Published online 19 February 2001 | Nature | doi:10.1038/news010222-7


Another reason to stay slim and eat your greens

Eating too much and being overweight can put you at risk of pancreatic cancer.

Vegetables that are high in antioxidants are thought to be the best at preventing cancers.Vegetables that are high in antioxidants are thought to be the best at preventing cancers.

Smoking and old age are known to increase the risk of contracting deadly pancreatic cancer, but a recent study suggests that obesity and overeating may also be risk factors.

Overweight people who eat too much have a 70% greater chance of developing pancreatic cancer, according to a study by Debra Silverman at the National Cancer Institute in Bethesda, Maryland, and her colleagues1. But eating more broccoli, cauliflower or cabbage may reduce that risk by 50%.

Pancreatic cancer kills over 95% of those who contract it. Patients live an average of three months after diagnosis, making this a tough cancer to study. Because it's such a fast killer, almost half of the people initially chosen to participate in Silverman's study died before they could be interviewed by the researchers.

Pancreatic cancer is the fifth deadliest cancer in the United States (the sixth deadliest in Europe). But it is only the tenth most common cancer, striking about 9 in 100,000 Americans. The disease is difficult to detect and control because of its vague symptoms (abdominal aches) and because the pancreas, buried deep inside the body behind the stomach, eludes examination and surgery. Often the disease is diagnosed only after the cancer has spread.

To learn more about possible causes, the researchers interviewed 526 Americans with pancreatic cancer. They compared their lifestyles, dietary habits and family history of cancer with those of people with similar backgrounds but who didn't have the disease.

Not surprisingly, they found that smoking played a part as previous studies had shown it is the single biggest risk factor for the disease. "Smoking is one of the best-established risk factors, but it accounts for only 25% of the disease," says Silverman. The remaining 75% of cases not attributable to smoking have no definite cause.

There is now increasing evidence -- including data from this study -- that obesity, large food intake and lack of vegetables in the diet also put people at risk of pancreatic cancer. Vegetables that are high in antioxidants, such as broccoli, cauliflower, cabbage and Brussels sprouts, are thought to be the best at preventing cancers.

Exercise may also be important in protecting against the cancer, as Silverman's study showed that people who ate a lot but had average body weight did not have an increased risk.

"This study did not find any striking risk factors that put people at very high risk," says David Whitcomb, a pancreas disease researcher at the University of Pittsburgh in Pennsylvannia. "There isn't enough to pinpoint a cause yet."

One drawback is that the research used interview data, relying on their subjects to accurately recall their dietary history. This isn't easy, says Albert Lowenfels, who studies the causes of pancreas and other cancers at the New York Medical College. "But this study is pointing in the right direction." 

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