Health Care Professional Information

Scientific Name
Dioscorea villosa, Dioscorea alata
Common Name

Colic root, devil’s bones, rheumatism root, yuma, wild yam root

Clinical Summary

Derived from the root of a twining vine, wild yam was traditionally used for its antispasmodic and anti-inflammatory properties to treat menopausal symptoms, gastrointestinal ailments, muscle spasm, asthma, joint pain, and rheumatoid arthritis (1) (2). Wild yam has antiproliferative (3) and antimitotic effects (4) in vitro, and animal models also suggest it has antinociceptive and anti-inflammatory properties (1). Diosgenin, the active ingredient in wild yam, was shown to have estrogenic and progestogenic effects in mice(3) (5) (6) (7). Two small studies on whether wild yam can relieve menopausal symptoms had opposing results, with one demonstrating an oral D. alata formula to be more effective than placebo (8), but another study showing a topical D. villosa formula to be ineffective (9). A study of dietary yam was found to improve sex hormone and lipid profiles (10). More studies are needed to confirm whether dietary or supplemental wild yam actually has any benefits for menopausal symptoms. Wild yam extract is sold as a dietary supplement, liquid extract or as a cream. Diosgenin in wild yam has been used as raw material for synthetic progesterone, but there is no evidence that the human body can convert diosgenin into progesterone.

Purported Uses
  • Cough
  • Menopausal symptoms
  • Rheumatoid arthritis
  • Spasms
Constituents

Saponins: Diosgenin
Lipidated steroid saponins: lipidated spirostanol glycosides, lipidated clionasterol glucosides
Furostanol saponins: parvifloside, methyl protodeltonin, and trigofoenoside A-1
Spirostanol saponins: zingiberensis saponin I, deltonin, dioscin, and prosapogenin A of dioscin Diarylheptanoids
(1) (2) (11) (12) (13)

Mechanism of Action

The steroid saponin diosgenin in wild yam modulates cell signaling involved in growth, differentiation, apoptosis, and oncogenesis (14). In vitro studies suggest wild yam extract protects against human breast cancer proliferation by acting as a weak phytoestrogen (3). However, the D. villosa species has been noted to induce chronic kidney injury via pro-fibrotic pathways in animal models (15).

Pharmacokinetics

Animal studies show that diosgenin is poorly absorbed. The absorbed portion is quickly distributed into the liver, adrenals, and walls of the gastrointestinal tract and undergoes extensive biotransformation. Diosgenin and the metabolites are eliminated through the bile and excreted in the feces (16) (17).

Warnings

Patients should be aware that creams containing extracts of wild yam have been promoted as a natural source of progesterone. However, the progesterone contained in these creams is synthetic or derived from other sources.

Contraindications

Patients with hormone-sensitive cancers (3) or compromised renal function (15).

Adverse Reactions

Although wild yam appears to be well tolerated (8) (9), it has weak estrogenic activity (3), and animal studies indicate a potential for kidney injury (15).

Literature Summary and Critique

Hsu CC, et al. The assessment of efficacy of Diascorea alata for menopausal symptom treatment in Taiwanese women. Climacteric.. 2011;14:132-139.
A double-blind placebo-controlled trial of D. alata to treat menopausal symptoms was conducted. A total of 50 menopausal women were randomized to either D. alata extract, two sachets daily (12 mg/sachet) or placebo for 12 months. Primary outcome measure was change in the Greene Climacteric Scale with changes in plasma hormone profiles as secondary outcomes. A one-way ANCOVA test was performed to determine significance. At 6- and 12-month assessments, women assigned to the intervention showed general improvements for most clinical symptoms, with significant reductions in total Greene scores at treatment end (P < .01), and particularly for anxiety. Improvements were also noted for feeling tense or nervous (P = .007), insomnia (P = .004), excitability (P= .047), and musculoskeletal pain (P= .019). Positive effects on blood hormone profiles were also noted. Compared with placebo, standardized extracts of D. alata appeared to be safe for daily administration over a period of 12 months, with particular improvement in psychological parameters for menopausal women.

Wu WH, et al. Estrogenic effect of yam ingestion in healthy postmenopausal women. J Am Coll Nutr. 2005;24:235-243.
This small study investigated the effects of yam ingestion on lipids, antioxidant status, and sex hormones in healthy postmenopausal women. A total of 24 women replaced their staple diet of rice with yam (D. alata) 390 g for 2 of 3 daily meals over 1 month. Fasting blood and first morning urine samples were collected for 22 participants who completed the pre-/post-yam intervention. A similar study that evaluated 19 postmenopausal women who ate sweet potato 240 g for 41 days was use as a reference control. The yam dietary intervention resulted in significant increases of serum estrone levels and sex hormone binding globulin, with near-significant estradiol increases. There were no significant changes in serum DHEA-sulfate, androstenedione, testosterone, follicular stimulating hormone, and luteinizing hormone, but free androgen index and levels of urinary estrogen metabolites, urinary isoprostane, and plasma cholesterol decreased. LDL oxidation was also prolonged. In contrast, reference study control subjects who ate sweet potato had no changes in hormone parameters post-intervention. Investigators concluded that a 30-day, two-thirds replacement of staple food with yam improved sex hormone, lipid, and antioxidant status in postmenopausal women.

Dosage (Inside MSKCC Only)
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References
  1. Lima CM, Lima AK, Melo MG, et al. Bioassay-guided evaluation of Dioscorea villosa — an acute and subchronic toxicity, antinociceptive and anti-inflammatory approach. BMC Complement Altern Med. Jul 28 2013;13(1):195.
  2. Manda VK, Avula B, Ali Z, et al. Characterization of in vitro ADME properties of diosgenin and dioscin from Dioscorea villosa. Planta Med. Oct 2013;79(15):1421-1428.
  3. Park MK, Kwon HY, Ahn WS, et al. Estrogen activities and the cellular effects of natural progesterone from wild yam extract in mcf-7 human breast cancer cells. Am J Chin Med. 2009;37(1):159-167.
  4. Mazzio E, Badisa R, Mack N, et al. High Throughput Screening of Natural Products for Anti-mitotic Effects in MDA-MB-231 Human Breast Carcinoma Cells. Phytother Res. Sep 17 2013.
  5. Aradhana, Rao AR, Kale RK. Diosgenin—a growth stimulator of mammary gland of ovariectomized mouse. Indian J Exp Biol. May 1992;30(5):367-370.
  6. Benghuzzi H, Tucci M, Eckie R, et al. The effects of sustained delivery of diosgenin on the adrenal gland of female rats. Biomed Sci Instrum. 2003;39:335-340.
  7. Accatino L, Pizarro M, Solis N, et al. Effects of diosgenin, a plant-derived steroid, on bile secretion and hepatocellular cholestasis induced by estrogens in the rat. Hepatology. Jul 1998;28(1):129-140.
  8. Hsu CC, Kuo HC, Chang SY, et al. The assessment of efficacy of Diascorea alata for menopausal symptom treatment in Taiwanese women. Climacteric. Feb 2011;14(1):132-139.
  9. Komesaroff PA, Black CV, Cable V, et al. Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women. Climacteric. Jun 2001;4(2):144-150.
  10. Wu WH, Liu LY, Chung CJ, et al. Estrogenic effect of yam ingestion in healthy postmenopausal women. J Am Coll Nutr. Aug 2005;24(4):235-243.
  11. Yoon KD, Chin YW, Yang MH, et al. Application of high-speed countercurrent chromatography-evaporative light scattering detection for the separation of seven steroidal saponins from Dioscorea villosa. Phytochem Anal. Sep-Oct 2012;23(5):462-468.
  12. Dong SH, Nikolic D, Simmler C, et al. Diarylheptanoids from Dioscorea villosa (wild yam). J Nat Prod. Dec 28 2012;75(12):2168-2177.
  13. Dong SH, Cai G, Napolitano JG, et al. Lipidated steroid saponins from Dioscorea villosa (wild yam). Fitoterapia. Dec 2013;91:113-124.
  14. Raju J, Mehta R. Cancer chemopreventive and therapeutic effects of diosgenin, a food saponin. Nutr Cancer. 2009;61(1):27-35.
  15. Wojcikowski K, Wohlmuth H, Johnson DW, et al. Dioscorea villosa (wild yam) induces chronic kidney injury via pro-fibrotic pathways. Food Chem Toxicol. Sep 2008;46(9):3122-3131.
  16. Cayen MN, Ferdinandi ES, Greselin E, et al. Studies on the disposition of diosgenin in rats, dogs, monkeys and man. Atherosclerosis. May 1979;33(1):71-87.
  17. Juarez-Oropeza MA, Diaz-Zagoya JC, Rabinowitz JL. In vivo and in vitro studies of hypocholesterolemic effects of diosgenin in rats. Int J Biochem. 1987;19(8):679-683.

Consumer Information

How It Works

Bottom Line: Wild yam has not been shown to prevent or treat cancer.

Wild yam contains a compound called diosgenin that mimics estrogen and progesterone in animals. Diosgenin can be converted into active steroid compounds in the lab. Small studies using different species and formulas of wild yam extract have had mixed results on menopausal symptoms. Another small study suggests that increasing yam intake through diet may improve sex hormone and cholesterol levels. A lab study showed that wild yam extract has weak hormonal activity against human breast cancer cells, but this does not mean it can prevent or treat cancer.

More studies are needed to confirm whether wild yam or its extract actually has any benefits. In addition, some animal and lab studies have shown that wild yam extract can cause chronic kidney injury.

Purported Uses
  • To relieve menopausal symptoms
    Wild yam has had mixed results in small studies. More research is needed.
  • To improve cough
    There are no studies to date that support this use.
  • To treat rheumatoid arthritis
    No scientific evidence supports this use.
Research Evidence

Menopausal symptoms: Two studies evaluated wild yam for menopausal symptoms and hormonal effect. In one study, a specific formula of yam extract was used. In another, participants were asked to replace the rice in their diet with yams. In both studies there appeared to be some symptom benefit or effect on hormone levels. However, these single studies are too small to draw any definite conclusions.

Patient Warnings
  • Some creams containing wild yam may be promoted as a natural source of progesterone, when it is really synthetic progesterone or comes from other sources. Wild yam itself does not contain progesterone, but diosgenin in wild yam can be used to make progesterone in the lab.

Do Not Take If

You have hormone-sensitive cancer: Wild yam acts as a weak estrogen.
You have kidney disease: Animal studies have shown wild yam extract may cause kidney injury.

Side Effects

Although wild yam appears to be well tolerated, it may have weak hormonal effects or cause kidney problems.

E-mail your questions and comments to aboutherbs@mskcc.org.