Consuming a high-quality diet is associated with lower risk of pancreatic cancer

People who reported dietary intake that was most consistent with the 2005 Dietary Guidelines for Americans had lower risk of pancreatic cancer, according to a new study published August 15 in the Journal of the National Cancer Institute.

Previous studies investigating the relationship between food and nutrient intake and pancreatic cancer have yielded inconsistent results. The U.S. Government issues evidence-based dietary guidelines that provide the basis for federal nutrition policy and education activities to promote overall health for Americans. The authors evaluated how closely study participants' diets matched the 2005 Dietary Guidelines for Americans, as measured by the Healthy Eating Index (HEI-2005), and then compared their risk of pancreatic cancer.

Hannah Arem, Ph.D.,, from the Division of Cancer Epidemiology and Genetics at the National Institutes of Health in Bethesda, MD, and colleagues calculated HEI-2005 scores for 537,218 participants in the NIH-AARP Diet and Health Study (ages 50-71 years), based on responses to food frequency questionnaires. Pancreatic cancer risk was then compared between those with high and low HEI-2005 scores, accounting for the influence of other known pancreatic cancer risk factors.

Among the study participants there were 2,383 new cases of pancreatic cancer. Overall, the investigators observed a 15% lower risk of pancreatic cancer among participants with the highest HEI-2005 score compared to those with the lowest HEI-2005 score. This association was stronger among overweight or obese men compared to men of normal weight, but there was no difference for normal vs. overweight or obese women. While the authors adjusted for known risk factors such as smoking and diabetes status, they caution that other health factors not collected in the questionnaires may be associated with a more healthful diet and might explain some of the observed reduced risk. They also noted that diet is difficult to measure and the HEI-2005 was not designed specifically for the purpose of overall cancer prevention.

According to Arem and colleagues "the Dietary Guidelines for Americans are issued to promote overall health, including the maintenance of a healthy weight and disease prevention. Our findings support the hypothesis that a high-quality diet may also play a role in reducing pancreatic cancer risk." Future studies are needed to confirm these findings.

In an accompanying editorial, Rachel Ballard-Barbash, M.D., and Susan M. Krebs-Smith, Ph.D., from the Applied Research Program at the National Cancer Institute (Bethesda, MD), and Marian L. Neuhouser, Ph.D., from the Cancer Prevention Program in the Division of Public Health Sciences at the Fred Hutchinson Cancer Research Center (Seattle, WA) discuss that progress has been made in understanding associations between diet and cancer risk, but they have not resulted in noticeable changes in cancer incidence in the US. They conclude, "Practical and actionable dietary recommendations that are based on sound research should ultimately reduce patient suffering and treatment-related expenditures from preventable cancers."