© Steven Foster
Parts used and where grown
Wild yam plants are found across the midwestern and eastern United States, Latin America (especially Mexico), and Asia. Several different species exist. All of which possess similar constituents and properties. The root is used medicinally.
Wild yam has been used in connection with the following conditions (refer to the individual health concern for complete information):
| Science Rating | Health Concerns |
|---|---|
 | High cholesterol Menopause |
 Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit. | |
Historical or traditional use (may or may not be supported by scientific studies)
Wild yam has been used by herbalists as an expectorant for people with coughs. It was also used for gastrointestinal upset, nerve pain, and morning sickness.1 Eventually, it was discovered that the saponins from wild yam could be converted industrially into cortisone, estrogens, and progesterone-like compounds. Wild yam and other plants with similar constituents continue to be a source for these drugs.
Active constituents
The steroidal saponins (such as diosgenin) account for some of the activity of wild yam. Another compound, dioscoretine, has been shown in animal studies to lower blood sugar levels.2 An extract of wild yam was also found in a clinical trial to have antioxidant properties and raised HDL, the “good,”cholesterol in elderly adults.3
Contrary to popular claims, wild yam roots do not contain and are not converted into progesterone or dehydroepiandrosterone (DHEA) in the body.4 5 Pharmaceutical progesterone is made from wild yam using a chemical conversion process. This can lead to confusion—while wild yam can be a source of progesterone, it cannot be used without this pharmaceutical conversion, which cannot be duplicated by the body. Women who require progesterone should consult with their physician and not rely on wild yam supplements.
How much is usually taken?
Up to 2–3 ml of wild yam tincture can be taken three to four times per day. Alternatively, 1 gram of dried, powdered root can be taken three times each day.6
Are there any side effects or interactions?
Some people may experience nausea or vomiting when taking large amounts of wild yam (several times the amounts listed above). The safety of wild yam during pregnancy and breast feeding has not been established.
References
1. Lust JB. The Herb Book. New York: Bantam Books, 1974, 401.
2. Iwu MM, Okunji CO, Ohiaeri GO, et al. Hypoglycaemic activity of dioscoretine from tubers of Dioscorea dumetorum in normal and alloxan diabetic rabbits. Planta Med 1990;56:264–7.
3. Araghiniknam M, Chung S, Nelson-White T, et al. Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans. Life Sci 1996;11:147–57.
4. Araghiniknam M, Chung S, Nelson-White T, et al. Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans. Life Sci 1996;11:147–57.
5. Dollbaum CM. Lab analyses of salivary DHEA and progesterone following ingestion of yam-containing products. Townsend Letter for Doctors and Patients Oct 1995:104.
6. Bertram T. Encyclopedia of Herbal Medicine. Dorset, England: Grace Publishers, 1995, 454.
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2006-09-07
