Wild yam

Wild yam is a plant also known as American Yam, Atlantic Yam, Barbasco, China Root, Chiense Yam, Colic Root, Devil's Bones, DHEA Naturelle, Dioscorea, Dioscorea alata, Dioscorea batatas, Dioscorea composita, Dioscorea floribunda, Dioscorea hirticaulis, Dioscorea japonica, Dioscorea mexicana, Igname Sauvage, Igname Velue, Mexican Yam, Ñame Silvestre, Phytoestrogen, Rheumatism Root, Shan Yao, Yuma, and other names.

Wild yam has been used to treat menopausal symptoms. However, research has shown that wild yam may not be effective in treating this condition.

Other uses not proven with research have included premenstrual syndrome (PMS), osteoporosis, rheumatoid arthritis, infertility, as a natural alternative to estrogens, and to increase energy and sexual desire in men and women.

It is not certain whether wild yam is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Wild yam should not be used in place of medication prescribed for you by your doctor.

Wild yam is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Wild yam may also be used for purposes not listed in this product guide.

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before using wild yam, talk to your healthcare provider. You may not be able to use wild yam if you have certain medical conditions.

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

• any hormone sensitive conditions such as breast, uterine or ovarian cancer, endometriosis, or uterine fibroids; or
• any bleeding or blood-clotting disorder (such as hemophilia or protein S deficiency).

It is not known whether wild yam will harm an unborn baby. Do not use this product without medical advice if you are pregnant.

It is not known whether wild yam passes into breast milk or if it could harm a nursing baby. Do not use this product without medical advice if you are breast-feeding a baby.

Do not give any herbal/health supplement to a child without medical advice.

Follow your healthcare provider's instructions about any restrictions on food, beverages, or activity.

Other drugs may interact with wild yam, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Do not take wild yam without medical advice if you are using:

• estrogens or any medicine containing estrogen.

This list is not complete. Other drugs may interact with wild yam, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this product guide.

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use wild yam, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Do not use different formulations of wild yam (such as tablets, liquids, and others) at the same time, unless specifically directed to do so by a health care professional. Using different formulations together increases the risk of an overdose.

Call your doctor if the condition you are treating with wild yam does not improve, or if it gets worse while using this product.

Store at room temperature away from moisture and heat.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra wild yam to make up the missed dose.

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Contraindications have not been identified.

Information regarding safety and efficacy in pregnancy and lactation is lacking.

D. villosa is a twining vine native to the central southeastern US and found less frequently in the Appalachian region. It is a dioecious plant with inconspicuous white to greenish-yellow female flowers and smooth, heart-shaped leaves. Plant synonyms include Dioscorea hirticaulis Bartlett and D. villosa L. var. hirticaulis (Bartlett) H.E. Ahles.

There are more than 500 species of Dioscorea worldwide, with Chinese yam ( D. oppositifolia ), water yam ( Dioscorea alata L. ), and wild yam commonly studied. 1

Wild yam was popularized by the Eclectic medical movement in the 19th century for its supposed antispasmodic properties and was therefore prescribed for biliary colic and spasm of the bowel. It was also promoted for the relief of nausea in pregnancy and for amenorrhea and dysmenorrhea. Wild yam has been used for urinary tract infections, rheumatoid arthritis, cholera, nervous excitement, and flatulence. 2 , 3

Much of the current herbal use of wild yam is predicated on the misconception that the diosgenin contained in the product can be converted by the human body into steroid hormones, particularly progesterone, through the intermediate dehydroepiandrosterone. This notion appears to be based on historical interest in diosgenin as a synthetic precursor of cortisone. 6 However, evidence suggesting that diosgenin or dioscin can be converted into human hormones is lacking. 7

Chinese yam polysaccharides have been evaluated in laboratory studies for potential as prebiotics, with varying results. 3 , 8 However, clinical studies are lacking.

D. oppositifolia (synonym Dioscorea batatas ) tubers have been used as a saliva substitute. 9 , 10

Topical formulations of Dioscorea are poorly evaluated, and it is unlikely that they are a source of progesterone. 11 , 12 , 13 Estrogenic compounds have been reported for D. alata , 5 while weak effects on progesterone receptor activity in human breast cells have also been demonstrated in vitro. 14 Inhibition of human breast cancer MCF-7 cell proliferation was also shown in vitro for D. villosa extracts. 14

Research reveals no animal data regarding the use of wild yam for menopausal symptoms.

Limited clinical trials exist evaluating the effect of wild yam and its extract on menopausal symptoms. One uncontrolled clinical study evaluated the effect of consuming 390 g of yam over 30 days and found increases in serum estrone and sex hormone-binding globulin, but not in estradiol. 15 Another randomized, double-blind, placebo-controlled trial evaluated daily topical application of D. villosa extract in menopausal women, finding no change in serum estrogen or progesterone, no effect on symptoms, and no effect on lipids, weight, or blood pressure. 4 , 7 Commercial preparations of topical progesterone creams have been evaluated for use in managing menopausal symptoms (for more information see the Progesterone monograph).

Isolated diosgenin decreased total cholesterol and increased high-density lipoprotein in rats. 16

Allantoin from yam decreased plasma glucose in diabetic rats. 17

Dioscorin protein from the tuber of D. alata and Dioscorea japonica showed immune-stimulatory effects in mice 18 , 19 and exhibited hypotensive effects in rats. 20

D. alata was hepatoprotective in rats exposed to acetaminophen. 21