Studies NOT Supporting I3C/DIM Anti-Cancer Action
|
Cancer Type
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I3C or DIM
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Study Findings
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StudyType#
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Study
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Breast
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I3C
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Shown INeffective in controlling experimental cancer growth in rats;
First study concluded that, over time, IC3increased carcinogenic estrogen
metabolites (E.g. 4-OH and 16-OH), which may be counteracting those
of the less estrogenic 2-OH metabolites
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A
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PubMed
PubMed+
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Liver
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I3C
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I3C promoted or enhanced cancer development when administered chronically
to rainbow trout AFTER administration of cancer promoting carcinogen
(post-initiation).
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A
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PubMed+
PubMed +
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Breast, liver,
colon
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I3C
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continuous I3C diet for 25 weeks did not alter tumor incidence or
multiplicity among surviving rats
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A
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PubMed+
PubMed+
PubMed+
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Liver,
Thyroid
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I3C
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Enhanced cancer development in rats
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A
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PubMed+
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Colon
|
|
Enhanced cancer development in rats; second study states I3C increased
proliferation and decreased apoptosis
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A
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PubMed
PubMed+
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Uterus
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I3C
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study concluded that excess increased activityof carcinogenic 4-OH
estrogen metabolites compared to 2-OH metabolites in the liver contributed
to increased uterine uterine adenocarcinomas and/or multiplicities of
uterine proliferative lesions; study showed no effect on 16-OHactivity.
|
A
|
PubMed+
|
# Study Type is Cultured (C), Animal(A)
or Human (H)
+ Administered post-initiation i.e. after
carcinogen (required to cause cancer in most animal models)
I3C reaction products have been shown
to reduce immune system natural killer cell activity in rats
Exon JH, South EH, "Dietary indole-3-carbinol alters immune
functions in rats."J Toxicol Environ Health A. 2000 Feb 25;59(4):271-9.
I3C reaction products associated with
reproductive toxicity in rats -similarly to dioxin
Wilker C, Johnson L, Safe S, "Effects of developmental exposure
to indole-3-carbinol or 2,3,7,8-tetrachlorodibenzo-p-dioxin on reproductive
potential of male rat offspring." Toxicol Appl Pharmacol. 1996 Nov;141(1):68-75.
Larsen-Su SA, Williams DE, "Transplacental Exposure to Indole-3-carbinol
Induces Sex-Specific Expression of CYP1A1 and CYP1B1 in the Liver of Fischer
344 Neonatal Rats." Toxicol Sci. 2001 Dec;64(2):162-8.
DIM is neither
Estrogen icor a growth promoter of cancer
cells. DIM exerts its control over cancer growth by promoting
production of beneficial 2OHE1 estrogen, whilstinducing
less of the unwanted enzymes that producehighly estrogenic and carcinogenic16OHE1from
I3C; (see below: IC3/DIM and Hormone Balancing
/Alterations in Estrogen Activity and Metabolism)
Other I3C reaction products have mixed
effects
-
Linear Trimer (LTR).
Anti-estrogenic, but activates dioxin receptor
-
Cyclic Trimer (CTR).
Directly activates the estrogen receptor, powerfully stimulates breast
cancer cell growth, whether or not estrogen is
present;
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Indole-3-acetonitrile
(IAN). Shown protective in animal model of stomach cancer,
but it has also been found to be mutagenic and to produce DNA-damaging reaction
products in the presence of nitrates (common in foods)
Yamashita K, Wakabayashi K, Kitagawa Y, Nagao M, Sugimura
T. "32P-postlabeling analysis of DNA adducts in rat stomach with 1-nitrosoindole-3-acetonitrile,
a direct-acting mutagenic indole compound formed by nitrosation." Carcinogenesis.
1988 Oct;9(10):1905-7.
Wakabayashi K, Nagao M, Ochiai M, et al., "A mutagen
precursor in Chinese cabbage, indole-3-acetonintrile, which becomes mutagenic
on nitrite treatment." Mutat Res 1985; 143(1-2):17-21.
IAN also found to activate inflammation-causing
leukotrienes in cell membranes (via arachadonic fatty acid cascade)
Maybe other ingredients in cruciferous vegetables
are responsible for their hypothesized lower risk for some types of cancer in
epidemiological studies.
Verhoeven DT, Goldbohm RA, van Poppel G, Verhagen
H, van den Brandt PA. Epidemiological studies on brassica vegetables and cancer
risk. Cancer Epidemiol Biomarkers Prev. 1996;5(9):733-748.
(PubMed).
-brassica are relatively good sources of other phytonutrients
including vitamin C, folate, selenium, carotenoids, fiber and other glucosinolates,
in addition to I3C, that may be hydrolyzed to a variety of potentially protective
isothiocyanates (E.g.
Sulforaphane -"Eat Your Broccoli").
The I3C reaction product ICZ (indolocarbazole) is generally undesireable
- ICZ has both antiestrogenic and estrogenic activities.
It down-regulatesestrogenreceptors,
but is itself estrogenic, promoting enzymes which produce
the carcinogenic estrogenic metabolite4-hydroxy
estrogenassociated with uterine tumors
- ICZ activates the dioxin receptors just like dioxin.
Although dioxin has toxic properties, it is a powerful estrogen
activity inhibitor, as is ICZ. ICZ is more quickly metabolized than dioxin,
but has been shown to damage the thymus gland and immune system and to damage
DNA.
d'Argy R, Bergman J, Dencker L, "Effects of immunosuppressive
chemicals on lymphoid development in foetal thymus organ cultures." Pharmacol
Toxicol. 1989 Jan;64(1):33-8.
Park JY, Shigenaga MK, Ames BN, "Induction of cytochrome
P4501A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin or indolo(3,2-b)carbazole [ICZ]
is associated with oxidative DNA damage," Proc Natl Acad Sci U S A. 1996 Mar
19;93(6):2322-7.
- Another I3C condensation product, ascorbigen (ASG)
is converted to ICZ in the lower intestine. In the
presence of vitamin C (naturally abundant in cruciferous vegetables), ASG
is the most plentifully produced reaction product from I3C, occurring in
the stomach.Some of this ASG is converted to ICZ in the lower intestine,
making it available for unwanted enzyme production to promote carcinogenic4-hydroxy
estrogen.
Preobrazhenskaya MN, Bukhman VM, Korolev AM, Efimov SA,
"Ascorbigen and other indole-derived compounds from Brassica vegetables and
their analogs as anticarcinogenic and immunomodulating agents." Pharmacol Ther.
1993 Nov;60(2):301-13.
- DIM cannot be converted to the undesireable ICZ
in vivo
I3C/DIM and hormone balancing /alterations
in estrogen activity and metabolism
"Good" and "Bad" estrogens at work in the
body
Estrogens must be removed from the
body when they have finished their work. Generally,
estrogens positively promote the tissue growth
predominately underlying female maturation. Ideally, once their job is done,
they are promptly metabolized and removed from the body. If this is not efficiently
achieved, they can hang around and wreak havoc.
Removal of hormones is achieved in two main ways:
1. Physically removed viaurination and bowel movements
2. Metabolized ( Chemically altered ) mainly by the liver to prepare them
for removal - requires certain nutrients and is achieved by two main pathways:
(i) CARCINOGENIC 16 alpha-hydroxylation
pathway - more active in women with estrogen-sensitive cancers; produces
the carcinogenic estrogen metabolite
16alpha-hydroxyestrone (16OHE1), which is
highly estrogenic and has been found to stimulate the proliferation of
several estrogen-sensitive cancer cell lines.
Telang NT, Suto A, Wong GY, Osborne MP, Bradlow HL. Induction
by estrogen metabolite 16 alpha-hydroxyestrone of genotoxic damage and aberrant
proliferation in mouse mammary epithelial cells. J Natl Cancer Inst. 1992;84(8):634-638.
(PubMed)
Yuan F, Chen DZ, Liu K, Sepkovic DW,
Bradlow HL, Auborn K. Anti-estrogenic activities of indole-3-carbinol in cervical
cells: implication for prevention of cervical cancer. Anticancer Res. 1999;19(3A):1673-1680.
(PubMed)
(ii) PROTECTIVE 2 hydroxylation
pathway - produces the cancer-protective
estrogen metabolite 2-hydroxyestrone
(2OHE1).
What factor(s) determine whether
estrogen is metabolized by the
carcinogenic or protective
pathway?
Removal of hormones is negatively impacted by low thyroid
function. Explains the link between hypothyroidism and
breast or prostate cancer.
Can depend on our genetic expression, diet, lifestyle
and elimination habits. E.g. a deficiency in B vitamins
(B6 in particular) and/or Magnesium reduces liver's
estrogen
clearance rate.
Several tactics can be used to reduce unwanted estrogen
presence in the body. E.g. A coffee enema will
stimulate bile production to cleanse liver. Attend to B6/
Magnesium deficiencies
How to Reduce
Estrogen levels
Many of estrogen's
risks can be related to a lack of its beneficial metabolites and
too many of its carcinogenic metabolites
It is now known that a lower risk of future breast
cancer is associated with high beneficial 2-hydroxy
estrogen levels and low carcinogenic
16OHE1. Which is prone to behave like "super-estrogen"
and its higher levels create a particularly carcinogenic form of estrogen dominance
which can result in:
•Mutations, abnormal growth (as in cervical dysplasia)
Sepkovic DW, Bradlow HL, Ho G, et al.Estrogen metabolite
ratios and risk assessment of hormone related cancers:assay validation and prediction
of cervical cancer risk.Ann NY Acad Sci. 1995; 768:312-316.
•Increased risk of breast cancer.
Muti P, et al.Metabolism and risk of breast cancer:A
prospective analysis of 2:16 hydroxyestrone ratio in premenopausal and postmenopausal
women.Cancer Epidemiol Biomarkers Prev, 2000; in press.
Overproduction of 16OHE1
is also seen in:
•Obesity
Hershcope RJ, Bradlow HL.Obesity, diet, endogenous estrogens,
and the risk of hormone-sensitive cancer.Am J Clin Nutl: 1987;45(1 Supp1):283-289.
•High-fat diets
Musey PI, Collins DC, Bradlow HL, Gould KG, Preedy JR.Effect
of diet on oxidation of 17-Beta-ESTRADIOL in vivo.J Clin Endoc Metab. 1987;65:792-795.
•Exposure to "estrogenic" environmental chemicals (xenoestrogens)
Bradlow HL, Davis DL, Lin G, Sepkovic D, Tiwari R.Effects
of pesticides on the ratio of 16/2-hydroxyestrone'a biologic marker of breast
cancer risk.Environ Health Perspect. 1995; 103(SuppI7): 147-150.
Endogenous estrogens
exert their estrogenic effects by binding to
estrogen receptors (ERs).
Within the nucleus, the estrogen-ER complex can bind to DNA sequences(estrogen
response elements/EREs) in estrogen-responsive
genes (stimulated by the ligand-activated transcription factor Aryl hydrocarbon
receptor/AhR) and thereby enhance transcription of these
estrogen-responsive genes. ER-mediated effects
that promote cellular proliferation in the breast and uterus can increase the
risk of developing estrogen-sensitive cancers.
Effect of I3C/DIM on estrogen metabolism
and receptor activity
IC3 /DIM creates more "good" estrogen
and less "bad" estrogen.
In controlled clinical trials, oral supplementation with:
300-400 mg/day of I3C has consistently increased
urinary 2OHE1 levels or urinary
2OHE1: 16OHE1
ratios in women.
McAlindon TE, Gulin J, Chen T, Klug T, Lahita R, Nuite
M. Indole-3-carbinol in women with SLE: effect on estrogen metabolism and disease
activity. Lupus. 2001;10(11):779-783.
(PubMed)
Bradlow HL, Michnovicz JJ, Halper M,
Miller DG, Wong GY, Osborne MP. Long-term responses of women to indole-3-carbinol
or a high fiber diet. Cancer Epidemiol Biomarkers Prev. 1994;3(7):591-595.
(PubMed)
Michnovicz JJ. Increased estrogen 2-hydroxylation
in obese women using oral indole-3-carbinol. Int J Obes Relat Metab Disord.
1998;22(3):227-229.
(PubMed)
Michnovicz JJ, Adlercreutz H, Bradlow
HL. Changes in levels of urinary estrogen metabolites after oral indole-3-carbinol
treatment in humans. J Natl Cancer Inst. 1997;89(10):718-723.
(PubMed)
Wong GY, Bradlow L, Sepkovic D, Mehl
S, Mailman J, Osborne MP. Dose-ranging study of indole-3-carbinol for breast
cancer prevention. J Cell Biochem Suppl. 1997;28-29:111-116.
(PubMed)
Reed GA, Peterson KS, Smith HJ, et al.
A phase I study of indole-3-carbinol in women: tolerability and effects. Cancer
Epidemiol Biomarkers Prev. 2005;14(8):1953-1960.
(PubMed)
108 mg/day of DIM increased urinary
2OHE1 levels in postmenopausal women.
Meaning the body was producing them.
Dalessandri KM, Firestone GL, Fitch MD, Bradlow HL, Bjeldanes
LF. Pilot study: effect of 3,3'-diindolylmethane supplements on urinary hormone
metabolites in postmenopausal women with a history of early-stage breast cancer.
Nutr Cancer. 2004;50(2):161-167.
(PubMed)
Oral I3C supplementation can increase production of
dangerous estrogen metabolites at the same time it increases
the beneficial 2-hydroxy metabolites.
Animal studies demonstrate unwanted enzyme-inducing effects from oral
I3C supplementation
Ritter CL, Prigge WF, Reichert MA, Malejka-Giganti D, "Oxidations
of 17 beta-ESTRADIOL and estrone and their interconversions catalyzed by liver,
mammary gland and mammary tumor after acute and chronic treatment of rats with
indole-3-carbinol or beta-naphthoflavone." Can J Physiol Pharmacol. 2001 Jun;79(6):519-32.
I3C/DIM downgrade estrogen receptor
activity. In culture, I3C has been found to INHIBIT
the transcription of estrogen-responsive genes stimulated by ESTRADIOL. Also,
it was found that DIM binds and activates the Ah receptor (AhR) with an anti-estrogenic
and anti-tumorigenic effect; it may inhibit the transcription of estrogen-responsive
genes by competing for coactivators or increasing ER degradation.
Chen I, McDougal A, Wang F, Safe S. Aryl hydrocarbon receptor-mediated
antiestrogenic and antitumorigenic activity of diindolylmethane. Carcinogenesis.
1998;19(9):1631-1639.
(PubMed)
Meng Q, Yuan F, Goldberg ID, Rosen EM, Auborn K, Fan S.
Indole-3-carbinol is a negative regulator of estrogen receptor-alpha signaling
in human tumor cells. J Nutr. 2000;130(12):2927-2931.
(PubMed)
In contrast, a RAINBOW TROUT model found that DIM
enhanced the transcription of
estrogen-responsive genes.
Shilling AD, Carlson DB, Katchamart S, Williams DE. 3,3'-Diindolylmethane,
a major condensation product of indole-3-carbinol, is a potent estrogen in the
rainbow trout. Toxicol Appl Pharmacol. 2001;170(3):191-200.
(PubMed)