Rachael Stolzenberg-Solomon, from the National Cancer Institute, Bethesda, Maryland and her co-workers did initially find prove of a correlation between a high carbohydrate diet and pancreatic cancer among more than 100,000 older women and men.
The top 10% of the participants in rankings of carbohydrate consumption had an almost 50% greater risk of the cancer than the bottom 10%, the researchers report in the American Journal of Epidemiology.
It’s important to note, however, that even with this increase in pancreatic cancer risk, the risk remained extremely low. Pancreatic cancer is rare: less than one-quarter of 1% of all participants were diagnosed over about a 7-year study period.
But what got the researchers’ attention was how this apparent increase in risk was limited to carbohydrate consumers followed fewer than 4 years.
The researchers only collected information on food intake at the start of the study. And follow-up ended when a cancer diagnosis was made. So those participants diagnosed early on, explained Stolzenberg-Solomon, may have already been suffering cancer-related indigestion when they filled out the dietary questionnaire.
Further, since fatty foods can exacerbate indigestion, they may have replaced some of the fat in their diet with more easily digestible carbohydrates. Stolzenberg-Solomon recalled that a fat-carbohydrate swap was common among the pancreatic cancer patients she saw during her previous work as a dietitian.
In other words, carbohydrate intake may be a consequence rather than a cause of pancreatic cancer. “It’s all very complex,” noted Stolzenberg-Solomon. “But it’s one possible explanation for this change in risk between 3 and 4 years.”
The finding could shed light on inconsistent results from previous studies that may not have been as careful or detailed in their data collection, Kristin Anderson, of the University of Minnesota and a co-author on other recent pancreatic cancer studies, told Reuters Health in an email: “You can’t try to understand a puzzle by looking at one piece.”
