November and December are the peak season for water chestnuts. The water chestnut has a purplish-black skin and white flesh, sweet, juicy, and crisp. It can be eaten as a fruit or a vegetable, and has been praised since ancient times as the "underground snow pear," while northerners consider it the "ginseng of Jiangnan."
Water chestnuts are rich in protein and carbohydrates but are not high in calories. Traditional Chinese medicine considers water chestnuts to be a cold-natured food that can clear heat and purge fire, as well as supplement nutrition. It has a very good fever-reducing effect for patients in the early stages of fever, with about 10 pieces being the recommended amount each time. It also has the effects of cooling the blood and detoxifying, promoting urination and bowel movements, resolving dampness and eliminating phlegm, and aiding digestion and relieving bloating.
"Five-Juice Drink," a famous formula from the Qing Dynasty by the renowned warm disease specialist Wu Jutong for treating fever injury to body fluids and thirst, is made by blending the juices of water chestnuts, pears, lotus root, reed rhizome, and Ophiopogon japonicus. These five juices are all sweet, cold, and cooling products that nourish yin, making them suitable for patients at the beginning of a fever or after a high fever has subsided. However, it is not suitable for consumption during a high fever. During seasons with many respiratory infectious diseases, eating fresh water chestnuts is also beneficial for the prevention and treatment of epidemic cerebrospinal meningitis, measles, whooping cough, and acute pharyngitis.
Children often experience fevers in the winter, and water chestnuts are also very suitable for them to eat. It not only helps to reduce fever but also promotes the development of children's teeth and bones.
This is because the phosphorus content in water chestnuts is relatively high among root and stem vegetables. It promotes human growth and development and meets the needs of maintaining physiological functions. At the same time, it can also promote the metabolism of the three major substances in the body—sugar, fat, and protein—and regulate the acid-base balance. In British research on water chestnuts, an antibacterial component that is not heat-resistant was discovered—puchiin. It has a certain inhibitory effect on *Staphylococcus aureus*, *Escherichia coli*, and others, and can also lower blood pressure. This substance also has a preventive and therapeutic effect on lung, esophageal, and breast cancer.
However, water chestnuts should not be eaten raw. As water chestnuts grow in mud, their outer skin and interior may be contaminated with a large number of bacteria and parasites. They must be thoroughly washed and cooked before consumption, and cooked water chestnuts are sweeter.