Yam tubers have flat-oval seeds, hence the name "yam egg." Both medicinal and edible, they're beloved and commonly found on tables across many regions. Some areas also call edible potatoes "yam eggs," though they're not the same thing.
Distinguishing Yam Eggs from Potatoes
1. Yam eggs refer to the above-ground portion of the yam plant, identical to the root yam in both culinary uses and medicinal properties. While their appearance resembles small potatoes, they are fundamentally distinct.
2. Potatoes, also known as spuds, are the underground tubers of a plant rich in starch. While their appearance resembles yam tubers, potatoes are generally larger in size.
3. Yam tubers do not produce toxins. However, potatoes stored for extended periods, especially those that have sprouted, develop sprouts that can produce toxins. Therefore, sprouted potatoes should not be consumed.
4. Yam offers significantly more benefits than potatoes, particularly due to its potent medicinal properties. It is an excellent food for strengthening the stomach and spleen, and is also beneficial for diabetics. Potatoes, however, serve only as a food source without any medicinal effects. They are primarily used in cooking to provide substantial nutrition.
Benefits of Chinese Yam
Chinese yam seeds are flat and oval-shaped, hence the name "yam" (which means "egg" in Chinese). It is both edible and medicinal, deeply loved by people and a staple on tables across many regions. As a medicinal herb, it is widely used, playing both leading and supporting roles in numerous prescriptions.However, its fame hasn't always been unblemished. Historically, it endured periods of misfortune, suffering the indignity of multiple name changes. Originally called "shuyu" (薯蓣), it faced an imperial taboo when Emperor Li Yu ascended the throne. Since "yu" (蓣) and "yu" (豫) share the same pronunciation, it was publicly renamed "shuyao" (薯药) to avoid the emperor's name.It hoped this change would bring lasting peace, but fate proved unforgiving. When an emperor named "Zhao Shu" ascended the throne, the character "shu" (薯) again sounded like "Shu" (曙). To avoid this taboo, it was renamed once more to "shanyao" (山药).
Modern research indicates that yam's primary components include mucilage, choline, amylase, glycoproteins, free amino acids, and vitamin C—all essential substances for human health. Within the body, mucilage breaks down into nourishing proteins and carbohydrates, while amylase hydrolyzes starch into glucose, serving as one source of energy for the body.
The claim that regular consumption of yam makes one "grow more beautiful over time" is not without basis. Many ancient scholars discovered and applied this property. Medical expert Li Shizhen noted its ability to "moisturize the skin." Li Zhi, one of the Four Great Masters of the Jin-Yuan period, stated: "For dry skin, use this substance (yam) to moisturize it."The Commentary on the Essence of Medicinal Substances records its ability to "nourish and warm the skin." The Divine Farmer's Classic of Materia Medica notes its use in "tonifying the middle energizer, boosting vitality, building muscle, and enhancing hearing and vision with long-term use." The Seeking Truth in Materia Medica explains its skin-moisturizing mechanism lies in its capacity to "nourish the yin of the spleen and lungs, thereby moisturizing the skin and hair and promoting muscle growth."Thus, its beautifying effect lies in internal nourishment—indirectly achieving skin rejuvenation through yin tonification. This constitutes a fundamental treatment, fundamentally distinct from cosmetic methods that merely cover or soak the skin superficially. It should be clarified that in some regions, the edible potato is also called "yam tuber," though the two are not the same.The potato, scientifically known as Solanum tuberosum, is an imported crop originating in Peru. It was introduced to China from Southeast Asia and Europe in the 18th century. Cultivation spread from southern China to northern and northwestern regions, reaching the northeast only in the 19th century. Due to its ease of cultivation, storage, and transportation—making it highly suited to China's conditions—it quickly gained popularity nationwide, becoming one of the staple vegetables in people's daily lives.
Abroad, potatoes are highly valued, earning titles like "underground apple," "ground pear," "second bread," and "perfect food." They can serve as either a staple or a side dish, rich in various nutrients.They contain 2.2% protein, 14.6% carbohydrates, 0.62% fat, and 0.7% crude fiber, along with significant amounts of calcium, phosphorus, iron, vitamin C, carotene, and B vitamins.Experts from an American agricultural research institute believe potatoes offer more advantages than rice or wheat. A meal consisting solely of potatoes and whole milk can provide all the essential nutrients the human body needs. In China, potatoes are primarily treated as vegetables, with fewer customs of consuming them as a staple food. Potatoes have long been used medicinally abroad, mainly for treating headaches, rheumatism, fractures, and indigestion.Traditional Chinese medicine classifies potatoes as sweet and neutral in nature, possessing properties that regulate the middle burner, harmonize the stomach, strengthen the spleen, and boost qi. They are recommended for treating stomach pain, abdominal pain, constipation, and skin eczema. Functionally, this "foreign yam tuber" shares similarities with China's traditional yam tuber, and regular potato consumption also promotes healthy physical development. Eating more yam tubers leads to better growth and appearance.