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Cancer is a leading cause of death worldwide, accounting for 7.6 million deaths in 2008. By 2030, global projection suggests that 22.3 million new cases of cancer will emerge and mortality will increase to 13.5 million deaths. In the recent past, to arrest this global pandemic natural dietary agents such as fruits, vegetables, and spices have drawn a great deal of attention from both the scientific community and the general public, owing to their putative ability to suppress cancers. Dietary agents consist of a wide variety of biologically active compounds that are ubiquitous in plants, and the relationship between diet and cancer has been recognized throughout the recorded history. In 168 BCE, Galen, a Roman physician, wrote that unhealthy diet and bad climate were directly connected to cancer. In the Middle Ages (1676), Wiseman suggested that cancer might arise from “an error in diet,” and recommended avoiding “salt, sharp and gross meats.” The scientific studies of diet in relation to cancer risk started from the observations of Peyton Rous, when in 1914 he observed that restriction of food consumption delayed the development of cancer metastases in mice and when Dr. Michael Sporn first coined the term “chemoprevention,” referring to the possibility that natural forms of vitamin A could prevent the development and progression of epithelial cancer. He probably did not imagine the impact that this new approach of chemoprevention would have had in cancer research. However, the study of diet and cancer risk reduction is complicated not only by the multistage, multifactorial nature of the disease, but also because of the inherent complexities of any diet. A diet is composed of a multitude of nutrients as well as nonnutritive components. In addition to the food itself, factors such as food preparation methods, portion sizes, nutrient synergy, the dietary pattern, and the role of physical activity on calorie balance are all a part of the nutritional picture that may affect cancer risk. In recent years, many studies have been carried out to investigate the potential cancer chemopreventive activities of natural antioxidants, in particular, dietary polyphenol. This chapter particularly deals with the chemopreventive properties of resveratrol and lycopene. |
