Starchy foods fingered for possible pancreatic cancer link

A diet high in potatoes, rice and white bread may slightly increase the risk of pancreatic cancer in women who are overweight and sedentary, a new study suggests.

In Canada, pancreatic cancer is the fourth leading cause of cancer deaths in both men and women. The aggressive disease accounted for more than 2,600 deaths in 1990, according to the Canadian Task Force on Preventive Health Care.

Until now, the only known risk factor for pancreatic cancer was smoking.

Researchers used data from the Nurses Health Study, an ongoing study of 80,000 nurses whose diet and health information has been systematically followed.

Dr. Charles Fuchs of the Dana-Farber Cancer Institute, Brigham and Women's Hospital and the Harvard School of Public Health in Boston led the 18-year study. It appears in the Sept. 4 issue of the Journal of the National Cancer Institute.

Fuchs and his colleagues found women who ate large amounts of unrefined starch, found in foods such as white bread and potatoes, slightly increased their risk of pancreatic cancer.

Researchers test insulin theory

Scientists suspect diet may play a role in up to a third of cancers, including pancreatic cancer. Factors such as obesity, a sedentary lifestyle and a diet high in sugar all increase insulin levels. Our bodies use insulin to process sugar.

Other studies have shown that people who are obese, physically inactive or have adult-onset diabetes tend to be insulin resistant, which causes them to produce more insulin than normal.

The researchers were testing a theory that insulin fuels the growth of pancreatic cancer. The body uses insulin to burn sugar, and starchy foods raise blood glucose levels.

Women who were significantly overweight and physically inactive were more than 2.5 times more likely to develop pancreatic cancer if they ate a high starch diet, Fuchs said.

Nutritional researchers note that although the study involved only women, there's no reason to believe the findings don't apply to men, too.

But because the study was done on 180 health professionals who tend to consume reasonably healthy diets, the range of findings may not reflect what the general North American population eats. The small number of cancer cases also meant the starchy findings alone weren't statistically significant.

• FROM OCT. 18, 2001: We love our bananas and spuds: Statistics Canada

Nutritionists suggest substituting less starchy vegetables such as broccoli for potatoes and rice. Canada's Food Guide recommends five to 10 servings of vegetables and fruit per day to prevent some cancers and heart disease, as part of a healthy lifestyle.