Study: Starchy Foods Up Pancreatic Cancer Risk for Overweight Women

For women who are overweight and sedentary, a diet high in starchy foods may increase their risk of developing pancreatic cancer, according to researchers at the Dana-Farber Cancer Institute.

Pancreatic cancer is highly aggressive and one of the least curable types of cancer. Only four percent of patients with the disease are still living five years after diagnosis.

"Our findings add to the growing body of evidence that suggests that insulin may have a role in the development of pancreatic cancer," said Dr. Charles Fuchs of Dana-Farber and senior author of the study. "Further research is needed, however, to track the connection in more detail."

Previous research has shown that insulin encourages the growth of pancreatic cancer cells. Also, people who are obese, physically inactive or have adult-onset diabetes tend to be insulin resistant, causing them to produce more insulin than normal to compensate, putting themselves at greater risk for pancreatic cancer.

This new study looked at whether women whose diets are heavy in foods that increase insulin production are likewise at an elevated risk for pancreatic cancer.

"Historically, cigarette smoking had been the only proven risk factor for developing pancreatic cancer," said Dominique Michaud, ScD, Harvard researchers and lead author of the study. "We're working to determine whether there are dietary or behavioral risk factors -- ones that can be modified. At the same time, we hope to learn more about the basic biology of the disease."

Data for the study came from the Nurses' Health Study, which tracks health information on female nurses across the country. Researchers reviewed the dietary records of approximately 89,000 nurses to measure their intake of sucrose, fructose and carbohydrates.

Investigators also measured the amount of glucose-stimulating foods being consumed by the participants. Each type of food increases glucose levels by a different amount. The ability of carbohydrates to raise glucose -- and thereby insulin -- levels is known as the "glycemic index." Starchy foods such as potatoes, white rice and breads have high glycemic indexes.

Researchers discovered that women who were significantly overweight and physically inactive (and therefore had higher than normal levels of glucose and insulin) were more than two and a half times more likely to develop pancreatic cancer if they had a high glycemic load than if they had a low glycemic load. (Glycemic load is a measurement that determines the impact of carbohydrate consumption.)

The high glycemic load did not increase the risk of pancreatic cancer in women who were lean and physically fit.

Although the study only included women, the researchers believe the findings would probably apply to men as well.

"The take-home message for women who are overweight and sedentary is that a diet high in starchy foods may increase their risk of pancreatic cancer," said Fuchs. "Substituting less starchy vegetables such as broccoli for potatoes and rice and snacking on fruit are some simple steps that they can take to reduce this potentially serious health risk."

Other sources: Dana Farber Cancer Institute