Think about two people (say a husband and wife) who live together and are exposed to the same pathogens. One gets sick, and the other doesn't. What makes the difference? Simply put, it's the effectiveness of their immune system.

In the last hundred years, the stresses on our immune system have multiplied dramatically. Stress itself causes a lowering of immune response, and life's stressors have increased exponentially. Some psychologists estimate that the 'average' person living in the industrialized world experiences as much stress in a week as someone living 100 years ago experienced in a whole lifetime!

And, a hundred years ago, there were no chemicals, no car exhaust, and minimal environmental pollution. What pollution there was came from the burning of coal, and from poor sanitation. But, even though the assaults on our immune systems have multiplied, our immune systems have not changed. Plus, repeated exposure to pathogens, and especially the toxic chemicals that surround all of us, actually weakens our immune systems over time. A prime example of this is the environmentally sensitive, or chemically sensitive person - a condition unknown fifty years ago, before the widespread use of chemicals. Another symptom of this problem is the rise in the incidence of cancers in the last century. Relatively rare a hundred years ago, cancer is estimated to affect one in five Americans today.

Allergies, arthritis, viral infections like colds and flu, bacterial infections - they all result either directly or indirectly from an immune system functioning at less than optimum levels. And all of us already have cancer cells in us, and we all have viruses in our bodies - all the time. The difference - whether we actually get cancer or not, or whether or not we come down with a viral infection, is simply based on whether or not we have a healthy, powerful immune system. So today, whether you're sick or not, the most important thing you can do for your health is to strengthen your immune system.