Lotus seed was listed as a superior grade in the "Shennong Ben Cao Jing" (The Divine Farmer's Materia Medica), and is also known as Lian Shi, Ou Shi, Lian Mi, Lian Rou, etc. Xianglian (Hunan lotus seeds) are considered superior. Xianglian has historically been presented as a precious tribute to the imperial court, hence it is also called "Gong Lian" (tribute lotus). Li Shizhen wrote in the "Ben Cao Gang Mu" (Compendium of Materia Medica): "The lotus seed is sweet in taste, mild in nature, and astringent. Its pure and fragrant aroma carries the essence of the harvest grains, making it the fruit of the spleen."
According to Traditional Chinese Medicine (TCM), lotus seed is neutral in nature, sweet and astringent in taste, and enters the heart, lung, and kidney meridians. It functions to tonify the spleen, benefit the lung, nourish the heart, strengthen the kidney, and secure the intestines. It is indicated for palpitations, insomnia, general debility, spermatorrhea, leukorrhea, and chronic abdominal pain. The greenish embryo in the center of the lotus seed is called Lian Xin (lotus plumule). It is extremely bitter but is considered a valuable medicinal herb. In TCM, it is believed to clear heat, secure essence, calm the mind, strengthen the heart, and lower blood pressure. It can be used to treat restlessness and delirium caused by high fever, as well as nocturnal emissions and spermatorrhea. The "house" where the lotus seed resides is called Lian Fang (lotus receptacle), also known as the lotus pod shell. It can be used to treat retained placenta after childbirth, abdominal pain from blood stasis, metrorrhagia and metrostaxis, and uterine bleeding. There is also "Shi Lian Zi" (rock lotus seed), also known as sweet rock lotus, which gets its name from being old lotus seeds that fall into the mud and become hard and black like stone over time. Clinically, it is often used to treat a bitter taste in the mouth and a dry throat, vexation and heat, chronic gonorrhea, and dysentery.
Lotus seeds are very rich in calcium, phosphorus, and potassium. Every kilogram of lotus seeds contains 81.3 grams of protein, 9.8 grams of fat, 304 mg of carbohydrates, 436 mg of calcium, 1.397 mg of phosphorus, and 31.4 mg of iron. They also contain various other vitamins, trace elements, nuciferine, and kaempferol glycosides. Besides being a component of bones and teeth, these substances also promote blood clotting, activate certain enzymes, maintain nerve conduction, calm the nerves, and maintain the contractility of muscles and the rhythm of the heartbeat. The abundant phosphorus is a main component of nucleoprotein, helps the body metabolize proteins, fats, and carbohydrates, and maintains the acid-base balance; it also plays an important role in sperm formation. Lotus seeds have the effect of nourishing the heart and calming the mind.
For middle-aged and elderly people, especially those who do mental work, regular consumption of lotus seeds can strengthen the brain, enhance memory, improve work efficiency, and prevent the onset of senile dementia. Lotus plumule is extremely bitter but has a significant cardiotonic effect, as it can dilate peripheral blood vessels and lower blood pressure. The plumule is also very effective at clearing heart-fire, treating canker sores, and aiding sleep. Lotus seeds benefit the heart and kidneys, strengthen the spleen to stop diarrhea, and secure essence to calm the mind. However, despite its many benefits, lotus seeds are not suitable for everyone. For example, people who often suffer from constipation are not advised to eat lotus seeds.