Eat Your Broccoli, Save Your Bladder

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Main Category: Cancer / Oncology
Also Included In: Urology / Nephrology;  Nutrition / Diet
Article Date: 29 Feb 2008 - 0:00 PST

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According to a recent report in the American Association for Cancer Research's journal Cancer Research, receiving a concentrated extract of freeze dried broccoli sprouts reduced the development of animal bladder tumors by more than half.

Researcher Yuesheng Zhang, the study's chief investigator, notes that the finding is in line with previous human epidemiological studies that have shown a relationship between eating cruciferous vegetables and reducing the risk of bladder cancer. Zhang remarks: "Although this is an animal study, it provides potent evidence that eating vegetables is beneficial in bladder cancer prevention."

It is strongly held that cruciferous vegetables are effective tissue protectors partly due to isothyiocyanates (ITCs) - phytochemicals with well-known cancer preventive traits. Cruciferous vegetables such as mature broccoli, cabbage, kale, and collard greens have ITCs. Zhang notes that the bladder is especially sensitive to these natural chemicals: "In our experiments, the broccoli sprout ITCs after oral administration were selectively delivered to the bladder tissues through urinary excretion."

Compared to mature broccoli, broccoli sprouts have about 30 times more ITCs. The extract of broccoli sprouts given to animals in the study contains about 600 times more ITCs than mature broccoli.

High doses of the extract were associated with the greatest protection against bladder cancer development. However, humans who are at an increased risk for the cancer and who seek to receive protective benefits from broccoli most likely would not have to consume copious amounts of broccoli sprouts.

"Epidemiologic studies have shown that dietary ITCs and cruciferous vegetable intake are inversely associated with bladder cancer risk in humans. It is possible that ITC doses much lower than those given to the rats in this study may be adequate for bladder cancer prevention," Zhang said.

The researchers studied five groups of rats in order to test if and how well the sprout concentrate prevents bladder tumors. One group was a control and received nothing, and a second was given only the broccoli extract. These two groups did not present any tumors nor toxicity from the broccoli extract.

Zhang and colleagues gave the remaining three groups a chemical, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water that stimulates bladder cancer development. Two of the three cancer groups received broccoli extracts two weeks prior to receiving the drinking water with the carcinogenic chemical.

Almost all (96%) of the rats who received only BBN developed an average of two tumors each. Of the rats who received a low dose of broccoli extract, 74% developed cancer - about 1.39 tumors on average.

A high dosage of extract was associated with the least amount of tumors - 38% of this group developed cancer and the average number of tumors per rat was 0.46. The tumors that did develop in these animals were small in size compared to the ones that developed in the other groups.

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Written by: Peter M Crosta
Copyright: Medical News Today
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