Wild Yam

Dioscorea villosa    Dioscoriaceae.  The common name is wild yam and the Chinese name is shu-yu.

Dioscorea villosa has some ethnobotanical use among the Fox Indians for relief of the pain of childbirth.¹  It was popularized during the Eclectic period of the 1800s, being marketed primarily as a nausea remedy, but was also used to treat painful menstruation, rheumatism, intestinal colic and other spasmodic problems.²

In 1940 it was discovered how to convert diosgenin from Dioscorea to progesterone, leading to the

oral contraceptive. The Mexican wild yam, Dioscorea macrostachya, was the primary source, but when that became overharvested, the pharmaceutical industry turned to Dioscorea villosa.  At one point steroids and other substances derived from diosgenin constituted 15 percent of the world pharmaceutical market.

There are 600 or so species of  Dioscorea world wide, most of them being found in the tropics or subtropics.  Only a few of these are edible.  Dioscorea villosa is native to the United States, growing in swampy woods from New England and Minnesota, down to Virginia and Texas.  It is a climbing vine that is a deciduous perennial. Dioscorea is not related to the yams we buy in the grocery store.  Those yams are actually a type of sweet potato, Ipomoea batatas.

The underground roots and rhizomes are the parts of the plant used.  It is readily available as a bulk herb, capsules, hydroalcoholic extract, and it is frequently mixed with other herbs.

The active constituents of Dioscorea are a group of steroidal saponins, the most important of which is diosgenin.  Dioscorea has been found to decrease lipid peroxidation and serum triglycerides and increased HDL levels. In addition diosgenin reduces fatigue, inflammation, stress and is a phytoestrogen.³

There has been a good deal of confusion about Dioscorea among the public as well as among professionals.  The Dioscorea group has been one of the primary contributors of steroid hormones for medicinal use and diosgenin can be converted to progesterone in a laboratory.  It was published in the popular press that progesterone and DHEA could be obtained from Dioscorea directly by the body, when in actuality it cannot.  There are no enzymatic pathways available to the body known to be able to produce the necessary chemical transformation. Trials have shown that there is no apparent increase of DHEA or progesterone in people taking Dioscorea.⁴  Women take Dioscorea hoping to increase their progesterone levels and in fact, may be raising their estrogen levels.

Dioscorea is used for such things as abdominal colic, spasmodic hiccough, painful vomiting, gastritis, irritable bowel symptoms, dysmenorrhea, chronic hepatic congestion, urinary tract spasms and rheumatism.⁵   It is also used as a diaphoretic and expectorant.⁶   Woman use it for menstrual and uterine cramps, morning sickness and threatened miscarriage.

Steroidal saponins are the primary constituents, diosgenin, dioscin, dioscorin and botogenin.  There is also a considerable amount of starch.

A tea can be decocted with 1 or 2 tsp. of the root to one cup of water, three times a day. Hydroalcoholic extract, 2-4 ml, three times a day.   Occasional gastric upset, although not as much as would be expected with that amount of saponins.  However, dioscin is used as a fish poison, so it is recommended that not more that triple dose be taken.⁷