modified to improve our resistance.

• Rest and rejuvenation. How often have you caught a cold after not getting enough sleep? We depend on adequate restful sleep to restore our bodies and refresh our minds. During deep sleep, our bodies release potent immune-enhancing substances that strengthen immune function. It is especially important to get additional rest when we are ill.

• Exercise. We need regular exercise. The body has a remarkable ability to increase its metabolic capacity through consistent regular physical conditioning. We all know how invigorated and strong we feel when we’re in shape. Overall fitness creates reserve capacity that not only serves as a buffer against disease but also helps us recover more quickly.

• Good nutrition. A healthy diet is absolutely essential to maintain good immunity. Food provides our cells with the raw materials they require to meet the body’s needs. We tend to take nutrition for granted, believing that we’ll get along just fine, even if we don’t consume all the nutrition we need. Yet we shouldn’t assume that just because we live in a modern society we have adequate nutrition. Hundreds of in-depth studies have documented that malnutrition exists in industrialized nations today, among both the rich and poor.

Widespread nutritional factors that can compromise our immune capacity include eating too much sugar or starch, obesity, high cholesterol, and the regular use of alcohol. If the immune system is malnourished, it may not have the resources needed to protect us against illness. A healthy immune system depends on adequate amounts of vitamins, minerals, and other important metabolic nutrients. For example, the vast majority of our immune function is dependent on vitamin A and zinc, nutrients that are often lacking in the modern diet.

• Toxins and pollution. The metabolic machinery of our cells is exquisitely sensitive to many toxins that can interfere with the body’s normal biochemical processes. Every day we are exposed to thousands (yes, thousands) of chemicals in our food, water, and air that were nonexistent until the Industrial Revolution of the nineteenth and twentieth centuries. As a result, our bodies must cope with manufactured chemicals, pesticides, heavy metals, petroleum products, and plastics that can accumulate in our tissues and that are toxic to the immune system. Clearing the body of these environmental toxins increases our requirement for antioxidants and various other nutrients. Because of these exposures, our nutritional requirements may be increased to higher levels than we can obtain in our diet, making it important to use nutritional supplements to remain healthy. And because of the prevalence of these exposures, it’s also important to build detoxification into our lifestyle.

Some toxic chemicals have been documented to cause cold-like symptoms. A committee of the World Health Organization reported that up to 30 percent of new and remodeled buildings emit air pollutants such as formaldehyde, asbestos, volatile chemicals, and other toxins and allergens. The effects of these emissions can cause "sick building syndrome." Solutions to the chemical sensitivity that may result include avoiding the sources of exposure, detoxifying the body and, when necessary, getting treatment from a physician trained in environmental medicine.

• The stress factor. There is now strong data that documents the impact of stress on immunity and susceptibility to illness. For instance, remember how many of your friends caught colds during final exams? A report of 276 volunteers exposed to a common cold virus showed that those who had been under stress for more than a month were most likely to get sick. In another study, children with a history of stress and recurrent colds were found to have lower localized immunity. Stress has also been found to stimulate immune-suppressing chemicals such as adrenaline. Fortunately, research has found that stress reducers such as meditation, relaxation, guided imagery, and hypnosis can effectively enhance immunity.

Len Saputo, M.D., is founder and director of Health Medicine Forum, a nonprofit educational foundation. He is also medical director of the Health Medicine Institute, an integrative medicine center in Walnut Creek, California.

Nancy Faass, M.S.W., M.P.H., is a writer and editor in San Francisco. Her work includes Optimal Digestion and Integrating Complementary Medicine into Health Systems.