Chinese yam, also known as Dioscorea opposita or Shan Yao in Pinyin, has long been used as a congenital and acquired tonic, earning it the name “fairy food.” Among all cooking methods, stir-fried thick yam slices and yam stew are the most common practices. Well, what is Chinese yam good for? From the perspective of traditional Chinese medicine, Chinese wild yam is credited with tons of health benefits since it is good at tonifying kidney and spleen. TCM believes that the kidney is the congenital origin and in charge of heredity and fertility while the spleen is the acquired foundation and responsible for digestion and absorption, which thus is the main source of body’s nutrition. So to speak, it benefits both the root of innate and acquired constitution, which is quite rare in dietary therapy. So, is Chinese yam good for you? If it is, do you know how to cook Chinese yam to make the most of it?
What is Chinese yam?
It mainly refers to the roots of Dioscorea opposita. Thunb., which is a vine plant in the family Dioscoreaceae. Besides, the root of Dioscorea japonica Thunb., a species of wildlife around China, is also used as Shan Yao medicinally because of the similar efficacy. Hence, other names of it include Rhizoma Dioscoreae, nagaimo, Common Yam Rhizome, Dioscorea oppoistifolia, Korean yam, Dioscorea batata, Chinese yam rhizome, Chinese mountain yam, dioscorea yam, Dioscorea villosa, dioscoreae rhizoma, and so on. In China it is basically produced in Henan, Hunan, and regions south of the Yangtze River. Traditionally the one from Henan (Huaiqing) is believed with highest medicinal properties and nutritional value. That’s the reason why it is often called “Huai Shan Yao.” It is usually harvested after Frost’s Descent (18th solar term). And there are two types of finished products available – “Mao Shan Yao” and “Guang Shan Yao”. The former one still needs to go through steps of scraping off the tertia and drying in the sun or over a fire; based the previous steps the latter one still needs to be soaked until it becomes soft, rubbed and pressed into cylinder, dried in the sun, and finally polished.
It is herbaceous twining vine. Tubers are oblong, straight, up to 1 meter, and with mucilaginous, white section when fresh. Stems are usually with purple, dextral, and hairless. Simple leaf is alternate in the lower part of the stem, opposite above the middle, and rarely in 3 whorls; blade is large, from ovate triangular to broadly ovate halberd, 3 to 9cm long, 2 to 7cm wide, and with acuminate apex and deeply cordate or halberd-shaped base. Inside the leaf axils, there are often bulbils. It is dioecious. Male inflorescence is spica, 2 to 8cm long, and nearly erect; 2 to 8 of them are located in leaf axils and occasionally in conical arrangement; rachis is clearly in the shape of zigzag; bracts and tepals are with purple brown spots; the outer petals are broadly ovate while the inner petals are oval; stamens are 6. Female inflorescence is spikes, 1 to 3 in the leaf axils. Capsule is not reflexed, in the shape of flat round trigone or round trigone, 1.2 to 2.0cm long, 1.5 to 3.0cm wide, and with white powder outside. Seed is located in the central axis of each room and surrounded by membranous wings. Bloom time is from June to September and fruiting time is from July to November. Wild habitats include hillslopes, valley forest, stream, roadside shrubs or weeds. Or it can be cultivated too.
It contains diosgenin, mucilage, choline, starch, sugar, protein, free amino acids, abscisin, vitamin C, amylase, and so on.
Chinese yam benefits
So, what is Chinese yam used for? Modern pharmacology finds that it has preventive and therapeutic effects on spleen-deficiency model experiments on rats, bidirectionally regulates the isolated intestinal movement, helps digestion, promotes cellular and humoral immune responses in mice, lowers blood sugar, inhibits oxidation, and more. Tang Ye Ben Cao (Materia Medica of Decoctions), published in 1289 and written by Wang Haogu, documents that it can tonify middle-Jiao and Qi, replenish qi, nourish blood, invigorate spleen and supplement qi. In addition, in combination with licorice root it can nourish Yin and generate body fluid while combined with Chinese privet it can invigorate the spleen and stop diarrhea. As you can see now, its medicinal uses are enormous.
What’s more, it can be used by people of all ages. For women who are suffering from hands and feet cold all the time due to blood-qi deficiency, Chinese yam chicken soup is a very good option; for men who are suffering from stomach problems caused by stress, Rice Chinese yam cake is an ideal pain reliever; for the elderly who are especially susceptible to illnesses like colds because of relatively weak constitution, yam ribs soup can be a good remedy; for babies who can afford tonics, dried Chinese yam baby food is the best choice.
Top 8 China yam health benefits
1) Strengthening the spleen and stomach to aid digestion. Fresh yam contains amylase, polyphenol oxidase, and other matters, which make it a perfect medicine and food to help digestion and absorption. It helps regardless of it is spleen-yang or stomach-yin deficiency. Therefore, clinically it treats deficient spleen-stomach, loss of appetite, body fatigue, diarrhea and other diseases;
2) Nourishing kidney and enriching essence. It contains a variety of nutrients, which can make body stronger, nourish kidney, increase sperm count, and improve sperm quality. So, it is widely used for impotence, nocturnal emission, abnormal vaginal discharge, frequent urination, and more;
3) Benefiting lung to stop cough. It contains saponins and mucilage, which have a lubricating and moisturizing effect. Hence, it benefits lung qi, enriches lung yin, and treat chronic cough due to lung deficiency and phlegm;
4) Lowering blood sugar. Fresh yam contains mucus protein that can lower blood sugar. Therefore, it can be used in the treatment of diabetes or a good diabetic diet;
5) Promoting longevity. Raw yam contains a lot of mucus protein , vitamins and trace elements, which can effectively stop the precipitation of lipids in the blood vessel wall and thereby prevent cardiovascular. In other words, it tranquilizes the mind, promotes intelligence, and prolongs life;
6) Preventing hepatic coma. Recent studies have found that it is with sedative effect and can be used to prevent hepatic coma;
7) Soothing mood and regulating sleep. Unlike ginseng, the medicinal properties of Chinese yams are quite mild and slow. And it can soothe mood and adjust sleep while regulating the function of spleen.
8) Tonifying deficiency. Zhang Zhongjing, one of the best Chinese physicians in TCM history, was very good at using this herb. In his medical book Jin Gui Yao Lue (Essential Prescriptions of the Golden Coffer), it is used to cure qi-blood deficiency, stomach pain, arthralgia, amenorrhea, irregular menstruation and other symptoms.
Sample Chinese yams recipes on herbal remedies
The Chinese Materia Medica says that it is sweet in flavor and neutral in nature and goes to meridians of lung, spleen, and kidney. Vital functions are tonifying spleen, nourishing lung, reinforcing the kidney, and benefitting essence. Essential Chinese wild yam uses and indications include diarrhea caused by deficient spleen, no desire to eat and edema, cough and asthma due to lung deficiency, consumptive thirst, emission, morbid leukorrhea, frequency of urination cause by kidney deficiency, carbuncles, and scrofula. Recommended dosage is from 15 to 30 grams (or 60 to 250 grams in large dose) in decoction. In addition, there are other forms available, such as Chinese yam supplement, tea, extract, diet pills, drink, powder, and more.
1) Shen Ling Bai Zhu San from Tai Ping Hui Min He Ji Ju Fang (Formulas of the Peaceful Benevolent Dispensary). It is combined with Ren Shen (Ginseng Root), Fu Ling (Poria), Bai Zhu (White Atractylodes), Bai Bian Dou (Hyacinth Bean), Sha Ren (Black Cardamom), etc. to treat today’s diseases such as chronic gastroenteritis, diabetes, anemia, pediatric dyspepsia, nutritional edema, chronic hepatitis, chronic nephritis, and more.
2) Wan Dai Tang from Fu Qing Zhu Nu Ke (Fu Qing-zhu’s Gynecology). It is formulated with White Atractylodes, Ginseng, Bai Shao (White Peony Root), Che Qian Zi (Plantain Seeds), Gan Cao (Licorice Root), etc. to cure morbid leukorrhea.
3) Shen Qi Wan from Essential Prescriptions of the Golden Coffer. It is joined with Di Huang (Rehmannia), Poria, Shan Zhu Yu (Asiatic Cornelian Cherry Fruit), Mu Dan Pi (Tree Peony), Ze Xie (Water Plantain Root), etc. to heal kidney-qi deficiency causing lower back pain and weak legs, nocturia or enuresis, spermatorrhea, premature ejaculation, and clear, watery vaginal discharge or kidney-yin deficiency causing weight loss, soreness and weakness of waist and knees, and nocturnal emission.
4) Liu Wei Di Huang Wan from Xiao Er Yao Zheng Zhi Jue (Key to the Therapeutics of Children’s Diseases). It is matched with Rehmannia, Zhu Yu, Mu Dan Pi (Tree Peony Root Cortex), Poria, and Ze Xie to treat kidney-yin deficiency, dizziness, tinnitus, weak knees and low back, hot flashes, night sweats, nocturnal emission, and more.
5) Yu Ye Tang from Yi Xue Zhong Zhong Can Xi Lu (Records of Heart-Felt Experiences in Medicine with Reference to the West). It is equipped with Huang Qi (Astragalus Root), Tian Hua Fen (Trichosanthes Root), Zhi Mu (Anemarrhena Rhizome), etc. to treat wasting and thirsting disorder.
Chinese yam side effects and contraindications
Chinese yam dishes are very popular thanks to their great taste, mild tonic properties, and high nutritional value. However, please pay attention to the following cases when you are eating it.
1) It contains estrogen and over consumption may over-stimulate the hormone and cause endometrial hyperplasia, menstrual disorder, prolonged menstrual period, menstrual pain, and so on;
2) It shouldn’t be used in excess syndrome. Or it will aggravate the symptoms;
3) Its mucilage contains plant alkaloid, which is prone to cause allergy symptoms like itch;
4) It may be eaten raw. But it is best not to do so since its mucilage contains saporin and plant alkaloid, which can be eliminated by only high temperature;
5) Don’t eat it along with Gan Sui (Euphorbia Kansui) since they have opposite efficacy. Otherwise, they will stimulate the stomach, accelerate gastrointestinal motility, and then lead to diarrhea;
6) Don’t consume it together with carp. Or it may cause adverse reactions, such as vomiting, nausea, abdominal pain, and others;
7) It is not suitable for people with constipation since it is of astringent nature. Or it will only aggravate the symptom of constipation.