Hormone-dependent breast cancer/ Interactions?
January 13, 2011 | 15,00 EUR | answered by Dr. med. Ralf Berg
Good day
Four years ago, I had breast cancer and have been taking Tamoxifen since then. I have read in various forums that one should not consume grapefruits and pomegranates while taking Tamoxifen. I have been eating a pomegranate daily for a few months now. Here are my questions:
- Do the phytoestrogens in these fruits promote a recurrence of hormone-dependent breast cancer?
- Do certain enzymes in pomegranates weaken the effectiveness of Tamoxifen?
I have read many different statements and am now very unsure. Should I just stop consuming them altogether?
Kind regards
Thank you
Dear Inquirer,
I wish you continued good appetite and enjoyment in consuming your pomegranate daily! In my opinion, you do not have to completely stop consuming it.
Your medication Tamoxifen is a substance from the group of aromatase inhibitors. These are proven to act as a recurrence prophylaxis for hormone-sensitive breast tumors and are therefore used in follow-up care.
Simply put, the enzyme aromatase promotes the regrowth of any remaining cancer cells in the breast. When this enzyme is blocked by Tamoxifen, no recurrence occurs. Conversely, all estrogens, whether artificial, endogenous, or of plant origin (phytoestrogens), promote the activity of aromatase.
Now it depends on the balance of power. As long as Tamoxifen can inhibit aromatase, low doses of estrogen remain ineffective on the target/tumor cells. While it is true that phytoestrogens also weaken the effect of Tamoxifen, I found no mention in any manufacturer's extended package inserts for healthcare professionals that grapefruit or pomegranates should be avoided due to possible interactions. Classic hormone tablets such as the pill are listed there and can have clinically relevant interactions, so they should not be taken. But a pomegranate a day certainly won't be enough. Just like you can't effectively contracept with pomegranates, even if you eat 10 pomegranates a day. So, don't be unsettled or bamboozled.
It is only recommended to take tablets together with or in close temporal relation to grapefruit juice in general, as grapefruit juice can actually prematurely dissolve many tablet coatings or interact with the active ingredients.
With best regards, R. Berg
