Antioxidative and antigenotoxic properties of vegetables and dietary phytochemicals: The value of genomics biomarkers in molecular epidemiology

Abstract

There is considerable evidence that consumption of fruits and vegetables may contribute to the prevention of cancer. It is however remarkable that evidence for such a preventive action arising from mechanistic studies is becoming stronger, whereas results of some recent prospective studies are less convincing. This apparent discrepancy may be overcome, or at least understood, by introducing molecular markers in future epidemiological studies, taking modulation of molecular processes as well as genetic variability in human populations into account. Both human and animal studies demonstrated that vegetable intake modulates gene expression in the gastrointestinal tract of many genes involved in biological pathways in favor of cancer risk prevention. Gene sets identified in this type of studies can be further evaluated, linked to the biological effects of phytochemicals and developed into biomarkers for larger human studies. Human dietary intervention studies have demonstrated that, apart from target tissues, also peripheral lymphocytes can be used for biomonitoring of chemopreventive effects. Transcriptomic responses and metabolite profiling may link phenotypic markers of preventive effects to specific molecular processes. The use of genomics techniques appears to be a promising approach to establish mechanistic pathways involved in chemoprevention by phytochemicals, particularly when genetic variability is taken into account.

Effect of smoking reduction and cessation on the plasma levels of the oxidative stress biomarker glutathione – Post-hoc analysis of data from a smoking cessation trial

“…Using a metabolic approach, antioxidant supplementation in smokers was found to alter lipid profiles in plasma in a manner consistent with reductions in oxidative stress [37]. However, disease outcome antioxidant clinical trials have provided less-than enthusiastic results and the ability of oral antioxidants to be absorbed and effectively reach target organs remains an area of active investigation [38]. Such studies have not been conducted in former smokers, who are at lower risk than smokers but still maintain a higher risk than nonsmokers.…”

Single Oral Administration of Anthocyanin Rescues Smoking-Induced Endothelial Dysfunction in Young Smokers but Facilitates Oxidative Stress in Non-Smokers

“…Antioxidant supplements altered plasma lipid profiles in smokers in a manner consistent with the reduction in oxidative stress [31]. However, disease outcome of antioxidant clinical trials have provided less than anticipated results [32], and meta-analyses of randomized controlled trials for high doses of antioxidants except polyphenols found no overall relationship between the consumption of antioxidant supplements and cancer risk [13].…”

A Lyophilized Red Grape Pomace Containing Proanthocyanidin-Rich Dietary Fiber Induces Genetic and Metabolic Alterations in Colon Mucosa of Female C57BL/6J Mice

“…The mechanisms by which fiber in general and proanthocyanidins in particular exert their effects are largely unknown (9) and any insight into the action of such preventive agents will help to clarify their role in living organisms. We hypothesized that GADF may induce a protective gene expression profile in the colon.…”