What is Chinese yam?
Chinese yam (Dioscorea
polystachya or Dioscorea batatas) is an ornamental vine that is
native to Asia. It also grows in North America, but it isn’t related to the
sweet potatoes called yams that are popular there. Other names for Chinese yam are
cinnamon vine, and shan yao.
Chinese yam is used in Chinese herbal medicine,
traditionally to treat disorders related to the stomach, spleen, lungs, and
The roots of Chinese yam contain diosgenin,
which can be used to produce steroids such as estrogen and progesterone in a
While the tuber and bulbs of Chinese yam are
edible, generally only the tuber is consumed as food.
What is Chinese yam used for?
As an herbal treatment, Chinese yam is mainly
used to target the stomach and spleen, but also thought to help the lungs and
kidneys. It can help treat:
- poor appetite
- chronic diarrhea
- dry coughs
- frequent urination
Chinese yam contains allantoin, a natural
compound that can accelerate the growth of healthy tissue and reduce healing
time. Topically, Chinese yam can be applied to ulcers, boils, and abscesses on
the skin for treatment. Its leaf juices can also treat scorpion stings and
The diosgenin in its roots is a
phytoestrogen, a natural, plant-based estrogen. When processed in a lab,
diosgenin can be used to manufacture progesterone, although in its original
form, Chinese yam doesn’t contain progesterone or other human hormones.
Chinese yam and other wild yam extracts are
often promoted to women as a natural alternative to postmenopausal hormone
therapy. However, there is no scientific evidence to support claims regarding
its safety or effectiveness.
What are the benefits of Chinese yam?
People with conditions related to the
stomach, spleen, kidneys, lungs, or skin may benefit from Chinese yam. In
addition to these uses, promoters of the herb claim it can be used as a remedy
for many conditions, including:
- hot flashes associated
- postmenopausal vaginal
- premenstrual syndrome
- gallbladder problems
- rheumatoid arthritis
- menstrual disorders
- digestion disorders
- dry or chronic cough
This study on the gastrointestinal function in rats
shows that Chinese yam extract not only aids in digestion but can help turn
some intestinal flora in the stomach into helpful bacteria.
shows that Chinese yam also has antioxidant properties. The study concludes
that Chinese yam contains trace amounts of zinc, manganese, iron, copper, and
selenium, and that taking it as a daily supplement is beneficial as an
Chinese yam can also help with diabetes, by
modulating oxidative stress, antioxidant activities, and lipid profiles, as
shows. It can also improve kidney and liver function.
Chinese yam extract also has the potential to
help prevent atherosclerosis, a disease in which plaque builds up in the
arteries, according to this study.
In addition to its potential medicinal
properties, Chinese yam is a nutritious food. It primarily consists of water
and starch and is a source of:
- vitamin B-1
- vitamin C
- amino acids
What are the risks of Chinese yam?
Chinese yam is safe for most adults, but if
you’re taking medication, talk to your doctor about possible side effects.
Though Chinese yam doesn’t contain estrogen,
it has properties that can cause it to act like a mild form of estrogen. It can
negatively interact with hormone replacement therapy or birth control pills,
and pregnant or breast-feeding women should avoid it, as should women with
hormone-sensitive disorders, such as:
- uterine fibrosis
- cancers of the breast, uterus, or ovaries
Allergic reactions are rare, but can include
rashes and asthma. Large doses of Chinese yam can cause:
People with a protein S-deficiency should also
avoid Chinese yam because its estrogen-like properties may increase the risk of
How is Chinese yam taken?
In its natural form, Chinese yam can be eaten:
- in soup
Chinese yam is also available as:
- dried root
- extract, or tea
Chinese yam is also administered in creams and
gels that can be applied directly to your skin. Some of these may contain
synthetic progesterone, though they may be promoted as containing natural
progesterone. Other additions to these compounds can include vitamins,
minerals, and other herbs.
Chinese yam is a versatile tuber, with many
beneficial health qualities, from helping with diarrhea, to relieving diabetes
symptoms, to general antioxidant benefits. It can also be prepared and taken in
many ways and eaten simply for its nutritional value. Be sure to talk to your
doctor before adding it to your diet and about potential side effects.