Clinical Research Update
Broccoli Nutrilite Studies the Effect of Cooking on Beneficial Compounds Found in Broccoli
AT A GLANCE: —Study Goal: To determine how heat affects the production of healthy plant compounds called glucosinolates in steamed versus fresh broccoli. —Study Results: In the body, glucosinolates are transformed into isothiocyanates (ITCs), which are believed to have anti-cancer properties. Within hours of consumption of either fresh or steamed broccoli, ITCs were present in the participants blood and urine, but the levels were three times greater in those consuming fresh broccoli. —Conclusion: In order to preserve the health benefits of broccoli, minimal exposure to heat is recommended in order to maximize the potential to generate beneficial ITCs.
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onsumption of diets high in cruciferous vegetables such as broccoli is associated with reduced risk for certain types of cancer. The anti-cancer properties of broccoli are thought to be due to
compounds called isothiocyanates (ITCs), which are formed in the body from glucosinolates, an abundant phytonutrient found in broccoli and other cruciferous vegetables.
Transforming glucosinolates to ITCs
Plasma Isothiocyanates Following Consumption of Steamed vs Raw Broccoli means± standard error
depends on an enzyme in broccoli, which is sensitive to heat. This suggests that cooking
Total Isothiocyanates
ITCs by damaging this enzyme. This study
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was undertaken at the American Health Foundation in New York, to determine how heat affects the production of glucosinolates in steamed versus fresh broccoli.
80 Isothiocyanates (µmol)
1.3 Isothiocyanates (nM)
broccoli may decrease the production of
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60 40 20 0
1.0
steamed raw Broccoli preparation
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Twelve volunteers took part in this six-day,
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two-period, cross-over study with healthy
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Raw Steamed
male non-smokers, aged 24-51. Each subject abstained from consuming cruciferous
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2
4
6
vegetables for two days before each test
8 10 12
24
Hours
day. Subjects consumed 200 grams of fresh or steamed broccoli (15 minutes in a food steamer), and then provided blood and urine samples for a 24-hour period. ITCs were detected in each subjects’ blood and urine within two hours of consuming the steamed or fresh broccoli. However, total ITCs were up to 3 times greater in subjects consuming fresh broccoli, as opposed to those consuming steamed broccoli, a difference that was most notable during the first four hours. These results can be seen in the figure at the right. The results of this study suggest that in order to preserve the health benefits of broccoli, much care must be taken in the preparation of broccoli concentrates to minimize exposure to heat in order to maximize the potential to generate beneficial ITCs. To learn more about this and other research, visit us at www.nutrilite.com.
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