Chinese yam

Dioscorea polystachya

También llamadaShan yao (Chinese) · Dioscoreae Rhizoma (pharmacy name)

En monografías antiguasDioscorea opposita, Dioscorea batatas

A temperate East Asian yam whose mucilage-rich tuber is both an everyday food and shan yao, a gentle 'superior' tonic of Chinese medicine first recorded in the Shennong Bencao Jing. Human evidence is thin: one randomised trial of yam porridge after bowel-cancer surgery in people with diabetes, plus animal studies.

Para qué se usa

Indigestión y dispepsia
Limitada
Eaten in East Asia as a medicinal food for digestive health. A 2025 systematic review found only two human studies (one randomised) and 25 animal studies, mostly favourable but small and heterogeneous.^2,1
Azúcar en sangre y diabetes
Limitada
In a randomised trial of 92 people with type 2 diabetes having colorectal cancer surgery, adding 150 g/day of yam porridge for 3 weeks improved fasting and after-meal glucose, healing time (11.0 vs 13.9 days) and infection rate (6.8% vs 22.2%). Multi-herb Chinese prescriptions containing Dioscorea have also been tested in diabetes.²
Diarrea
Tradicional
Chinese medicine uses it to tonify the spleen and stomach and to stop diarrhoea and discharges. Animal studies show protective effects on the gut lining, including in antibiotic-associated diarrhoea in mice.^1,2
Tónico general
Tradicional
A superior-grade tonic in the Shennong Bencao Jing for the lungs, spleen and kidneys and the 'five fatigues'; used in formulas such as Liuwei Dihuang pills.^1,4

Cómo se prepara

food

The fresh tuber cooked into porridge or other dishes; in TCM it is also cooked with astragalus as a medicinal porridge.

Liang et al. trial (as summarised by Lee 2025): yam porridge 150 g/day for 3 weeks.

Azúcar en sangre y diabetes · Indigestión y dispepsia

decoction

Dried sliced tuber simmered, usually within multi-herb Chinese formulas.

Diarrea · Tónico general

Las cantidades son las que registra la fuente citada, no una recomendación.

Seguridad

Embarazo: Datos insuficientes
Lactancia: Datos insuficientes

No usar si

Yam allergy (dioscorin)

Efectos secundarios

Rare food allergy: anaphylaxis and oral allergy syndrome after boiled yam have been reported

Toxicidad

Eaten widely as a food. The storage protein dioscorin (DB3S) survives cooking and caused anaphylaxis in three people who ate boiled yam; people with this allergy should avoid both raw and cooked yam.

En las tradiciones curativas

Traditional Chinese Medicine
Shan yao (Dioscoreae Rhizoma)
Sweet and neutral, entering the lung, spleen and kidney meridians: tonifies the spleen and benefits the stomach, generates fluids and benefits the lungs, nourishes the kidneys and secures essence, and stops discharge and diarrhoea. Cooked with astragalus as a medicinal porridge, and an ingredient of Liuwei Dihuang and Shanyao Shenqi pills.
Shennong Bencao Jing (superior grade)
Modern pharmacology
Diosgenin source
The tuber contains dioscin and its sapogenin diosgenin, the type of plant steroid used industrially (mostly from other yam species) as a starting material for cortisone, pregnenolone and progesterone.

Compuestos activos

mucilage polysaccharides: the main focus of research; immunomodulatory and gut-protective in animal studies
resistant starch: about half the dry weight of the tuber; raw yam starch lowered triglycerides and LDL cholesterol in rodents
dioscin and diosgenin: steroidal saponin and sapogenin; diosgenin is a precursor for semi-synthesis of steroid hormones
dioscorin: main storage protein, a carbonic anhydrase with antioxidant activity; also the heat-stable allergen behind yam anaphylaxis
allantoin: present in the tuber

Historia

Shan yao was recorded in the Shennong Bencao Jing as a superior herb, first as a wild plant, but has been almost entirely cultivated for about the last 400 years; Henan province is its main and most prized production area. It has been used in China for more than 2,000 years for diarrhoea, diabetes and asthma, and is now exported worldwide as a food.

Fuentes

Referencia, no receta. Nada de esto es consejo médico. Las hierbas pueden interactuar con medicamentos y ser peligrosas en el embarazo; informa a tu médico o farmacéutico de todo lo que tomes.