Diet-induced epigenetic changes and cancer prevention: A mantra for healthy living

Abstract

In today's world, survival is mostly about making smart choices. Keeping our body healthy and disease free too is about making smart lifestyle and dietary choices. There is a growing sense that diet becomes a part of 'who we are' and 'how we express ourselves' in the world. As a matter of fact one question that is often raised is why is diet so important? The answer is that diet is the vehicle for obtaining the nutrients our bodies require to function optimally. What we eat and how much we eat dramatically influences the nutrition our cells receive. Therefore, the health and vitality of our bodies, on a cellular level, is directly determined by the state of nutrition. As a result, diet has become one of the fundamental contributors to both health and disease. Recent scientific evidence suggests that in addition to the presence of other dietary nutrients, diets are also an important source of essential dietary phytochemicals, also referred to as 'polyphenols'. Growing body of literature indicates that some of these dietary compounds and their secondary metabolites can have a tremendous effect on the way our bodies respond to various challenges posed by various diseases and aging. Not only this, preclinical and clinical studies in the last decade have convincingly demonstrated that the health promoting effect of various dietary agents extend far beyond than what was initially perceived, and that some of these compounds also possess potent anti-cancer activities. In this regard, multiple lines of evidence have provided unprecedented clues that dietary and environmental factors not only regulate various cell-signaling and growth regulatory pathways within cancer cells, but also directly influence epigenetic mechanisms. Epigenetic changes subsequently permit re-expression of tumor suppressor genes that promote apoptosis and growth inhibition of the tumor cells- a novel and previously unrecognized molecular mechanism supporting the underlying chemopreventive potential of many dietary agents. The term 'epigenetics' refers to heritable changes that are not encoded in the DNA sequence itself, but plays an important role in the control of gene expression. In mammals, the three key epigenetic mechanisms include changes in DNA methylation, histone modifications and non-coding RNAs. Although epigenetic changes can be inherited in the somatic cells, unlike genetic alterations, these modifications are potentially reversible. This potentially reversible nature of epigenetic signatures within growth regulatory genes makes them attractive avenues for developing innovative and promising chemopreventive and therapeutic endeavors in the future. From a nutritional perspective, this is quite fascinating because people are becoming increasingly aware of the beneficial effects of various food sources that are rich in dietary polyphenols, also referred to as superfoods. Although at this point in time we may not appreciate the significance of the dietary changes we all are making, nonetheless, such a behavior sets the stage for generating more scientific and epidemiologic data that will further help in highlighting the concept of chemoprevention by dietary agents at an epigenetic level. Cancer chemoprevention through the use of diet-derived, safe and natural polyphenols certainly seems to be a promising and inexpensive way to alleviate the pressure that weighs down the healthcare system because of rapidly increasing number of cancer patients throughout the world.