Antioxidants & phytoestrogens
After trying to give a reply to
rinaina on antioxidants when one is on chemotherapy ( I failed to give a clear cut answer) I am about to add more confusion in elaborating on my interpretation of various readings. Not being a scientist & in view of the very limited amount of good data to base on I am bound to be found wrong ,sometimes in the future, in some or all parts of the following comments. It will probably take a long time to happen since no pharmaceutical firm is going to start clinical trials on natural compounds which cannot be patented. And government agencies are not often funding this type of long term studies. Occasionaly a private company (such as Mars for its chocolate) may subsudize a small study related to its business but not large scale investigations.
This lack of good data is one of the main reason for the lack of consistancy between the small bits of knowledge accumulated by different researchers in the laboratory or even by large scale epidemiological surveys.
In addition, even more so than single component drugs which have more than one mode of action, natural compounds may include up to several hundreds chemicals with numerous modes of action. And these various modes of action may sometimes be antagonistic (as described later).
Finally (enough confusion!) different patients at different stages of their disease may react in different ways to the same compound depending ,for instance, on the relative proportions & bioavailability of antagonist chemicals.
So I feel that each one has to make her own mind (or rely on her onc) because even the experts can't agree on all facets of antioxidant activities in cancer.
One area where there seems to be agreement is in the field of prevention.
Antioxidants by suppressing free radicals which may be cancer causing are reducing the risk of initiating a cancerous tumour.
However once the disease is in progress the use of antioxidants is still debated as you will be aware after reading about the controversy between Dr Gabriella D’Andrea who published a paper in 2005 (after several more by other researchers, against the use of
antioxidants while undergoing cytotoxic treatments such as chemo drugs generating free radicals to kill cancer cells), & Ralph Moss Phd who published an essay of counter arguments.
However when the cancer treatment does not involve an oxidative process it could be that antioxidants may still play a usefull role. But I am not an expert on the subject to make a recommandation.
Ref.
http://www.annieappleseedproject.org...unchemanr.html
http://www.cancerdecisions.com/112005_page.html
Regarding phytoestrogens (as in soybean products or flax seeds) the controversy is long standing & not yet resolved. It even leads to violent verbal exchanges between "experts" (at least one side must be wrong!) as shown in links below.
My feeling is that for healthy women phytoestrogens may provide protection against ER+ cancer since they are weakly estrogenic & by attaching to estrogen receptors they may inhibit the attachment of the more carcinogenic estradiol in blood. So it looks like a tradeoff : the better of two evils.
But even under these conditions I would check cancer markers before & periodically after starting on a phytoestrogen regimen.
But once the disease is in progress, especially in the case of ER+ cancer, it would be wise to monitor closely the effect of such a regimen if one is intent on trying it.
In the special case of patients stopping Letrozole(=Femara), estrogen in blood circulation is almost nil but the receptors are not only there but have been found to to be about 6 orders of magnitude more sensitive to estrogen. So it appears to be a bad time to try phytoestrogen.
On a personal note, a relative (ER+ breast cancer) tried ground flax seeds in yogourt (22g per day) imitating the women (in a study by Dr Paul Goss in Toronto) who ate 25g a day of baked ground seeds in a muffin prior to surgery. The biopsies showed anticancer activity.
But in her case (this was 2 years after a lumpectomy, no recurrence,no mets) her CEA rose moderatly from a low level. When the dose of seeds was reduced to 11g the CEA increase was cut in half. So the regimen was stopped & the CEA returned to baseline.
Initially the only reason to try explaining the disparity in outcomes was the difference in raw vs baked seeds. But long afterwards I rather settled on bad timing when I learned about the after effect of Femara. She had taken the seeds soon after stopping Femara. The women in the study were younger & were probably free of heavy pretreatment & the status of their disease was not revealed in abstracts. In addition the seeds have multiple functions.
An example of conflicting data & potential antagonist activities relates to a phytoestrogen & apigenin found in parsley.
In one cell study the phytoestrogen & apigenin stimulate the growth one cancer cell line while in an other apigenin inhibits VEGF & HIF-1 which would make it a potent antiangiogenesis agent since according to an other of piece of research HIF-1 may be the master switch of angiogenesis. Fortunately in normal diet the doses of the 2 chemicals in parsley are too low to have any effect & of course in vivo studies might have different outcomes.
http://cpb.pharm.or.jp/abst/200007/ac48071039.html
Phytoestrogen & apigenin in parsley
http://www.fasebj.org/cgi/content/abstract/19/3/342
Apigenin inhibits VEGF & HIF-1
http://www.charitywire.com/charity280/05584.html
HIF-1 angiogenesis master switch. Duke University.
As regards soy the controversy is perhaps even more acerbic judging from these links:
http://www.mercola.com/article/soy/avoid_soy.htm
http://www.soya.be/mercola.php
http://www.campaignfortruth.com/Eclub/220405/CTM%20-%20Soy%20rebuttal.htm
Even large scale epidemiological studies on soy consumption have been inconsistant in their conclusions. While most studies in Japan show preventive effectiveness against cancer, in the US results are not as positive even among japanese emigrants of the first generation.
Dr M.J. Folkman may have provided an explanation for this discrepancy.
In a comment at the end of a presentation on angiogenesis (see vido link:
http://webcast.ucsd.edu:8080/ramgen/UCSD_TV/9341.rm) he stated that the kind of soybeans grown in the US is devoid of the genetic make up to create genestein while the japanese variety does comprise genestein. So that japanese emigrants in the US who consume imported soybean products still benefit from the protection .
Linear Mode
