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Raw broccoli doubles survival in bladder cancer patients

Jacob Schor, ND, FABNO

July 1, 2010

An interesting paper came out a few weeks ago of particular interest to people with bladder cancer but that is worth all of us noticing.  The paper is the latest in a sequence of papers authored by Li Tang and colleagues at the Roswell Cancer Research Center in New York.

Tang has been studying the effect of cruciferous vegetables on bladder cancer for years. In 2004, Tang reported that cruciferous vegetables inhibit the growth of human bladder cancer cells in 2004.   In 2008, Tang, using data from a hospital based case-controlled study, reported that consumption of raw cruciferous vegetables lowered the risk of getting bladder cancer.  They found a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetable intake (adjusted OR for highest versus lowest category = 0.64).  In the early study, as in the current study, no significant benefit was found for fruit, total vegetables, or cooked cruciferous vegetable consumption.  Only eating raw cruciferous vegetables provided protection.   In a February 2010 paper, Tang reported that the isothiocyanates found in cruciferous vegetables inhibited the growth of bladder tumor cells in a rat model of human bladder cancer.   The results of Tang’s current paper are fully congruent with the earlier findings.

 

Tang’s most recent paper was published June 15.  In this paper, data from the Roswell Park Cancer Institute’s Tumor Registry, patient medical records, and routinely collected questionnaire data, were analyzed for potential associations between intake of cruciferous vegetables and survival among bladder cancer patients.

A total of 239 bladder cancer patients were included in the study. After an average of 8 years of follow-up, 179 deaths occurred, with 101 deaths attributable to bladder cancer.

Analysis of the data revealed a strong and statistically significant inverse association between raw broccoli intake and bladder cancer mortality. Those eating one or more servings of raw broccoli a month compared to those eating less than one serving a month reduced their chance of dying from bladder cancer by 57% and reduced the risk of dying from all causes by 45%. No significant associations were found in the data for total vegetables, total fruits or for other individual cruciferous vegetables. 

These effects, though striking, are entirely plausible.  Consumption of cruciferous vegetables is associated with reduced risk of bladder cancer.  These plants contain a number of chemopreventive agents, including isothiocyanates.  Isothiocyanate metabolites that reach the bladder still retain their anti-cancer action. They concentrate in the urine, reaching levels two to three times higher in the bladder than in the blood serum.   Cooking lowers isothiocyanate levels: urinary levels are 3-4 times higher after eating raw broccoli than cooked broccoli.   Broccoli contains higher levels of isothiocyanates than any other cruciferous vegetable, 40% more than cabbage and more than double the amount found in cauliflower.  The type of isothiocyanate found varies with type of vegetable.  In broccoli, the major isothiocyanate is sulforaphane; cabbage and cauliflower contain allyl isothiocyanate. 

 

 It is not just in bladder cancer where raw is better.  Li Tang had another important study published in April 2010 that reported cruciferous vegetable consumption lowers the risk of lung cancer in smokers.  Only consumption of raw cruciferous vegetables had a statistically significantly effect on lung cancer risk, those smokers in the middle tertile of consumption had half the risk of those in the lower tertile.

 

These studies give us good reason to be more specific in what we tell our patients.  Not only should we encourage patient to eat cruciferous vegetables but, we should tell them to eat broccoli and make a point to eat it raw. 

Bottom Line:

References:

Tang L, Zhang Y. Dietary isothiocyanates inhibit the growth of human bladder carcinoma cells. J Nutr. 2004 Aug;134(8):2004-10.

Tang L, Zirpoli GR, Guru K, Moysich KB, Zhang Y, Ambrosone CB, McCann SE. Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk.  Cancer Epidemiol Biomarkers Prev. 2008 Apr;17(4):938-44.

Bhattacharya A, Tang L, Li Y, Geng F, Paonessa JD, Chen SC, Wong MK, Zhang Y. Inhibition of bladder cancer development by allyl isothiocyanate.  Carcinogenesis. 2010 Feb;31(2):281-6.

Tang L, Zirpoli GR, Guru K, Moysich KB, Zhang Y, Ambrosone CB, et al. Intake of Cruciferous Vegetables Modifies Bladder Cancer Survival. Cancer Epidemiol Biomarkers Prev. 2010 Jun 15.

Tang L, Zirpoli GR, Jayaprakash V, Reid ME, McCann SE, Nwogu CE, Zhang Y, Ambrosone CB, Moysich KB. Cruciferous vegetable intake is inversely associated with lung cancer risk among smokers: a case-control study.  BMC Cancer. 2010 Apr 27;10:162.

Tang L, Zhang Y. Dietary isothiocyanates inhibit the growth of human bladder carcinoma cells. J Nutr. 2004 Aug;134(8):2004-10.

Tang L, Zirpoli GR, Guru K, Moysich KB, Zhang Y, Ambrosone CB, McCann SE. Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk.  Cancer Epidemiol Biomarkers Prev. 2008 Apr;17(4):938-44.

Bhattacharya A, Tang L, Li Y, Geng F, Paonessa JD, Chen SC, Wong MK, Zhang Y. Inhibition of bladder cancer development by allyl isothiocyanate.  Carcinogenesis. 2010 Feb;31(2):281-6.

Tang L, Zirpoli GR, Jayaprakash V, Reid ME, McCann SE, Nwogu CE, Zhang Y, Ambrosone CB, Moysich KB. Cruciferous vegetable intake is inversely associated with lung cancer risk among smokers: a case-control study.  BMC Cancer. 2010 Apr 27;10:162.