| Dietary sources | |
| The wild yam is widely used in the tropics and Asia as both a food and medicinal plant. The starchy tuber is used as food, similar to the potato. Its taste is slightly sweet and is reminiscent of potatoes or sometimes chestnuts or sweet potatoes. In many tropical countries, certain types of yams are consumed as a staple food. | |
| Physiological effects | |
| Hormone balance |
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| Cholesterol level |
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| Diosgenin, the active ingredient of the yam root |
| Dioscorea villosa belongs to the large family of Yam plants. In the tropics, many yams are planted as food due to their high starch and micronutrient content. The active ingredient diosgenin contained in the tuber, a saponin similar to the hormone progesterone, is used in naturopathy. Like progesterone, diosgenin supports and harmonizes the body's hormonal balance. The genus name of the yam family, Dioscorea, dates back to the Greek physician Dioskurides. |
| Hormonal balance via diosgenin |
| Since the production of synthetic progesterone takes place via the precursor diosgenin, it has long been discussed whether this conversion process also takes place in the human body. The observed and anecdotal positive effects on hormone balance in animal experiments increasingly speak in favor of this. In rats, for example, the effects of an ovariectomy could be compensated by diosgenin supplementation. This affects the kidney tissue (1), the adrenal glands (2) and the bone tissue (3). In Vivo a positive effect was observed in glucocorticoid-induced osteoporosis (14). In addition, diosgenin can displace estradiol bound to receptors (4) and thus – like the known phytohormones - exert an estrogen-modulating effect. |
| Health-promoting effects of diosgenin |
| The successful use of yams in alternative and complementary medicine mayalso be explained by other properties of diosgenin. For example, diosgenin improves antigen-specific IgG2a and IFN expression and thereby promotes the immune system (5). Several in vitro and in vivo studies deal with the anticarcinogenic effect of diosgenin. Diosgenin has an inhibitory effect on hepatic tumor cells (6) and prevents the proliferation of tumor cells (7). This has also been demonstrated for leukemia cells in which diosgenin blocks cell proliferation and induces apoptosis (8). By opening the Ca2+ channels in the nerve membranes, diosgenin affects the influence of calcium on the nerve cells and can thus modulate neural activities (9). In addition to hormonal control, the positive effects of yams could also affect the neural systems. |
| Cholesterol reduction and antioxidant protection |
| Yam root and its ingredients could also be of interest for the treatment of elevated cholesterol levels under a holistic therapy framework. In animal studies, diosgenin shows significant therapeutic and preventive effects in hypercholesterolemia (10) (11). In estrogen-induced hypercholesterolemia, diosgenin can also lower cholesterol levels. This happens through an increased production of bile acids, which in turn seems to be related to the hormonal balance (12). In addition to an improvement of the lipid profile, an increase in antioxidative status was achieved by diosgene intake (13). |
| Effect | Indication | Dosage |
| Physiological effects at a low intake |
For age-related hormonal imbalance and to maintain cell health | 600 mg/d |
| Supportive therapy for hypercholesterolemia | 600 mg/d |
| General mode of administration | |
| When |
Yam root extract should be taken with meals. |
| Side effects | |
| No side effects are known to date. | |
| Contraindications | |
| No contraindications are known to date. | |
| Drug interactions | |
| None | No interactions are known to date. |
| Nutrient interactions | |
| None | No interactions are known to date. |
| References |
|
(1) Tucci M, Benghuzzi H: Structural changes in the kidney associated with ovariectomy and diosgenin replacement therapy in adult female rats. Biomed Sci Instrum. 2003;39:341-6. |
