The immune system is a scheme through which the body identifies harmful pathogens and attempts to eliminate them in order to maintain health. A healthy immune system is able to distinguish between harmful and non-harmful agents so that the body has an appropriate response. It is incredibly adaptable and can remember past pathogens in order to prepare for future threats (by building antibodies, for instance). When the immune system responds, an elaborate network of events takes place to neutralize or destroy the harmful pathogen, and in so doing, symptoms may become evident. For instance, when a cold virus invades the body and the immune system tries to ward it off, a runny nose, cough and other symptoms emerge. These symptoms are a sign that the body is struggling to fight the virus. A person with a weak immune system is someone who gets sick often or takes a long time to heal from illness (“I can’t get rid of this cold.” “I always get sick this time of year.” Sound familiar?).
Traditional Chinese Medicine (TCM) developed thousands of years ago before anyone knew what a germ was and before any understanding of immune system mechanisms. But the elegant theories behind TCM do explain how the body’s energy works and how it defends itself against disease and external pathogens and how it becomes susceptible- so in a sense, it does address immunity.
Wei Qi or Defensive Qi
A fundamental concept in TCM is the idea of qi (or chi). Simply put, qi is the vital energy that animates all living things. In TCM, this energy is divided into sub-categories: the energy that is inborn, and the energy that is acquired. One type of acquired qi is called Wei Qi, or defensive qi. Wei qi is derived from the air we breathe and the food we eat and it is known as defensive qi because it acts to protect the body against pathogens.
Defensive qi courses through the body not inside the meridians, but between the skin and muscle. It protects the surface of the body and is responsible for the opening and closing of pores, and thus, controls sweating and body temperature. It also nourishes the organs, muscles, skin and hair. While the heart, spleen, kidneys and liver all play a role in the immune system and wei qi, it is dominated by the lungs.
If the defensive qi is weakened, the immune system is compromised and the body is very susceptible to illness, for instance the cold or flu. If the defensive qi is extremely weakened, a serious illness may develop affecting the internal organs. Defensive qi can be weakened by a number of things: stress, improper diet, overexposure to the elements like cold or wind, overwork, lack of exercise, emotional distress, or a general imbalance between the yin and yang energies in the body.
How to Strengthen Defensive Qi
When the wei qi is weak, acupuncture and Chinese herbs can help. Herbs like Astragalus (also known as Huang qi) can boost the immune system and strengthen the constitution. Acupuncture points such as stomach 36 (below the knee) and large intestine 4 (between the thumb and forefinger) are also good at tweaking the immune system. I usually also tell patients to get more rest and to take supplements containing zinc and vitamin C, as well as eat healthy, hearty meals. Mushrooms such as maitake and shiitake are also supposed to boost immunity. TCM emphasizes moderation in all things, and a lifestyle of adequate sleep, exercise and a varied, wholesome diet while avoiding extremes (excessive alcohol, drugs, too little or too much sleep, over-work, high stress, consumption of junk food, lack of exercise) can keep the wei qi strong and ward of illnesses.