Wild yam

Wild yam (Dioscorea villosa L.) root extract is a medicinal herb that is commonly used to treat hot flushes symptoms of menopause, premenstrual syndrome, osteoporosis, prophylactic against breast cancer and rheumatoid arthritis. Wild yam is most commonly used as a “natural alterative” to estrogen therapy for symptoms of menopause, infertility, menstrual problems, and other conditions, but there is no good scientific evidence to support these or other uses ¹. Wild yam root and the bulb contains a chemical called diosgenin, which is prepared as an “extract,” a liquid that contains concentrated diosgenin. This chemical can be converted in the laboratory into various steroids, such as estrogen and dehydroepiandrosterone (DHEA). However, while wild yam does seem to have some estrogen-like activity, it is not actually converted into estrogen in the body, because humans cannot convert diosgenin into progesterone, so eating or applying wild yam extract or diosgenin does not result in increased progesterone levels ². It takes a laboratory to do that. Sometimes wild yam and diosgenin are promoted as a “natural DHEA.” This is because in the laboratory DHEA is made from diosgenin. But this chemical reaction is not believed to occur in the human body. So, taking wild yam extract will not increase DHEA levels in people.

Wild yams also make a significant contribution both as root crops and vegetables to the diets of tribal people in the world especially in the tropics and sub tropics ³. Furthermore wild yam roots were found to be fairly good sources of dietary minerals such as calcium (18.08–74.79 mg/100 g), iron (11.15–28.61 mg/100 g), zinc (2.11–6.21 mg/100 g) and phosphorous (179–248 mg/100 g) with the levels of heavy metal concentrations that are lower than the recommended tolerable levels proposed by World Health Organization (WHO) Expert Committee on Food Additives ⁴. The heavy metals concentration (mg/100 g) ranged from: cobalt (1.06–1.98 mg/100 g), nickel (0.30–0.89 mg/100 g), chromium (2.10–4.53 mg/100 g) and lead (0.11–0.93 mg/100 g) among the studied yam species ⁴.

Vasomotor symptoms (e.g, hot flashes and night sweats) are the primary symptoms of menopause. Vasomotor symptoms affect more than 80% of women in menopause and are the menopause symptoms for which most women seek treatment ⁵.

Nonhormonal agents used as therapy for hot flushes (hot flashes) in menopause ⁶:

• Nonprescription
  • Black cohosh
  • Dong quai
  • Evening primrose oil
  • Ginseng
  • Melatonin
  • Red clover isoflavones
  • Soy isoflavones
  • Vitamin E
  • Wild yam
• Prescription
  • Belladonna/ergotamine tartrate/phenobarbital combination (Bellamine)
  • Clonidine (Catapres)
  • Fluoxetine (Prozac)
  • Gabapentin (Neurontin)
  • Mirtazapine (Remeron)
  • Paroxetine (Paxil)
  • Trazodone (Desyrel)
  • Venlafaxine (Effexor)

Existing research indicates that mind-body interventions such as relaxation, mindfulness, and cognitive behavioral therapy (CBT) can reduce stress and bothersomeness associated with menopausal symptoms ⁷. Hypnosis intervention for hot flashes has been shown to result in a clinically significant reduction (ie, 50% or more) in hot flashes and associated symptoms. Mind-body interventions have few negative side effects and seem to provide safe treatment options worthy of consideration ⁷.

Hypnosis

Hypnosis, a mind-body therapy that involves a deeply relaxed state of focused attention, individualized mental imagery, and suggestion ⁸, has been investigated for menopausal symptom management. Two randomized clinical trials of 5 sessions of hypnotherapy for hot flashes among breast cancer survivors demonstrated a clinically meaningful (≥69%) reduction in hot flash severity and frequency ⁹, ¹⁰. These results are comparable to pharmacological interventions ¹¹. In an randomized controlled trial of 187 women ¹², hypnosis was compared with an active structured attention control and found to significantly reduce subjective hot flash frequency (74%) and interference (80%), and physiologically monitored hot flashes (57%). In addition, hypnosis improved self-reported sleep quality and sexual function ¹³. In a 2017 pilot study ¹⁴, 71 women were randomized to 1 of 4 groups: venlafaxine 75 mg + hypnosis, venlafaxine 75 mg + sham hypnosis, placebo pill + hypnosis, and placebo pill + sham hypnosis. Hypnosis alone was as effective (50% reduction) as venlafaxine 75 mg alone in reducing hot flash score (frequency × severity). The placebo group reported a 25% reduction. Hypnosis has been recommended by the North American Menopause Society, and others, for the treatment of menopausal symptoms and poses little risk ¹⁵.

Cognitive behavioral therapy (CBT)

Cognitive behavioral therapy (CBT) is a form of psychological treatment that has been used to treat hot flashes, depression, and other menopausal symptoms. Cognitive behavioral therapy (CBT) is a time-limited treatment that focuses on changing cognitive appraisals and behavior choices to alter symptoms. Cognitive behavioral therapy (CBT) may include education, motivational interviewing, relaxation, paced breathing, and other strategies to improve symptoms ¹⁶. Mann et al ¹⁶ compared the effects of a 6-week cognitive behavioral therapy (CBT) intervention to usual care (eg, standard follow-up care) among 96 female breast cancer survivors and found hot flash interference was reduced on average 52%. Women receiving usual care reported a 25% decrease in hot flash interference. Hot flash frequency was reduced by 38% in both groups, 38% indicating cognitive behavioral therapy (CBT) was no better than usual care for reducing the frequency of hot flashes ¹⁶. In a second randomized controlled trial, 65% of women receiving a 4-week cognitive behavioral therapy (CBT) intervention and 21% of a no-treatment control group, reported clinically significant improvements (eg, 2-point change on a 10-point numerical rating scale) in hot flush interference ¹⁷. Cognitive behavioral therapy (CBT) did not demonstrate a clinically significant reduction (eg, 50%) in hot flash frequency ¹⁷. Both of these trials used objective and subjective measures for hot flash frequency ¹⁶

In a pilot study of 39 women randomized to cognitive behavioral therapy (CBT) or waitlist control, there was a statistically significant reduction in hot flash distress, but not in interference or frequency of hot flashes/night sweats, in the immediate treatment group ¹⁸. The authors reported a 48% positive treatment effect for the 17 women who completed the cognitive behavioral therapy (CBT) program, but it is unclear how that effect was calculated ¹⁸. In addition, there is some evidence to suggest that cognitive behavioral therapy (CBT) may reduce mild depression in menopause comparable to placebo ¹⁹. To date, no randomized controlled trials of cognitive behavioral therapy (CBT) have demonstrated clinically significant improvements in hot flash frequency, but may be beneficial in reducing hot flash distress and interference and other psychological symptoms (eg, depression) associated with menopause. cognitive behavioral therapy (CBT) has been recommended by the North American Menopausal Society for reducing the bothersomeness of vasomotor symptoms, but not for frequency ²⁰.

Wild yam benefits

Wild yam is a tuber that has been historically used in traditional Chinese medicine to treat multiple symptoms, including symptoms of menopause ²¹. However, there is limited and inconsistent evidence for the effects of wild yam on menopause symptoms ⁷. In a double blind, placebo controlled, cross-over study of the effects of a wild yam cream for 3 months in 23 healthy women suffering from troublesome symptoms of the menopause such as hot flashes and night sweats ²². After 3 months treatment with topical wild yam extract in women suffering from menopausal symptoms it was found that the wild yam cream is free from side-effects and has little effect on menopausal symptoms ²². Wild yam cream was no better than placebo in reducing menopause symptoms or improving levels of estrogen or progesterone ²². In contrast, a randomized controlled trial of 50 women consuming 12 mg of purple yam (Dioscorea alata) extract twice daily for 12 months reported significant improvements (90%) in menopause symptoms (primarily psychological) compared with the placebo group (70%) as measured by the Greene Climacteric Scale ²³. The authors note that sexual functioning symptoms did not show the same levels of improvement ²³. Because of the small number of studies and insufficient information regarding long-term safety, more research is needed in order to determine the efficacy of wild yam for menopause symptoms ¹.

There is insufficient evidence to rate effectiveness of wild yam extract for:

• Memory and thinking skills (cognitive function). Early research shows that taking wild yam extract daily for 12 weeks might improve thinking skills in healthy adults.
• Use as a natural alternative to estrogens.
• Postmenopausal vaginal dryness.
• Premenstrual syndrome (PMS).
• Weak and brittle bones (osteoporosis).
• Increasing energy and sexual desire in men and women.
• Gallbladder problems.
• Increasing appetite.
• Diarrhea.
• Menstrual cramps (dysmenorrhea).
• Rheumatoid arthritis (RA).
• Infertility.
• Menstrual disorders.
• Other conditions.

Wild yam dosage

The appropriate dose of wild yam depends on several factors such as your age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for wild yam. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Wild yam side effects

When taken by mouth, wild yam is POSSIBLY SAFE. Large amounts may cause vomiting, upset stomach, and headache.

When applied to the skin, wild yam is POSSIBLY SAFE.

Special precautions and warnings

There was an increase in fibrosis in the kidneys and in inflammation in livers of rats consuming wild yam (dioscorea villosa) for 28 days ¹. Long term supplementation with wild yam (dioscorea villosa) may be best avoided, especially in people with compromised renal function and in those who need to take other drugs which may alter kidney function ¹.

• Pregnancy and breast-feeding: There isn’t enough reliable information to know if wild yam is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.
• Hormone-sensitive condition such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids: Wild yam might act like estrogen. If you have any condition that might be made worse by exposure to estrogen, do not use wild yam.
• Protein S deficiency: People with protein S deficiency have an increased risk of forming clots. There is some concern that wild yam might increase the risk of clot formation in these people because it might act like estrogen. One patient with protein S deficiency and systemic lupus erythematosus (SLE) developed a clot in the vein serving the retina in her eye 3 days after taking a combination product containing wild yam, dong quai, red clover, and black cohosh. If you have protein S deficiency, it is best to avoid using wild yam until more is known.

Interactions with medications

Be cautious when using wild yam extract with this combination.

Estrogens

• Wild yam might have some of the same effects as estrogen. Taking wild yam along with estrogen pills might decrease the effects of estrogen pills.
• Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

References

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4. Padhan, B., Biswas, M., Dhal, N. K., & Panda, D. (2018). Evaluation of mineral bioavailability and heavy metal content in indigenous food plant wild yams (Dioscorea spp.) from Koraput, India. Journal of food science and technology, 55(11), 4681–4686. https://doi.org/10.1007/s13197-018-3388-3
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