What does it do?
Indole-3-carbinol is one of the major anticancer
substances found in cruciferous (cabbage family)
vegetables. It is a member of the class of sulfur-containing chemicals called
glucosinolates.1 It is formed from parent compounds whenever cruciferous vegetables
are crushed or cooked.2 3
Indole-3-carbinol and other glucosinolates (e.g., other indoles and isothiocyanates such as
sulforaphane) are
antioxidants and potent stimulators of natural detoxifying
enzymes in the body.4 5 Indole-3-carbinol and other glucosinolates
are believed to be responsible for the lowered risk of cancer in humans that is associated
with the consumption of broccoli and other
cruciferous vegetables like cauliflower, cabbage, and
kale.6 7 8 9 10 11
12
Feeding indole-3-carbinol or broccoli extracts rich in indole-3-carbinol has dramatically
reduced the frequency, size, and number of tumors in laboratory rats exposed to a carcinogen.
It appears to be especially protective against
breast13 14 15 16 and cervical17
18 cancers because of a number of actions, including an ability to increase the
breakdown of estrogen. However, while most animal studies
report protective effects, a few indicate that indole-3-carbinol may actually promote cancer
formation in certain situations, depending upon the chemical initiator of cancer, method of
exposure, and species of animal studied.19 20
Until there is further research and more human clinical data to determine if
indole-3-carbinol actually inhibits rather than stimulates cancer formation, some researchers
have recommended proceeding with caution when using isolated indole-3-carbinol as a dietary
supplement.21 The areas where its use has currently been documented in humans are
only preliminary, but the results are promising. Indole-3-carbinol reduced or halted the
formation of precancerous lesions (papillomas) in 12 out of 18 people with recurrent
respiratory tract papillomas.22 In addition, in a small double-blind trial,
supplementation with 200 or 400 mg of indole-3-carbinol per day for 12 weeks reversed
early-stage cervical cancer in 8 of 17 women.23 Preliminary studies have also shown
indole-3-carbinol has significantly increased the conversion of estrogen from cancer-producing
forms to nontoxic breakdown products.24 25
References
1. Stoewsand GS. Bioactive organosulfur phytochemicals in Brassica
oleracea vegetables—a review. Food Chem Toxicol 1995;33:537–43.
2. Broadbent TA, Broadbent HS. The chemistry and pharmacology of
indole-3-carbinol (indole-3-methanol) and 3-(methoxymethyl)indole. [Part I]. Curr Med
Chem 1998;5:337–52.
3. Broadbent TA, Broadbent HS. The chemistry and pharmacology of
indole-3-carbinol (indole-3-methanol) and 3-(methoxymethyl)indole. [Part II]. Curr Med
Chem 1998;5:469–91.
4. Broadbent TA, Broadbent HS. The chemistry and pharmacology of
indole-3-carbinol (indole-3-methanol) and 3-(methoxymethyl)indole. [Part I]. Curr Med
Chem 1998;5:337–52.
5. Broadbent TA, Broadbent HS. The chemistry and pharmacology of
indole-3-carbinol (indole-3-methanol) and 3-(methoxymethyl)indole. [Part II]. Curr Med
Chem 1998;5:469–91.
6. Hecht SS. Chemoprevention of cancer by isothiocyanates, modifiers of
carcinogen metabolism. J Nutr 1999;129:768S–74S [review].
7. Verhoeven DT, Goldbohm RA, van Poppel G, et al. A review of mechanisms
underlying anticarcinogenicity by brassica vegetables. Chem Biol Interact
1997;103:79–129 [review].
8. Verhoeven DT, Goldbohm RA, van Poppel G, et al. Epidemiological
studies on brassica vegetables and cancer risk. Cancer Epidemiol Biomarkers Prev
1996;5:733–48 [review].
9. Talalay P, Zhang Y. Chemoprotection against cancer by isothiocyanates
and glucosinolates. Biochem Soc Trans 1996;24:806–10.
10. Maheo K, Morel F, Langouet S, et al. Inhibition of cytochromes P-450
and induction of glutathione S- transferases by sulforaphane in primary human and rat
hepatocytes. Cancer Res 1997;57:3649–52.
11. Barcelo S, Gardiner JM, Gescher A, Chipman JK. CYP2E1-mediated
mechanism of anti-genotoxicity of the broccoli constituent sulforaphane.
Carcinogenesis 1996;17:277–82.
12. Plumb GW, Lambert N, Chambers SJ, et al. Are whole extracts and
purified glucosinolates from cruciferous vegetables antioxidants? Free Radic Res
1996;25:75–86.
13. Bradlow HL, Sepkovic DW, Telang NT, Osborne MP. Multifunctional
aspects of the action of indole-3-carbinol as an antitumor agent. Ann N Y Acad Sci
1999;889:204–13.
14. Bradlow HL, Sepkovic DW, Telang NT, Osborne MP. Indole-3-carbinol. A
novel approach to breast cancer prevention. Ann N Y Acad Sci
1995;768:180–200.
15. Bradlow HL, Sepkovic DW, Telang NT, Osborne MP. Multifunctional
aspects of the action of indole-3-carbinol as an antitumor agent. Ann N Y Acad Sci
1999;889:204–13.
16. Meng Q, Qi M, Chen DZ, et al. Suppression of breast cancer invasion
and migration by indole-3-carbinol: associated with up-regulation of BRCA1 and
E-cadherin/catenin complexes. J Mol Med 2000;78:155–65.
17. Yuan F, Chen DZ, Liu K, et al. Anti-estrogenic activities of
indole-3-carbinol in cervical cells: implication for prevention of cervical cancer.
Anticancer Res 1999;19(3A):1673–80.
18. Jin L, Qi M, Chen DZ, et al. Indole-3-carbinol prevents cervical
cancer in human papilloma virus type 16 (HPV16) transgenic mice. Cancer Res
1999;59:3991–7.
19. Oganesian A, Hendricks JD, Pereira CB, et al. Potency of dietary
indole-3-carbinol as a promoter of aflatoxin B1-initiated hepatocarcinogenesis: results from a
9000 animal tumor study. Carcinogenesis 1999;20:453–8.
20. Kim DJ, Han BS, Ahn B, et al. Enhancement by indole-3-carbinol of
liver and thyroid gland neoplastic development in a rat medium-term multiorgan carcinogenesis
model. Carcinogenesis 1997;18:377–81.
21. Dashwood RH. Indole-3-carbinol: anticarcinogen or tumor promoter in
brassica vegetables? Chem Biol Interact 1998;110:1–5 [review].
22. Rosen CA, Woodson GE, Thompson JW, et al. Preliminary results of the
use of indole-3-carbinol for recurrent respiratory papillomatosis. Otolaryngol Head Neck
Surg 1998;118:810–5.
23. Bell MC, Crowley-Nowick P, Bradlow HL, et al. Placebo-controlled
trial of indole-3-carbinol in the treatment of CIN. Gynecol Oncol
2000;78:123–9.
24. Michnovicz JJ. Increased estrogen 2-hydroxylation in obese women
using oral indole-3-carbinol. Int J Obes Relat Metab Disord 1998;22:227–9.
25. Bradlow HL, Michnovicz JJ, Halper M, et al. Long-term responses of
women to indole-3-carbinol or a high fiber diet. Cancer Epidemiol Biomarkers Prev
1994;3:591–5.
26. Wong GY, Bradlow L, Sepkovic D, et al. Dose-ranging study of
indole-3-carbinol for breast cancer prevention. J Cell Biochem Suppl
1997;28–29:111–6.
Reliable and relatively consistent scientific data showing a substantial health benefit.
For an herb, supported by traditional use but
minimal or no scientific evidence. For a supplement, little scientific support and/or minimal
health benefit.
