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| estrogen response. These plant compounds, sometimes referred to as phytoestrogens, can also inhibit the aromatase enzyme, which can decrease the conversion of androgens to estrogens. Both saw palmetto and nettle root extracts have been shown to inhibit aromatase. Inhibition of aromatase is very important in the prevention and treatment of both breast and prostate cancers. When aromatase is inhibited, it leads to the deactivation of cancer-driving hormones (such as sex-hormone-binding globulin, a hormone that increases as we age), which would otherwise bind to receptor sites. 37 |
| In some breast cancers, for example, the aromatase enzyme is responsible for causing androgens to convert to estrogen. Flavones, such as those found in Chinese skullcap, and isoflavones, like those found in red clover and soy products, interrupt that process and actually redirect androgens for ultimate elimination rather than conversion into estrogen. |
| In prostate cancer, the importance of androgens to fuel the cancer is significant; at least 75 percent of all tumors in men with metastatic prostate cancer are androgen-dependent at initial diagnosis. Also, the enzyme 5-alpha-reductase is at least in part responsible for converting testosterone into its more active cancer-promoting form, dihydrotestosterone (DHT). That is why certain herbs such as nettle root and saw palmetto, for instance, which inhibit the enzyme 5-alpha-reductase from testosterone, can be effective at both preventing and treating prostate cancer when combined with other herbs. |
| Androgens in prostate cancer, as well as estrogens in breast cancer, also alter intracellular glutathione levels and the activity of certain detoxification enzymes. Physiologic levels of these hormones are capable of increasing oxidative stress, perhaps due to increased mitochondrial activity.38 Because of this, it is important to include herbs that can enhance the detoxification and excretion of cancer-promoting hormone metabolites. Another example of this in breast cancer is to enhance detoxification and reduce the levels of the estrogens estradiol-17B and 16-alpha-hydroxylase. The liver plays a key role in the metabolism of hormones and carcinogens, and it can use all the help it can get. |
| One interesting note on the subject of breast and prostate cancers is that they can both manipulate hormones, causing estrogens to fuel prostate cancer and androgens to fuel breast cancer. This means that the drug tamoxifen used in treating breast cancer and flutamine used in treating prostate cancer start out inhibiting cancer, but over time their effects can actually be reversed and they can promote cancer. |
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