The solar calendar dates from September 7th to 9th mark the White Dew (Bailu) solar term. White Dew is a typical autumn solar term. From this day on, dew becomes increasingly condensed, hence its name. The traditional Chinese calendar states: "When the Dipper points to Gui, it is White Dew. The yin qi gradually becomes heavy, condenses into dew, hence the name White Dew." At this time, the sun's ecliptic longitude is 165 degrees. As the weather cools, water vapor in the air often condenses into white dewdrops on trees and plants at night, and birds also begin to prepare for winter. The "Rites of Zhou, Monthly Ordinances" records the景象 of this solar term: "The fierce wind arrives, the wild geese come, the swallows return, and the flocks of birds store their provisions." This means that during this solar term, it is precisely when wild geese fly south to escape the cold, and all birds begin to store dried fruits and grains to prepare for winter. Thus, White Dew is actually a symbol of the weather turning cool.
As the same solar term, the scenery in different regions of China varies. In the north, water vapor is already condensing, while in some southern areas, the fragrance of flowers is still abundant. There is a saying, "When White Dew arrives, the osmanthus fragrance fills the air." There is also a belief about avoiding wind and rain during the White Dew solar term, such as "If there is a northeast wind on the day of White Dew, nine out of ten cotton bolls will be rotten; if there is a northwest wind, nine out of ten will be empty," and so on. In these proverbs, it is not difficult to see the importance that farmers place on the solar terms.
The White Dew solar term marks the beginning of the truly cool season. When many people regulate their health, they excessively emphasize supplementing with nutritious foods like seafood and meat, while ignoring seasonal illnesses, causing harm to themselves and their families, and affecting their studies and work. Here, I want to remind everyone to prevent nasal diseases, asthma, and bronchial diseases during the White Dew solar term. This is especially important for those whose conditions are triggered by allergies, who must be even more cautious with dietary adjustments. For patients with bronchial asthma triggered by allergies, they should usually eat less or avoid fish, shrimp, and other seafood, raw, cold, grilled, braised, and pickled foods, as well as spicy, sour, salty, sweet, and greasy foods. The most common culprits include hairtail, crabs, shrimp, chive flowers, daylilies, and pepper. It is advisable to consume a light, easily digestible diet rich in vitamins. Modern medical research has shown that a high-sodium diet can increase bronchial reactivity; in many regions, the incidence of asthma is directly proportional to the sales of salt, indicating that asthma patients should not eat too salty. In the properties of food, different diets have different "natures," "flavors," "meridian tropisms," "directions of action," and "tonifying or purging" effects. Different properties have different effects and are suitable for different people. Therefore, everyone should adjust their dietary structure according to the changes in the solar terms.
As a health measure, diet is primarily aimed at preventing disease and prolonging life. The nourishing effect of food on the human body is, in itself, an important health and preventive measure. A reasonable diet can ensure the body's nutrition, making the five organs function well and qi and blood abundant. As the "Neijing" states: "When righteous qi is stored within, evil cannot interfere." This means that when the body's righteous qi is strong, evil qi has no opportunity to invade the body, and a healthy state is naturally maintained. Modern medical research has proven that if the body lacks certain nutrients, it will lead to disease. For example, a lack of protein and carbohydrates can cause liver dysfunction; a lack of certain vitamins can cause night blindness, beriberi, stomatitis, scurvy, rickets, etc.; a lack of certain trace elements, such as calcium, can cause rickets, a lack of phospholipids can cause neurasthenia, a lack of iodine can cause goiter, a lack of iron can cause anemia, and a lack of zinc and molybdenum can cause poor physical development. Only through a comprehensive combination of foods, or by selectively increasing these food components, can these diseases be prevented and treated. Chinese medical predecessors recorded over a thousand years ago using animal liver to prevent night blindness, seaweed to prevent goiter, rice bran and wheat bran to prevent beriberi, and fruits and vegetables to prevent scurvy.
In autumn health preservation, especially during the change of solar terms, we must not only embody a comprehensive adjustment of diet and targeted strengthening of certain nutrient-rich foods to prevent disease, but also make use of the specific effects of certain foods to directly prevent certain diseases. For example, scallion white, ginger, cardamom, and coriander can be used to prevent and treat colds; beetroot and cherry juice can prevent measles; white radish and fresh olive juice can prevent diphtheria; lychee can prevent bad breath caused by stomatitis and gastritis; and red radish congee can prevent dizziness. As our country's people increasingly pursue a higher quality of life, the international medical community is also paying more and more attention to the preventive effects of food on disease. Scientists have already discovered and confirmed that many foods can prevent and assist in the treatment of various diseases. For example, it has been found that bitter melon, asparagus, and purslane all have anti-cancer effects. In addition, the role of dietary habits and methods in disease prevention is also receiving increasing attention from scientists.
The "Nan Jing" records: "People rely on food to live. The flavors of the five grains nourish the skin, fill the body, and moisten the hair." This is a description of the nutritional effects of food by the ancients two thousand years ago. It can be seen that the nourishment of food is not only the foundation for human survival, but when the nutrients in food (what TCM calls 'the essence of water and grains') are converted into the body's tissues and energy, it is also the material guarantee for meeting the needs of life's activities. Bian Que, a famous physician of the Warring States period, said: "The foundation of a stable body must rely on food. Those who do not know what is suitable to eat cannot survive." He emphasized that the properties of food vary from person to person.