In addition to green tea (& its extract) there is a number of dietary items, supplements & synthetic compounds that have been shown (mostly in the lab) to enhance the antitumour activity of Tamoxifen or to reverse resistance to Tamoxifen such as:
EPA (omega-3):
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum
Eicosapentaenoic acid restores tamoxifen sensitivity in breast cancer cells with high Akt activity
Vitamin A,D,tocotrienols:
http://72.14.209.104/search?q=cache:...n&ct=clnk&cd=1
GLA
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=15027132&query_hl=12&itool=pubmed_docsum
Omega-6 polyunsaturated fatty acid gamma-linolenic acid (18:3n-6)...synergistically enhances tamoxifen ...
GLA
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum
Gamma linolenic acid with tamoxifen as primary therapy in breast cancer.
This report includes the results of a small human study
DISULFIDE BENZAMIDE (DIBA)
http://www.ncbi.nlm.nih.gov/entrez/q...arch&DB=pubmed
Disruption of estrogen receptor DNA-binding domain and related intramolecular communication restores tamoxifen sensitivity in resistant breast cancer