I3C for ER+ tamoxifen user

Husband11

Please refresh my memory as to whether there are any reasons not to use I3C where the tumor is ER+ and the patient is on tamoxifen.  For some reason one naturopath recommends it, and the other is silent on the issue.  Was there any negative side effects of I3C reported?

Husband11

From the Memorial Sloan Kettering website on herbs:

Herb-Drug Interactions

Theoretically, I3C induces cytochrome P450 1 family and reduces serum concentration of medications metabolized by this enzyme. top

I think this is what had me worried it might interfere with tamoxifen metabolism, which relies on cyp2d6 coded enzymes for metabolism into its active form, endoxifen.  That and my wife is classed as an intermediate metabolizer.

hlth4513

Timothy-

I take DIM, but I am not on Tamoxifen -  I found this article in my saved folder.

http://annieappleseedproject.stores.yahoo.net/i3cdiimlivme.html

"The data suggest that oral intake of I3C or DIM at lower dose levels will not alter CYP-mediated metabolism of TAM, and hence, its therapeutic efficacy."

Beth

mollyann

Tim, I3C and DIM block the effect of iodine.

Husband11

Thanks hlth4513.  I also found a study of I3C with human subjects. 

http://cebp.aacrjournals.org/content/14/8/1953.full

They had 15 women who where extensive cyp2d6 metabolizers, and when they treated them with 400mg or 800mg daily of I3C, 7/14 showed a decease in cyp2d6 activity, and 7/14 showed an increase.  Net effect appears to be no statistically significant effect of I3C on cyp2d6 metabolism.  But still leaves me wondering if half benefited, and half had detrimental effects.  Both groups remained in the range of extensive metabolizers, nevertheless.

Husband11

thanks Mollyann, where did you find this information on iodine and I3C?

Lili46

I'd like to hear the information about iodine and DIM too. I have been on DIM and tamoxifen for 1 1/2 years with no real improvement of my estrogen ratio. My integrative doctor suggested I start taking iodine but never told me to stop my DIM. I was hoping to get the iodine this week. I'll stop the DIM if it's going to interfere with the iodine.

Thanks. Li 

sakura73

Until I stopped recently because of possible pregnancy I was taking I3C (instead of Tamoxifen) and iodine. I was told by my naturopath that the i3C can interfere with iodine absorption and that for that reason an iodine supplement was recommended.

Husband11

Based on my above post of the article on I3C and its effect on various enzyme pathways, I don't see it as safe for tamoxifen users, especially intermediate metabolizers.  The annie appleseed article posted saying its safe, looked at its metabolism in rats, not humans.   It could just as easily decease tamoxifen effectiveness as benefit it.  Unless its benefit is proven, its not worth the risk for a tamoxifen user that it may harm the cyp2d6 conversion of tamoxifen to endoxifen.  Better to wait until Bev is on an aromatase inhibitor before introducing this supplement.

mollyann

Tim, you asked about I3C cancelling out Iodine. Dr. Brownstein was specifically asked about this at a conference and said cooking brassicas (cabbage, brocolli, cauliflower, etc) removes the goitrogens (anti-iodines). So that's fine.

But I3C and DIM are concentrated from RAW brassicas which makes them block iodine uptake. See http://en.wikipedia.org/wiki/Goitrogen 

Dr. Jonathan Wright has prescribed iodine longer than anyone and has found that it gradually shifts the so-called bad estrogens into the protective estriol in his patients. You can find that on the web. So you don't need I3C anyway if estrogen shifting is the goal because iodine already does it.

hlth4513

mollyann-

Thanks for spurring my curiousity on DIM and Iodoral.

When I had my consult with Dr. Fletchas, who is a big proponent of Iodoral, he told me that it was Ok to take my DIM with Iodoral. So I guess I will have to do some more research on this. ( I did find this article by Fletchas http://cpmedical.net/articles.aspx?ProdID=art1959&zTYPE=2 )

 I was aware that DIM and I3C are goitrogenic. I'm hypothyroid and on time-release Natur-throid, but both my functional med doc and pharmacist/LNC said that the benefts of DIM outweigh it's affect on my thyroid and that we would just need o keep a closer eye on my thyroid levels. My doc has had to increase my T3 slightly, but my estrogen profile and metabolism has greatly improved.

It is such a balancing act in finding that optimal wellness.

Beth