LOTUS SEED: FOOD AND MEDICINE
The lotus (Nelumbo nucifera; see Figure 1) is a fresh-water plant that grows in semitropical climates. It originated in India and was brought to other countries, ranging from Egypt to China, about 2,000 years ago. It is cultivated extensively in Southeast Asia (mostly in China), primarily for food, with much smaller amounts for herbal medicine. All parts of the plant are utilized, but the primary reason for its current widespread cultivation is to collect the rhizomes (sometimes referred to as roots) and seeds. The whole plant is harvested in late summer when the seeds have matured.
The rhizomes are a food used extensively in China and Japan, sold whole or in cut pieces, fresh, frozen, or canned. They are consumed as a vegetable, usually fried or cooked in soups. Japan is one of the primary users of the rhizomes, representing about 1% of all vegetables consumed there. Japan grows its own lotus but still has to import 18,000 tons of lotus rhizome each year, of which China provides 15,000 tons.
Lotus seeds (lianzi) are a major product of southern China, though production figures are not available. There is substantially less weight of the dried seeds per plant than the weight of the fresh rhizomes, so the total production quantities may be on the order of a few thousand tons. Additionally, lotus leaves are used as a flavoring and a wrapper for rice preparations in making dim sum; the plumules (large seed cases) are dried for use as decorations. Lotus stems are used in preparing salads and the dried flowers are used in cooked dishes, such as Mandarin Duck and Lotus Flowers; the fresh flowers are a common decoration. The bitter lotus embryos within the seeds, and the lotus stamens are primarily used as medicines rather than foods.
The seeds are roasted or candied for eating directly; made into a paste for producing sauces and cake fillings (in mid-Autumn it is customary to serve "moon cakes" which have a filling made of lotus seeds and walnuts); and cooked in soups, usually with chicken or beans. An example of the latter is a soup presented at banquets for newlyweds, made with red beans and lotus seeds. Red beans (hongdou) represent strength, while lotus seeds (lianzi) symbolize the newlyweds being blessed with a child each year. The soup is also presented at the New Year's festival.
In a large pot, combine 7 cups cold water, red beans, lotus seeds and tangerine skin. Bring to a boil over high heat, reduce heat and simmer, covered, with pot lid slightly ajar, for 1 and 1/4 hours to 1 and 1/2 hours or until beans become tender. When beans are tender and open, and lotus seeds soften, add sugar; stir. Turn off the heat, pour into a heated tureen and serve. Makes 6 servings. Because the soup is sweet, it is also served as a desert. Another desert preparation is:
Soak the lotus seeds in water overnight; combine drained lotus seeds and 3 cups water and bring to boil over medium heat for 15 minutes; remove from heat and drain. Smash the cooked lotus seeds in a blender and pour the resulting paste into a big bowl. Dissolve the cornstarch in four tablespoons of water, pour into a small cup and set aside. Bring 6 cups of water to a boil over medium heat in a non-stick pot, then add the sugar, salt, pineapple, and lotus paste. Return to a boil and mix in the cornstarch liquid. Stir constantly until smooth and thickened. Reduce the heat and simmer for one minute. Remove from heat, pour into a large bowl, place pieces of the cherries on the top and serve hot. Makes 6 servings.
Yet another example is this one with lotus and longan:
Put dried lotus seeds into a basin. Put just enough cold water to cover the lotus seeds and add bicarbonate of soda. Set aside for 2 to 2 1/2 hours. Drain, then wash thoroughly. Bring 5 cups of water to a boil. Add soaked lotus seeds and cook until the seeds turn soft. Add dried longan and rock sugar. Simmer until longan turns soft and sugar dissolves. Serve this dessert either hot or cold. In Asia, this mixture is flavored with pandan leaves (two leaves are added during the last few minutes of simmering the longan and sugar).
Lotus seeds have been analyzed to determine their nutritional value. In 100 grams (yielding about 350 calories of energy), there are 63-68 grams carbohydrate (mostly starch), 17-18 grams of protein, and only 1.9-2.5 grams fat; the remainder is water (about 13%), and minerals (mainly sodium, potassium, calcium, and phosphorus). As a protein source, lotus seeds are relatively good, with a one ounce serving (of dried seeds) providing 5 grams. The seeds are low in fiber and not a good source of vitamins. All the recipes given above are very low in fat, but high in carbohydrates.
Lotus seeds are classified as astringents, being sweet and neutral, and benefiting the spleen, kidney, and heart. The sweet taste and nourishing qualities of the seed are responsible for the benefit to the spleen; this helps stop diarrhea associated with qi deficiency. The astringent quality helps prevent loss of kidney essence, so the seeds are used to treat weak sexual function in men and leukorrhea in women. The seed also has calming properties that alleviate restlessness, palpitations, and insomnia (more so in the whole seed with embryo). The medicinal dosage is 6-15 grams when it is combined with other herbs that have similar applications and double that when used as the main ingredient (the amount in the bean and lotus soup is about 7 grams per serving and in the cream lotus soup and sweet lotus desert about 37-40 grams per serving).
As an example of a therapy for diarrhea, one ounce of lotus seed is soaked in warm water for a few hours, then an adequate amount of rock sugar is added (to taste), and the mixture is simmered until the lotus seeds are well done. To this thick soup a cup of tea-made by steeping 5 g of black tea in boiling water-is added to yield the medicinal food. Traditional herb formulas for diarrhea are described in the next section.
Inside the seed there is a green embryo that is quite bitter; it is usually removed before the seed is provided as a food product. The embryo (lianzixin; heart of the lotus seed), is classified as bitter and cold and benefiting the heart; it dispels pathogenic heat from the heart to treat fidgets and spontaneous bleeding due to heat. The bitter components are isoquinoline alkaloids with sedative and antispasmodic effects. The alkaloids dilate blood vessels and thereby reduce blood pressure. Small amounts of the alkaloids are found in the seeds with embryo removed, and these may contribute an antispasmodic action for the intestines, helping to alleviate diarrhea.
The lotus leaves (heye) are also bitter, but neutral, and are said to benefit the stomach, spleen, and liver. They are used for treatment of summer heat syndrome and dampness accumulation; they also contain the lotus alkaloids with hypotensive effect. Lotus leaf has become popular for lowering blood lipids and treating fatty liver; it is commonly combined with crataegus, which promotes blood circulation and lowers blood fats, for that purpose. Lotus stems (hegeng) are used medicinally in the same way as the leaves for treatment of summer heat and are used also to treat tightness in the chest due to obstruction of qi circulation.
Lotus stamen (lianxu) is sweet, astringent, and neutral, benefiting the heart and kidney; it is mainly used for preventing discharge, such as treatment of leukorrhea or for frequent urination. It contains flavonoids and a small amount of alkaloids. Lotus nodes, the rhizome nodes (oujie), are astringent and neutral, benefiting the liver, lung, and stomach. They are mostly used to control bleeding. All the parts of the lotus have some antihemorrhagic effect, but the rhizome nodes are relied upon for that purpose specifically. The active component for reducing bleeding is not yet established, though quercetin and other flavonoids may play a role by improving capillary wall strength. By charcoaling the lotus plant parts, as is sometimes done, a hemostatic effect is assured, as charcoal itself has this effect (it promotes blood coagulation).
There are some well-known traditional formulas relying on lotus seeds as an important component. The best known is Sheng Ling Baizhu San (Ginseng and Atractylodes Combination), which is comprised of lotus seed, ginseng, hoelen, atractylodes, licorice, coix, dolichos, dioscorea, cardamon, atractylodes, and platycodon. The herbs tonify the spleen and aid circulation of moisture. The formula is indicated for weak digestion with chronic diarrhea. First described in the Hejiju Fang (1110 A.D.), Shen Ling Baizhu San has been made into a popular patent remedy.
Another lotus seed formula is Qipi Tang (Lotus and Citrus Combination), which is also a therapy for weak digestion leading to diarrhea. The formula contains lotus seed, ginseng, atractylodes, hoelen, licorice, alisma, dioscorea, citrus, and crataegus. All the ingredients are used to improve digestion and aid circulation of moisture to alleviate diarrhea. The formula Sishen Tang (Four Wonders Decoction; also called Dioscorea Combination) is made with lotus seed, dioscorea, hoelen, euryale (a seed from a relative of lotus), and coix. It is used for indigestion and diarrhea, and is considered a mild sedative.
A formula using lotus seed for a different application is Qingxin Lianzi Yin (Clear the Heart Lotus Seed Drink; or simply, Lotus Seed Combination), comprised of lotus seed, ginseng, astragalus, ophiopogon, plantago seed, lycium bark, hoelen, scute, and licorice. It is used for urinary disorders, including urinary stones, kidney inflammation, and urinary tract infection; it is also used for disorders of the reproductive organs, such as prostatitis and leukorrhea. The formula addresses a combination of dampness accumulation (ginseng, astragalus, lotus seed, hoelen, and licorice tonify the spleen to aid moisture circulation; plantago seed and hoelen drain excess moisture) and heat (lycium bark, scute, and ophiopogon clear heat, and are selected for persons of weaker constitution). The damp-heat syndrome leads to tenderness, swelling, and pain in the lower abdomen, urinary irregularity, and discharge of fluids.
Another astringent formula is Jinsuo Gujing Wan (Pill of Golden Lock; also called Lotus Stamen Formula), comprised of lotus stamen and lotus seed, dragon bone, oyster shell, tribulus, and euryale. All the ingredients have some astringent properties. Its basic function is to restrain (like a lock) any further loss of essence due to disease or aging. It is often used for urinary disorders, especially frequent urination and turbid urine. Jinsuo Gujing Wan, first described in Yifang Jijie (Analytic Collection of Medical Formulas, by Wang Ang, 1682), has been made into a popular patent remedy.