Yam

Wild yam/Drug Interactions:

  • AntiandrogensAntiandrogens: In a pilot study, a wild yam preparation was found to suppress progesterone synthesis (10). However, clinical trial evidence is lacking, and there are anecdotal reports of adulteration with synthetic progesterone. Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).
  • Antidiabetic agentsAntidiabetic agents: It is unclear to what extent serum glucose is lowered by Dioscorea villosa (wild yam), if at all. Although dioscoretine, a component of the related species Dioscorea dumentorum (Bitter or African yam), has been shown to lower blood glucose in rabbits, this reaction has not been demonstrated for D. villosa, and has not been documented in humans (12). Nonetheless, caution is warranted.
  • AntiestrogensAntiestrogens: Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).
  • Antilipemic agentsAntilipemic agents: Positive interaction: Diosgenin, the purported active constituent of wild yam, has been found in animals to decrease intestinal cholesterol absorption and reduce total serum cholesterol levels (13; 14; 15; 16; 17; 18; 19; 20; 2). Preliminary human evidence from case studies demonstrates reductions in low density lipoprotein (LDL) and triglycerides, and increases in high density lipoprotein (HDL) (despite a lack of change in total serum cholesterol), and may potentiate the effects of other lipid-lowering agents (3; 21; 2; 18; 22). Furthermore, when clofibrate has been given in combination with wild yam, it has exerted a greater lipid-lowering effect in animals (18; 22). Theoretically, other fibric acid derivatives, such as gemfibrozil (Lopid?) and fenofibrate (Tricor?), may show similar effects.
  • DisulfiramDisulfiram: Some tinctures contain high concentrations of ethanol, and may lead to vomiting if used concomitantly with disulfiram (Antabuse?) or metronidazole (Flagyl?).
  • Hormonal agentsHormonal agents: In a pilot study, a wild yam preparation was found to suppress progesterone synthesis (10). However, clinical trial evidence is lacking, and there are anecdotal reports of adulteration with synthetic progesterone.
  • MetronidazoleMetronidazole: Some tinctures contain high concentrations of ethanol, and may lead to vomiting if used concomitantly with disulfiram (Antabuse?) or metronidazole (Flagyl?).
  • Nonsteroidal antiinflammatory agents (NSAIDs)Nonsteroidal antiinflammatory agents (NSAIDs): Wild yam has been found to lower serum indomethacin levels and to attenuate indomethacin-induced intestinal inflammation in rats (23). Human data are lacking.
  • SteroidsSteroids: Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).

    • Wild yam/Herb/Supplement Interactions:

  • AntiandrogensAntiandrogens: In a pilot study, a wild yam preparation was found to suppress progesterone synthesis (10). However, clinical trial evidence is lacking, and there are anecdotal reports of adulteration with synthetic progesterone. Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).
  • AntiestrogensAntiestrogens: Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).
  • Anti inflammatory herbsAnti inflammatory herbs: Wild yam has been found to lower serum indomethacin levels and to attenuate indomethacin-induced intestinal inflammation in rats (23). Human data are lacking.
  • AntilipemicsAntilipemics: Positive interaction: Diosgenin, the purported active constituent of wild yam, has been found in animals to decrease intestinal cholesterol absorption and reduce total serum cholesterol levels (13; 14; 15; 16; 17; 18; 22; 19; 20; 2). Preliminary human evidence from case studies demonstrates reductions in low density lipoprotein (LDL) and triglycerides, and increases in high density lipoprotein (HDL) (despite a lack of change in total serum cholesterol), and may potentiate the effects of other lipid-lowering agents (3; 21; 2; 18; 22).
  • Hormonal herbs and supplementsHormonal herbs and supplements: In a pilot study, a wild yam preparation was found to suppress endogenous progesterone synthesis (10). However, clinical trial evidence is lacking, and there are anecdotal reports of adulteration with synthetic progesterone.
  • HypoglycemicsHypoglycemics: It is unclear to what extent serum glucose is lowered by Dioscorea villosa (wild yam), if at all. Although dioscoretine, a component of the related species Dioscorea dumentorum (Bitter or African yam), has been shown to lower blood glucose in rabbits, this reaction has not been demonstrated for D. villosa and has not been documented in humans (12). Nonetheless, caution is warranted.
  • PhytoprogestinsPhytoprogestins: In a pilot study, a wild yam preparation was found to suppress endogenous progesterone synthesis (10). However, clinical trial evidence is lacking, and there are anecdotal reports of adulteration with synthetic progesterone.
  • PotassiumPotassium: Based on one assay study, white, yellow, and black yams may have a potassium content >200mg (5.1mEq)/100g following leaching in water, normal cooking, and double cooking (24).
  • SteroidsSteroids: Based on in vitro study, wild yam root may possess antagonistic (blocking) activity, including antiestrogenic activity (11).
  • Vitamin CVitamin C: Positive interaction: Vitamin C has been shown to enhance the cholesterol-lowering effects of diosgenin and clofibrate (20).

    • Wild yam/Food Interactions:

  • Potassium-containing foodsPotassium-containing foods: Based on one assay study, white, yellow, and black yams may have a potassium content >200mg (5.1mEq)/100g following leaching in water, normal cooking, and double cooking (24).

    • Wild yam/Lab Interactions:

  • Serum glucoseSerum glucose: It is unclear to what extent serum glucose is lowered by Dioscorea villosa (wild yam), if at all. Although dioscoretine, a component of the related species Dioscorea dumentorum (Bitter or African yam), has been shown to lower blood glucose in rabbits, this reaction has not been demonstrated for D. villosa, and has not been documented in humans (12). Nonetheless, caution is warranted.
  • Serum lipidsSerum lipids: Diosgenin, the purported active constituent of wild yam, has been found in animals to decrease intestinal cholesterol absorption and reduce total serum cholesterol levels (13; 14; 15; 16; 17; 18; 22; 19; 20; 2). Preliminary human evidence from case studies demonstrates reductions in low density lipoprotein (LDL) and triglycerides, and increases in high density lipoprotein (HDL) (despite a lack of change in total serum cholesterol) (3; 21; 2; 18; 22).
  • Serum potassium levelsSerum potassium levels: Based on one assay study, white, yellow, and black yams may have a potassium content >200mg (5.1mEq)/100g following leaching in water, normal cooking, and double cooking (24).