Immunity

Immunity is the body’s own defense mechanism.[1] It is the ability of the human body to identify and eliminate any foreign invading substances (such as viruses and bacteria), deal with aging, damaged, dead, or degenerated cells, and to recognize and process mutated cells and virus-infected cells within the body. It is a physiological reaction of the human body to identify and exclude “non-self” elements.

The term “immunity” (免疫, mian yi) first appeared in the Ming Dynasty medical text “Immunity-Type Formulas” (免疫类方), where it referred to “warding off pestilence,” meaning the prevention and treatment of infectious diseases. The term “immunity” can also refer to the body’s ability to resist viruses and harsh external environments, as well as mental resistance.

Immunity refers to the body’s ability to resist external invasion and maintain the stability of its internal environment. The air is filled with a variety of microorganisms: bacteria, viruses, mycoplasma, chlamydia, fungi, and so on. When the body’s immunity is insufficient, any of these can become pathogens. Although the human body produces corresponding antibodies against different pathogens to resist reinfection, these antibodies have specificity and are time-limited. For example, the antibody against streptococcus can only protect the body from reinfection by streptococcus for a short period and cannot defend against other viral infections.

Modern medical science has discovered that immunity is a factor closely related to aging; a decline in immune function is one of the most important causes of aging. Some special cells in the body’s immune system can engulf and eliminate invading bacteria and viruses, as well as senescent and dead cells, mutated cells, and substances that cause allergic reactions, thereby maintaining the stability of the internal environment and keeping the body healthy. However, the body’s immune function begins to decline around the age of 30, a change that is silent, slow, and continuous.

So, how can one improve the body’s own immunity? The World Health Organization has summarized a healthy lifestyle in four phrases: a reasonable diet, moderate exercise, smoking cessation and alcohol limitation, and psychological balance. Research has shown that this healthy lifestyle can reduce hypertension by 55%, stroke by 75%, diabetes by 50%, and tumors by one-third, and can extend the average lifespan by more than 10 years.

People who pay attention to health preservation have conducted considerable research into this healthy lifestyle. For a reasonable diet, there is even a saying: “one, two, three, four, five; red, yellow, green, white, black.” Specific practices include details like drinking a bag of milk every day, appropriately supplementing with carbohydrates, high-protein foods, vitamin A, vegetables, and fruits, and achieving a diet that is both refined and coarse, not too sweet or salty, with three to five meals a day, eaten to seven or eight-tenths of fullness. Of course, frozen, raw, and cold foods should be consumed sparingly.

It is important to maintain a moderate amount of exercise, with the best forms being walking and Tai Chi. One should adhere to smoking cessation and alcohol limitation; if quitting completely is not possible, smoking should not exceed 5 cigarettes per day, and the alcohol content per meal should not exceed 15 grams. Maintaining psychological balance is also crucial, and its effect can surpass the sum of all other health measures. Being open-minded, easy-going, and kind-hearted are naturally indispensable.