Wild Yam (Dioscoreaceae)

Wild Yam (Dioscoreaceae)

Synonyms

Atlantic yam, barbasco, China root, colic root, D. barbasco, D. hypoglauca, D. macrostachya, D. opposita, D. villosa , devil's bones, dioscorea, dioscoreae, diosgenin, Mexican yam, natural DHEA, phytoestrogen, rheumatism root, shan yao, wild yam root, yam, yuma.

Note : "Yams" sold in the supermarket are members of the sweet potato family and are not true yams.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidenceGrade*Menopausal symptoms
Studies have not shown a benefit from wild yam given by mouth or used as a vaginal cream, in reducing menopausal symptoms.

C

High cholesterol
Animal studies have shown that wild yam can reduce absorption of cholesterol from the gut. Early studies in humans have shown changes in the levels of certain sub-types of cholesterol, including decreases in low-density lipoprotein (LDL, or "bad cholesterol") and triglycerides, and increases in high-density lipoprotein (HDL, or "good cholesterol"). However, no changes in the total amount of blood cholesterol have been found. More studies are needed in this area.

C

Hormonal properties (to mimic estrogen, progesterone, or DHEA)
Despite popular belief, no natural progestins, estrogens, or other reproductive hormones are found in wild yam. Its active ingredient, diosgenin, is not converted to hormones in the human body. Artificial progesterone has been added to some wild yam products. The belief that there are hormones in wild yam may be due to the historical fact that progesterone, androgens, and cortisone were chemically manufactured from Mexican wild yam in the 1960s.

D

* Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use (it may not work);
F: Strong scientific evidence against this use (it likely does not work).

Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Antifungal, anti-inflammatory, asthma, bile flow improvement, biliary colic, breast enlargement, childbirth, cramps, croup, decreased perspiration, diverticulitis, expectorant, flatus prevention, energy improvement, excessive perspiration, intestinal spasm, irritable bowel syndrome, joint pain, libido, liver protection, low blood sugar, menopause, menstrual pain or irregularities, morning sickness, nerve pain, osteoporosis, pelvic cramps, pancreatic enzyme inhibitor, postmenopausal vaginal dryness, premenstrual syndrome, rash, spasms, urinary tract disorders, uterus contraction, vomiting.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. Typical standardization of wild yam products is to 10% diosgenin per dose. Diosgenin is considered the primary active ingredient in wild yam, and is similar in structure to cholesterol. There are reports that synthetic progesterone has been added to some wild yam products.

Topical (on the skin) :

Cream : Vaginal creams containing wild yam are available, but there is no widely accepted dose. Effects from absorption into the bloodstream have not been shown. Some products may contain synthetic progesterone, a steroid hormone with potential activity in vaginal changes.

Oral (by mouth) :

Note: safety and effectiveness of oral doses have not been proven .

Dried root : 2-4 grams or 1-2 teaspoons daily in 2-3 divided doses is sometimes recommended.

Capsules : 250 milligrams of wild yam taken 1-3 times daily is often recommended, or 450-900 milligrams per day of dioscorea extract from wild yam.

Liquid (1:1 in 45% alcohol) : 2-4 milliliters daily in 3 divided doses has been used.

Tincture : 4-12 drops or 2-4 milliliters taken 3-5 times daily has been used.

Children (younger than 18 years)

Not enough evidence is available to recommend use in children. In unofficial reports, doses in children have been calculated in proportion to the weight of the child relative to a 70 kilogram (150 pound) adult. Divide the child's weight in kilograms by 70 (or weight in pounds by 150); this number multiplied by the recommended adult dose = the child's dose. Safety and effectiveness have not been proven, and dosing should be supervised by a licensed healthcare provider.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Rubbing the skin with Dioscorea batatas (a yam species related to Dioscorea villosa ) has been reported to cause allergic rash. Workers exposed to Dioscorea batatas in large amounts and for a prolonged time have developed asthma that is made worse by exposure to the yam. A person who is known to have an allergy to Dioscorea batatas may also be allergic to other Dioscorea types.

Side Effects and Warnings

Rubbing the skin with Dioscorea batatas , a related yam species, has been reported to cause a rash at the site of contact. Wild yam cream caused no rash in 23 healthy women in one reported study. In another study, wild yam given by mouth was reported to cause stomach upset at high doses.

Wild yam was believed in the past to have properties similar to the reproductive hormone progesterone, but this has not been supported by scientific studies. It has been suggested that some wild yam creams might be tainted with artificial progesterone. Based on theoretical hormonal properties and possible progesterone contamination, people with hormone-sensitive conditions should use wild yam products with caution. This caution applies to people who have had blood clots or strokes and to women who take hormone replacement therapy or birth control pills. In addition, women with fibroids, endometriosis, or cancer of the breast, uterus, or ovary should be aware that these are hormone-sensitive conditions that may be affected by agents with hormonal properties.

In animal studies, compounds from the Dioscorea dumentorum species lower blood sugar levels. It is not clear whether wild yam ( Dioscorea villosa ) lowers blood sugar in humans. Caution is advised in patients with diabetes or hypoglycemia and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary.

Pregnancy & Breastfeeding

Use of wild yam is not recommended during pregnancy or breastfeeding due to lack of safety information. Wild yam is believed to cause uterine contractions, and therefore use is discouraged during pregnancy. Wild yam was once thought to have effects similar to those of reproductive hormones, although this has not been proven in scientific studies. Artificial progesterone may be added to some products.

Methodology

This patient information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration () .

Selected references

1. Araghiniknam M, Chung S, Nelson-White T, et al. Antioxidant activity of Dioscorea and dehydroepiandrosterone (DHEA) in older humans. Life Sciences 1996;59:L147-L157.

2. Hudson t, Standish L, Breed C, et al. Clinical and endocrinological effects of a menopausal botanical formula. J Naturopath Med 1997;7:73-77.

3. 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 2001;4(2):144-150.

4. Kubo Y, Nonaka S, Yoshida H. Allergic contact dermatitis from Dioscorea batatas Decaisne. Contact Derm 1988;18(2):111-112.

THIS EVIDENCE-BASED MONOGRAPH WAS PREPARED BY THE NATURAL STANDARD RESEARCH COLLABORATION ().

January 01, 2004