Dr. Ghieth A. Kazkaz, Oncology Center of Excellence, International Medical Center: Jeddah The relationship between dietary habits and the risk of developing is not as popular as it is for famous carcinogens. Yet, the percentage of individuals affected due to dietary habits is greater than those affected due to tobacco or exposure to certain industrial materials. Designing studies to prove the effect of regimes on cancer risk is challenging. The study would require the participation and observation of a great amount of people for a long period of time. Most of the data on this subject results from observational studies which are considered to be weak evidence. However, the amalgamation of evidence over the decades has proved substantial enough for some health societies to flag certain dietary substances as cancer risk prone and others as not. Recently, the World Health Organization (WHO) has added processed meat to the list of carcinogens, which includes factors known for their ability to cause cancer, like tobacco, ionized radiation, and many chemical and pharmaceutical compounds. Processed meat has been defined by WHO as meat that has been transformed through salting, curing, fermentation, smoking, or any processes to enhance flavor and improve preservation. Nitrate and salt compounds found in processed meat are known to cause an increase in probability for colon and stomach cancer. Researchers have proved that the consumption of 50 grams of processed meat per day would increase the risk of colon cancer by 15-20%. It is estimated that 34,000 cancer deaths per year globally are linked to the excessive consumption of processed meat. Evidence has suggested that high intake of dietary fiber decreases the risk of developing colon cancer. It is believed that fiber consumption speeds up bowel motion; therefore, decreasing the exposure time of the lining of the bowel to possible carcinogenic contents. Moreover, increased consumption of fiber contributes indirectly to a decreased risk of developing the cancers linked to obesity like gastrointestinal, uterine and breast cancers by decreasing obesity prevalence. Fibers are found in whole grains and most fresh vegetables and fruits. Fresh vegetables and fruits are naturally rich with antioxidants that protect the body from some carcinogens. These nutrients are found in higher amounts in colored fruits and vegetables like berries, carrots and tomatoes. The effect of these naturally present vitamins could not be duplicated by laboratory techniques like the pharmaceutically prepared beta carotene.
