Diet and Cancer Prevention

Home Foodtypes Mechanisms Treatments Specialists' Views Summary & Links Specialist's Views The need for a specialist's opinion seemed indispensable for credibility and further judgement of this issue. Information was therefore gathered from 3 different interviews with the following experts who dedicate their research to this cause: Prof. Antonio Parreira of the Faculty of Medical Sciences, the Universidade Nova of Lisbon Ian Macdonald, Professor of Metabolic Physiology at the University of Nottingham, UK Daniel W. Nixon, M.D. Prof. Antonio Parreira The first interviewee is Prof. Antonio Parreira of the Faculty of Medical Sciences of the Universidade Nova of Lisbon, lecturer in Medicine and director of the Haematology Service of the Portuguese Institute of Oncology (IPO). How can nutrition affect the development of cancer? Carcinogenic agents found in food can lead to the development of particular tumours, such as in the colon or stomach. However, cancer is not a disease caused by a single factor. Even if someone has a genetic predisposition to cancer development, a variety of factors and events need to interact and take place, and many of these might even still remain unknown. Nevertheless, there are many intracellular mechanisms that overcome these obstacles caused by nutritional and other carcinogens. Can the dietary habits of a particular population be therefore reflected in the incidence of cancer in that respective region? Yes. For instance the incidence of stomach cancer is considerably higher in Japan. It is thought it may be due to the Nipponese nutritional habits. What are the active elements in foods that could enhance potential tumour growth? Many substances with a carcinogenic potential do exist in nutritional products, which could damage the DNA. But beware! The trendily called ‘organic’ foods can actually contain more carcinogens - due to the substantial use of pesticides and other chemicals - than the so-called junk-food type. Food cooked in the open air, as in the case of barbecues, are also more prone to contain carcinogenic agents, due to fumes and consequent biochemical modifications (also seen in extensively processed types of food). Ian Macdonald According to Ian Macdonald, Professor of Metabolic Physiology at the University of Nottingham (UK), ‘diet is a very important external factor in the modulation of many cancers’. He is also chairman of the finance committee of the International Association for the Study of Obesity (IASO). How can nutrition affect the development of cancer? By either the phytochemical and anti-oxidant components protecting against free radical damage and thus reducing cancer incidence, or specific dietary constituents increasing cell damage and promoting the development of cancer. Are there foods that can prompt the growth of a specific type of cancer? Yes. For instance, it is thought that saturated fat containing foods appear to stimulate the development of colon cancers. What is the prospective regarding scientific research in this domain? Identify specific nutrients that suppress cancer cell growth and increase dietary intake of them. This might lead to the development of specific pharmaceuticals. What would be an ideal diet to avert potential tumour growths? Low fat and low saturated fat, high fibre, low meat content along a large amount of fruit and vegetables. Maintain a body weight within the non-obese range and have a high level of physical activity. Daniel W. Nixon, M.D. Finally, Daniel W. Nixon, M.D., expresses his views on certain aspects related to cancer and nutrition. He is president of Institute for Cancer Prevention, and director of the American Health Foundation Cancer Center. (Taken from Food Insight, March/April 2001) It’s not only what you eat, but how much It's clear from animal studies that both fat itself and calories, whether from fat or from other foods, play a role as cancer promoters. There’s a need to limit or control obesity. When people consume excess calories, it stimulates the metabolic overdrive into making cells divide faster. This increases the risk that something can go awry, resulting in cancerous cells. Then too, fat people have more cells, so there is an increased statistical chance that some of those cells might become cancerous. The importance of vitamins in cancer prevention Vitamins A, C and E are known to have certain antioxidant properties. These work by stopping damage to the DNA, or help in its repair. But there are also other agents in vitamins that work to prevent cancer. For example, vitamin A retinoids take cells that are on the way to becoming malignant and help restore them to normal activity. Foods, including fruits and vegetables, have many more potentially beneficial chemicals in them besides vitamins that are not nutrients, as we understand them. It's rather the combination of vitamins and these compounds that can help reduce cancer risk. Children should eat well too In terms of dietary guidelines for young children, I think parents should be more concerned about their overall nutritional patterns. It’s important that good eating habits are set for a lifetime, because the diet-related tumours are those that affect adults - breast cancer, colon cancer and prostate cancer, for example.