This root is familiar in daily life and is also considered a valuable remedy in traditional medicine. In Vietnam, it is easily found, inexpensive, yet offers numerous health benefits, particularly in nourishing the kidneys, regulating blood sugar, and promoting longevity.

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Dioscorea opposita (commonly known as yam or “Hoài sơn” in Vietnamese) is a climbing medicinal plant with smooth, slightly angled, pale pink stems that often grow wild in the mountainous forests of northern Vietnam. The part used medicinally is the tuber root, which is brownish-gray on the outside and contains abundant white starch inside. After harvesting, the roots are washed, peeled, and then sun-dried or oven-dried before being processed into medicine in traditional Eastern medicine.

According to modern research, yam contains about 63.25% starch, 0.45% lipids, 6.75% protein, and 2–2.8% mucilage. It is also rich in bioactive compounds such as dioscin, allantoin, steroidal saponins, choline, as well as various amino acids, oxidative enzymes, vitamin C, and trace minerals. These constituents make yam a valuable medicinal resource with wide-ranging health benefits.

Notable Health Benefits of Yam

1. Blood sugar control

In traditional medicine, yam is described as sweet and neutral in nature, used to tonify the lungs and kidneys, strengthen the spleen and stomach, generate fluids, and quench thirst. It is often prescribed for conditions such as diabetes, nocturnal emissions, chronic cough, and frequent urination. Modern studies show that yam enhances the secretion of GLP-1 hormone, stimulates the pancreas to produce insulin, and helps regenerate pancreatic beta cells. Regular consumption also slows down the conversion of starch into sugar, reduces carbohydrate cravings, stabilizes post-meal blood sugar, and lowers the risk of diabetes complications.

2. Kidney nourishment

Yam is considered a “kidney-nourishing food,” known to replenish kidney energy while also supporting the spleen, stomach, and lungs. In traditional medicine, it is commonly used for weak kidney yang, low vitality, cloudy urine, loose stools, and general body weakness.

3. Digestive support

Yam protects the gastric mucosa, reduces inflammation, and neutralizes stomach acid by maintaining the enzyme carbonic anhydrase. Dioscin (a saponin) acts as an antioxidant, reducing mucosal damage, while diosgenin promotes the growth of beneficial gut bacteria, thereby improving digestion.

4. Antioxidant effects

Rich in manganese, vitamin C, and powerful antioxidants, yam helps eliminate free radicals, protect DNA, and reduce the risk of cardiovascular diseases and cancer.