NEW YORK (Reuters Health) - A look at the eating patterns of 183,518 California and Hawaii residents has found evidence that a diet high in flavonols might help ward off pancreatic cancer. Flavonols are found in plant-based foods with onions, apples, berries, kale, and broccoli having the highest concentrations.

During an average of 8 years, 529 subjects developed pancreatic cancer. People who had the largest amount of flavonols in their diet -- measured with a "food frequency" questionnaire -- had a 23-percent lower risk of developing pancreatic cancer compared with people with the lowest levels, Dr. Ute Nothlings from the German Institute of Human Nutrition Potsdam-Rehbruecke reported at the annual meeting of the American Association for Cancer Research in Los Angeles.

Smokers benefited most, presumably because they are at high risk for pancreatic cancer already. Smokers who ate the most flavonols reduced their risk of developing pancreatic cancer by 59 percent, compared with smokers who at the least flavonols.

Smoking is currently the only known risk factor for the disease and "short of stopping tobacco use, it has been difficult to consistently show lifestyle factors that might help protect against this deadly cancer, Nothlings noted in a statement.

Of the three individual flavonols studied (kaempferol, quercetin and myricetin), kaempferol, abundant in spinach and some cabbages, was associated with the largest risk reduction (22 percent) among all study subjects.

Across levels of intake, total flavonol consumption as well as consumption of quercetin, which is most abundant in onions, and myricetin, found mostly in red onions and berries, were all associated with a statistically significant trend toward reduced pancreatic cancer risk in current smokers, but not in former smokers or those who never smoked.

The study did not investigate the biologic mechanisms by which flavonols might protect against pancreatic cancer. But the anti-cancer effects of these compounds, in general, have been attributed to their ability to inhibit cell growth and oxidative stress, and induce detoxification enzymes and programmed cell death.

Summing up, Nothlings told Reuters Health that the "key finding is that a high intake of flavonols might help reduce the risk of pancreatic cancer, especially in smokers. The study, therefore, underlines the current recommendation of consuming a plant-based diet, although the findings will have to be confirmed in other studies to draw firm conclusions."