Cruciferous Vegetables, Genetic Polymorphisms in Glutathione S-Transferases M1 and T1, and Prostate Cancer Risk

Abstract

Cruciferous vegetables contain anticarcinogenic isothiocyanates (ITCs), particularly the potent sulforaphane, which may decrease risk of prostate cancer through induction of phase II enzymes, including glutathione S-transferases (GSTs). We evaluated this hypothesis in a population-based, case-control study of prostate cancer, including 428 men with incident prostate cancer and 537 community controls. An in-person interview included an extensive food-frequency questionnaire. Genotyping for deletions in GSTM1 and GSTT1 was performed in a subset of men who provided blood. Intakes of cruciferous vegetables and of broccoli, the greatest source of sulforaphane, were associated with decreased prostate cancer risk at all levels above the lowest consumers [adjusted 4th quartile odds ratio (OR)=0.58; 95% confidence interval (CI)=0.38, 0.89, and 0.72 (95% CI=0.49, 1.06)], respectively. In relation to genotypes, there was a nonsignificant increase in risk with the GSTT1 null genotype (OR=1.51; 95% CI=0.98, 2.31) but no effects of GSTM1 genotype. However, men with GSTM1-present genotype and high broccoli intake had the greatest reduction in risk (OR=0.49; 95% CI=0.27, 0.89). Our findings provide evidence that two or more servings per month of cruciferous vegetables may reduce risk of prostate cancer, especially among men with GSTM1-present alleles, and are consistent with a role of dietary ITCs as chemopreventive agents against prostate cancer.

Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis

“…Four out of eight casecontrol studies published since 1990 found that some measure of cruciferous vegetable intake was significantly lower in men diagnosed with prostate cancer than men in a cancer-free control group [47][48][49][50]. Of the 4 prospective cohort studies that have examined associations between cruciferous vegetable intake and the risk of prostate cancer, none found statistically significant inverse associations overall [51][52][53][54].…”

Staying a Step Ahead of Cancer

“…For instance, consumption of a known amount of the phytonutrient sulforaphane does not guarantee absorption of a predicted amount of anti-cancer molecule since differences in the glutathione S transferase M1 gene influences the metabolic rate of sulforaphane, a phytonutrient present in broccoli. The faster it is metabolized, the faster it is expelled from the body , Gasper et al 2005, Gross-Steinmeyer et al 2010, Joseph et al 2004, Lampe 2007, Lampe 2009, McWalter et al 2004, Riedl, Saxon and Diaz-Sanchez 2009, Ritz, Wan and Diaz-Sanchez 2007, Traka et al 2008. Similarly, a number of the nutrients, e.g.…”

Cruciferous vegetable intake and the risk of human cancer: epidemiological evidence

“…A 2002 review has concluded that the epidemiological literature provides modest support for the premise that high cruciferous vegetable intake lowers prostate cancer risk (48) . The examples are case-control studies (49)(50)(51)(52) . Two studies have previously reported inverse associations for cruciferous vegetables, with marked reductions in risk for high cruciferous vegetable intake v. low intake (49,52) .…”