By Todd Zwillich

WASHINGTON, Sep 06 (Reuters Health) - Preliminary results from the world's largest-ever study of the role of diet in the development of cancer confirm a link between the consumption of red meat and colorectal cancer.

"It is just what we hoped to find," said Dr. Elio Riboli, a researcher with the International Agency for Research on Cancer, an arm of the World Health Organization that is conducting the study. Investigators were encouraged by the data because they confirm that the huge study is likely to have enough power to uncover even small variations in cancer risk, he said.

The European Prospective Investigation into Cancer and Nutrition (EPIC) has enrolled nearly half a million persons in nine nations in Western Europe over the last 9 years in an attempt to find nutritional and lifestyle causes for Europe's widely fluctuating cancer rates.

The first round of results from the study will not be available until April of next year. But early data presented here Friday at the annual meeting of the American Institute for Cancer Research show that red meat consumption is significantly associated with an elevated risk of intestinal tumors. Among 385 patients with colorectal cancer, the risk of cancer was increased by 40% in subjects in the highest quartile of meat consumption, while the risk was reduced by 40% in subjects with the highest quartile of vegetable consumption.

Further analysis will look at the influence of lifestyle factors such as smoking, drinking, and exercise on cancer, as well as the effect of over 300 different foods. Participants are being asked to keep detailed records of what they eat, and the results will be backed up with blood samples that can be tapped for biomarkers of food intake and DNA for genetic testing.

Researchers have already noticed large regional fluctuations in several nutritional biomarkers thought to influence cancer risk. For instance, fatty acids found in fish are more than three times as abundant in the blood of people from Denmark as in the blood of people from Oxford, England. Study subjects in Naples have twice the levels of lycopene, a chemical associated with prostate cancer, than that found in residents of northern Spain, Dr. Riboli said.

The study will hinge eventually on explaining the huge variations in different forms of cancer proliferating across Europe that make the continent "a natural laboratory," he added. For instance, breast cancer incidence is four times higher in Scotland than in Sicily, while stomach cancer rates are several times higher in Spain than they are in England.

The early results with colorectal cancer confirm what researchers have known for 10 years: that a diet high in fruits and vegetables can help prevent cancer. "But we need to know which fruits, which vegetables and how they specifically protect against cancer," Dr. Riboli said.

(From Reuters Health)