Sulforaphane

What is it?

Sulforaphane is a compound that was identified in broccoli sprouts by scientists at the Johns Hopkins University School of Medicine in Baltimore, MD.¹

These researchers were investigating the anticancer compounds present in broccoli when they discovered that broccoli sprouts contain anywhere from 30 to 50 times the concentration of protective chemicals that are found in mature broccoli plants.² Sulforaphane is one of a class of chemicals called isothiocyanates. Sulforaphane and other isothiocyanates are antioxidants and potent stimulators of natural detoxifying enzymes in the body. These compounds are believed to be responsible for the lowered risk of cancer that is associated with the consumption of broccoli and other cruciferous vegetables, such ascauliflower, cabbage, andkale.³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹

Feeding sulforaphane-rich broccoli-sprout extracts to laboratory rats exposed to a carcinogen dramatically reduced the frequency, size, and number of the rats’ tumours.¹⁰ ¹¹ ¹² Human studies with sulforaphane and other cruciferous-vegetable components have shown that these compounds stimulate the body’s production of detoxification enzymes and exert antioxidant effects.¹³ ¹⁴ ¹⁵

Preliminary studies suggest that in order to cut the risk of cancer in half, the average person would need to eat about two pounds of broccoli or similar vegetables per week. Since the concentration of sulforaphane is much higher in broccoli sprouts than in mature broccoli, the same reduction in risk theoretically might be had with a weekly intake of just over an ounce of sprouts.

Where is it found?

Sulforaphane is found in highest concentrations in broccoli sprouts, but it is also found in mature broccoli and other cruciferous vegetables, such as cauliflower, cabbage, and kale.

Sulforaphane has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings	Health Concerns
	Cancer (risk reduction)
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Who is likely to be deficient?

Sulforaphane is not an essential nutrient, and thus no deficiency state exists.

How much is usually taken?

The optimal level of intake is not known, but some doctors recommend 200 to 400 mcg of sulforaphane daily from broccoli-sprout extracts.

Are there any side effects or interactions?

No side effects or drug interactions have been reported, although sulforaphane and dietary consumption of cruciferous vegetables does interact with drug detoxifying enzymes.¹⁶ People taking prescription drugs should therefore consult a doctor before taking sulforaphane or broccoli-sprout extracts.

At the time of writing, there were no well-known drug interactions with sulforaphane.

References
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1. Zhang Y, Talalay P, Cho CG, Posner GH. A major inducer of anticarcinogenic protective enzymes from broccoli: isolation and elucidation of structure. Proc Natl Acad Sci 1992;89:2399–403.

2. Fahey JW, Zhang Y, Talalay P. Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens. Proc Natl Acad Sci 1997;94:10367–72.

3. Hecht SS. Chemoprevention of cancer by isothiocyanates, modifiers of carcinogen metabolism. J Nutr 1999;129:768S–74S [review].

4. 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].

5. 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].

6. Talalay P, Zhang Y. Chemoprotection against cancer by isothiocyanates and glucosinolates. Biochem Soc Trans 1996;24:806–10.

7. 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.

8. Barcelo S, Gardiner JM, Gescher A, Chipman JK. CYP2E1-mediated mechanism of anti-genotoxicity of the broccoli constituent sulforaphane. Carcinogenesis 1996;17:277–82.

9. 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.

10. Nestle M. Broccoli sprouts in cancer prevention. Nutr Rev 1998;56:127–30 [review].

11. Fahey JW, Talalay P. Antioxidant functions of sulforaphane: a potent inducer of Phase II detoxication enzymes. Food Chem Toxicol 1999;37:973–9.

12. Nestle M. Broccoli sprouts as inducers of carcinogen-detoxifying enzyme systems: clinical, dietary, and policy implications. Proc Natl Acad Sci 1997;94:11149–51 [review].

13. Clapper ML, Szarka CE, Pfeiffer GR, et al. Preclinical and clinical evaluation of broccoli supplements as inducers of glutathione S-transferase activity. Clin Cancer Res 1997;3:25–30.

14. Nijhoff WA, Mulder TP, Verhagen H, et al. Effects of consumption of Brussels sprouts on plasma and urinary glutathione S-transferase class-alpha and -pi in humans. Carcinogenesis 1995;16:955–7.

15. Nestle M. Broccoli sprouts as inducers of carcinogen-detoxifying enzyme systems: clinical, dietary, and policy implications. Proc Natl Acad Sci 1997;94:11149–51 [review].

16. Kall MA, Vang O, Clausen J. Effects of dietary broccoli on human drug metabolising activity. Cancer Lett 1997;114:169–70.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2007.

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