The high calorie, low fiber dietary pattern associated with the Western diet are associated with a 39% increased risk of colorectal cancer compared to a Mediterranean diet, says new research from France.
In an epidemiological study from researchers at the French Institute Gustave Roussy, the link between dietary patterns and the incidence of colorectal tumors in 516 adenoma cases and 4,804 polyp-free women and in 172 colorectal cancer cases and 67,312 cancer-free women.
People with a dietary pattern closely matching the "Western" diet, rich in processed foods and dairy, were found to significantly increase the risk of colorectal cancer, said the researchers.
Lead researcher Marie-Christine Boutron-Ruault said that the new findings "demonstrate that among women with Western dietary habits, those with a typical Western pattern (high energy foods, snacks etc..) and those who regularly drink alcohol are at high risk of colorectal adenomas, while those who consume a lot of meat (together with other Western habits such as preferential consumption of potatoes rather than vegetables) are at high risk of cancer."
Eighty percent of colorectal cancers may be preventable by dietary changes. It is also one of the most curable cancers if diagnosis is made early.
This is not the first time that such a dietary pattern has been linked to increased risk of the cancer. According to the British charity Cancer Research UK: "Countries that have had a rapid 'westernisation' of diet, such as Japan, have seen a rapid increase in the incidence of colorectal cancer. Consumption of meat and dairy products in Japan increased ten-fold between the 1950s and 1990s."
The new research, published in the American Journal of Epidemiology, was based on the French cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) study.
Four dietary patterns were identified by the authors and classified as "healthy" (rich in fruit and vegetables, olive oil, and fish), "Western" (rich in processed meat, eggs, and butter, potatoes, processed grain products, and cheese), "drinker" (emphasis on alcoholic beverages, snacks, sandwiches and processed meat), and "meat eaters" (meat and poultry).
For those people whose diet closely matched the Western diet, the researchers calculated that the risk of adenoma was increased by 39 percent, while those with a diet closely matching the "drinker" pattern were associated with an increased adenoma risk of 42 percent, compared to the "healthy" pattern.
They also report that people whose diet most closely resembles the meat-eaters pattern were associated with an increased risk of colorectal cancer risk of 58 per cent, compared to the healthy diet pattern.
"These findings may help clinicians to rapidly assess if their patients have a high risk diet and if they should be proposed screening and/or dietary advice for primary prevention," Dr. Boutron-Ruault told this website. "Dietary patterns that reflect a Western way of life are associated with a higher risk of colorectal tumors," concluded the researchers.
The researchers believe the health effects of fish consumption in relation to colorectal cancer may lie in their content of the omega-3 fatty acids, that acts as a mediator of inflammatory responses. DHA and EPA are omega-3 fatty acids commonly found in fish and fish oil. Krill oil is another important source of DHA and EPA.
E Kesse, F Clavel-Chapelon and MC Boutron-Ruault; Dietary Patterns and Risk of Colorectal Tumors: A Cohort of French Women of the National Education System (E3N). American Journal of Epidemiology; 2006 Dec; Volume 164, Issue 11, Pages 1085-1093; doi:10.1093/aje/kwj324