Chinese Yams, Sweet Potatoes, and Unpolished Grains for Yin Fluids to Protect the Body

Yin and yang are the two complementary principles of Chinese philosophy. Yin is negative, dark, and feminine; yang is positive, bright, and masculine. The interaction of these principles is thought to maintain the harmony of the universe. The theory of yin and yang is also fundamental to traditional Chinese medicine.

Chinese yams and sweet potatoes are the primary sources of sticky fluids for the body, and such sticky fluids are the most precious yin energy in the body, according to traditional Chinese medicine. When the body lacks yin energy, it is called yin deficiency, which can cause a wide range of symptoms and diseases. Yin deficiency has been known to particularly cause consumptive diseases, like tuberculosis, but it also causes other disorders, such as hyperthyroidism, insomnia, fatigue, excessive perspiration, night sweat, and constipation. In short, diseases characterized by weight loss and loss of strength are most likely due to yin deficiency; so patients with such diseases should consume more foods that can increase yin energy in the body.

Take hyperthyroidism, for example. It is a condition due to excessive secretion of the thyroid gland. Patients with hyperthyroidism may increase their consumption of foods but still keep losing energy and weight. How do we account for this phenomenon? Normally, when people eat more food, they put on weight and increase their energy proportionally, but what happens to patients with hyperthyroidism seems to run counter to this general rule. The fundamental reason is that there's a shortage of yin energy in their body that creates an imbalance between their yin and yang energies. Yin energy nourishes the body to save its energy; whereas yang energy uses the body and spends its energy. Therefore, when yin energy is in short supply, yang energy will be in excess, causing these patients to keep losing energy and body weight while consuming nutritious foods in great amounts.

Some doctors tend to treat hyperthyroidism with large dosages of iodine, but according to the Shanghai College of Chinese Medicine, large dosages of iodine will not do the job because iodine can merely inhibit the release of thyroxine (a principal thyroid hormone) but not inhibit its synthesis. A time-honored Chinese herbal formula that has proven very effective in the treatment of hyperthyroidism contains two categories of ingredients: iodine-rich foods, such as kelp and seaweed, and foods and herbs rich in yin fluids.

Unlike water that flows quickly, yin energy consists of glutinous and sticky fluids that circulate throughout the body very slowly to perform a number of important functions. Many parts of the body are covered with mucous membranes full of glutinous fluids-from the mouth to the esophagus, stomach, small intestine, large intestine, rectum and anus, which is the digestive tract, and from the nose to the throat, trachea and bronchi, which belong to the respiratory system. Such glutinous fluids serve to protect different parts of the body from infections by lubricating them constantly the way oil lubricates an automobile engine. If we compare the human body to an automobile, then yang energy can be compared to gas, which runs out quickly, and yin energy to oil, which lubricates different parts of the automobile slowly. Just as gas is consumed quickly in an automobile, so is yang energy in the body, and just as oil is consumed slowly, so is yin energy in the body.

When the glutinous fluids are in short supply, the parts of the body affected will become more susceptible to infection, inflammation, and cancer. No other foods seem to be able to 

supply the body with glutinous fluids as effectively as Chinese yams, sweet potatoes, and unpolished grains. Glutinous fluids also play a crucial role in retaining the elasticity of blood vessel walls, lubricating joints and cavities, preventing the atrophic degeneration of connective tissues in the liver and kidneys, and resisting diseases related to a shortage of glutinous fluids. Therefore, incorporating these foods into one's diet can be incredibly beneficial for overall health and well-being.