Study Suggests A Possible Link Between High-Starch Diet And Pancreatic Cancer

Published in the Sept. 4 issue of the Journal of the National Cancer Institute, the study suggests that excess insulin – a substance used by the body to process the sugar in foods – can promote the development of pancreatic cancer.

Nearly 30,000 men and women in the United States are diagnosed with pancreatic cancer each year, and an equal number die from it. Pancreatic cancer typically is highly aggressive and is one of the least-curable malignancies. Only four percent of the people with pancreatic cancer are alive 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," explains senior author Charles Fuchs, MD, of Dana-Farber. "Further research is needed, however, to track the connection in more detail."

Earlier laboratory studies have demonstrated that insulin encourages the growth of pancreatic cancer cells. Other studies have shown that people who are obese, physically inactive or have adult-onset diabetes mellitus tend to be "insulin resistant," causing them to produce larger-than-normal amounts of insulin to compensate and putting themselves at greater risk for pancreatic cancer. The new study explored whether women whose diets are heavy in foods that increase insulin production are likewise at elevated risk for pancreatic cancer.

"Historically, cigarette smoking had been the only proven risk factor for developing pancreatic cancer," says the study's lead author, Dominique Michaud, ScD, of the National Cancer Institute, who initiated the research while at Harvard School of Public Health. "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."

The researchers reasoned that if insulin fuels the growth of pancreatic cancer, then foods that prompt the body to produce large amounts of insulin should be associated with a greater occurrence of the disease. Knowing that the body uses insulin to burn sugar, the researchers focused on foods that raise blood levels of glucose, a sugar that is a main energy source for cells.

Data for the study came from the Nurses' Health Study, a project at Brigham and Women's Hospital that tracks health information on female nurses across the country. The researchers reviewed the dietary records of nearly 89,000 nurses to measure their intake of sucrose (the type of sugar in candy), fructose (the sugar in fruit juices and honey) and carbohydrates.

The researchers also calculated the amount of glucose-stimulating foods (known as the "glycemic load") every study participant consumed. Each type of food increases glucose levels by a different amount. The ability of carbohydrate-containing foods to boost glucose – and thereby insul