Nagaimo (ナガイモ, Dioscorea japonica) is an elongated tuber known as Chinese yam, Korean yam, and Japanese mountain yam. In Chinese, it is called Shan-Yao(山药) and used as a TCM herb, in Korea, it is called ma(마). It is commonly severed in Japnanese restaurant as an appitizer. It’s most known for its slimy and gooey texture.
On you dinner table
In Japanese cuisine, nagaimo, which is a type of yamaimo(ヤマノイモ), is commonly used in dishes such as tororo soba and udon noodles. It is also enjoyed raw in a chilled Japanese salad with soy sauce or ponzu citrus soy sauce. The slimy and gooey texture of nagaimo adds a unique taste and mouthfeel to dishes.
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| tororo with rice |
In Korea, the peeled tubers are often cut into pieces and served raw, cooked, steamed, or fried with seasoning sauces. The blended roots can also be made into a nourishing drink known as majeup (ma juice). I personally enjoy peeled raw "ma" in my salad as it is. But, my wife complains often with itching after preparing 'ma'. It is important to handle 'ma' carefully, as it is very slimy and slippery and can cause a mild allergic reaction if touched with bare hands.
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As a medicine
Nagaimo is a popular herb used in Traditional Chinese Medicine (TCM). In China, mountain yam is called Shan Yao. According to TCM, Shan Yao has a neutral temperature and sweet taste, and it is associated with the Spleen, Lung, and Kidney channels.
Nagaimo, also known as Shan Yao, holds a special place in Traditional Chinese Medicine (TCM). This is primarily due to its ability to tonify the Spleen, Kidney, and Lung meridians. The Spleen and the Lungs are sources of Qi and Yang, while the Kidney is the origin of Yin and Jing. These are two contrasting energy properties, and interestingly, Shan Yao is able to tonify both. This gives it a unique ability to strengthen both post-heaven Qi (from the Spleen) and pre-heaven Qi (from the Kidneys).
Further, Shan Yao tonifies both Yin and Yang. It is not limited to either Yin-tonifying or Yang-tonifying categorizations. For instance, in formulations like Sān Líng Bái Zhú Sǎn, Shan Yao works alongside Ren Shen and Bai Zhu to tonify the Spleen Qi (Yang), aiding in treating diarrhea. Conversely, in Liu Wei Di Huang Tang, it partners with Shu Di Huang and Shan Zhu Yu to tonify the Kidney Yin, providing treatment for conditions like sexual dysfunction.
Additionally, its capacity to simultaneously tonify the Spleen and Lungs is exceptional. The Spleen governs 'Grain Qi' or Qi derived from food, and the Lungs handle 'Heavenly Qi' or Qi from respiration. Therefore, Shan Yao can be used to treat both gastrointestinal symptoms like diarrhea, and respiratory issues such as cough.
What's more, the Qi (nature of herb, temperature) of this herb is neutral, meaning it doesn't have any particularly sharp characteristics, making it a very gentle tonifying herb.
Hence, it is no surprise that Shan Yao is one of my personal favorites among tonifying herbs. Its versatility and gentle nature make it a unique and valuable herb in TCM.
Dual Nourishment of Shan Yao
Kidney - Spleen
Yin (Jing) - Yang (Qi)
Pre-heaven - Post-heaven
Spleen - Lung
Grain Qi - Heavenly Qi
It is typically consumed in a dosage of 9-30 grams. One of the key actions of Shan Yao is that it tonifies and strengthens the Spleen and Stomach. This means that it can improve digestion and absorption of nutrients. This action is particularly useful for individuals who have weak digestive systems, experience bloating or indigestion, or diarrhea. Another important action of Shan Yao is that it tonifies the Kidneys and stabilizes them. The Kidneys are an important organ in TCM and are responsible for a wide range of functions such as regulating water metabolism, storing essence, and controlling the bones. By tonifying the Kidneys, Shan Yao can help to improve overall kidney function and enhance overall vitality. In addition, Shan Yao is also known for its ability to tonify Lung Qi and augment Lung function. This means that it can be beneficial for individuals who suffer from respiratory problems such as chronic cough, asthma, or shortness of breath. By strengthening the Lung Qi, Shan Yao can help to improve lung function and enhance overall respiratory health.
Nutrition
Chinese yam is also known for its nutritional benefits. It is a good source of vitamins B1 and C and contains significant amounts of potassium, phosphorus, calcium, magnesium, iron, zinc, copper, and manganese. It is also rich in diosgenin, a phytoestrogen that acts like estrogen in the body. It can be a supplement for menopausal women. (Folwarczna J, Zych M, Nowińska B, Pytlik M, Bialik M, Jagusiak A, Lipecka-Karcz M, Matysiak M. Effect of diosgenin, a steroidal sapogenin, on the rat skeletal system. Acta Biochim Pol. 2016;63(2):287-95)
Shan Yao or tororo, or ma is a popular ingredient in both TCM and Japanese and Korean cuisine. It has various health benefits and nutritional value, making it a great addition to any diet. However, it is important to handle it with care and consult with a healthcare professional before incorporating it into your diet for medicinal purposes.